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  • 1
    Electronic Resource
    Electronic Resource
    Organic Syntheses via Transition Metal Complexes. 72. (2-(Acyloxy)ethenyl)carbene Complexes by Michael Addition of Carboxylic Acids to Alkynylcarbene Complexes (M = Cr, W). (2-(Acyloxy)ethenyl)ketene Imines by Ligand Disengagement with Isocyanide (1994)
    s.l. : American Chemical Society
    Organometallics 13 (1994), S. 3502-3509 
    Details
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/om00021a025
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  • 2
    Electronic Resource
    Electronic Resource
    Organic Syntheses via Transition Metal Complexes. 73. Acylation of Metalcarbene Complexes (M = Cr, W) with Formation of (2-(Acyloxy)ethenyl)-, (4-(Acyloxy)butadienyl)-, and Alkynylcarbene Complexes (1994)
    s.l. : American Chemical Society
    Organometallics 13 (1994), S. 3510-3516 
    Details
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/om00021a026
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  • 3
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetall-Komplexen, 50 2H-Pyrrol-Komplexe durch stufenweise Insertion von Alkinen und Isocyaniden in M=C-Bindungen von Chrom- und Wolfram-Carbenkomplexen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 213-218 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes of chromium and tungsten ; 1-Metalla-1,3-dienes ; Insertion of alkynes and isocyanides into M = C bonds ; 2H-Pyrrole complexes of chromium and tungsten ; [1+2+2] Cycloaddition reactions of carbene complexes, alkynes and isocyanides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 501). - 2H-Pyrrole Complexes by a Stepwise Insertion of Alkynes and Isocyanides into M=C Bonds of Carbene Chromium or Tungsten Complexes2H-Pyrrole complexes 6a, b are obtained in two step by [1+2+2] cycloaddition reactions of the carbene complex (CO)5W=C(OEt)C6H5 (1d), the alkyne EtO-C≡CH (2) and isocyanides R1-NC 4a, b [R1 = CH3, c-C6H11). Ln=C(OEt)R 1 [LnM = Cr(CO)5, W(CO)5; R = C6H5, CH3] reacts with 2 to give 1-metalla-1,3-dienes 3a-d. (E)/(Z)-3d and 4 yield 6a, b via 1-aza-1,2,4-pentatriene complexes 5, which are open-chain precursors of 6. 2H-Pyrrole complexes 11 and 14 are synthesized in overall [2+1+2] cycloadditions withe reversed connectivity, or formation of 1-chroma-1,3-dienes 10 and 13 by condensation of the methylcarbene complex 1a with acid amides, and cyclisation again with isocyanides 4.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240132
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  • 4
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 53 4-Methylencyclopentene und 5-Methylencyclohexenone aus „Fischer-Carben“- Chromkomplexen, Allenen und Alkine (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2335-2342 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopentenes, 4-methylene-, synthesis of ; Cyclohexenones, 5-methylene-, synthesis of ; Tri(methylene)-methane chromium complexes ; [3 + 2]Cycloadditions with tri(methylene)methane complexes ; Carbene chromium complexes for organic synthesis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 53.  -  4-Methylenecyclopentenes and 5-Methylenecyclohexenones from “Fischer Carbene” Chromium Complexes, Allenes, and AlkynesA method is described for the two-step construction of 4-methylenecyclopentenes 6 and 5-methylenecyclohexenones 7 from Fischer carbene chromium complexes, allenes, and alkynes. In the first step a tri(methylene)methane complex 3 is generated by the addition of the carbene chromium complex (CO)5Cr = C(0Et)Ph (1) to the allene 2. The second step involves an addition of 3 to alkynes HC≡CR [5: R = Ph (a), SiMe3 (b)] at 75°C to give 6 and/or 7 in high chemical yields. The product ratios strongly depend on the substituents R.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241029
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  • 5
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 48. Methyl(thiocarben)- und Alkenyl(thiocarben)-Chrom-Komplexe: Darstellung und Reaktionen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2053-2058 
    Details
    ISSN: 0009-2940
    Keywords: Methyl thiocarbene chromium complexes, aldol condensation of ; Alkenyl thiocarbene chromium complexes, preparation of ; 1-Chroma-1,3-dienes, degradation on silica gel ; 1-Aza-1,2,4-pentatriene ; Thioenol ethers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 48.  -  Methyl Thiocarbene and Alkenyl Thiocarbene Chromium Complexes: Synthesis and ReactionsThiocarbene chromium complexes (CO)5Cr=C(SR1)R (4: R = Me, Ph; R1 = c-C6H11, CH2CH=CH2, C2H5, C6H5) were readily obtained in up to 97% isolated yields from the corresponding ethoxycarbene chromium complexes 5a, b and thiols 6 in methanol in the presence of Na2CO3 as a catalyst. Reaction conditions, which lead to unfavorable side products, like thioacetals 8 and or thioenol ether 10, are discussed. Methyl thiocarbene complexes 4b-d undergo a facile aldol condensation with the aromatic aldehydes 14 or 16 to give alkenyl thiocarbene complexes 15b-d and 17, respectively. The Cr=C bonds of 15 prove to be reactive towards the insertion of isocyanides or oxygen. Thus, on addition of two equivalents of the isocyanide 18 to 15d, 1-aza-1,2,4-pentatriene 20 is obtained. The oxidative decomposition of 15d on silica gel leads to the formation of thioester 25 and thioindene 26. Characteristic differences in the reactivity of thiocarbene complexes and ethoxycarbene complexes are discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901231017
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  • 6
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetall-Komplexen, 57. 4,5-Homotropilidene durch intramolekulare Cyclopropanierung von (Cycloheptatrienylmethyl)carbenchrom- oder -wolfram-Komplexen (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 259-264 
    Details
    ISSN: 0009-2940
    Keywords: (Cycloheptatrienylmethyl)carbene complexes ; 4,5-Homotropilidenes ; Cyclopropanation, intramolecular ; Carbene complexes ; Cope rearrangement, metal influence on ; Rhodium complexes ; Iron complexes ; Chromium complexes ; Tungsten complexes ; Calculations, AM1, MNDO, PM3 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 57[1].  -  4,5-Homotropilidenes by Intramolecular Cyclopropanation of (Cycloheptatrienylmethyl)carbenechromium or -tungsten Complexes(Cycloheptatrienylmethyl)carbene complexes LnM=C(OEt)-CH2C7H7 [3: LnM=Cr(CO)5 (a), W(CO)5 (b)] are obtained in yields of 80% by the reaction of the corresponding methylcarbene complexes LnM=C(OEt)CH3 1 with tropylium tetrafluoroborate (2) in THF/Et3N. Alkylation of 3 with 2 gives [bis(cycloheptatrienyl)methyl]carbene complexes LnM=C(OEt)CH(C7H7)2 [4: LnM=Cr(CO)5 (a), W(CO)5 (b)]. Thermolysis of 3 leads to the formation of an equilibrium mixture of the 4,5-homotropilidenes 5 and 6. According to NMR measurements and AM1 calculations the formation of 6 is strongly favored. An equilibrium between 4,5-homotropilidene complexes is significantly different from that of the metal-free ligands. By the reaction of 5/6 with bis(ethylene)rhodium 1,3-pentanedionate (8) the complexes 9 and 10 of both 4,5-homotropilidenes 5 and 6 are obtained in a 1:3 ratio. The (1,5-diene)rhodium(I) complexes 9 and 10 are nonfluxional and configurationally moderately stable at 20°C. The reaction of 5/6 with Fe2(CO)9 gives the π-allyl,σ complexes 11 and 12 in a 10:3 ratio, both of which may be derived from the minor 4,5-homotropilidene isomer 5. In 11 a vinylcyclopropane unit of 5 serves as a four-electron donor for a Fe(CO)3 group. In 12 the 4,5-homotropilidene unit is coordinated as a six-electron donor to a Fe2(CO)6 unit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250141
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  • 7
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 42 Allene als Liganden in zweikernigen Eisencarbonyl-Komplexen; Carbonylierungen von Allenen sowie deren Kupplung mit Alkinen und Allenen; dynamische “Keten-Scheibenwischer”-Komplexe (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 351-356 
    Details
    ISSN: 0009-2940
    Keywords: Allene diiron complexes / Ketene diiron complexes, fluxional / Allenes, carbonylation of / Allene coupling with alkynes, metal-induced / Allenes, dimerization of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 42. - Allenes in Dinuclear Iron Carbonyl Complexes; their Carbonylation and Coupling with Alkynes and Allenes; Fluxional “Ketene Windshield-Wiper” ComplexesOn photochemically induced metallation with pentacarbonyl iron allenes H2C = C = CHR 1 (R = H, C6H5) give dinuclear acyl iron complexes 2, in which the central carbon of the C = C = C unit is attached to a carbonyl group. 2 on warming yield π-ally1,σ complexes 3 by loss of carbon monoxide. The reaction 2 ⇌ 3 + CO is reversibel. 3 add alkynes R1 - C = C - R24 (R1 = C6H5r, CH2OCH3; R2 = Hr C6H5) with insertion of the C = C triple bond into the M - C σ-bond to give dinuclear ketene complexes 5. The latter are fluxional, as was shown by NMR measurements. The ketene unit is moving back and forth like a windshield wiper. Thermolysis of 5 under normal pressure affords ferracyclopentadiene iron complexes 6 (by 1,3-hydrogen shifts) and 4-methylene-2-cyclopenten-1-one 7 (by cyclocarbonylation). Thermolysis of 5 under CO pressure gives 7 as the sole products. Complexes 3 also add allenes 1 with insertion into the M-C σ-bond and formation of a C-C bond between the central carbon atoms of both allene units to give dinuclear bis(allyl) complexes 8 and 8′.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230221
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  • 8
    Electronic Resource
    Electronic Resource
    Pyrrole durch metallinduzierte [3 + 2]-Cycloaddition von 2-Azaallenyl-( = Iminocarben-)Komplexen unter Übertragung einer CNC-Einheit auf ein Alkin; ein Chromacyclopropen durch Cyclocarbonylierung eines 1-Aminoalkins (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 599-604 
    Details
    ISSN: 0009-2940
    Keywords: 2-Azaalienyl chromium complexes / Pyrroles by [3+2] cycloadditions of CNC units / Umpolung of nitrile ylides, metal-induced / 1-Aminoalkynes, cyclocarbonylation / Chromacyclopropene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 40. - Pyrroles by Metal-Induced [3 + 21 Cycloadditions of 2-Aza-allenyl (= Iminocarbene) Complexes with Transfer of a CNC Unit to Alkynes; a Chromacyclopropene Complex by Cyclocarbonylation of a 1-AminoalkyneThe 2-azaallenyl (= iminocarbene) complex LnM⊖ - CR = N⊕ = CXR1 1a [LnM = Cr(C0)5 = OEt, R1 = Ph] adds to the polarized alkyne Et2N - C≡C-CH3 (3) to give a 2H-pyrrole complex 4 in a metal-induced [3+2] cycloaddition. On warming 4 yields the 2H-Pyrrole 5. Since the regiochemistry of the addition of the CNC unit is opposite to that of a nitile ylide, we consider 1 as an Umpolung equivalent (RC⊕ = N - C⊖XR1) of a nitrile ylide (RC⊕ = N - C⊖XR1). The 2H-pyrrole 5 is kinetically unstable and isomerizes smoothly to the 1H-pyrrole 7 under the influence of base by an intramolecular redox reaction. A novel (cyclopentadienyl)chromacyclopropene complex 8 resulting from a cyclocarbonylation of the iminoalkyne 3 is obtained as a minor side product. The structural data of 4 and 8 have been determined by X-ray analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230328
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  • 9
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit übergangsmetall-Komplexen, 51. 1-Metalla-1,3,5-triene und 1-Metalla-1,3-dien-5-ine von Chrom und Wolfram durch Insertion von Alkinen in M=C- bzw. C=C-Bindungen von 1-Metalla-1,3-dienen bzw. 1-Metalla-1-en-2-inen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1229-1236 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes of chromium and tungsten ; 1-Metalla-1,3,5-trienes ; 1-Metalla-1,3-dien-5-ynes ; Insertion of alkynes into M=C and C=C bonds ; [2 + 2] Cycloaddition reactions of carbene complexes and alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 51. - 1-Metalla-1,3,5-trienes and 1-Metalla-1,3-dien-5-ynes of Chromium and Tungsten by Insertion of Alkynes into M=C and C=C Bonds of 1-Metalla-1,3-dienes and 1-Metalla-1-en-3-ynes, respectively1-Metalla-1,3,5-trienes LnM=C(NEt2)-C(Me)—C(OEt)-CH=CHPh (3,4) and LnM=C(OEt)- CH=C(NEt2) - C(Me)=CHPh [5, LnM=Cr(CO)5 (a), W(CO)5 (b)] are obtained for the first time from the corresponding 1-metalla-1,3-dienes LnM=C(OEt) - CH=CHPh (1a, b) under very mild conditions by the insertion of the electron-rich alkyne Et2N-C ≡ C - Me (2) into the M=C and the C=C bonds, respectively, of 1. The chelate complex (6b) and the cyclobutenyl carbene complex 7b are isolated as minor side products. 1-Metalla-1,3-dien-5-ynes LnM=C(NEt2) - C(Me)=C(OEt) - C ≡ CPh [9, 10, LnM=Cr(CO)5 (a), W(CO)5 (b)] are formed with high regio- and stereoselectivity on insertion of 2 into the M=C bonds of 1-metalla-1-en-3-ynes 8. X-ray data are given for the tungsten complex 3b.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240541
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  • 10
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetall-Komplexen, 55 5-Aza-1-metalla-1,3,5-triene von Chrom und Wolfram sowie deren Cyclisierung zu 2H-Pyrrol-Komplexen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2587-2593 
    Details
    ISSN: 0009-2940
    Keywords: Aminocarbene complexes, of chromium and tungsten ; 3-Aza-1-metalla-1,3-dienes, of chromium and tungsten ; 5-Aza-1-metalla-1,3,5-trienes, cyclization to 2H-pyrroles ; 2H-Pyrrole complexes, of chromium and tungsten ; Pyrroles, syntheses by metal-induced [3 + 2] cycloaddition reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 551). - 5-Aza-1-metalla-1,3,5-trienes of Chromium and Tungsten, and Their Cyclization to 2H-Pyrrole Complexes5-Aza-1-metalla-1,3,5-trienes 5 and 6 [LnM = C - C = C - N = C, a: LnM = Cr(CO)5, b: W(CO)5] are obtained in two steps from aminocarbene complexes 1 [LnM = C(NH2)Ph, a: LnM = Cr(CO)5, b: W(CO)5]. The first step involves the condensation of 1 with benzaldehyde (2) in the prescence of TiCl4/Et3N to give 3-aza-1-metalla-1,3-dienes 3 (LnM = C - N = C). 3 adds to the 1-aminoalkyne 4 to give 5 and 6 by a chain extension of two carbon atoms. The trans isomers 5 are formed as the major products and are stable both in the solid state and in solution. The cis isomers 6 undergo a novel-type cyclization to give 2H-pyrrole complexes 8. Triene 5b was characterized by an X-ray analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241131
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