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  • 1990-1994  (1,337)
  • 1920-1924
  • 1991  (1,337)
  • Inorganic Chemistry  (773)
  • Engineering General  (564)
  • 201
    Electronic Resource
    Electronic Resource
    Kristallisiertes Natrium-triethylhydroborat  -  Bildung und Charakterisierung (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2259-2262 
    Details
    ISSN: 0009-2940
    Keywords: Hydroborate ; triethyl ; sodium salt ; Sodium  -  arene addition compound ; Mesitylene ; Tricoordinated H atoms ; Solid-solid phase transformation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystalline Sodium Triethylhydroborate  -  Formation and CharacterizationTwo equiv. of NaHBEt3 (1) and one equiv. of mesitylene form a crystalline compound, which is characterized by DSC and by a single-crystal X-ray structure analysis at 190 K as the solid phase 2.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241019
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  • 202
    Electronic Resource
    Electronic Resource
    Tin for Organic Synthesis, 5 A New and Regioselective Synthesis of Aromatic Diazene Derivatives (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2297-2301 
    Details
    ISSN: 0009-2940
    Keywords: Aromatic substitution, electrophilic ; Azo compounds, synthesis of ; Diazonium compounds, aromatic, coupling reaction of, with trialkylarylstannanes ; Trialkylarylstannanes, application of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method for the preparation of aromatic diazene derivatives 3a  -  1, 5, 7a, b, 9 under very mild conditions is described. The reaction of trialkylarylstannanes with nitro-substituted benzenediazonium tetrafluoroborates leads, by strict ipso substitution, to the corresponding diaryldiazenes in satisfactory to high yields. Due to the excellent leaving group quality of the stannyl group azo compounds may be prepared which are not accessible by normal electrophilic azo coupling. The products can be valuable precursors, obtained by reduction to the amines or other derivatizations, for consecutive aromatic compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241023
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  • 203
    Electronic Resource
    Electronic Resource
    BN-Achtringe (RBNR')4 aus BN-Vierringen (RBNtBu)2 durch NtBu/NR'-Austausch (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2209-2216 
    Details
    ISSN: 0009-2940
    Keywords: Tetrazatetraborocanes ; Boron-nitrogen ring compounds ; [2 + 3] Cycloadditions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eight-Membered BN Rings (RBNR')4 from Four-Membered BN Rings (RBNtBu)2 by an Exchange NtBu/NR'Reactions of the four-membered BN ring compounds (RBNtBu)2 (1a - e: R = Me, Et, iPr, iBu, Pr) with azides R'N3 (R' = PhCH2, Pr, iBu, Ph) and with the nitrone PhHC=N(Me)=O are studied. The five-membered ring [=(Me)B=N(tBu)-N=N-(PhCH2)N=] (2a) is formed from the four-membered ring 1a and PhCH2N3 in the ratio 1:2. An exchange of NtBu for NR' with elimination of tBuN3 is observed, however, in the reaction of the ring compounds 1b -d with R'N3. Instead of four-membered BN rings, the six-membered BN ring (RBNR')3 (3a: R/R' = Et/PhCH2) and the eight-membered BN rings (RBNR')4 (4a -h: R/R' = iPr/PhCH2, iBu/PhCH2, iPr/Pr, iBu/Pr, iPr/iBu, iBu/iBu, Et/Ph, iBu/Ph) are formed, respectively. The NMR spectra reveal diastereotopic methylene protons (Et, Pr, iBu, PhCH2) and methyl groups (iPr, iBu) and thus elucidate the tub-like structure of the eight-membered rings. 3a and 4a crystallize in the space group P2,/c. The reaction of the four-membered rings 1c - e with the nitrone gives five-membered rings [=(R)B=N(tBu)=B(R)=N(Me) - O=] (5c - e). Both of the reactions of the four-membered rings with azides and with the nitrone can be rationalized in terms of a similar sequence of reaction steps.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241011
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  • 204
    Electronic Resource
    Electronic Resource
    Half-Sandwich Pentamethylcyclopentadienyl Iridium Complexes Containing Sulfido and Selenido Ligands X-Ray Crystal Structures of Cp*Ir(PMe3)(S6) and Cp*Ir(PMe3)(Se4) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2245-2248 
    Details
    ISSN: 0009-2940
    Keywords: Half-sandwich complexes ; Iridium complexes ; cyclo-Sulfido ligands ; cyclo-Selenido ligands ; Iridacycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cp*Ir(PMe3)Cl2 (1) reacts with chalcogenide ligand sources such as (NH4)Sx (x ≍ 10), (NEt4)2Se6, and H2Se to yield the half-sandwich complexes Cp*Ir(PMe3)(Sn) [n = 4 (2a), 6 (4a)] and Cp*Ir(PMe3)(Sen) [n = 2 (5b), 4 (2b)]. Desulfurization of 4a by PPh3 leads to Cp*Ir(PMe3)(S5) (3a), while both 4a and 3a react with excess P(nBu)3 to give 2a. The geometries of the cyclo-oligochalcogenide ligands in 4a and 2b have been determined by X-ray crystallography.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241016
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  • 205
    Electronic Resource
    Electronic Resource
    η2- und η4-[(Dimethylamino)vinylboran]eisencarbonyl-Komplexe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2255-2258 
    Details
    ISSN: 0009-2940
    Keywords: Boranes, amino-vinyl ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: η2- and η4-[(Dimethylamino)vinylborane]iron Carbonyl Complexes1)Amino-vinylboranes can act as η2 (via the C = C bond) and as η4 ligands (via the C = C and B = N group) in iron carbonyl complexes. From bromo(dimethylamino)vinylborane and (dime-thylamino)methylvinylborane and Fe2(CO)9 [η2-bromo(dimethylamino)vinylborane] tetracarbonyliron (1) and tetracarbonyl[η2-(dimethylamino)methylvinylborane]iron (2), respectively, are formed in the absence of light. The η2 coordination via the C = C group in 1 is proved by an X-ray structure analysis. The C2BN frame is trans-arranged. By the action of light, 1 and 2 are transferred into the very unstable tetrahapto complexes [η4-bromo(dimethylamino)vinylborane]tricarbonyliron (3) and tricarbonyl[η4-(dimethylamino)methylvinylborane]- iron (4), which can only be investigated in solution. By using tert-butyl(dimethylamino)vinylborane the reaction leads, even in the absence of light, directly to [η4-tert-butyl(dimethylamino)vinylborane)tricarbonyliron (5), a compound likewise easily unstable. The transition of the η2 into the η4 complexes can be followed IR- and 11B-NMR-spectroscopically.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241018
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  • 206
    Electronic Resource
    Electronic Resource
    Cathodic Reduction of 1-Nitroalkenes to Oximes and Primary Amines (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2303-2306 
    Details
    ISSN: 0009-2940
    Keywords: Electrochemistry ; 1-Nitroalkenes, reduction of ; Oximes ; Amines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Nitroalkenes are reduced in high yields at -0.3 to -0.5 V (vs. SCE) at a mercury or graphite cathode to oximes. At higher cathodic reduction potentials (- 1.1 V) primary amines are selectively obtained in fair yields. Nitroalkadienes are selectively reduced at the double bond conjugated with the nitro group to either the oxime or amine.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241024
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  • 207
    Electronic Resource
    Electronic Resource
    Lösliche (Tetraethylphthalocyaninato)eisen(II)- und -cobalt(II)-Verbindungen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2315-2321 
    Details
    ISSN: 0009-2940
    Keywords: Tetraethylphthalocyanine, metal complexes of ; Isocyanide complexes, bridged ; Porphyrines ; Semiconductors, organic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Soluble (Tetraethylphthalocyaninato)iron(II) and -cobalt(II) CompoundsThe (tetraethylphthalocyaninato)iron and -cobalt compounds Et4PcFe (9), Et4PcCo (8), and Et4PcH2 (7) have been synthesized starting from 3,4-dibromoacetophenone (1) via the corresponding dinitrile 5 or isoindolenine 6, respectively. Et4PcFe (9) reacts with tBuNC, p-diisocyanobenzene (dib), and me4dib to form the bisaxially coordinated compound Et4PcFe(tBuNc)2 (10) and the oligomers [Et4PcFe(dib)]n (11) and [Et4PcFe- (me4dib)]n (12). All of the synthesized compounds, except the oligomers with a chain length of more than 8 - 14 units, are soluble in organic solvents such as chloroform or toluene. The new compounds were characterized by 1H-, 13C-NMR, 13C-CP/NMR, UV/Vis, and IR spectra. In addition the redox properties of Et4PcCo (8) were studied by cyclic voltammetry and spectroelectrochemical methods. The Mößbauer spectra of the (phthalocyaninato)iron compounds 9, 11, and 12 demonstrate the bridged structure of [Et4PcFe(L)]n (L = dib, me4dib) (11, 12). The powder conductivity of [Et4PcFe(dib)]n (11) (σRT = 5·10-6 S/cm) is ca. 106 times higher than that of Et4PcFe (9) (σRT = 9·10-12 S/cm). After doping with iodine the oligomers 11 and 12 show an increase in conductivity of 105 and 104, respectively (σRT ≍ 10-2 S/cm for [Et4PcFe(dib)I0.85]n).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241026
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  • 208
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    Electronic Resource
    Sulfur Compounds, 144 Synthesis of Sulfur-Rich Organic Polysulfanes Utilizing Titanocene Pentasulfide as a Sulfur-Transfer Reagent (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2357-2359 
    Details
    ISSN: 0009-2940
    Keywords: Heptasulfanes, cyclic ; Pentasulfane, linear ; Polysulfanes, organic, HPLC of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titanocene pentasulfide, Cp2TiS5 (1) reacts with Ph3CCl (4), C2H4(SCl)2 (6), and CH3C6H3(SCl)2 (9) to give the corresponding polysulfanes (Ph3C)5 (5), C2H4S7 (7), and CH3C6H3S7 (8) which have been characterized by NMR, mass, and Raman spectroscopy. By interconversion reactions the mentioned polysulfanes yield homologous molecules with up to 11 sulfur atoms which have been separated by reversed-phase HPLC. Linear relationships between the capacity factor and the number of sulfur atoms in the molecule have been derived for each series, and retention indices have been calculated.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241032
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  • 209
    Electronic Resource
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    Notiz/Note Zur Stereochemie der Reaktion von Vinylhalogeniden mit Perchlorcyclopentadien: Cycloaddition über Vinylkationen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2373-2375 
    Details
    ISSN: 0009-2940
    Keywords: Cycloaddition ; Perchlorocyclopentadiene ; Vinyl halides ; Haloethenes ; Vinyl cations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Stereochemistry of the Reaction between Vinyl Halides and Perchlorocyclopentadiene: Cycloaddition via Vinyl CationsIn the presence of aluminium chloride vinyl halides react with perchlorocyclopentadiene to yield stereoselectively bicyclic compounds (e.g. 2a), the structure of which is determined in two cases (2a, b) by X-ray analysis. Vinyl cations are proposed as intermediates.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241035
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  • 210
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    Mehrfachbindungen zwischen Hauptgruppenelementen und Übergangsmetallen, XCVI Niob- und Tantalkomplexe mit Imido-Liganden (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2401-2404 
    Details
    ISSN: 0009-2940
    Keywords: Niobium complexes ; Tantalum complexes ; Siloxy group ; Silylamide ; Silylimide ; NMR, 17O ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiple Bonds Between Main-Group Elements and Transition Metals, XCVI. - Niobium and Tantalum Complexes Having Imido LigandsThe new niobium and tantalum complexes 2b and 2c of formula M[N(SiMe3)2]2(NSiMe3)(OSiMe3) (M = Nb, b; Ta, c) are accessible by the reaction of the oxychlorides MOCl3 with the lithium amide LiN[Si(CH3)3]2 in 36 and 27% isolated yield, respectively.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241104
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  • 211
    Electronic Resource
    Electronic Resource
    Isocyanatosulfonium-Salze (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2411-2416 
    Details
    ISSN: 0009-2940
    Keywords: Sulfur imides, N-(fluoroformyl)-, preparation of, reactions with AsF5 ; Isocyanatosulfonium salts, preparation and structures of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isocyanatosulfonium SaltsRR'SF2 reacts with Me3SiNCO to give the corresponding N-(fluoroformyl)sulfur imides FC(O)NSRR' [R = NMe2, R' = F (7); R' = CF3 (9)]. From these AsF5 abstracts F- with formation of isocyanatosulfonium salts ONC - SRR' + AsF-6 [R = F, R' = CF3 (6); R = NMe2, R' = F (8); R = NMe2, R' = CF3 (10)]. The spectroscopic properties of the fluoroformyl derivatives and of the isocyanato salts are discussed. The structures of 8 and 10 are determined by X-ray analyses.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241106
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  • 212
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    Kohlenwasserstoffverbrückte Metallkomplexe, XXII1) Addition von anionischen Fischer-Carben-Komplexen an koordinierte ungesättigte Kohlenwasserstoffe unter C - C-Kupplung (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2431-2434 
    Details
    ISSN: 0009-2940
    Keywords: Fischer carbene complexes, anionic ; Carbene, methoxy(pentacarbonylrheniopropyl) ; Chromium complexes ; Molybdenum complexes ; Tungsten complexes ; Rhenium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrocarbon-Bridged Metal Complexes, XXII1). - Addition of Anionic Fischer Carbene Complexes to Coordinated Unsaturated Hydrocarbons with C - C CouplingThe addition of [(OC)5MC(OMe)CH2]- (M = Cr,W) to the cationic complexes [(OC)5Re(C2H4)]+ and [(OC)3M' (λ7-C7H7)]+ (M' = Cr, Mo) affords the bimetallic hydrocarbon-bridged complexes (OC)5M = C(OMe)CH2CH2CH2Re(CO)5 (1) and (OC)5M = C(OMe)CH2C7H7 - λ6 - M'(CO)3 (2), respectively. The structures of 1a and 2d have been determined by X-ray diffraction.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241110
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  • 213
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    Synthesis and Crystal Structure of an Arsolyl Anion and Preparation of an Arsinogallate (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2453-2456 
    Details
    ISSN: 0009-2940
    Keywords: Arsolyl anion ; Heteroaromatics ; Gallium compounds ; Arsoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The permethylated arsolyl anion C4Me4AsLi(TMEDA) (5) has been prepared; its crystal structure (determined by X-ray diffraction) revealed an aromatic heterocycle comparable to the homologous pyrrolyl and phospholyl anions.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241114
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  • 214
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    Preparation and Selected Reactions of t-Butyl 2-Methylene-3-oxoalkanoates (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2475-2480 
    Details
    ISSN: 0009-2940
    Keywords: Ethylenes, 1,1-diactivate ; Michael acceptors ; 1-Oxa-1,3-butadienes ; Hetero Diels-Alder reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title class of 1,1-diactivated ethylenes has been prepared in two steps from aldehydes and t-butyl acrylate by (i) DABCO-catalyzed coupling to give t-butyl 2-(hydroxyalkyl)-2-propenoates 11 and (ii) low-temperature Jones oxidation, followed by swift work up at low temperature. The resulting t-butyl 2-methylene-3-oxoalkanoates 12 are stabilized by sterically demanding and also by aromatic groups R. For primary unhindered alkyl groups, stability is low. The compounds enter into Michael reactions, hetero Diels-Alder additions with enol ethers, and self-dimerization.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241118
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  • 215
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    Photochemische Mitteilungen, 76 Studien im Umfeld der Oxanorbornadien → Oxepin-Isomerisierung. Eine intramolekulare Dien/Enon-[4 + 2]-Photocycloaddition (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2465-2474 
    Details
    ISSN: 0009-2940
    Keywords: Oxanorbornadiene → oxepine isomerization, limitations ; [6 + 4] Tropone dimerization ; Diene enone [4 + 2] photocycloaddition, intramolecular ; Oxaquadricyclanes, X-ray structure, thermolysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemical Transformations, 761). - Studies in the Area of the Oxanorbornadiene → Oxepine Isomerization. An Intramolecular Diene/Enone [4 + 2] PhotocycloadditionAt room temperature, the “tropone-annulated” oxanorborna diene 2b dimerizes regio- and stereospecifically to give a [6 + 4] adduct (5). Direct photoexcitation of this adduct induces intramolecular diene/enone [4 + 2] addition to 16 followed by a [2 + 2] cycloaddition to provide the dodecacycle 17. An X- ray crystal structure analysis of 17 documents the influence of the heteroatom and of the quasi-bisected ester functions on the length of the three types of oxaquadricyclane - three-membered ring bonds. Direct and sensitized excitation of 2b, c produces polymers; yet, after changing the troponoid chromophor (9, 10) oxaquadricyclane formation takes place (13, 14). In the thermolysis of the annulated oxaquadricyclanes (13, 14) the different cyclopropane C - C bonds are cleaved at a comparable rate.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241117
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  • 216
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    Reactions of 1-Thia-3-azoniabutatriene Salts with Alcohols, Carbonyl Compounds, Diazoalkanes, Nitrile Oxides, Nitrones, Enamines, and Butadienes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2537-2544 
    Details
    ISSN: 0009-2940
    Keywords: 1-Thia-3-azoniabutatriene salts ; 2-Azoniaallene salts ; 1,3-Dipolar cycloadditions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Thia-3-azoniabutatriene salts 1 react with alcohols, carbonyl compounds, diazo alkanes, nitrile oxides, nitrones, enamines, and 1,3-butadienes in all cases at the C=S double bond to yield new types of 2-azoniaallene salts (3, 9a, b, 13a, b, 18, 22) and other imines (2, 20). An X-ray diffraction analysis for 9b, the reaction product of 1b with 9-diazofluorene, confirms the proposed constitution.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241124
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  • 217
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    1,2,3,4,5,6-Hexa(eq)alkylcyclohexan-Modellverbindungen für Struktur-Eigenschafts-Vergleiche gesättigter discotischer Flüssigkristalle (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2523-2529 
    Details
    ISSN: 0009-2940
    Keywords: Cyclohexane ; Liquid crystals ; Oxygen effect ; Scyllitol ; Stereochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,2,3,4,5,6-Hexa(eq)alkylcyclohexane Model Compounds for Structure-Property Comparisons of Saturated Discotic Liquid CrystalsThe new hydrocarbon (1α, 2β, 3α, 4β, 5α, 6β)-hexahexylcyclohexane (19) and a number of new and differently functionalized scyllo-hexaalkylcyclohexane derivatives (16a, b, 18a - c) with identical stereochemistry were synthesized stereospecifically starting from simple chemical materials. In comparison to the known scyllitol hexaester 1 and the hexaether 2 none of the novel compounds 16, 18, and 19 were thermomesomorphic. This extreme difference in the thermotropic liquid-crystalline behaviour of the hexa(eq)hydroxycyclohexane (scyllitol) derivatives 1 and 2 on the one hand and of our varied hexa(eq)alkylcyclohexans 16, 18, and 19 on the other obviously is a function of the presence and the position of the element oxygen within the side chains of these symmetric star-/disc-shaped compounds. Details concerning this oxygen effect are discussed briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241122
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  • 218
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    Organic Electron Transfer Systems, II Substituted Triarylamine Cation-Radical Redox Systems - Synthesis, Electrochemical and Spectroscopic Properties, Hammet Behavior, and Suitability as Redox Catalysts (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2557-2567 
    Details
    ISSN: 0009-2940
    Keywords: Triarylamines ; Cation radicals ; Electrochemistry ; Redox catalysts ; Voltammetry, cyclic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 21 triarylamines (1n - 1z, 1za, 1zb) and triarylamine analogs (2a, 2b, 3a, 3b, 4a, 4b) with substituents in at least all three p positions and some of their cation-radical hexachloroantimonates have been synthesized. The electrochemical behavior has been studied by cyclic voltammetry. Most of the compounds show chemically and electrochemically reversible first oxidation waves in the formation of the cation radicals. With the exception of 4a and 4b, the second wave for the formation of the dication is chemically irreversible. The UV spectra of the triarylamine cation radicals have been obtained in the presence of a slight excess of SbCl5. A good Hammett correlation between the first anodic potential of only p-substituted triarylamines and the σ/σ values has been established. Some redox-catalytic properties of triarylamine cation radicals are described.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241127
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    Synthese mittlerer und großer Ringe, XXX Regioselektive Thermolyse von Oligomethylen-oxaquadricyclan-dicarbonsäureestern zu 3,6-Alkanooxepindicarbonsäureestern - Röntgenstrukturanalysen und semiempirische Rechnungen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2577-2582 
    Details
    ISSN: 0009-2940
    Keywords: Oxaquadricyclanes ; Donor-acceptor cyclopropanes ; Calculations, AM1, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Medium and Large Rings, XXX1). - Regioselective Thermolysis of Oligomethylene Oxaquadricyclanedicar-boxylic Esters to 3,6-Alkanooxepinedicarboxylic Esters - X-ray Structural Analyses and Semiempirical CalculationsX-ray structural analyses and semiempirical calculations for the oxaquadricyclanes 1 - 3 are discussed. The regioselectivity observed for the thermolyses of 1 - 3 (exclusive formation of 3,6-alkanooxepines 6) is in line with the assumption that preferential cleavage of the long C - C bonds between the donor and acceptor substituents of the cyclopropane rings determines the reaction course.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241129
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    Organische Synthesen mit Übergangsmetall-Komplexen, 56 Homopyrrole und Dihydropyridine aus N-Vinylaminocarben-Eisenkomplexen und Alkinen durch Cyclisierung intermediärer 5-Aza-1-metalla-1,3,6-triene (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2595-2602 
    Details
    ISSN: 0009-2940
    Keywords: Homopyrroles, mono- and bicyclic ; [3 + 2] Cycloadditions of N-vinylaminocarbene iron complexes to alkynes ; 5-Aza-1-ferra-1,3,6-trienes ; Intramolecular cyclopropanation, metal-induced ; 2H-Pyrrolium tricarbonyl iron complexes ; Pyridine, 1,2-dihydro-, tricarbonyl iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 561). - Homopyrroles and Dihydropyridines from N-Vinylamino-carbene Iron Complexes and Alkynes by Cyclisation of Intermediate 5-Aza-1-metalla-1,3,6-trienes2,3-Homopyrroles 5 and dihydropyridines 7, 8 are obtained by the light-induced addition of alkynes 4a - d (RC = CR1; R, R1 = H, CH3, C6H5, CO2CH3) to the N-vinylaminocarbene iron complex (= 3-aza-1-ferra-1,4-diene) 3. The formation of the N-heterocycles 5 and 7 as well as that of the pyrrolium carbonylferrates 6 can be explained by assuming the chelated 5-aza-1-ferra-1,3,6-trienes A to be key intermediates in this reaction. Stereochemical considerations lead to the conclusion that the ring expansion of the 4 1/2-membered ring of 3 to the 6 1/2-membered ring of A occurs without prior ≡ decomplexation by the insertion of a C = C unit into the M = C bond. NMR measurements and MNDO calculations suggest that the bicyclic homopyrroles 5 are in equilibrium with the novel monocyclic homopyrrole species 9. The structure of 6c has been established by X-ray diffraction analysis.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911241132
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    HCl-Abspaltung aus Ethansulfenylchlorid und Chlordimethylsulfid (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2609-2612 
    Details
    ISSN: 0009-2940
    Keywords: Matrix isolation ; Elimination of HCl, photochemically ; Flash pyrolysis ; Calculations, ab initio ; Photochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: HCl Elimination from Ethanesulfenyl Chloride and Chlorodimethyl SulfideThioacetaldehyde (5) is prepared by matrix photolysis of ethanesulfenyl chloride (3) or thiirane (4) and by flash pyrolysis of allyl ethyl sulfide (6). Matrix irradiation of 3 or 5 with 222-nm light results in a dehydrogenation, and a mixture of thiirene (7), ethynethiol (8), and thioketene (9) is formed. Flash pyrolysis of chlorodimethyl sulfide (1) yields ethenethiol (11) together with thiirane (4), whereas ethanesulfenyl chloride (2) gives ethene under the same conditions. The identification of thioacetaldehyde (5) is based on the comparison between the experimental and calculated IR spectra.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241134
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    A New Access to Sterically Shielded Allenes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2633-2635 
    Details
    ISSN: 0009-2940
    Keywords: Allenes, sterically shielded ; synthesis of ; Organocuprates ; 1,4-Addition ; 1,6-Addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the sterically shielded allenes 2 and 5 by 1,6-and 1,4-addition of organocuprates to acceptor-substituted enynes and diynes, respectively, is described. Treatment of the di-tert-butyl-substituted allenes 2 with aqueous base does not cause double bond isomerization; whereas ester 2a is converted into the corresponding β-allenic acid, ketone 2b yields the 2H-pyran 6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241139
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    On the Utility of 13C (CPMAS) NMR in Conformational Studies of Simple Hydroxy-, Alkoxy- and Acetoxycalixarenes in the Solid State (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2637-2639 
    Details
    ISSN: 0009-2940
    Keywords: NMR, 13C, solid-state ; Calixarenes ; Conformations ; Guest-host chemistry ; Macrocyclic compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potentiality of 13C (CPMAS) NMR as a conformational probe for the oligomeric macrocycles p-(tert-butyl)calix-[n]arenes (n = 4, 6, 8) and their alkoxy/acetoxy derivatives in the solid state is explored.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241140
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    Synthesen und Strukturen von cyclischen und acyclischen Vanadium(V)- und Molbydän(VI)-haltigen Verbindungen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2655-2661 
    Details
    ISSN: 0009-2940
    Keywords: Metallacyclic systems ; Vanadium ; Molybdenum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses and Structures of Cyclic and Acyclic Compounds Containing Vanadium(V) and Molybdenum(VI)The reaction of (C2F5)2P(Cl)=NSiMe3 (2) with Cl3V=NSiMe3 in CH2Cl2 yields the eight-membered ring [(C2F5)2PN2VCl2]2 (3). (CF3)2P(Cl)=NSiMe3 (1) reacts with VOCl3 to form the eight-membered ring [(CF3)2PN]3NVCl2 (4). A six-membered ring [Ph2PN]2NVCl2 (5) can be isolated from the reaction of Ph2P(Cl)=NSiMe3 with VOCl3. 1 reacts quantitatively with MoO2Cl2 and MoOCl4 to form [MoOCl3-O-P(CF3)2=N-SiMe3]4 (6) and (CF3)2P(Cl)=N-MoOCl3 (7), respectively. The molecular structures of 3, 5, and 6 have been determined by X-ray diffraction.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241204
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    Synthesis and Reactions of P-Supermesityl-C-halophosphaalkenes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2677-2684 
    Details
    ISSN: 0009-2940
    Keywords: Phosphaalkenes, C-halo, C-metal ; “Phospha-isonitrile” ; Phosphinylidenemethylene ; Phosphaalkyne, E/Z isomers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: C-Halophosphaalkenes (1, 2) were prepared in high yield by a one-pot synthesis from HCX3 or CI4 and Mes* PCl2 (Mes* = supermesityl = 2,4,6-tri-tert-butylphenyl). The C-iodophosphaalkenes Mes* P = Cl2 (1 C) and Mes*P = CHI (2c) undergo halogen-metal exchange with n-BuLi at low temperatures. The resulting carbenoids Mes*P = CILi (11 c) and Mes*P = CHLi (6) reacted with ClMMe3 (M = Si, Ge, Sn) to give Mes*P=CIMMe3 [(Z)-13: M = Ge; (Z)-14: M = Sn] or Mes*P = CHMMe3 (8-10), respectively. Further reaction of (Z)-13 and (Z)-14 with nBuLi and ClMMe3 gave Mes*P=C(MMe3 (18: M=Ge; 19: M = Sn). The carbenoid (Z)-11 c decomposed at -85°C; instead of the expected “phosphaisonitrile” Mes*P = C : (21), only Mes*C≡P (15) was obtained which lends experimental support to the theoretically predicted instability of 21.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241207
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    Azoalkan- und Nitren-verbrückte Carbonylmetall-Cluster des Eisens und Rutheniums (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2697-2704 
    Details
    ISSN: 0009-2940
    Keywords: Clusters, trinuclear and tetranuclear ; Iron clusters ; Ruthenium clusters ; Azoalkane and nitrene bridging ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Azoalkane- und Nitrene-Bridged Carbonyl Metal Clusters of Iron and RutheniumBy using cluster buildup reactions, the new azoalkane-bridged clusters Ru3(CO)9(RN=NR) (3a, R=Me, 3b, R=Et), Fe2Ru(CO)9(EtN=NEt) (4), Ru4(CO)12(RN=NR) (5a, R=Me, 5b, R=Et), and FeRu3(CO)12(EtN=NEt) (6) were obtained. Upon attempts to prepare further such compounds, the N-N bond was cleaved resulting in nitrene-bridged clusters including the new compound Fe4(CO)11(μ4-NEt)2 (9). Cluster buildup starting from Ru3(CO)9(μ3-NPh)2 resulted in Ru4(CO)11(μ4-NPh)2 (10) and FeRu3(CO)11(μ4-NPh)2 (11). The crystal structures of 5b and 9 as well as some reactions of the nitrene-bridged clusters are described.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241210
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    Gold Complexes with Selenium Ligands, IV(1) Preparation, Crystal Structures and Reactions of Phosphine(selenourea)gold(I) Complexes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2725-2729 
    Details
    ISSN: 0009-2940
    Keywords: Gold complexes ; Selenium ligands ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Triphenylphosphine)(selenourea)gold(I) chloride [Ph3PAuSeC- (NH2)2]+ Cl- (1) and the corresponding dppm derivative dppm[AuSeC(NH2)2]22+ 2l- (2) are prepared from SeC- (NH2)2 and the appropriate chloro(phosphine)gold(I) complex. The reaction between 1 and aqueous Na2CO3 leads to the neutral complex μ-selenido{bis[(triphenylphosphine)gold(I)]} (Ph3PAu)2Se (3). An analogous reaction with 2 leads to a dark red oil, which has not yet been characterized. The reaction between 3, Ph3PAuCl, and AgSbF6 leads to the ionic complex [(Ph3PAu)3Se]+SbF6- (4) in good yield. X-ray structure analyses of 1,2, and 3 confirm the expected linear geometry at the gold atom and reveal short intramolecular Au - Au contacts for 2 and 3. Short nonbonding distances between the nitrogen atoms of the amino groups and the chloride ions in the crystal structures of 1 and 2 probably indicate hydrogen bonds.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19911241213
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    Metal Ion Binding by Dipeptides: Structure of the Product Generated in “Aspartame” Hydrolysis, Sodium cyclo(L-α-Aspartyl-L-phenylalanine) Tetrahydrate, Na[c(L-Asp-L-Phe)] 4H2O (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2743-2746 
    Details
    ISSN: 0009-2940
    Keywords: L-α-Aspartyl-L-phenylalanine, cyclisation of ; Dipeptides, cyclic ; Metal complexation by cyclic dipeptides ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ester cleavage of aspartame (L-α-aspartyl-L-phenylalanine methyl ester, 1) by equimolar quantities of NaOH is accompanied by intramolecular cyclisation to sodium 3-benzyl-6-(carboxylatomethyl)-2,5-dioxopiperazine (2). The solid-state structure of the crystalline tetrahydrate has been determined by single-crystal X-ray diffraction analysis. The cations are arranged in strings, and each sodium atom is in a distorted octahedral environment of six oxygen atoms, including a β-carboxylato (O1) and an oxo function (O4) of two different dioxopiperazines and four water molecules. No nitrogen coordination is observed. Through the ligand bridging (O1, O4) of the metals and a set of hydrogen bonds involving the amide and carboxylate groups and all water molecules a three-dimensional network is established.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241216
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    Carbonyl(η5-cyclopentadienyl)(trimethylphosphan)[η2-(methylthio)-phenylcarben]molybdän-tetrafluoroborat - ein amphiphiler Carbenkomplex (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2747-2748 
    Details
    ISSN: 0009-2940
    Keywords: η2-Thiocarbene complex, amphiphilic ; Molybdenum, carbene complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbonyl(η5-cyclopentadienyl)(trimethylphosphane)[η2-(methylthio)phenylcarbene]molybdenum Tetrafluoroborate - an Amphiphilic Carbene ComplexThe title complex 1 adds the electrophile SMe+ as well as the nucleophilic PMe3 at the carbene carbon to form the complexes 2 and 3, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241217
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    Synthese von nichtsymmetrisch substituierten Perylen-Fluoreszenzfarbstoffen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 529-535 
    Details
    ISSN: 0009-2940
    Keywords: Perylene dyes ; Hydrocarbons polycyclic ; Fluorescent dyes ; Fluorescent labelling ; Fluorescent tracer ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Nonsymmetrically Substituted Perylene Fluorescent DyesA general method for the preparation of perylene-3,4:9,10-tetracarboxdiimides 1 with two different substituents at the nitrogen atoms is described: The easily prepared symmetrical tetracarboxdiimides 1 (R1=R2) are transformed into carboxdiimide anhydrides 2 and condensed with primary amines to the corresponding tetracarboxdiimides 1 (R1 ≢ R2). Applications as fluorescent tracers in biochemistry and polymer chemistry are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240319
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    Stereoselective Synthesis of Alcohols, XXXVII. Origins of Stereoselectivity in Reactions of α-Substituted Allylboronates with Aldehydes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 563-569 
    Details
    ISSN: 0009-2940
    Keywords: Allylboration reaction ; Stereoselectivity in electrophilic attack on C—C double bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rate constants for the addition of α-substituted allylboronates 4 (X=H, Cl, Br, OCH3, SCH3] to aldehydes have been measured. The results have been used to differentiate between different models that have been advanced to account for the high proportion of (Z)-configurated homoallyl alcohols 5 formed in allylboration reactions. Attempts have been made in this context to detect ate-complex formation between benzylboronates and aldehydes.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240323
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    Inter- and Intramolecular Hetero Diels-Alder Reactions, 31. Synthesis of D-Homoestrone Derivatives by Tandem Knoevenagel Hetero Diels-Alder Reactions from Natural Estrone (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 591-594 
    Details
    ISSN: 0009-2940
    Keywords: Hetero Diels-Alder reaction ; Knoevenagel reaction ; D-Homoestrones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tandem Knoevenagel hetero Diels-Alder reaction of the secoestrone derivative 8 with dimethylbarbituric acid (9a). Meldrum's acid (9b), and the pyrazolones 13a-c stereoselectively affords the D-homoestrone derivatives 11a, 12, and 14a-c, respectively, with the 16α,17aα configuration in excellent yield. In the reaction of 8 with 9a, b only one diastereomer can be detected, whereas in the reaction of 8 with 13a-c a small amount of the isomeric adducts 15a-c has also been found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240327
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    Photochemical Transformations, 75. The Azo/Nitrene Route to cis,cis-Trialkyltriaziridines, 21b) Photolysis of syn-Azo Azides of Defined Proximity - Attempts for N3 → N3X Ring Enlargement (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 621-633 
    Details
    ISSN: 0009-2940
    Keywords: syn-Azo azides ; Triaziridines, cis,cis-trialkyl- ; Stabilization, kinetic ; Ring expansion ; Calculations, MMX ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The as yet unknown route to triaziridines by the addition of nitrenes to the π side of the N=N bond is achieved intramolecularly by the photolysis (thermolysis) of syn-azo azide substrates with high proximity; the yields reflect the sterical (and possibly inductive) influences of the skeleton. The product composition is rather independent of the exciting light; intramolecular azo → azide energy transfer is assumed. The kinetic skeleton stabilization of the triaziridines permits the synthesis of 17 (18) by the thermolysis of 7 (8) at 200°C with the product composition deviating only marginally from that of the photolysis. Attempts towards enlargement of the triaziridines to N3X rings (X=CHR, O, NR) lead exclusively to products of intramolecular fragmentation.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240330
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    Tellurium Cations by Lewis Acid-Base Reactions: Syntheses and Crystal Structures of (Te24⊕)Zr2Br210⊖ and (TeBr3p⊕)(Zr2Br9⊖) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 677-681 
    Details
    ISSN: 0009-2940
    Keywords: Bromozirconate(IV) ; Di-μ-bromooctabromodizirconate(2-) ; Tri-μ-Bromohexabromodizirconate(-) ; Tetratellurium(2+) ; Tribromotellurium(+) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ZrBr4 reacts with Te2Br in a sealed evacuated ampoule at 210°C in quantitative yield to afford (Te24⊕)(Zr2Br210⊖) as blueblack, moisture-sensitive crystals. The crystal-structure determination shows, that (Te4)(Zr2Br10) consists of planar, nearly square Te24⊕ and Zr2Br210⊖ ions, that form edge-sharing double octahedra. Both ions possess crystallographic 2/m (C2h) symmetry. At temperatures above 250°C (Te4)(Zr2Br10) decomposes with cleavage of Te -Te bonds into (TeBr3⊕)(Zr2Br9⊖), which forms yellow, hygroscopic crystals. (TeBr3)(Zr2Br9) can also be obtained by the reaction of two equivalents of ZrBr4 with TeBr4 at 260°C. The crystal structure is built of Zr2Br9⊖ ions, that form face-sharing double octahedra, and of pyramidal TeBr3⊕ ions. Each TeBr3⊕ ion exhibits three Te - Br contacts to two different Zr2Br9⊖ ions, resulting in a strongly deformed octahedral coordination for the Te atom. The Zr2Br9 double octahedra and the TeCl6 octahedra are connected by common edges and corners to infinite chains.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240402
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    Metallkomplexe mit biologisch wichtigen Liganden, LVII. 1-Selenoglucose als Ligand in Metallkomplexen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 713-717 
    Details
    ISSN: 0009-2940
    Keywords: Transition metal complexes with 1-selenoglucose ; Glucose as ligand ; Selenoglucose ; Carbohydrates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Complexes of Biologically Important Ligands, LVII. - 1-Selenoglucose as Ligand in Metal ComplexesReactions of the in situ-prepared anion of acetylated 1-selenoglucose with chloro complexes give the compounds R'3 PAuSeR (R'=Me, El, Ph), cis;-(Ph3P)2Pt(SeR)2 and (η5C5H5)2Ti(SeR)2 (SeR=2,3,4,6-tetra-O-acetyl-1-seleno-β-D-glucopyranosato-Se). The complexes (η5-C5H5)(OC)2FeSeR and (OC)3M(μ-SeR)2M(CO)3 (M=Fe, Ru) are prepared by the reaction of the diselenide RSeSeR with the dinuclear compound [η5-C5H5Fe(CO)2]2 and M3(CO)12 (M=Fe, Ru), respectively.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240407
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    Übergangsmetall-Stannyl-Komplexe, 31) Metall, Wasserstoff, Zinn-Dreizentrenbindung bei Hydrido-Stannyl-Komplexen der 6. Nebengruppe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 743-751 
    Details
    ISSN: 0009-2940
    Keywords: Stannyl complexes ; Hydride complexes ; Three-center bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal Stannyl Complexes, 3. - Metal, Hydrogen, Tin Three-Center Bonding in Group VI Hydrido Stannyl ComplexesThe hydrido stannyl complex (π-1,3,5-Me3C6H3)(CO)2Cr(H)-SnPh3 (1) is prepared by photochemical reaction of (π-1,3,5-Me3C6H3)(CO)3Cr with HSnPh3. The 119SnHCr coupling constant (327.6 Hz) and an X-ray structure analysis [Sn - H 202(4), Cr - H 159(4), Cr - Sn 270.16(6) pm] show that the Sn - H bond is coordinated in an η2 fashion. The complexes (CO)4(R3P)-W(H)SnPh3 (R3P=Ph3P, MePh2P) (2) and (CO)3(dppe)M(H)-SnR3 (M=Cr, SnR3=SnPh3; M=Mo, SnR3=SnMe3, SnPh3; M=W, SnR3=SnMe3, SnPh2Me, SnPh3) (4 - 6) are obtained either by thermal reaction of (CO)4(R3P)W(THF) or (CO)3(dppe)ML (L=THF, acetone) with HSiR3, or by photochemical reaction of (CO)4(dppe)M with HSnPh3. Reaction of (CO)4(Ph3P)W(THF) with HSnMe3 yields (CO)4(Ph3P)W(Sn-Me3)2 (3). The Sn,M,H coupling constants in the complexes 2 and (CO)3(dppe)M(H)SnR3 (M=Cr, Mo) are in the range of 250 - 315 Hz and therefore these complexes seem to contain an η2-coordinated stannane. Contrary to this, the SnWH coupling constants in (CO)3(dppe)W(H)SnR3 are considerably lower (70 - 90 Hz), suggesting complete oxidative addition of the H - Sn bond. The complexes (CO)3(dppe)M(H)SnPh3 decompose in benzene solution at room temperature to give, inter alia, hexaphenyldistannane. Ph6Sn2 · 2 C6H6 crystallizes in the space group \documentclass{article}\pagestyle{empty}\begin{document}$ R\bar 3 $\end{document} (Z=1); in the crystal lattice the benzene molecules are perpendicular to the three-fold axis of symmetry of the distannane molecule.
    Additional Material: 2 Ill.
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    Anticancer Agents, 15. Squaric Acid Diethyl Ester: A New Coupling Reagent for the Formation of Drug Biopolymer Conjugates. Synthesis of Squaric Acid Ester Amides and Diamides (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1215-1221 
    Details
    ISSN: 0009-2940
    Keywords: Squaric acid ; ester amides of ; diamides of ; Coupling reagents ; Biopolymers ; Anticancer agents ; Conjugates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of squaric acid diethyl ester (1) with a slight excess of a primary or secondary amine 2 in ethanol, dichloromethane or aqueous buffer (pH 7) at 20°C for 0.3-12 h gives the squaric acid amide esters 3 in mostly excellent yields. Treatment of 3 with amines 2 or 4 in organic solvents in the presence of triethylamine or in aqueous buffer (pH 9) leads to the corresponding symmetrical and unsymmetrical squaric acid diamides 5, respectively. The reaction can be followed by UV spectroscopy.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19911240539
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    Chiral Organometallic Reagents, III. On the Configurational Stability of α-Bromoalkyllithium Compounds (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1259-1264 
    Details
    ISSN: 0009-2940
    Keywords: Carbenoids ; Configurational stability ; Organolithium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The carbenoids 2 undergo at -110°C a bromine/lithium exchange reaction with 1,1-dibromo alkanes. This leads to partial equilibration of the carbenoids 2 during their generation from the 1,1-dibromo compound 1. In the absence of the precursor 1, the carbenoids 2 have been found to be configurationally stable at -110°C.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240545
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    Übergangsmetall-substituierte Diphosphene, XX1) Synthese und Eigenschaften des Tetrahedrans [(η5-C5Me5)(CO)2FeP-PtBu]Fe2(CO)6 und der metallierten 1,3-Diphospha-2-propanone [(η5-C5Me5)(CO)2Fe-PC(O)-PR]Fe2(CO)6 [R = tBu, 2,4,6-(CF3)3C6H2] (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 265-269 
    Details
    ISSN: 0009-2940
    Keywords: Tetrahedranes, organometallic ; 1,3-Diphospha-2-propanone derivatives ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal-Substituted Diphosphenes, XX1). - Synthesis and Properties of the Tetrahedrane [(η5-C5Me5)(CO)2-FeP-PtBu]Fe2(CO)6 and the Metalated 1,3-Diphospha-2-propanones [(η5-C5Me5)(CO)2Fe-PC(O)-PR]Fe2(CO)6 [R = tBu, 2,4,6-(CF3)3C6H2]The reaction of [η5-C5Me5)(CO)2FeP(SiMe3)2 (1) with tBuPCl2 (2a) affords the metalated cyclotetraphosphane [(η5-C5Me5)-(CO)2FeP-PtBu]2 (4a) besides the metal-substituted cyclotriphosphane (η5-C5Me5(CO)2Fe-P[PtBu]2 (5a) and the diphosphane (η5-C5Me5)(CO)2FeP(SiMe3)P(Cl)tBu (3a), which are detected in the reaction mixture by 31P-NMR spectroscopy. Treatment of 4a with excess of Fe2(CO)9 leads to the tetrahedrane [(η5-C5Me5)(CO)2FeP-PtBu]Fe2(CO)6 (6a) and the 1,3-diphospha-2-propanone derivative [(η5-C5Me5)(CO)2FePC(O)-P-tBu]Fe2(CO)6 (7a). Similarily, an analogous complex 7c is obtained from the reaction of in situ prepared (η5-C5Me5)-(CO)2FeP=P-C6H2(CF3)3-(2,4,6) with an excess of Fe2(CO)9.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240204
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    Kristallines Tl2B9H9C2Me2: Synthese und Festkörperstruktur; ein Beitrag zum Problem “attraktive Tl(I)-Tl(I)-Wechselwirkungen” (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 295-299 
    Details
    ISSN: 0009-2940
    Keywords: Dithallium dicarbollide, crystal structure ; Nonclassical Tl(I)-Tl(I) interactions ; Thallium nonahydro-2,3-dimethyl-1-thalla-2,3-dicarba-closo-dodecaborate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystalline Tl2B2H9C2Me2: Synthesis and Solid State Structure; a Contribution to the Problem of Tl(I)-Tl(i) InteractionsCrystalline Tl2B9H9C2Me2 (1) is obtained in the reaction of the carborane B9H11C2Me2 with two equivalents of thallium(I) ethanolate. An X-ray diffraction study of 1 shows - contrary to the expectation - the presence of isolated thallium ions and thalladicarbollide counteranions. The latter represent ion pairs composed of Tl(I)+ and B9H9C2Me212- units forming slipped icosahedrons. All possible Tl-Tl distances in 1 are too long for even weak attractive interactions, with one exception: A set of symmetry-equivalent cations possesses a Tl-Tl distances of 3.67 A, which is in a range postulated by calculations for weak bonding.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240209
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    Photocycloadditionen mit α- und β-Naphthaldehyd: Vollständige Umkehr der Diastereoselektivität als Konsequenz unterschiedlich konfigurierter elektronischer Zustände (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 407-410 
    Details
    ISSN: 0009-2940
    Keywords: Paternò-Büchi reaction ; Spin-correlation effect ; Photocycloadditions ; Naphthaldehydes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photocycloadditions with α- and β-Naphthaldehyde: Complete Inversion of Diastereoselectivity as a Consequence of Differently Configurated Electronic StatesThe diastereoselectivity of the [2 + 2] photocycloaddition reaction between aromatic aldehydes and 2,3-dihydrofuran (3) is completely inverted when changing the electronic configuration of the excited triplet from 3(nη*) to 3(nπ*). Mesitylenaldehyde, which corresponds to the first case, reacts endo- selectively, whereas α- and β-naphthaldehyde (with low-lying ππ* triplets and reactive nπ* singlets) react exo-selectively. The configuration of the α-naphthaldehyde adduct is proven by means of X-ray structure analysis. This type of spin-correlation effect can be rationalized by comparing the conformation of the reactive biradical intermediates for rapid inter-system crossing and/or bond closure. In the furan (1) case, this effect cannot be observed. All carbonyl compounds investigated here react exo-selectively. A possible explanation for this pronounced selectivity is the assumption of a secondary orbital effect.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240227
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    Schwefel(IV)-Verbindungen als Liganden, XIII. Schwefeldioxid als Brückenligand in unsymmetrischen Zweikernkomplexen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 433-439 
    Details
    ISSN: 0009-2940
    Keywords: Dinuclear complexes ; Sulfur dioxide bridges ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sulfur(IV) Compounds as Ligands, XIII. - Sulfur Dioxide as a Bridging Ligand in Unsymmetrical Dinuclear ComplexesA series of known or newly synthesized dinuclear complexes with the following combinations of elements: Mo/Ir, Mo/Pd, W/Pd, Mn/Pd, Fe/Rh, Rh/Pt, Ir/Pd, and Ir/Pt has been treated with sulfur dioxide. Only electron-rich systems are capable of taking up SO2 into a bridging position. [Mo(CO)3(η2-dppe) (η1-dppm)] (2) reacts with [PdCl2(C8H12)] to form [MoPdCl2(CO)3(dppe)(μ-dppm)] (3), which is unstable and does not take up SO2. However, the complexes [FeRhCl(CO)4(μ-SO2)(μ-dppee)] (5), [MoIr(μ-Cl)(CO)3(μ-SO2)(μ-dppm)2] (8), and [MnPdBr(CO)2(μ-SO2)(μ-dppm)2] (14) have been obtained. Reactions of fac;-[M(CO)3(η2-dppm)(η1-dppm)] (M=Mo: 6a, W: 6b) or the corresponding mer-isomers 10a, b with [PdCl2;-(C8H12)] give the dinuclear complexes [MPdCl(μ-Cl)(CO)2(μ-CO)(μ-dppm)2] (11a, b). From [Ir(CO)(dppm)2]Cl and [Pd(dba)2] in the presence of CO [IrPdCl(CO)2(μ-dppm)2] (16) is obtained, whereas in dichloromethane under an inert gas the oxidation product [IrPdC]3(CO)(μ-dppm)2] (17) is formed. 11a, b, 16, and 17 apparently are too electron-poor to form stable adducts with SO2. However, from 17 and (Me3Si)2S the sulfur-bridged complex [IrPdCl(μ-S)(CO)(μ-dppm)2] (18) is obtained. The alkynyl complexes [MPtCl(C=CPh)2(μ-dppm)2] (M — Rh: 19, Ir: 21) readily add SO2, reversibly in the case of 19. From [IrPtCl-(C ≡ CPh)2(μ-SO2)](μ-dppm)2] (22) the salt [IrPt(C ≡ CPh)2(SO2) (μ-dppm)2]PF6 (23) is formed by Cl abstraction. 23 is one of the rare examples of terminal coordination of SO2 in a dinuclear complex.
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    URL: http://dx.doi.org/10.1002/cber.19911240305
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    Synthesis, Characterization, and Some Reactions of Tricarbonyl(cyclobutabenzene)chromium(O) Derivatives (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 465-474 
    Details
    ISSN: 0009-2940
    Keywords: Chromium complexes ; Cyclobutabenzene ; Differential scanning calorimetry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tricarbonyl(cyclobutabenzene)chromium(O) complexes 12 - 20, have been prepared from the free ligand and triammintricarbonylchromium(O) or hexacarbonylchromium(O). The complexes have been characterized by spectroscopic methods (IR, 1H NMR, 13C NMR) and mass spectrometry, and 1H-NMR signal assignments have been verified by an NOE experiment. Diastereomeric ratios have been determined by 1H NMR and the diastereomers of the 1-methyl derivative 16 separated by HPLC. A crystal-structure analysis is presented for exo;-16. A photochemical ligand exchange takes place in 70% yield for the 1-trimethylsilyl derivative 19. Metalation with n-butyl-lithium/tmeda at -78°C has been observed only for the aromatic and not for the benzylic protons.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240308
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    Synthese und Reaktionen von Eisen-Clustern mit μ3;-λ2-koordiniertem Trifluormethylisocyanid-Liganden. Bildung eines N;-(Trifluormethyl)-formimidoyl-Liganden (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 497-502 
    Details
    ISSN: 0009-2940
    Keywords: Iron clusters ; Trifluoromethyl isocyanide, μ3;-λ2-coordinated ; Hydrogenation ; N;-(Trifluoromethyl)formimidoyl ligand ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses and Reactions of Iron Cluster Compounds with a μ3;-λ2-Coordinated Trifluoromethyl Isocyanide Ligand. Formation of an N;-(Trifluoromethylformimidoyl LigandPyrolysis of the iron clusters Fe3(CO)10(L)(μ2-CNCF3) (1a - d) [L=P(OCH3)3 a, P(OC2H5)3 b, P(CH3)3 c, P(C2H5)3 d] in n-heptane at 95°C results in the reversible elimination of two mol of carbon monoxide and formation of the cluster compounds Fe3(CO)8(μ3;-λ2-CNCF3)L (2a-d). According to the crystal structure determination of 2a trifluoromethyl isocyanide acts as a μ3;-λ2-bridging ligand with its C=N bond perpendicular to one iron-iron edge. 2a reacts with molecular hydrogen to yield Fe3(CO)8(L)(μ3;-λ2-HC=NCF3)(μ2-H) (3a) containing a μ3;-λ2;-N;-(trifluoromethyl)formimidoyl ligand. 3a exists as a mixture of three isomers. The isomerization of two of these isomers is studied by variable temperature 1H-, 19F-, and 31P-NMR spectroscopy. Reaction of 2a with NaBH4 leads to the ionic cluster Na[Fe3(CO)8(L)(μ3;-λ2-HC=NCF3)] (4a), which yields 3a on protonation with trifluoroacetic acid.
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    URL: http://dx.doi.org/10.1002/cber.19911240313
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    Über die Funktion von Di(tert-butyl)silandiolat als Anker für Metallfragmente in hohen und mittleren Oxidationsstufen. Synthese und Strukturen von (tBu2SiO2(TeCl2-μ-Cl2 - TeCl2) und (tBu)2Si(OReO3)2 (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 519-521 
    Details
    ISSN: 0009-2940
    Keywords: Siloxanes ; Rhenium(VII) compounds ; Tellurium(IV) compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Function of Di(tert-butyl)silanediolate as an Anchor for Metal Fragments in High and Medium Oxidation States. Synthesis and Structures of (tBu)2SiO2(TeCl2 - μ-Cl2 - TeCl2) and (tBu)2Si(OReO3))2The compounds (tBu)2SiO2(TeCl2 - μ-Cl2 - TeCl2) (2) and (tBu)2Si(OReO3)2 (3) have been prepared by the reactions of (tBu)2Si(OH)2 (1) with TeCl4 and Re2O7. The single-crystal X-ray structures of 2 and 3 are reported. The (tBu)2SiO2 group functions as an anchor for the metal fragments TeCl3 and ReO3.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240317
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    Röntgenstrukturuntersuchung von α-(Trimethylsilyl)benzyllithium·Tetramethylendiamin [C6H5CH(SiMe3)Li·TMEDA] und α-(Phenylthio)-benzyllithium·3 Tetrahydrofuran [C6H5CH(SPh)Li·(THF)3] - zwei zentral-chirale Benzyllithium-Verbindungen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 543-549 
    Details
    ISSN: 0009-2940
    Keywords: Benzyllithium compounds ; Chirality, central ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystal Structure of α-(Trimethylsilyl)benzyllithium·Tetramethylethylendiamin [C6H5CH(SiMe3)Li·TMEDA] und α-(Phenylthio)-benzyllithium·3 Tetrahydrofuran [C6H5CH(SPh)Li - (THF)3] - Two Benzyllithium Compounds with Central ChiralityThe crystal structure analyses of [C6H5CH(SiMe3)Li·TMEDA] (6) and of [C6H5CH(SPh)Li·(THF)3] (7, in which the positions of the benzylic hydrogen atoms have been determined experimentally, reveal compounds with pyramidal benzylic carbon atoms. In 6 lithium is λ2-bound to Cipso and α of the substituted benzylic anion which leads, together with the TMEDA molecule, to a tetra-coordinated lithium atom. In 7 only one Li - C bond is formed, namely that to Cα. Additional coordination with three THF molecules results also in a tetracoordinated lithium atom, The extent of the pyramidalization in 6 and 7 is qualitatively in agreement with quantum-mechanical ab initio calculations [G86, MP2/6-311+ + G(d,p)].
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    URL: http://dx.doi.org/10.1002/cber.19911240321
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    Synthesis of Monosubstituted [1.1.1]Propellanes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 587-590 
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    ISSN: 0009-2940
    Keywords: [1.1.1]Propellanes, substituted ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis (up to the 10-g scale) and purification of alkyl- and methoxyalkyl-substituted [1.1.1]propellanes are described.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240326
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    Geminale Vinyldiazide, X. 3,3-Diazido-2-cyanacrylsäure-methylester: Synthese von Vinylaziden, 4,5-Dihydro-1H-tetrazol-5-ylidenen, Oxazolen und N-Cyaniminen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 595-608 
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    ISSN: 0009-2940
    Keywords: Azirines ; Oxazoles ; Pyrrolines ; Vinyl azides ; Tetrazoles ; Pyridines, tetrahydro- ; Cyanoacrylates ; Calculations, AM1 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Geminal Vinyl Diazides, X. - Methyl 3,3-Diazido-2-cyanoacrylate: Synthesis of Vinyl Azides, 4,5-Dihydro-1H-tetrazol-5-ylidenes, Oxazoles, and N-CyaniminesReaction of methyl 3,3-diazido-2-cyanoacrylate (1) with amines 2 at -30°C yields aminovinyl azides 4. In the presence of equivalent amounts of triethylamine the vinyl azides 4 undergo 1,5′-ring closure to afford the triethylammonium salts 5. Treatment of 5 with hydrochloric acid gives the corresponding 4,5-dihydro-1H-tetrazol-5-ylidene derivatives 6. In contrast thermolysis of 4 leads via azirines 7 to oxazoles 8. Reaction of vinyl diazide 1 with lysine and cystine, respectively, yields bis(vinyl azides) 9. Triethylamine-induced 1,5′-ring closure of 9 produces the bis(triethylammonium) salts 10, which can be transformed under acidic conditions into the corresponding bis(4,5-dihydro-1H-tetrazol-5-ylidene) derivatives 11. With methyl acrylate (17) oxazole 15 reacts via carbonyl ylide 16 in a 1,3-dipolar cycloaddition to give pyrroline 18 (X-ray structure analysis). Thermolysis of the geminal vinyl diazide 1 in the presence of alcohols 19 or primary amines 21 forms the cyanimines 20 and 22, respectively, via methyl 3-aza-2,3-dicyanoacrylate 25. 25 exists as syn/anti isomers which fully agrees with AM1 calculations carried out on cyanimine model systems.
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    URL: http://dx.doi.org/10.1002/cber.19911240328
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    Zur Struktur von 2-Azapentadienyllithium-Verbindungen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 655-663 
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    ISSN: 0009-2940
    Keywords: 2-Azapentadienyllithium compounds ; Structure in solution ; Calculations, ab initio, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Structures of 2-Azapentadienyllithium Compounds2-Azapentadienyllithium compounds 3 - 10 are easily accessible by deprotonation of N-allylimines 1,2 with lithium diisopropylamide. Their structures in THF solution at various temperatures are studied by means of 1H- and 13C-NMR spectroscopy. 1-Phenyl-substituted 2-aza-pentadienyllithium derivatives adopt all-trans W conformations, whereas 1-alkylsubstituted 2-azapentadienyllithium compounds show s-cis conformations (sickle shapes). 13C shifts of the 2-azapentadienyl carbon atoms are discussed in terms of HOMO coefficients. The experimental structural results are compared with theoretical data obtained by MNDO and ab initio calculations for the corresponding anions. MNDO results are also given for monomeric 2-azapentadienyllithium conformers 13,14.
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    URL: http://dx.doi.org/10.1002/cber.19911240333
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240401
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    Synthesen neuer Azofarbstoffe mit 1,6-Methano[10]annulen-Partialstruktur (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 537-542 
    Details
    ISSN: 0009-2940
    Keywords: 1,6-Methano[10]annulene ; Quinones, bridged ; Acylations ; Azo dyes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of New Azo Dyes with 1,6-Methano[10]annulene Partial StructureBridged quinone hydrazones 1 are transformed by aromatic acyl chlorides to the corresponding azo dyes 3a -6. Nitro derivative 1a reacts analogously with p-tolylsulfonyl chloride, acetyl chloride, methyl chlorocarbonate, and dimethylcarbamoyl chloride to give the corresponding azo dyes 7 and 8a -c. Reaction of 1a with diphenylcarbamoyl chloride unexpectedly leads to Berson-Wilcott rearrangement with formation of the azo dye 9. Acylations of 1a with the bifunctional acyl chlorides diphosgene and terephthaloyl chloride yield the azo derivatives 11 and 12.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240320
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    β-Aminoketone als Schlüsselverbindungen zur Synthese von Pyridinen: Ein neuartiger, leistungsfähiger Zugang zu kondensierten Bi- und Terpyridinen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 571-576 
    Details
    ISSN: 0009-2940
    Keywords: Annelated pyridines, preparation from Mannich bases ; 5,6-Dihydro-1,10-phenanthrolines, substituted ; 4,5-Diazafluorenes, substituted ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: β-Amino Ketones as Key Intermediates in the Synthesis of Pyridines: A Novel and Efficient Route to Annelated Bi- and TerpyridinesThe hydrochlorides of β-amino ketones 1a - e (Mannich bases) are easily obtained starting compounds for a novel synthesis of pyridines. Condensation with the heteroaromatic ketones 8, 9, and 10 yields 5,6-dihydro-1,10-phenanthrolines 3a - d, 13 and 4,5-diazafluorenes 4a - d, which have not yet been described in literature. Symmetrical terpyridines 3e, 4e are formed in a one-step reaction of 8, 9 with dimethylmethylenammonium chloride in the presence of an ammonia source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240324
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    The Azo/Nitrene Route to cis,cis-Trialkyltriaziridines, 1 Synthesis of syn-Azo Azides of Defined Proximity (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 609-620 
    Details
    ISSN: 0009-2940
    Keywords: syn-Azo azides ; Proximity effects ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bi- and polycyclic syn-azo azide substrates H, 5, 14 and I, 15-18, 36, 41d, respectively, of varying rigidity and proximity (with the potential nitrene nitrogen atom in the π plane of the azo function) are prepared in order to synthesize kinetically stabilized cis,cis-trialkyltriaziridines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240329
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    Struktur und Reaktivität von isoanellierten heterocyclischen Systemen mit 4n;-π- und (4n + 2)-π-Elektronen, XVIII. Benzo[c]thiophene mit symmetrischer Struktur: Modifizierte und optimierte Herstellung nach der S-Oxid-Route (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 645-654 
    Details
    ISSN: 0009-2940
    Keywords: Benzo[c]thiophenes ; preparation by the S-oxide route ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure and Reactivity of Isoannullated Heterocyclic Systems with 4n;-π and (4n + 2)-π Electrons, XVIII. - Benzo[c]thiophenes with Symmetric Structure: Modified and Optimized Preparation by the S-Oxide RouteBenzo[c]thiophenes (15) with symmetric structure have been prepared efficiently from 1,3-dihydrobenzo[c]thiophene 2-oxides (9) by reaction with aluminium oxide, by O-acylation with trifluoroacetic anhydride, or O-alkylation with methyl trifluoromethanesulfonate. The aromatization of the S-oxides 9 is achieved by O-functionalization, subsequent elimination, and consecutive deprotonation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240332
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    Acetylierung von N-(Trimethylsilyl)keteniminen: N-Acylketenimine und α-Cyanketone (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 673-673 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240336
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    Stabile Tellur-Ylide: Darstellung und Reaktivität von Diorganyltelluronium-4,5-dicyanimidazol-2-yliden (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 699-705 
    Details
    ISSN: 0009-2940
    Keywords: Tellurium ylides ; Diorganyltelluronium 4,5-dicyanoimidazole-2-ylides, stability of, reactivity of, Stevens rearrangement ; Imidazole, 2-(methyltelluro)- ; Imidazolide, 2-(methyltelluronio)- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stable Tellurium Ylides: Synthesis and Reactivity of Diorganyltelluronium 4,5-Dicyanoimidazol-2-ylidesDiorganyl tellurides R2Te (R=Me, Me3SiCH2, Ph) react with 2-diazo-4,5-dicyano-2H-imidazole (1) at - 30°C to form the title compounds 2 - 4. The ylides 3 and 4 are thermally stable up to their melting points of 159 and 243°C, resp., whereas 2 undergoes a modified Stevens rearrangement at 190°C with formation of a 2-(methyltelluro)imidazole (10). The reactivity of 2 - 4 is determined by an extreme charge separation between the onium centre and the ylide entity. No Wittig reactivity is observed, alkylation occurs at the imidazole nitrogen and carbanions lead to tetraorganyl tellurium compounds with limited stability.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240405
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    d8-Eisennitrosylhydride (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 719-724 
    Details
    ISSN: 0009-2940
    Keywords: Transition metal hydrides ; Oxidative addition reaction ; Nitrosyl compounds ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: d8 Iron Nitrosylhydride ComplexesThe nitrogen complex [(OC)2(Et3P)2Fe]2N2 (1) reacts with carboxylic acids to form the complexes (OC)2(Et3P)2Fe(H)OC(O)R [R=4-methoxyphenyl, 2a; R=2,4-dimethoxyphenyl, 2b; R=2,4,6-trimethoxyphenyl, 2c; R - Ph, 2d; R - CF3, 2e]. Treatment of 2 with N-methyl-N-nitroso-p-tolylsulfonamide produces the nitrosylcarboxylato complexes (OC)(ON)-(Et3P)2FeOC(O)R (3a - d) in addition to the side product Fe(NO)2(PEt3)2 (4) except for 2e which forms 4 exclusively. Reaction of 3 with LiAlH4 yields the hydridonitrosyliron complex (OC)(ON)(Et3P)2FeH (5a). A different synthetic route to the phosphorus donor-substituted iron hydride complexes involves starting material (OC)2(L)2FeCl2 [L=PEt3, 6a; L - PMe3, 6b; L=P(OiPr)3, 6c]. Compounds 6 react with tBuLi and NOBF4 to form (OC)(ON)L2FeCl (7). Subsequent treatment with NaBH4 gives (OC)(ON)(L)2FeH [L=PEt3, 5a; L=PMe3, 5b; L=P(OiPr)3, 5c]. The structures of 5b and 7a are determined by X-ray crystallography.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240408
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    [K{V4O4(μ-O)4(μ-O2CCH2tBu)4}] [O2CCH2tBu] · 2 tBuCH2CO2H, ein Kaliumkomplex eines „anorganischen Kronenethers“ (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 761-764 
    Details
    ISSN: 0009-2940
    Keywords: Vanadium carboxylate ; Oxovanadium cluster ; Potassium complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [K{V4O4(μ-O)4(μ-O2CCH2tBu)4}][O2CCH2tBu] · 2 tBuCH2CO2H, a Potassium Complex of an “Inorganic Crown Ether”The reaction of VOCl3 with Ag/KO2CCH2tBu yields the title compound (characterized by crystal and molecular structure analyses), which is the first oligonuclear vanadium complex with monofunctional carboxylate containing Vv centres exclusively. The potassium ion is coordinated by two planes of O2;-: the four μ-oxo bridges of the puckered V4(μ-O)4 ring and the plane spanned by the eight oxygen functions of the bridging carboxylate ligands, from wich it protrudes only slightly.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240414
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    Small and Medium Rings, 74. Syntheses and Photoelectron Spectra of 7-Azanorbornadiene and Related Compounds An Analysis with Fragment Orbitals (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 791-801 
    Details
    ISSN: 0009-2940
    Keywords: Lone-pair orientation ; Lone pair interaction ; Precanonical orbitals ; Orbitals, localized ; Calculations, ab initio STO-3G, MNDO, MM2 force field ; PE Spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The He(I) photoelectron spectra (PE) of 7-azanorbornane (5), 7-azanorbornene (6), and 7-azanorbornadiene (7) as well as of related urethanes have been recorded. The syntheses of these bicyclic compounds are described in detail. A most convenient analysis of the PE spectroscopic results is based on the procedure of Heilbronner-Schmelzer on an ab initio STO-3G level. This method allows to construct fragment orbitals elucidating the orientation of the nitrogen lone pair, the through-space interaction with π bonds, and the participation of σ bond orbitals. The result is remarkable: whereas the direct interaction of localized lone-pair and π orbitals is significant in both syn;- and anti-orientation, the interaction of a localized lone pair with a precanonical fragment π orbital is completely different in the two geometries. In 6;-syn a considerable interaction matrix element FantiΨnπ=-0.71 eV comes to the fore, whereas the corresponding parameter in 6;-anti turns out to be almost zero, FantiΨnπ=+ 0.09 eV. Since 6;-syn is calculated to be more stable than 6;-anti, it is this invertomer, 6;-syn, which is likely to be responsible for the main bands in the PE spectrum of 6. The comparatively large experimental split between the first two PE bands of 6 (0.98 eV) is in accord with the 6;-syn geometry and compares well with the calculated band separation of 1.26 eV for 6;-syn.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240420
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    Monomere und überbrückte oligomere (Tetrasulfophthalocyaninato)eisen(II)-Komplexe mit Isocyaniden und N-Donoren als axialen Liganden (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 833-839 
    Details
    ISSN: 0009-2940
    Keywords: Tetrasulfophthalocyaninato ligand ; Iron complexes ; Isocyanide ligands ; Mößbauer spectroscopy, 57Fe ; Semiconductors, organic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomeric and Bridged Oligomeric (Tetrasulfophthalocyaninato)iron(II) Complexes with Isocyanides and N-Donors as Axial Ligands(Tetrasulfophthalocyaninato)iron(II) (TsPcFe) (1) is treated with the isocyanides tert-butyl isocyanide (tBuNC), 1,4-diisocyanobenzene (dib), 2,3,5,6-tetramethyl-1,4-diisocyanobenzene (me4dib), and 4-isocyano-3,5-dimethylpyridine (me2pyNC), and also with pyrazine (pyz) leading to bisaxially coordinated monomers TsPcFe(L)2 (L=tBuNC, dib, me4dib) and the bridged oligomers [TsPcFe(L)]n (L=dib, me4dib, me2pyNC, and pyz). All these complexes are soluble in methanol or water. The spectroscopic properties of the complexes are described, and the average chain lengths of the bridged oligomers are determined by 1H-NMR spectroscopy. The bridged stacked systems exhibit semiconducting properties with and without iodine doping.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240425
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    Vinylcyclopropan-Komplexe und Vinylcyclopropane aus Carben-Komplexen und 1,3-Dienen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 981-988 
    Details
    ISSN: 0009-2940
    Keywords: Benzylidene complexes ; Vinylcyclopropane complexes ; Vinylcyclopropanes ; Cyclopropanation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinylcyclopropane Complexes and Vinylcyclopropanes from Benzylidene Complexes and 1,3-DienesBenzylidenepentacarbonyl complexes (CO)5M[C(C6H4R-p)H] (1) [M - W:R=H (a), OMe (b); M=Cr: R - H (c), OMe (d)], react with cyclopentadiene by stereospecific transfer of the benzylidene ligand to one C=C bond of the diene and coordination of the resulting endo;-6-arylbicyclo[3.1.0]hex-2-ene (4) to the metal. The [CO]5M fragment occupies the exo-position. Addition of bromide liberates 4 from the metal. The reaction of 1a with 1,3-cyclohexadiene gives the corresponding (endo;-7-phenylbicyclo[4.1.0]hept-2-ene)tungsten complex (6) and, after addition of Br-, the free bicyclic compound. The sequential reaction of 1a with 1,2,3,4,5-pentamethylcyclopentadiene and Br- affords the endo;-6-phenyl-exo;-4-methyl isomer of pentamethylphenylbicyclo[3.1.0]hex-2-ene 9 with more than 85% stereoselectivity. The benzylidene transfer from 1a to cis-and trans-pentadiene, isoprene, and 2-chloro-1,3-butadiene proceeds regiospecifically to the more electron-rich C—C bond to give (E)- and (Z)-phenylvinylcyclopropanes. The E/Z ratio ranges from 0.52 to 2.2. The structures of the complexes 3d and 6 were established by X-ray analyses.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240503
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    Makrocyclisch modifizierte Verbindungen vom TTF- und TCNQ-Typ (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 897-902 
    Details
    ISSN: 0009-2940
    Keywords: Biphenylophane ; Kharasch coupling reaction ; Macrocycles ; TCNQ ; TTF ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecules of the TTF and TCNQ Type with Macrocyclic SkeletonsThe electron-rich and electron-poor macrocycles 1 - 3 have been synthesized. Their [1.1](3,3′)biphenylophane framework is formed by Kharasch reaction. Whereas in the well-known donors and acceptors I-III the functionalities are conjugated, in their macrocyclic “analogues” 1-3 the conjugation is prevented by the meta-connection of the phenylene rings. The redox properties  - studied by cyclovoltammetry  -  are discussed. The X-ray analysis of 3 shows considerable deviations from a planar structure.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240433
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    Synthese mittlerer und großer Ringe, XXVIII. Die Rutheniumtetroxid-Oxidation von 3,6-Alkano-4,5-oligomethylenoxepinen Ein neuer Weg zu makrocyclischen Di-, Tri- und Tetraketonen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 923-931 
    Details
    ISSN: 0009-2940
    Keywords: Oxepines ; Ruthenium tetroxide oxidation ; Macrocyclic di-, tri-, and tetraketones ; Quinoxaline derivates ; Ether cleavage ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Medium and Large Rings, XXVIII. - The Ruthenium Tetroxide Oxidation of 3,6-Alkano-4,5-oligomethyleneoxepines - A New Approach to Macrocyclic Di-, Tri-, and TetraketonesThe oxepines 3, 7, and 9 are oxidized by means of ruthenium tetroxide to give various types of macrocyclic ketones such as 4, 8 and 10. The diketones 12 can be synthesized by ether cleavage of 9a to give 11a and subsequent oxidation of 11b and 11d to the monocyclic compounds 12a and 12b.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19911240437
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    Chiral Induction in Photochemical Reactions, XIII. The Paternó-Büchi Reaction of Achiral and Chiral Acyl Cyanides with Furan (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 967-969 
    Details
    ISSN: 0009-2940
    Keywords: Paternó-Büchi reaction ; Photochemistry ; Chiral induction ; Acyl cyanides ; achiral and chiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The acyl cyanides 1a - d are prepared from the corresponding acyl chlorides. The Paternó-Büchi reaction of 1a  -  f with furan (2) yields the bicyclic oxetanes 3a - f with an endo/exo ratio varying from 3.5: 1 (1a) to 16: 1 (1d). However, in the reaction of the chiral acyl cyanides 1b and 1c, a low chiral induction is observed (maximum de: 13%).
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240442
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    (Butadien)(cyclopentadienyl)niob-Komplexe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 975-980 
    Details
    ISSN: 0009-2940
    Keywords: Niobium complexes ; Cyclopentadienyl derivatives ; Butadiene derivatives ; Acetylene derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Butadiene)(cyclopentadienyl)niobium ComplexesThe known bis(butadiene)(cyclopentadienyl)niobium complex (C5H4R)Nb(C4H6)2 (1, R=H) exists in solution as a 1 : 1 mixture of a bis(cis-butadiene) isomer 1a and a (cis-butadiene)(trans-butadiene) isomer 1b. In solution the barrier to isomerisation is 80 ± 2 kJ/mol. New derivatives 2 (R=Me) and 3 (R=SiMe3) of 1 are described. One of the butadiene ligands in 1 - 3 is readily substituted with CO, CNtBu, P(OMe)3, and PMe3. CpNb(PMe3)2(C4H6) (7) reacts with disubstituted acetylenes to form acetylene complexes CpNb(PMe3)(C4H6)(RC=CR') (8: R, R'=Ph, 9: R=Me, R'=Ph, and 10: R=Ph, R'=SiMe3), The structure of 9 resembles that of bent metallocene derivatives with the acetylene acting as a 2-e ligand.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240502
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    Organosubstituierte 2,5-Dihydro-1,2,5-oxoniasilaboratole Charakterisierung und Reaktivität (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1003-1016 
    Details
    ISSN: 0009-2940
    Keywords: O-Lewis base - triorganoboranes, cyclic ; Boranes, vinyl-, diethyl-substituted ; 1,2,5-Oxoniasilaboratoles, 2,5-dihydro-, organo-substituted ; 1,2,5-Oxasilaboraolanes, organo-substituted ; 1,2,5-Oxasilaboroles, 2,5-dihydro-, organo-substituted ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organosubstituted 2,5-Dihydro-1,2,5-oxoniasilaboratoles - Characterization and Reactivity.The potassium salts of the anions (2a-d, a: R2,3 = CH3; b: R2 = C2H5, R3 = CH3; c: R2 = C6H5, R3 = CH3; d: R3 = C6H5), prepared from the organosubstituted cis;-2-boryl-1-silylalkenes 1a - d and KOH, react with the electrophiles R1Hal [R1 = H: HCl, (CH3)3NHCl; R1 = CH3: (CH3)I, (CH3)4NCl; or (CH3)3ElIV(CH3)3, ElIV=Si, Ge, Sn, Pb] to give the neutral five-membered ring compounds [R1 = H: 3H; CH3; 3Me; ElIV(CH3)3: 3ElIV]. On heating of 3H or 3Sn either ethyl migration occurs to yield the saturated diastereomers (4) [4/4′: R3′ = H; 4Sn/4′Sn: R3′ = Sn(CH3)3], or elimination of ethane takes place to give the unsaturated compounds (5). The reaction of 2 with ClPb(CH3)3 leads to 3Pb [R1=Pb(CH3)3] (11B-NMR), which exclusively form 5 with elimination of C2H5Pb(CH3)3.
    Additional Material: 8 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19911240506
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    Tetrahydrofuran-Soluble Magnesium Dihydride by Catalytic Hydrogenation of Magnesium*) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1041-1050 
    Details
    ISSN: 0009-2940
    Keywords: Magnesium, catalytic hydrogenation of ; Magnesium hydride, soluble, IR spectrum of ; Magnesium hydride-quinuclidine complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Upon hydrogenation of magnesium in THF using homogeneous magnesium-anthracene transition-metal halide catalysts in the presence of small amounts of MgCl2 and solubilizing agents L, a dissolved form of magnesium hydride (MgH'2) is produced. The preferred L's are quinuclidine (QC) or organomagnesium compounds; however, organoaluminium and -boron compounds can also be used. The fraction n of magnesium hydride produced in the dissolved form and the stability of the MgH'2 solutions are investigated as a function of the kind and the amount of solubilizing agents and catalysts. The optimized method for the preparation of MgH'2 is described. The magnesium hydride dissolved in THF is characterized by IR spectroscopy. In order to elucidate the role of the solubilizing agents, THF-soluble MgCl2-containing stoichiometric MgH2 · QC model complexes are also prepared and characterized by IR spectra. Advantages and disadvantages of using MgH'2 for synthetic purposes instead of catalytically prepared suspensions of magnesium hydride (MgH2) are discussed.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240510
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    Redoxreaktivität Phosphido-verbrückter Heterodimetallkomplexe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1075-1082 
    Details
    ISSN: 0009-2940
    Keywords: Reduction ; Halogenation ; Voltammetry, cyclic ; Heterodimetallic complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Redox Reactivity of Phosphido-Bridged Heterodimetallic ComplexesThe metal-metal bond in (3a,b,e) [L=CO: R=Ph (a), Cy (e); L=PMe3: R=Ph (b)] is cleaved reductively, oxidatively, and by nucleophiles by using Na[HBEt3], bromine or iodine, and PMe3, respectively. The action of PMe3 on 3a affords Me3P(OC)4Mn - PPh2 - Fe(CO)4 (5), which is photolyzed to give 3b. While the reduction of 3a can be regarded as a nucleophilic bond opening functionalizing only manganese, oxidation of 3a,b with halides results in the formation of the complexes XMn(CO)4 - PPh2 - Fe(X)(CO)3L (4a - d) [L=CO: X=I (a), Br (c); L=PMe3: X=I (b), X=Br (d)], which provide two functionalized metals. To elucidate the redox behavior of 3a cyclovoltammetric investigations were carried out. They indicate a complex reaction scheme including reactions of higher order.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240514
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    Mehrfachbindungen zwischen Hauptgruppenelementen und übergangsmetallen, XC. Selektive Bildung von Alkylrheniumoxiden aus Glykolat-Komplexen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1101-1106 
    Details
    ISSN: 0009-2940
    Keywords: Organic metal oxides ; Alkylation ; Chelate ligands ; Rhenium glycolates ; Multiple bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multiple Bonds between Main Group Elements and Transition Metals, XC. - Selective Formation of Alkylrhenium Oxides from Glycolato ComplexesAlkylrhenium(VII) and alkylrhenium(VI) oxides, previously not known or hardly accessible, are selectively synthesized from glycolato(O,O') complexes. These are formed in easy terms from methyltrioxorhenium(VII) and aliphatic vic-diols, e.g. glycol and pinacol, by both redoxneutral and reductive condensation reactions (ReVII → ReVI), respectively. The dinuclear glycolato complex 3 exhibits a centrosymmetric molecular structure with an octahedral core geometry around the metal atom. The mononuclear Re(VII) compound 2 forms a distorted trigonal bipyramidal structure (single crystal X-ray diffraction).
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240518
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    Darstellung und Struktur von Thallium(I)-2,4,6-tris(trifluormethyl)thiophenolat, einer Verbindung mit faltblattartig-polymerem Aufbau (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1127-1129 
    Details
    ISSN: 0009-2940
    Keywords: Thallium compound ; Polymeric structure ; Organo fluorine ligand ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation and Structure of Thallium(I) 2,4,6-Tris(trifluoromethyl thiophenolate, a Compound with a Folded Polymeric StructureThe title compound, thallium(I) 2,4,6-tris(trifluoromethyl)thiophenolate (1) has been prepared by using either TlOEt and (CF3)3C6H2SH or Tl2CO3 and (CF3)3C6H2SNa. A single X-ray structural analysis shows a folded polymeric structure for 1; the crystal lattice incorporates half of a 1,4-dioxane molecule per Tl atom. This compound has a surprisingly high kinetic stability compared to known thallium(I) thiolates.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240522
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    Tris(diethylamino)cyclotriboran sowie Konstitutionsisomerie zwischen cyclo;- und closo-Hexakis(diethylamino)hexaboran(6) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1149-1152 
    Details
    ISSN: 0009-2940
    Keywords: Cyclotriborane, diethylamino ; cyclo-Hexaborane(6), diethylamino ; closo-Hexaborane(6), diorganylamino ; Hexaboranes(6), constitutional isomerism, polyhedron ring rearrangement ; Aminopolyboranes, cyclic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(diethylamino)cyclotriborane and Constitutional Isomerism Between cyclo;- and closo-Hexakis(diethylamino)hexaborane(6)The reaction of Et2NBCl2 with potassium in boiling cyclohexane provides a mixture of aminopolyboranes, containing 20-25 mol-% (BNEt2)3 (1), (BNEt2)4 (2), and cyclo;-(BNEt2)6 (3), respectively, as well as varying amounts of closo;-(BNEt2)6 (4). Whereas 1 and 3 have been highly enriched by means of HPLC, 4 has been isolated by column chromatography and crystallization. On standing in solution at room temperature, the cyclo-isomer 3 slowly rearranges to the closo-isomer 4, while at elevated temperatures the reverse conversion occurs. Hence 4, which is the first neutral B6 compound with octahedral structure, has a relatively higher thermodynamic stability at normal conditions.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240526
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    Lösliche Lanthanid-alkoxide mit niedrigen Koordinationszahlen am Metall-Atom (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1163-1165 
    Details
    ISSN: 0009-2940
    Keywords: Lanthanide alkoxides ; Tritox ligand ; Neodymium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Soluble Lanthanide Alkoxides with Low Coordination Numbers at the Metal AtomNd[N(SiMe3)2]3(thf)2 (1) reacts with tBu3COH (2) to give the monomeric lanthanide alkoxide (tritox)3Nd(thf) (3). The chloro-bridged dimer [(tritox)2Nd(μ-Cl)thf]2 (6) is obtained by treatment of NdCl3(thf)2 (4) with LiOCtBu3 (5). The structure of 6 has been determined by X-ray crystallography.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240530
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    Azobrücken aus Azinen, XII. Transannulare Hydroborierung von parallel benachbarten C=C/N=N-Bindungen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1187-1190 
    Details
    ISSN: 0009-2940
    Keywords: Transannular reactions ; Hydroboration ; B-N compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Azo Bridges from Azines, XII., - Transannular Hydroboration of Close Parallel C=C and N=N BondsIn the systems 3 and 5 9-borabicyclo[3.3.1]nonane (9-BBN) adds to the close parallel C=C/N=N bonds in a transannular reaction. A B - N bond is formed and the borane hydrogen transferred to the C=C bond regio- and stereospecifically. The structure of the adducts 4 and 6 is elucidated by NMR spectroscopy and in the case of 4a by an X-ray analysis. The catecholborane 9 forms with 3 an azo - borane adduct at first, pointing to a stepwise transannular reaction.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240534
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    {Bis[bis(trimethylsilyl)methyl]stannio(II)}bis(η2-ethen)nickel(O) und verwandte Verbindungen, Teil I (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1321-1325 
    Details
    ISSN: 0009-2940
    Keywords: Alkenes ; Nickel complexes ; Stannenes ; Metal-metal bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: {Bis[bis(trimethylsilyl)methyl]stannio(II)}bis(η2-ethene)nickel(O) and Related Compounds, Part IThe reaction of Ni(C2H4)3 and bis{bis(trimethylsilyl)methyl}-stannene affords the crystalline, coordinatively unsaturated complex (C2H4)2Ni = Sn{CH(SiMe3)2}2 (1). The NMR spectra of 1 show for the tin moiety a temperature-dependent solvate complex formation (thf) and for the nickel moiety a hindered rotation of the ethene ligands at low temperature. X-ray structure analysis indicates Sn - Ni multiple-bond character. Upon addition of donor molecules to 1 the addition compounds (C2H4)2Ni - Sn{CH(SiMe3)2}2(donor) [donor = NH3: 2a; pyridine: 2b; (Me2N)3PO: 2c] are obtained. According to the low-temperature NMR spectra the complexes are asymmetric in their ground state. Similar to the formation of the adducts 2a - c, the title compound 1 reacts with LiHAliBu3 as a source of LiH in ether/tmeda to form the hydride adduct [Li(tmeda)2]+ [(C2H4)2Ni - Sn{CH(SiMe3)2}2}2(H)]ominus; (2d). Displacement of the ethene ligands in 1 by CO yields with conservation of the Ni - Sn bond the complex (CO)3Ni= Sn{CH(SiMe3)2}2 (3). From this complex the donor adducts (CO)3Ni - Sn{CH(SiMe3)2}2(donor) [donor = NH3: 4a; pyridine: 4b; (Me2N)3PO: 4c] are prepared. For the donor-ligand carbonyl complexes the ground state has been shown to be asymmetric by low-temperature NMR spectra.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240603
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    Synthese und Reaktionen von Bis(fluorsulfinyl)difluormethan, F2C(SOF)2 (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1353-1356 
    Details
    ISSN: 0009-2940
    Keywords: Difluoromethane, bis(trifluoro-α4-sulfanyl), bis(halosulfinyl) ; Bis(sulfinamides) ; 1α4,3α4,2-Dithiazetidines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactions of Bis(fluorosulfinyl)difluoromethane, F2C(SOF)2From F2C(SF3)2 (1) and AsF5 the thermally labile monosulfonium salt F3SCF2SF2+ AsF6- (2) is prepared in SO2 as a solvent, while under the same conditions the corresponding tetrafluoroborate is solvolyzed to give an isomeric mixture of F2C(SOF)2 (5a,b). In the reaction of 5a,b with N-silylated amines F2C[S(O)NMe2]2 (7a,b), (8a,b), and (9a,b) are formed. The structure of the cis derivative 8b has been determined by X-ray diffraction. From 5a,b and HCl the rather unstable F2C[S(O)Cl]2 (10a,b) is obtained, which is hydrolyzed to F2C[S(O)OH]2 (11a,b).
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240607
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    Substituent Effects on Folding in Cyclotetraphosphane (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1369-1371 
    Details
    ISSN: 0009-2940
    Keywords: Cyclotetraphosphanes, substituent effects, vibrational analysis ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio quantum chemical calculations evidence a very flat potential hypersurface for folding of parent cyclotetraphosphane. This is in accord with a corresponding vibrational analysis. Electronegative substituents increase folding of the fourmembered ring system.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19911240610
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    Photolytische und thermische Umsetzungen von μ3-As[WCp(CO)2]3 mit Fe(CO)5 und Fe2(CO)9; Röntgenstrukturanalysen der Cluster FeW2Cp2(CO)7[μ3-As-WCp(CO)3], Fe2WCp(CO)8H[μ3-As - WCp(CO)3] und Fe2WCp(CO)8H[μ3-As-FeCp(CO)2] (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1327-1333 
    Details
    ISSN: 0009-2940
    Keywords: Hydrido cluster ; Hydrido cluster ; Iron-Tungsten-Arsenic tetrahedranes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photolytic and Thermic Reactions of μ3-As[WCp(CO)2]3 with Fe(CO)5 and Fe2(CO)9; X-Ray Structure Analyses of the Clusters FeW2Cp2(CO)7[μ3-As-WCp(CO)3], Fe2WCp(CO)6H[μ3-As-WCp(CO)3]μ3-As[WCp(CO)2]3 (1) (Cp = C5H5) reacts with Fe(CO)5 photolytically and thermically to yield FeW2Cp2(CO)7[μ3-As-WCp(CO)3] (5) and Fe2WCp(CO)8H[μ3-As-WCp(CO)3] (6), respectively. Thermal reaction of 1 with Fe2(CO)9 leads to the compound Fe2WCp(CO)8H[μ3-As-FeCp(CO)2] (7 besides 5 and 6. The products have been characterized by spectroscopic methods and X-ray crystallography.
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    URL: http://dx.doi.org/10.1002/cber.19911240604
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    Cycloadditionen von 6H-1,3,4-Oxadiazin-6-onen (4,5-Diaza-α-pyronen), 10. Reaktionen von Bicyclo[2.1.1] hexenen mit 6H-1,3,4-Oxadiazin-6-onen und dynamische Effekte in einem neungliedrigen, überbrückten, α,β-ungesättigten Enollacton 2) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1435-1444 
    Details
    ISSN: 0009-2940
    Keywords: 1,3,4-Oxadiazin-6-ones ; Diels-Alder reactions ; Enol lactones ; Lactone conformations ; Line-shape analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cycloadditions of 6H-1,3,4-Oxadiazin-6-ones (4,5-Diaza-α-pyrones), 10 1). - Reactions of Bicyclo[2.1.1]hexenes with 6H-1,3,4-Oxadiazin-6-ones and Dynamic Effects in a Nine-Membered, Bridged, α,β-Unsaturated Enol Lactone 2)The reactions of bicyclo[2.1.1]hexene (2) and its tricyclic derivative 3 with 2,5-diphenyl-6H-1,3,4-oxadiazin-6-one (1 a) gave the 3,4-dihydro-α-pyrones 6 and 7, respectively. In contrast, the methyl phenyloxadiazinonecarboxylate 1 b and 2 afforded a mixture of the nine-membered, bridged, α,β-unsaturated enol lactone 11 and the β-lactone 12 in a ratio of about 10: 1. Olefin 3 reacted with 1 b to furnish small amounts of the bridged derivative 16 of 11 as well as the 2:1 product 14, a saturated δ-lactone. Unlike 16, enol lactone 11 reveals dynamic phenomena, which have been investigated by means of line shape analyses of the temperature dependent 13C-NMR spectra. The interconvertion of the cis- and trans-lactone conformers (11 a ⇄ 11 b), being present in a 1:2 ratio, proceeds with δH
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240619
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    Notizen/Notes Selective Alkylations of Tricyclic Pyrrolo- and Pyridazino-as-Triazines1). - A Novel Evidence of the Importance of the Lone-Pair Densities (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1477-1479 
    Details
    ISSN: 0009-2940
    Keywords: as-Triazinium salts, fused ; Alkylations ; Lone electron pair density ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methylation of 2, 3, and 4 obtained by ring transformations of 1 gives selectively 5, 6, and 7, respectively. These regiospecific electrophilic attacks are interpreted by a modified application of the FMO theory involving consideration of the in-plane lone electron pairs of the ring nitrogens.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19911240624
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    Regioselektive Substitution an [2.2]Metacyclophanen via Chromtricarbonyl-Komplexe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1415-1423 
    Details
    ISSN: 0009-2940
    Keywords: [2.2]Metacyclophanes ; Chromium tricarbonyl complexes ; Chirality, helical, planar ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Regioselective Substitution of [2.2]Metacyclophanes via Chromium Tricarbonyl ComplexesThe [2.2]metacyclophanes 6, 8, and 9 are regioselectively complexed with triammintricarbonylchromium. The complexes are lithiated with nBuLi/TMEDA at -78°C, and the resulting aryllithium complexes are trapped with electrophiles to give new phanes exhibiting substitution patterns, which are not or more difficult available by other routes. Complex 6a gives 5-substitution almost exclusively, while the chiral complex 8a is substituted in positions 5 and 4 in a ratio of 3:1. Steric effects, caused by the large dithiane group, seem to play a role in both complexation and derivatisation of these substrates. An X-ray crystal structure analysis of the chromium tricarbonyl phane complex 11 is performed.
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    URL: http://dx.doi.org/10.1002/cber.19911240616
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    Synthese und Kristallstruktur von Li2[(Me3SiCH2)3Al—CH2—Al(CH2SiMe3)3]  -  ein Addukt des Dilithiomethans CH2Li2? (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1511-1516 
    Details
    ISSN: 0009-2940
    Keywords: Dilithium bis(aluminate) ; methylene-bridged ; Hexacoordinated carbon atom ; Dilithiomethane derivative ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Crystal Structure of Li2[(Me3SiCH2)3Al—CH2—Al(CH2SiMe3)3] - a Dilithiomethane Derivative?Reaction of (trimethylsilyl)methyllithium with the methylene-bridged aluminium tetrachloride Cl2Al—CH2—AlCl2 yields dilithium methylenebis[tris(trimethylsilylmethyl)aluminate] (2) as the only isolable product. All attempts for preparing the tetraalkyl analogue have been unsuccessful. The crystal structure of 2 exhibits a hexacoordinated central carbon atom with short Li—C distances. Both lithium atoms and the methylene hydrogens of the Al—CH2— Al unit are almost coplanar. The discussion of the structure and properties leads to the attractive description of 2 as an adduct of tris(trimethylsilylmethyl)-aluminium to dilithiomethane CH2Li2.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240705
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    Darstellung, Struktur und Komplexierung von 2,2′,5,5′-Tetrahydro-1,1′-bi(1H-1,2,5-phosphadiborol)-Derivaten (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1497-1503 
    Details
    ISSN: 0009-2940
    Keywords: 1H-1,2,5-Phosphadiboroles, dihydro ; 1,1′-Bi(1H-1,2,5-phosphadiborole) ; Chromium complexes ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, Structure, and Complexation of 2,2′,5,5′-Tetrahydro-1,1′-Bi(1H-1,2,5-phosphadiborole) DerivativesReactions of (Z)-1,2-diborylethenes [HC  -  B(Cl)R]2 with LiPH2 and LiP(SiMe3)2 lead to the 2,5-dihydro-1H-1,2,5-phosphadiboroles 1a  -  d in good yields. 1a, b react with (Me3C)2Hg to give yellow 2a (56%) and 2b (90%), which are also obtained from 1c, d and TlCl or C2Cl6, respectively. The constitution of 2b is established by an X-ray structure analysis. 2a reacts with Cr(CO)3(CH3CN)3 to yield the bis(pentacarbonyl)chromium complex 4a, whereas 2b and Fe(CO)3(C8H14)2 form the bis(tricarbonyliron) compex 5b. Spectroscopic studies and X-ray structure analyses of 4a and 5b show that in 4a the chromium atom is η1-bound to phosphorus, whereas in 5b the iron interacts with all atoms of the folded C2B2P ring.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240703
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    Synthese und Strukturen von Imidotitanverbindungen  -  Steuerung der Bildung monomerer und dimerer Spezies durch Änderung der Basizität des Lösungsmittels (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1521-1523 
    Details
    ISSN: 0009-2940
    Keywords: Titanium-nitrogen bonds ; Dimer-monomer formation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Structures of Imidotitanium Compounds  -  Directing the Monomer-Dimer Formation by Changing the Basicity of the SolventsThe reaction of (i-Pr)2PN(SiMe3)2 (1) with elemental sulfur leads to (i-Pr)2P(S)N(SiMe3)2 (2). Compound 2 reacts with TiCl4 with elimination of chlorotrimethylsilane to yield the adducts [(i-Pr)2P(S)NTiCl2-MeCN]2 (3) and (i-Pr)2P(S)N = TiCl2.3py (4), crystallized from MeCN or pyridine, respectively. Compound 3 crystallises in the space group Pbca, 4 in the space group p&1macr;.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240707
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    Dicarbonylgold(I)-hexafluorouranat(VI), Au(CO)2UF6 (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1559-1561 
    Details
    ISSN: 0009-2940
    Keywords: Gold carbonyl complexes ; Uranium hexafluoride ; Gold(I) bis(carbonyl) cation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dicarbonylgold(I) Hexafluorouranate(VI), Au(CO)2UF6Elemental gold reacts with UF6 in the presence of CO in anhydrous HF to form quantitatively a complex compound, whose IR spectra and analysis are consistent with the formula [Au(CO)2][UF6].
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19911240712
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    Umwandlung der Cluster Fe3(CO)9(μ3-η2-N2Et2) und Fe3(CO)9(μ3-NEt)2 zu organischen Produkten 1) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1549-1557 
    Details
    ISSN: 0009-2940
    Keywords: Azoalkane ligand ; Nitrene ligand ; Clusters ; Iron complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conversion of the Clusters Fe3(CO)9(μ3-η2-N2Et2 and Fe3(CO)9(μ3-NEt)2 into Organic ProductsThe azoalkane-bridged cluster Fe3(CO)9(μ3-η2-N2Et2) (1) and its thermal rearrangement product Fe3(CO)9(μ3-NEt)2 (2) are converted by standard routes into derivatives with one carbene ligand C(Ph)OEt (3, 4). Degradation (thermally or oxidatively) of these compounds produces the diaziridine (5) and/or the iminoester EtN = C(Ph)OEt (6). 4 and moist p-tolyl isocyanide form the indole derivative 8. 1 adds one or two equiv. of alkynes leading to the alkyne-bridged cluster 9 or the ferrole-type clusters 10. The clusters 10, resulting from HC≡CPh, exist as two isomers 10a and b which can be equilibrated and separated. An alternative route to 10 c (alkyne: MeC≡CMe) starts from Fe2(CO)6(C4Me4) by treating it with Fe2(CO)9 and N2Et2. Photolytic or oxidative degradation of the clusters 10 produces substituted furan 13, pyrrole 14, or dihydropyridazine 15. The crystal structures of the clusters 4, 9, 10a, and 10b have been determined.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240711
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    Optische Aktivität und absolute Konfiguration von 1,4-Dihydroxytricyclo[6.4.0.04,9]dodecan-7,10-dion und -7-on (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1581-1584 
    Details
    ISSN: 0009-2940
    Keywords: Circular dichroism ; Tricyclo[6.4.0.04,9]dodecane-7,10-dione and -7-one,1,4-dihydroxy- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical Activity and Absolute Configuration of 1,4-Dihydroxytricyclo[6.4.0.04,9]dodecane-7,10-dione and -7-one(±)-1,4-Dihydroxytricyclo[6.4.0.04,9]dodecane-7,10-dione (1) has been resolved into the pure enantiomers through chromatographic separation of the diastereomeric dithioacetals 3A and 3B prepared with (-)-(2R,3R)-2,3-butanedithiol (2). The dithioacetals were converted into the acetals 4, from which the monoketones 6 were obtained by Raney nickel desulfurization/deprotection. The absolute configuration of (1R,4S,8S,9S)-(-)-6 is correlated with that of (1R,4S,8S,9S)-(-)- 1 by means of Cotton effects and its chromatographic behavior on potato starch. Some interaction between the carbonyl groups in the diketone 1 is demonstrated by comparison of UV, CD, and PE spectra with those of the monoketone 6.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240718
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  • 287
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    Synthesis and Properties of (Phthalocyaninato)ruthenium(II) with Bisaxially Coordinated Azanaphthalenes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1607-1612 
    Details
    ISSN: 0009-2940
    Keywords: Phthalocyanine ; Ruthenium complexes ; Azanaphthalenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Phthalocyaninato)ruthenium(II) (PcRu) reacts with different azanaphthalenes such as quinoxaline, 2-methylquinoxaline, quinazoline, phthalazine, quinoline, pyrido[2,3-b]pyrazine, pteridine, isoquinoline and 1,5-naphthyridine to form the corresponding bisaxially coordinated PcRuL2 complexes 1-9. The IR, 1H-NMR, UV/Vis, TG/DTA, and FD-MS data are discussed in detail for all the complexes prepared.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240722
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    Retention of Configuration and E/Z Stereoselectivity in the Photolysis of cis- and trans-Tetraalkyl-4-methylene-1-pyrazolines (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1619-1626 
    Details
    ISSN: 0009-2940
    Keywords: 4H-Pyrazoles, 3,3,5,5-tetraalkyl-3,5-dihydro-4-methylene- ; Cyclopropanes, 2,2,3,3-tetraalkyl-1-methylene- and 2,2-dialkyl-1-alkylidene- ; Photolysis ; Extrusion of molecular nitrogen ; Configuration, retention of ; E/Z Stereoselectivity ; Trimethylenemethanes, bis-orthogonal and mono-orthogonal ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The isomeric 4-methylene-1-pyrazolines cis- and trans-2 are synthesized by a Wittig reaction from the pyrazolin-4-ones cis- and trans-1, respectively. Direct irradiation with 350-nm light of cis-2 affords the alkylidenecyclopropanes cis-8, (E)- and (Z)-9 (64: 17: 19) besides molecular nitrogen and small amounts of the 4-methylenepyrazolidine cis-7 as a result of photoreduction. Under the same conditions, trans-2 is converted into trans-8 as well as (E)- and (Z)-9 (64: 14: 22). The configurations of cis- and trans-8 have been established by means of a 1,3-dipolar cycloaddition with mesityl nitrile oxide which furnishes two cycloadducts from cis-8, e.g. cis-14A and B, but only one cycloadduct from trans-8, viz. trans-14. The configurations of (E)- and (Z)-9 have been assigned on the basis of homoallylic 1H,1H coupling constants and nuclear Overhauser experiments. The results demonstrate that, on the least-motion paths leading to cis- and trans-8, the configuration of the ring substituents in cis- and trans-2 is completely retained. Of the non-least-motion products (E)- and (Z)-9 the latter is favoured regardless of the configuration of the precursors cis- and trans-2 though the extent of (Z) selectivity depends on that configuration. The results are interpreted in terms of bis-orthogonal trimethylenemethane diradicals as primary intermediates from which irreversible paths bifurcate. Cyclization yields cis-8 (from cis-2) or trans-8 (from trans-2) and 90°-bond rotations afford two diastereomeric mono-orthogonal trimethylenemethane diradicals [(E)- and (Z)-18] which eventually cyclize to the corresponding non-least-motion products (E)-9 and (Z)-9.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240724
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  • 289
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    Carbodesilylierung von (Trimethylsilyl)imidazolen und -pyrazolen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1639-1650 
    Details
    ISSN: 0009-2940
    Keywords: Imidazoles, (trimethylsilyl) ; carbodesilylation of ; Pyrazoles, (trimethylsilyl) ; carbodesilylation of ; Carbodesilylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbodesilylation of (Trimethylsilyl)imidazoles and -pyrazolesThe preparation of the 1-methyl(trimethylsilyl) (TMS)-substituted imidazoles 3a, 4a, 8, 9, and 11a by silylation of the corresponding metallated imidazoles is described. Carbodesilylation of 3 with aldehydes or carboxylic halogenides occurs selectively in 2-position. In the presence of a strong base (CsF) the reactivity against carbon electrophiles correlates well with the stability of the imidazolyl anions; regioselective carbodesilylation in 2-, 5-, or 4-position of the twofold TMS-substituted imidazoles 3a and 9 therefore is possible, which allows the synthesis of a great variety of hydroxyalkyl-substituted imidazoles and of acylimidazoles. By using the dimethylsulfamoyl substituent as an N-protecting group, the N- unsubstituted 5-benzoylimidazole (26) as well as the comparable 5-benzoyl-pyrazole (30b) and 5-(hydroxyphenylmethyl)-pyrazole (30a) are accessible.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240727
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  • 290
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    Untersuchung zum Reaktionsverhalten von Nitrilen RCN gegenüber [I3]+[AsF6]- (R = CH3, CF3, Br, I, H) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1571-1573 
    Details
    ISSN: 0009-2940
    Keywords: Nitrogen-iodine chemistry ; HSAB principle ; Nitrile chemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigation on the Reactivity of Nitriles RCN towards [I3]+[AsF6]- (R = CH3, CF3, Br, I, H)The reaction behaviour of cyanogen compounds R  -  CN (R = CH3, CF3, Br, I, H) towards [I3]+[AsF6]- is investigated. Whereas CF3CN and BrCN do not react, acetonitrile and cyanogen iodide react with the [I3]+ cation to yield the linear species [ICNI]+ and [CH3CNI]+. The different reactivity of RCN towards [I3]+ is discussed on the basis of the substituent electronegativity X(R) and the HSAB principle. Simple thermodynamic estimations (Born-Haber cycle) explain the greater stability of the (acetonitrile)iodonium cation compared with the inorganic (iodocyan)iodonium salt.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240715
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  • 291
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    Berichtigung (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1578-1578 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240717
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  • 292
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    Synthesis and Characterization of Organogallium and Organoindium Compounds with Tridentate 2,6-Bis[(dialkylamino)methyl]phenyl Ligands (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1567-1569 
    Details
    ISSN: 0009-2940
    Keywords: Organogallium compounds ; Organoindium compounds ; Intramolecular base stabilization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intramolecularly stabilized five-coordinated organogallium and organoindium compounds {2,6-[(CH3)2NCH2]2C6H3H3}-GaMe2 (1), {2,6-[(CH3)2NCH2]2C6H3}InR2 (2-4), and {2,6-[(C2H5)2-NCH2]2C6H3}InEt2 (5) have been synthesized from {2,6-bis-[(dimethylamino)methyl]phenyl)}lithium or from {2,6-bis[(diethylamino)methyl]phenyl}lithium and the corresponding diorganogallium or diorganoindium chloride. The 1H-, 13C-NMR and mass spectra of the new compounds are reported and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240714
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  • 293
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    Methine-Brigded Five-Membered Heterocycles as Precursors for Low-Gap Polymers (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1597-1605 
    Details
    ISSN: 0009-2940
    Keywords: Polymers, low-gap ; Polyarenemethines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of suitable precursors of polyarenemethines (PAM) 1, which are predicted to be potential low gap polymers, is described. The Knoevenagel condensation of heteroaromatic aldehydes with 2,5-dihydrothiophene 1,1-dioxide (5), 2,5-dihydrothiophene 1-oxide (9), and its benzo-annulated analogs [6 and [10] yields the methine-bridged compounds 7, [8], 11, and [12], respectively. Reduction of the methine-bridged sulfoxides 11 and [12] leads to the corresponding sulfides 13 and [14]. For compound 18 with a high sterical demand another route has been developed. Thus, the reaction of the dicarbinol 17 with HI yields directly the heteroaromatic quinodimethane 18. The molecular structures of 7a and 18 are determined by X-ray analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240721
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    Notiz/Note P4O7 und P4O6S, Vergleich der Molekül- und Kristallstrukturen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1711-1714 
    Details
    ISSN: 0009-2940
    Keywords: 2,4,6,8,10-Hexaoxa-1,3,5,7-tetraphosphatricyclo[3.3.1.1]decane 1-sulfide, molecular and crystal structure ; P4O6 derivatives ; Calculations, SCF, for P4O7 and P4O6S ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: P4O7 and P4O6S, Comparison of Molecular and Crystal StructureSingle crystals of P4O6S were grown for the first time. By X-ray diffraction the space group (P21/c), the unit cell [α = 813.5(1), b = 938.3(1), c = 993.1(1) pm; β = 90.27(1)°], and the crystal and molecular structure have been determined. As compared to P4O7, the geometry of the P4O6 cage remains virtually unchanged upon substitution of the terminal oxygen atom by a sulfur atom. Calculated charge distributions clearly confirm the experimental results. With the exception of P(1), to which the additional chalcogen atom is attached, the effective charges at all other atoms seem not to be affected by an exchange of the terminal oxygen atom by a sulfur atom.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240807
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    Photoreduction on Irradiation of 3,3,5,5-Tetramethyl-4-methylene-1-pyrazoline.  -  An Overlooked Example of a Reaction Competing with the Extrusion of Molecular Nitrogen from Reluctant Azoalkanes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1613-1618 
    Details
    ISSN: 0009-2940
    Keywords: 4H-Pyrazoles, 3,5-dihydro-3,3,5,5-tetramethyl- ; 1-Pyrazoline, 4-methylene- ; 1H-Pyrazole, 2,3,4,5-tetrahydro-3,3,5,5-tetramethyl-4-methylene- ; Photolysis ; Photoreduction ; Extrusion of molecular nitrogen ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photolysis of the 4-methylene-1-pyrazoline 1 is reinvestigated under a variety of experimental conditions. Direct irradiation (350-nm light) affords the alkylidenecyclopropanes 4 and 5 as predominant products, besides molecular nitrogen, and in a constant ratio of (55 ± 1): (45 ∓ 1), which is not altered in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) or piperylene nor in [D6]acetone solution. When oxygen is excluded, an additional compound is formed whose proportion depends on the capability of the solvent to act as hydrogen donor. In the presence of three equivalents of DABCO, it eventually becomes the major product. The 4-methylenepyrazolidine structure 13 of the novel photoproduct is established by NMR spectroscopy, a comparison with an authentic sample, obtained in quantitative yield by zinc reduction of 1, and reoxidation to 1 as well. An extensive investigation to detect any traces of the 4-isopropylidene-2-pyrazoline 6 in the irradiated solutions has failed. This result is at variance with recent disclosures reporting evidence for a turnaround photoisomerization of 1 via diazenylallyl diradicals. The contribution of photoreduction to the decay of the first excited singlet state of reluctant azo compounds is emphasized.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240723
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    Darstellung O-geschützter (R)-2-Hydroxyaldehyde und ihre Hydrocyanierung (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1651-1659 
    Details
    ISSN: 0009-2940
    Keywords: (R)-2-Hydroxy aldehydes, O-protected ; Hydrocyanation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of O-Protected (R)-2-Hydroxy Aldehydes and Their HydrocyanationThe synthesis of O-silyl- and O-benzyl-protected (R)-2-hydroxy aldehydes (R)-6 from (R)-2-hydroxy carboxylic acids (R)-1 is described. While attempts for their diastereoselective hydrocyanation with hydrocyanic acid and (R)-oxynitrilase as catalyst have not been successful, the cyano silylation with trimethylsilyl cyanide occurred diastereoselectively with a ratio of 81 : 19 preferring the threo form without racemization at C-2 of the 2-hydroxy aldehyde.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240728
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    Neue Synthesen für Ibuprofen und Naproxen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1667-1672 
    Details
    ISSN: 0009-2940
    Keywords: Isocyanide - cyanide rearrangement ; Ibuprofen ; Naproxen ; Optically active 1-arylethylamines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Syntheses of Ibuprofen and NaproxenA new route for the synthesis of α-arylpropionic acids, in particular for the two most important non-steroidal antiinflammatory compounds Ibuprofen (5) as well as racemic and optically active Naproxen (12), has been developed. N-(1-Arylethyl)formamides 2, 9 are dehydrated to the corresponding isocyanides 3, 10, and these are rearranged by flash pyrolysis to α-arylpropionitriles 4, 11 which are converted into α-arylpropionic acids 5, 12 by hydrolysis under standard conditions. The intermediate 1-(6-methoxy-2-naphthyl)-ethylamine is resolved via its tartrate or mandelic salts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240730
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240801
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    Synthese mittlerer und großer Ringe, XXIX. Oxidation von 3,4-Hexamethylenfuran zu 2,9-Dioxodecan-10-olid (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1875-1877 
    Details
    ISSN: 0009-2940
    Keywords: Furans ; Oxidation ; Cyclohexenone, 3-(phenylsulfonyl)- ; Butenolide ; Macrolide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Medium and Large Rings, XXIX. - Oxidation of 3,4-Hexamethylenefuran to 2,9-Dioxodecan-10-olide3,4-Hexamethylenefuran (1 a) is oxidized by various methods to give the butenolide 2. Ozonolysis of 2 affords 2,9-dioxodecan-10-olide (3) in 80% yield.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240828
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240901
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