Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Reaction of 1,3-Dialkyl-4,5-dimethylimidazol-2-ylidenes with 2-Bromo-2,3-dihydro-1H-1,3,2-diazaboroles (Alkyl=iPr and tBu)Dedicated to professor Adolf Zschunke on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 705-710 
    Details
    ISSN: 0009-2940
    Keywords: Boron ; Diazaboroles ; Carbenes ; Heterocycles ; Imidazoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Bromo-2,3-dihydro-1H-1,3,2-diazaboroles (3a-c) were synthesized by cyclocondensation of dilithiated 1,4-diazabutadienes (5a-c) with boron tribromide in hexane. 3a was also obtained by sodium amalgam reduction was conducted in ether solvents, diboroxane (2) resulted as the main product. Compound 3a and 1,3-dialkyl-4,5-dimethylimidazol2-ylidenes (6a, b) underwent halide displacement to afford the borolylimidazolium salts 7a, b. Compounds 2, 3a-c, and 7a, b were characterized by elemental analyses and spectroscopic methods (1H, 11B, 13C NMR; Ir; MS). The molecular structures of 2 and 7a were established by single-crystal X-ray diffraction analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300606
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Phosphanyl-Substituted Phosphaferrocenes as p,p-Chelate Ligands (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1771-1776 
    Details
    ISSN: 0009-2940
    Keywords: Chelates ; P ligands ; Phosphaferrocene ; Carbonyl complexes ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dicyclohexyl-acid diphenylphosphanyl-substituted phosphaferrocenes 2 and 3 were synthesized by substitution of the amino group in 2-dimethylaminomethyl-3,4,-dimethylphosphaferrocene 1 · Homologization of 2-formyl-3,4-dimethylphosphaferrocene 4 by one CH2 unit via Wittig olefination provided access to the phosphanylethyl derivative 9. Ligands 2, 3 and 9 formed P, P-chelate complexes with tetracarbonyl metal fragments in good yield. X-ray crystal structure determinations were carried out for the five-ring chelate complex 2. Mo(CO)4 (≡ l0), and the six-ring chelate complex 9 . Mo(CO)4, (≡ 13).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301211
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Palladium  -  Catalyzed Reactions, 1 Palladium-Catalyzed Enantioselective Hydrophenylation and Hydrohetarylation of Bicyclo[2.2.1]Hept-2-ene: Influence of the Chiral Ligand, the Leaving Group, and the Solvent (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1327-1331 
    Details
    ISSN: 0009-2940
    Keywords: Asymmetric catalysis ; Hydroarylation ; Palladium ; P-N ligands ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of optically active biaryl bisphosphanes 10-12, a diphenylphosphanylphenyloxazoline 8, and a (β-N-sulfonyl-aminomethyl)bisdiphenylphosphane 7 as ligands in the Pd-catalyzed Heck-type hydroarylation of norbornene (1) with phenyl 2 and various hetaryl derivaties 3-5 leads exclusively to the formation of exo-2(het)arylnorbornanes 6 with asymmetric inductions of up to 86.4% ee. In addition to an investigation into the effects of different chiral ligands, a systematic study has been made of the influence of various (het)aryl compounds, leaving groups, and solvents on the chemical and optical yields of this reductive arylation.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300924
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Diastereoselective Synthesis of Tricarbonyl(thiophene)chromium Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 659-662 
    Details
    ISSN: 0009-2940
    Keywords: Thiophene derivatives ; Complexation, diastereoselective ; Chromium ; Heterocycles ; Steric hindrance ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,3-Disubstituted 2-hydroxyalkylthiophenes 9 and 10 were synthesized in a five-step sequence and their diastereoselective complexation with the Cr(CO)3 fragment leading to the corresponding tricarbonyl(thiophene)chromium complexes 11 and 12 was investigated. The diastereoselectivity achieved in the complexation reaction was up to 85% d. e. and depends primarily on the bulkiness of the substituent in the 3-position of the thiophene. The relative configuration of the stereogenic center and the planar element of chirality of complex 11a was determined by X-ray diffraction analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300518
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Iminoacylcobalt Compounds as Starting Materials for the Synthesis of Alkynylcobalt Halfsandwiches and CobaltaheterocyclesDedicated to Professor Günter Schmid on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 565-570 
    Details
    ISSN: 0009-2940
    Keywords: Cobalt ; Cycloadditions ; Heterocycles ; Alkynyl complexes ; Cyclopentadienyl complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The iminoacylcobalt compound [C5H5Co(C(CH3)=NCH3)(PMe2Ph)] (3) reacts with propargylic acid ester HC=CCO2R (R = Me, Et) to give the alkynylcobalt halfsandwich-type complexes [C5H5Co(C(CH3)=NHCH3)(C=CCO2R)-(PMe2Ph)]I (5, 6). With HC=CCO2Me as the substrate, besides 6 (R = Me) the five-membered cobaltaheterocycle [C5H5Co{K2(N, C)-N(CH3)C(CH3)CHC(CO2Me)}(PMe2Ph)]I (7) is also obtained. The reactions of 3 and the analogous benzyl derivative 4 with terminal alkynes HC=CR' (R' = CH2OH, CMe2OH, [CH2]2OH, CH2OMe, H, Me, nBu, Ph) afford exclusively the heterocyclic complexes [C5H5Co(K2(N,C)-N(R)C(CH3CHCR')(PMe2Ph)]I (R = CH3, CH2Ph) (8-18) in 60-70% yield. The molecular structures of 5 (R = Et) and 16 (R = Me, R' = Ph) have been determined by X-ray crystallography.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300506
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Organo-Substituted 1,2-Dihydro-1,2,5-Disilaborepines (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1349-1352 
    Details
    ISSN: 0009-2940
    Keywords: Heterocycles ; 1,1-Organoboration ; Disilanes ; 1- Alkynylsilanes ; NMR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,2-Di-1-propynyl-tetramethyldisilan (1) reacts with triorganoboranes R3B [R = Et (2a), CH2Ph (2c), 2-thienyl (2d)], 9-ethyl-9-borabicyclo[3.3.1]nonane (3), and diethyl(N-pyrrolyl)borane (4) by twofold 1,1-organoboration to give selectively the respective organo-substituted 1,2-dihydro-1,2,5-disilaborepines 5a-d,6, and 7 in high yields. The compounds 5-7 were characterized by 1H-, 11B-, 13C-, and 29Si-NMR spectroscopy in solution. The molecular structures of the distance 1 and of the heterocycle 5c were determined by X-ray structure analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300928
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Concave Reagents,22. Cyclopropanation of Alkenes with Ethyl Diazoacetate: Copper(I) Complexes of Concave 1,10-Phenanthrolines as Diastereoselective Catalysts (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 231-234 
    Details
    ISSN: 0009-2940
    Keywords: Diasteroselective cyclopropanation ; Copper compounds ; Homogeneous catalysis ; Molecular recognition ; Bimacrocycles ; Alkenes ; Macrocyclic ligands ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Concave 1,10-phenanthrolines 1a-c have been used as ligands in the copper(I)-catalyzed cyclopropanation of alkenes 2 with ethyl diazoacetate. The complexes proved to be efficient cyclopropanation catalysts and exhibited an enhanced diastereoselectivity, particularly in the reactions of cyclic alkenes 2b-d. The preferred formation of exo-cyclopropanes 3b-d can be explained by the concave shape of these catalysts.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Mono- and Bicyclic Organometallic Ring Systems with Exocyclic C=C and C=S BondsDedicated to Professor Joachim Strähle on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 871-877 
    Details
    ISSN: 0009-2940
    Keywords: Cobalt ; Cyclopentadienyl complexes ; Heterocycles ; Electrophilic addition ; Insertion reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cobaltaheterocycles [C5H5Co{κ2(C,S)-C(=CH2)-N(R)C(=S)S](PMe2Ph)] (5-7), which contain both an exocyclic C=C and C=S bond, were prepared from the iminoacylcobalt compounds [C5H5Co(C(CH3)=NCH} (PMe2Ph)]I (2-4) on treatment with either CS2/NaOCH3 or K[S2CNMe2], respectively. While protonation of 5 (R = CH3) and 7 (R = CH2Ph) with HBF4 occurs at the exocyclic C=CH2 bond to give cations containing a CoC(CH3)N(R)C(=S)S ring, the methylation of 5 and 7 with [OMe3]BF4 takes place at the exocyclic C=S bond and generates five-membered heterocycles heterocycles with an SCH4 substituent. The reaction of 5-7 with S8 leads to the elimination of the phosphane ligand and affords the bicyclic dithiolenecobalt complexes 14 - 16 in moderate to good yields. On treatment of 5-7 with C2(CO2R′)2 (R′ = Me,Et), an insertion of the alkyne into the C=CH2 bond occurs and five-membered ring systems 19-22 with an unsaturated exocyclic =C(CO2R′)-C(CO2R′)=CH2 group are formed. As in the case of 5 and 7, protonation and methylation reactions of 19 also take place at different sites leading to cations with either a delocalized CoCN or NCS unit.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300710
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    2,4-Diphosphoranediyl-1,3-diphosphetanes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1519-1527 
    Details
    ISSN: 0009-2940
    Keywords: Phosphorus ; Heterocycles ; Phosphorus ylides ; Phosphoranediyl ; Phosphonio substituents ; P-Cl bond dissociation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1,3-dichloro- and 1,3-dibromo-substituted title compounds 5b, c result from the condensation of triphenylphosphonium-bis(trimethylsily1)methylide 1 with PC13 and PBr3. The chloro derivative 5b undergoes a variety of single and double substitution reactions, of which some have merely been tested and others have been made preparative use of. The substitution of one chloride by an ylidyl, amino, phosphino, or metal carbonyl group is accompanied by the spontaneous dissociation of the other P-CI bond to yield the, 1,3-diphosphetenium chlorides 14/15, 19, 31 and 36, respectively. In other cases (9, 27, 32) dissociation can be achieved by means of a Lewis acid. Protonation of 5b occurs at the carbon ring members; methylation and formation of transition metal complexes occurs at a phosphorus ring member. PCl3 degrades the four-membered ring of5b or enlarges the ring to yield 3,5-diphosphoranediyl-l,2,4-triphospholane derivatives 39, 40, 42.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301027
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Balanced Decarboxylation of Aromatic Polyacids - A One-Step Synthesis of Perylene-3,4-dicarboxylic Anhydride (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 467-468 
    Details
    ISSN: 0947-3440
    Keywords: Decarboxylation ; Carboxylic acids ; Fluorescence spectroscopy ; Perylenes ; Heterocycles ; Dyes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Perylene-3,4-dicarboxylic anhydride (3) is prepared from technical grade perylene-3,4:9,10-tetracarboxylic anhydride (1) in 25% yield by a partial decarboxylation reaction using noncondensing amines. Perylene-3-carboxylic acid (4) and perylene-3,4-dicarboxylic imide (5) are prepared in the same way in yields of 24% and 76%, respectively, by a variation of the reaction conditions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970305
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Stereoselective Synthesis of Alcohols, LPart L: See ref.[1]; also Part VI of studies on “Flexible Molecules with Defined Shape”, for part V see ref.[2].. Synthesis and Conformational Studies of 1,5-Dioxa-cis-decalin (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1143-1150 
    Details
    ISSN: 0947-3440
    Keywords: Intramolecular allylboration ; 1,5-dioxa-cis-decalins ; Preferred conformation ; Conformation analysis ; Heterocycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: cis-2-Vinyltetrahydropyran-3-ol (6) is accessible by a selective intramolecular allylboration reaction. Compound 6 was converted into 1,4-dioxa-cis-decaline (4) and cis-syn-cis-perhydrotrioxaanthracene 32; heterocycles with fused tetrahydropyran rings. These ring systems populate predominantly the conformation in which the oxygen atoms are in a gauche arrangement. The tricycle 31 is a rigid derivative of 14-crown-3 and, as in the case of 12-crown-3, it forms complexes with lithium ions in acetonitrile.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970614
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Synthese und Konformation von Hexahydro-isochino[1,2-b][3]benzazepinen (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 447-457 
    Details
    ISSN: 0947-3440
    Keywords: Isoquino[1,2-b][3]benzazepines ; Iso-C-homoberbines ; Conformation analysis ; Bischler-Napieralski reaction ; Methyl ∊-hydroxycarboxylates ; Heterocycles ; Alkaloids ; Drug research ; Medicinal chemistry ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Conformation of Hexahydro-isoquino[1.2.-b][3]benzazepinesThe synthesis of the six hexahydro-isoquino[1,2-b][3]benzazepines 13a-f is described; their conformation is investigated by NMR spectroscopic methods, X-ray analysis and dehydrogenation with mercury(II) acetate.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970225
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Regiospecific Synthesis of 3,4-Disubstituted Furans and ThiophenesDedicated to Professor Xi-Kui Jiang, Shanghai Institute of Organic Chemistry, on the occasion of his 70th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 459-466 
    Details
    ISSN: 0947-3440
    Keywords: Furans ; Thiophens ; Palladium catalysis ; Coupling reactions ; Heterocycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The regiospecific synthesis of 3,4-disubstituted furans and thiophenes is reviewed. Our initial approach used 3,4-bis(tri-n-butylstannyl)furan as a building block, which led to many structurally diverse 3,4-disubstituted furans. Another avenue was explored by using 3,4-bis(trimethylsilyl)furan and 3,4-bis(trimethylsilyl)thiophene as precursors. A variety of unsymmetrically 3,4-disubstituted furans and thiophenes were prepared in this way. The advantages of our strategy lie in its stepwise manner as well as its prospect of yielding 3,4-disubstituted furans and thiophenes with rather different substitution pattern.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970304
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Demethyl(trifluoromethyl)actinomycins, IIPart I: Ref.[1].. Bis(trifluoromethylated) 4-(2′-Benzoxazolyl)actinocin Derivatives (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 999-1003 
    Details
    ISSN: 0947-3440
    Keywords: Antibiotics ; Actinomycins ; Trifluoromethyl actinocins ; Heterocycles ; NMR spectroscopy ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a previous study, performed in connection with the total synthesis of trifluoromethylated actinocinyl peptides 2a, the oxidative condensation of the corresponding o-aminophenol precursor 1 furnished a novel trimerisation product, which had been tentatively assigned to the triphenedioxazine structure 3[1]. Now, an improved synthesis of the trimer and extensive 1- and 2D-NMR studies have resulted in a new, quite unexpected structure: the 4-(2′-benzoxazolyl)actinocin derivative 8a, which replaces 3. Apparently, the quinone-sided CF3 group of an actinocin intermediate is unusually activated and reacts with a third o-aminophenol unit. The modifications to the synthesis increase the overall yield of demethyl-(trifluoromethyl)actinomycins by a factor of five.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970531
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Metallated 2-Alkenyl Sulfoximines in Asymmetric Synthesis: Regio- and Stereoselective Synthesis of Highly Substituted Tetrahydrofurans (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1881-1886 
    Details
    ISSN: 0947-3440
    Keywords: Asymmetric synthesis ; Sulfoximines ; Homoallylic alcohols ; Heterocycles ; Tetrahydrofurans ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting from the enantiopure 2-alkenyl sulfoximines 4/5 and epi-4/5, a one-pot procedure has been developed for the synthesis of tri- and tetrasubstituted tetrahydrofuran derivatives with excellent control of all relevant aspects of their structural description. The cyclization of the intermediate γ-hydroxyvinyl sulfoximines is strictly regioselective due to the electronic properties of the double bond involved. The absolute configuration at C-2 can be selected at will by a proper choice of the corresponding lactaldehydes 14 or ent-14 respectively. The absolute configuration at the 3- and 4-positions of the THF derivatives is under control of the sulfoximine moiety during aldehyde uptake, whereas their relative configuration is fixed due to the 1k relative topicity of attack of the reactands involved in their generation. The configuration at position 5 is determined mainly by the release of 1,3-allylic strain and is therefore the only stereogenic centre under substrate control. This becomes obvious in two cases (17a and 18a) where stereocontrol at this position is diminished. Here, the absence of a 3-methyl group as a control element reduces the energetic difference between the Re- and the Si-side attack.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970912
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Synthetic Microbial Chemistry, XXXPart XXIX: A. Yajima, K. Mori, Liebigs Ann. 1996. 1091-1093.. Synthesis of Acetophthalidin, a Fungal Metabolite which Inhibits the Progression of the Mammalian Cell Cycle (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 721-723 
    Details
    ISSN: 0947-3440
    Keywords: Acetophthalidin ; Fungal metabolite ; Isocoumarin ; Mammalian cell cycle ; Phthalide ; Natural products ; Heterocycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acetophthalidin [(±)-3-acetyl-5,7-dihydroxyphthalide (1)] was synthesized from 6,8-diacetoxy-3-methylisocoumarin (8) by its epoxidation followed by hydrolysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970412
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Methylchalcogen Derivatives of 1,4,5,8-TetrathiatetralinThis paper is dedicated to Professor Klaus Hafner. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 729-732 
    Details
    ISSN: 0947-3440
    Keywords: Organic donor ; Tetrathiatetralin ; Tetrathiafulvalene ; Solvent effects ; Heterocycles ; Sulfur ; Selenium ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetrakis(methylthio)- and tetrakis(methylseleno)-1,4,5,8-tetrathiatetralin 3 and 4 were prepared by the reaction of tetrathiatetralin 2 with LDA (lithium diisopropylamide) and MeS-SMe or MeSeSeMe in diethyl ether. A remarkable solvent effect was observed in that the similar reaction in tetrahydrofuran gave tetrakis(methylthio)tetrathiafulvalene 5 through a novel rearrangement. The iodine complex of 3 was prepared to be a rare example of complex formation in the tetrathiatetralin series.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970414
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Intramolecular Heck Reaction for the Synthesis of Isochromanes under Ambient and High pressure (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 887-891 
    Details
    ISSN: 0947-3440
    Keywords: Heck reaction, intramolecular ; Isochromane ; Palladium ; Heterocycles ; High-pressure chemistry ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The iodoarenes 9 and 10, bearing (E)- and (Z)-alkene moieties, respectively, easily prepared by alkylation of the corresponding alcohols 7a-c and 8a-c with 2 iodobenzyl iodide, undergo intramolecular Heck reactions to give the isochromanes 12-15a-c in good yields. The selectivity of the reaction depends on the size of the substituent R in 9 and 10; increasing bulkiness of R leads to a decrease in diastereoselectivity and an increase in regioselectivity. High-pressure experiments confirm the proposed mechanism and show that bromoarenes such as 11, which tend to be unreactive at ambient pressure, give good results when the cyclisation is performed under high pressure.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970516
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Chiral Bifluorophoric Perylene Dyes with Unusually High CD Effects - a Simple Model for the Photosynthesis Reaction Center (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1151-1153 
    Details
    ISSN: 0947-3440
    Keywords: Fluorescent dyes ; Perylenes ; Heterocycles ; Photosynthesis reaction center ; CD effects ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a bifluorophoric perylene dye (4a) is described, in which the two chromophores are linked by a chiral binaphthyl unit. A strong exciton coupling of the two chromophores, a bathochromically shifted fluorescence and strong CD effects are observed. The structure of 4 is compared to the photosynthesis reaction center.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970615
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Cycloaddition Reactions of 2H-Benzo[b]thiete and Thiocarbonyl Compounds (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1603-1605 
    Details
    ISSN: 0947-3440
    Keywords: 4H-1,3-Benzodithianes ; Heterodienes ; Heterodienophiles ; Spiro compounds ; Heterocycles ; Cycloaddition ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2H-Benzo[b]thiete (1) reacts in the o-quinoid form 1′ with the cyclic trithiocarbonates 4 and 6a, b and with the thioketones 8, 10 and 12 in [8π + 2π] cycloaddition reactions to the spiro compounds 5, 7a, b, 9, 11a, b. Irrespective of the presence of C=C double bonds, chemoselective and regioselective addition processes at the C=S double bonds take place that lead to 4H-1,3-benzodithianes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970743
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Rearrangement Reactions, 6.Part 5: Ref. New Functionalized Allenes: Synthesis Using Sigmatropic Rearrangements and Unusual ReactivityIn memoriam of Professor Gerrit L'abbé. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2005-2018 
    Details
    ISSN: 0947-3440
    Keywords: Allenes ; Sigmatropic rearrangements ; Heterocumulenes ; Cyclizations ; Metastable compounds ; Heterocycles ; 1,3-Butadienes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present article summarizes the synthesis of allenes, which bear a functional group with at least two heteroatoms, by [2,3] or [3,3] sigmatropic rearrangements of appropriate propargyl precursors. Recently, this method has been extended to prepare new types of functionalized allenes such as isocyanates, isothiocyanates, isoselenocyanates, azides, thiocarbonates, and azo compounds. The title compounds are very reactive as shown by rapid intra- and intermolecular consecutive reactions. This reactivity can be used to synthesize heterocycles and doubly functionalized 1,3-butadienes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971003
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Preparation of 1-Azacyclododeca-3,8-diynes and 1,6-Diazacyclododeca-3,8-diynes (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2113-2118 
    Details
    ISSN: 0947-3440
    Keywords: Medium-sized rings ; Cyclizations ; Alkynes ; Heterocycles ; Multicomponent reactions ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of N,N′-dialkyl- and N,N′-diaryl-1,6-diazacyclodeca-3,8-diynes was achieved by reaction of alkyl- or arylamines with 1,4-dihalobut-2-yne under dilution conditions in yields of 5-15%. The compounds synthesized by this procedure were the N,N′-dimethyl (2b), N,N′-diethyl (2c), N,N′-diisopropyl (2d), N,N′-di-tert-butyl (2e), N,N′-dicyclohexyl (2f), N,N′-diphenyl (2g), and N,N′-di-p-tolyl (2h) derivatives. The parent compound 2a was obtained in ca. 40% yield by heating 2d with α-chloroethylchloroformate (20). Using 1,9-dibromonona-2,7-diyne (10) and methylamine or isopropylamine, respectively, the corresponding N-alkyl-1-azacyclodeca-3,8-diynes 4b and 4d were synthesized under dilution conditions. By heating 4d with 20 we obtained 1-azacyclodeca-3,8-diyne (4a). As side products of the cyclization reactions the trimers 18 and tetramers 12 and 19 were isolated and characterized. N-methyl-1-azacycloundeca-3,9-diyne (14b) was prepared by reaction of 1,10-dibromodeca-3,8-diyne (13) with methylamine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971013
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Reactions of Uracils, 22.Part 21: Ref. Synthesis of Pyrimido[5,4-c]quinolizines (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1619-1625 
    Details
    ISSN: 0947-3440
    Keywords: Heterocycles ; Anellation ; Pyrimido[5,4-c]quinolizines ; 6-tert-Aminouracil-5-ylmethylenemalonodinitriles ; Pyrido[2,3-d]pyrimidine ; [1,4]Oxazino[3,4-a]pyrido[2,3-d]pyrimidone ; Aza-Wittig reaction ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several heterocyclization reactions of uracil derivatives are described. 1,3-Dimethyl-6-(triphenylphosphoranylideneamino)uracil-5-acrylic ester (1) undergoes aza-Wittig cyclization to give pyrido[2,3-d]pyrimidine 2. In a special application of the tert-amino effect, 6-tert-amino-substituted uracil-5-ylmethylenemalodinitriles 8a-f are cyclized with ZnCl2/toluene to afford pyrimido[5,4-c]quinolizines 10b, d-f, and 1,4-oxazino[3,4-a]pyrido[2,3-d]pyrimidine 10c, while the corresponding diesters 12a, b and 13 could not be cyclized. Alternative reaction mechanisms involving 1,6- and 1,5-H shifts are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970746
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Application of Vicarious Nucleophilic Substitution in Organic SynthesisDedicated to Professor Waldemar Adam on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1805-1816 
    Details
    ISSN: 0947-3440
    Keywords: Nucleophilic aromatic substitution ; σ-Adducts ; Aromatic nitro compounds ; Heterocycles ; Carbanions ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vicarious Nucleophilic Substitution (VNS) provides the possibility of the replacement of hydrogen atoms in electrophilic arenes with α-functionalized alkyl substituents. This review focuses on the transformations of products obtained by VNS, particularly into heterocyclic compounds. In addition, some characteristic features of the VNS mechanism are briefly described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970903
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    An Intramolecular 1,3-Dipolar Cycloaddition Involving One Alkyne and Two Nitrone Groups (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 469-471 
    Details
    ISSN: 0947-3440
    Keywords: Cycloadditions ; Asymmetric Synthesis ; Heterocycles ; Alkynes ; Reductions ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chiral nonracemic compound 4 was prepared from ethyl (S)-(-)-lactate and 1,4-dibromo-2-butyne. Reduction with DIBAH at -72°C and subsequent treatment of the resulting dialdehyde with N-methylhydroxylamine yielded the dinitrone 5, which underwent two consecutive intramolecular cycloadditions to give the chiral nonracemic compound 7. The structure of 7 was confirmed by an X-ray analysis. Reductive ring opening afforded compound 8.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970306
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Photochemical Formation of Heteromethylenecyclopropanes, 27Part 26: Ref.[1].. Annulated Tetrazolium Salts (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 671-683 
    Details
    ISSN: 0947-3440
    Keywords: Alkylations ; Annulation ; Azides ; Cations ; Cyclizations ; Cycloadditions ; Heterocycles ; Lithiation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithiation of the annulated tetrazoles 6a, c with butyllithium yields the N-lithiotetrazoles 7a, c which are allowed to react with alkyl halides. Alkylation at the α-carbon atom is observed in the reaction with methyl iodide (→ 6b, d), 1-bromo-2-chloroethane (7c→14a), and 1,3-dibromopropane (→ 16, 17), while 1,2-dichloro- and 1,2-dibromoethane give other products, viz. 11-13. Quaternisation of 6 with dimethyl sulphate affords mixtures of 1-methyl- (1) and 2-methyltetrazolium salts (8) (3:1-4:1) from which the hexafluorophosphates 1 PF6 are obtained by crystallisation. Methyl triflate converts the ω-azidonitriles 9 into the N-methylnitrilium triflates 10 which immediately undergo an intramolecular 1,3-dipolar cycloaddition to afford the 1-methyltetrazolium triflates 1 F3CSO3. Cyclisation of 16 by intramolecular N-alkylation furnishes the bisannulated tetrazolium bromide 3a · Br. Attempts to obtain the lower homologue 15, either from 14a or from 17, met with failure. Instead, 17 rearranges via 15b into 14b. The α-branched tetrazole 24 is synthesised from ethyl cyanoacetate and the bromide 18. Double cyclisation of 24 affords the bisannulated tetrazolium chloride 3b · Cl. The analogous scheme, envisaged for the synthesis of the lower homologue 32, failed in the last step owing to the high strain of this system.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970408
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Diastereo- and Regioselective Intramolecular Heck Reaction of α-Amino Alcohol Derivatives for the Synthesis of Enantiomerically Pure Isoquinolines and Benzazepines at Ambient and High Pressure (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1407-1413 
    Details
    ISSN: 0947-3440
    Keywords: Heck reaction, intramolecular ; α-Amino acids ; Isoquinolines ; Palladium ; Heterocycles ; Synthesis, enantioselective ; High pressure ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkylation and acylation of the alkenes 9b, c and 10a, b, which are easily prepared from the corresponding α-amino alcohols, with 2-halobenzyl and 2-halobenzoyl halides respectively, gives 11-15. These compounds cyclize with excellent diastereo- and regioselectivity to the enantiomerically pure N-heterocycles 18-20 in an intramolecular Heck reaction using 5 mol-% of Pd(OAc)2 in the presence of PPh3, TPAB and KOAc. Under the same conditions substrate 17 leads to the enantiomerically pure benzazepine 24. The reaction of the bromoarene derivatives 14-15 must be performed under high pressure to give good results.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970718
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    The Reaction of Hexachloroacetone with Diamines (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 925-929 
    Details
    ISSN: 0947-3440
    Keywords: Amides ; Heterocycles ; Bisimidazolidine ; Tetrahydrobenzimidazolidinene ; Bisbenzimidazol ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of hexachloroacetone (HCA) with various diamines led either to the corresponding diamides or to cyclic ureas, depending on the molar ratio of the reactants. In the cases of ethylenediamine, 1,2-diaminocyclohexane and o-phenylenediamine, the reaction with HCA also formed bisimidazole derivatives. These latter unexpected products were also formed when the diamine reacted with trichloroacetate esters or with carbon dioxide.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970521
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    A DFT Study on the Vinylcyclopropanecarbaldehyde-to-2,5-Dihydrooxepin Hetero-Cope-type Rearrangement and on Related ReactionsDedicated to Prof. Dr. Klaus Hafner on the occasion of his 70th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2443-2449 
    Details
    ISSN: 0947-3440
    Keywords: Pericyclic reactions ; Hetero-Cope-type rearrangement ; Cyclopropanes ; Heterocycles ; Substituent effects ; Transition structures ; Density functional calculations ; Ab initio calculations ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The prototypical 1,2-cis-vinylcyclopropanecarbaldehyde-to-2,5-dihydrooxepin hetero-Cope-type rearrangement was studied by “exact” first-principle methods. The reaction pathway was examined. The reaction, as well activation energies, was calculated for the unimolecular transformation of vinylcyclopropanecarbaldehyde and various derivatives. The derivatives differ from vinylcyclopropanecarbaldehyde by replacement of the formyl (CH=O) by the thioformyl (CH=S) or formiminyl (CH=NH) group and, in part, by replacement of hydrogen atoms at the substituted carbon atoms of the cyclopropane ring by hydroxyl or formyl substituents. The experimental reaction parameters of vinylcyclopropanecarbaldehyde are surprisingly well reproduced by B3LYP/6-31G* density functional and MP2/6-31G* ab initio quantum theoretical calculations. Reactant and product are nearly isoenergetic, while the activation energy amounts to about 25 kcal/mol. In the case of the nitrogen and sulfur containing compounds the isomeric seven-membered ring structures are considerably favoured over the cyclopropanes. Due to a low calculated activation energy a rapid formation of the 2,5-dihydrothiepin is expected. Substitution of the hydrogen at the substituted ring carbon atoms in vinylcyclopropanecarbaldehyde by OH and CH=O also lowers the barrier and increases, in general, the exothermicity of the reaction. As shown by the reaction energies of isodesmic reactions both reactants and products are stabilized by substitution. However, the seven-memberd ring compounds are more strongly stabilized than the cyclopropanes. The OH group exerts a different effect depending on whether the linkage is geminal or vicinal to the C=X group. The difference is caused by hydrogen bond formation in geminal arrangements. The substituent effects in the cyclopropane series parallel those for the prototypical Cope-type and Claisen-type series. The particular feature of the cyclopropane series is the lower stability of the cyclopropanes relative to the corresponding open chain congeners. This is obviously due to the ring strain which over-compensates for attractive interactions between cyclopropane and the substituents. In consequence, the formation of seven-membered ring compounds proceeds more easily than the formation of the corresponding compounds in related Cope-type rearrangements.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    N-Heterocyclic CarbenesEssays on Organometallic Chemistry, Part 9. Part 8: W. A. Herrmann, B. Cornils, Angew. Chem. 1997, 109, 1074; Angew. Chem. Int. Ed. Engl. 1997, 36, 1047.Dedicated to Professor Heribert Offermanns on the occasion of his 60th birthday (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 36 (1997), S. 2162-2187 
    Details
    ISSN: 0570-0833
    Keywords: carbenes ; heterocycles ; homogeneous catalysis ; metal complexes ; Carbenes ; Heterocycles ; Homogeneous catalysis ; Metal complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemistry of N-heterocyclic carbenes has long been limited to metal coordination compounds derived from azolium precursors, a development that was started by Öfele and Wanzlick in 1968. Since free carbenes are now available through the work of Arduengo (1991), a renaissance in this little-recognized area of chemistry has occurred. A leading motive is the advantages of N-heterocyclic carbenes as ligands in organometallic catalysts, where they extend the scope of application reached by phosphanes (functionalized, chiral, water-soluble, and immobilized derivatives). The present review summarizes the state of the art with regard to synthesis, structure, bonding theory, metal coordination chemistry, and catalysis. Chelating, functionalized, chiral, and immobilized ligands can be generated and attached to metal centers in straightforward procedures under mild conditions. A wealth of new chemistry is thus opened. It is also shown how carbenes derived from imidazoles and triazoles behave as ligands in catalysis. It is reasonable to assume that N-heterocyclic carbenes surpass the ubiquitous phosphanes as ligands in a number of organometallic catalytic reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.199721621
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...