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  • 1
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 34 Neuartiger Aufbau von C = C-Bindungen durch Kondensation von Carbenkomplexen mit Säureamiden unter Insertion von C2-Einheiten in M=C-Bindungen (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 365-370 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Synthesis via Transition Metal Complexes, 34. - Novel Formation of C=C Bonds by Condensation of Acid Amides with Carbene Complexes Involving an Insertion of C2 Units into M=C BondsCarben complexes LnM=C(OEt)C6H5 1 [LnM = Cr(CO)5, Mo(CO)5, W(CO)5] and acid amides RCH2CONMe2 2 undergo a novel condensation reaction in presence of POCl3/Et3N to give alkenyl aminocarbene complexes 3. The reaction involves an insertion of a C2 unit of 2 into the M=C bond of 1 to give a C=C bond. It can be achieved with open-chain and cyclic amides like N-methyl-2-pyrrolidone (8). the structures of the complexes have been determined spectroscopically. A mechanism of the reaction is suggested.
    Notes: Carbenkomplexe LnM=C(OEt)C6H5 1 [LnM = Cr(CO)5, Mo(CO)5, W(CO)5] lassen sich mit Säureamiden RCH2CONMe2 2 und POCl3/Et3N zu Alkenyl-Aminocarben-Komplexen 3 kondensieren. Dabei wird eine C2-Einheit von 2 in die M=C-Bindung von 1 eingeschoben und eine C=C-Bindung neu geknüpft. Die Reaktion gelingt mit offenkettigen und cyclischen Amiden wie N-Methyl-2-pyrrolidon (8). Die Strukturen der Komplexe wurden spektroskopisch ermittelt und Vorschläge zur Deutung des Reaktionsablaufs gemacht.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220226
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  • 2
    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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  • 3
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 46. Alkenylcarben-Chrom- und -Wolframkomplexe; Protonierung und Aktivierung durch Elektronen-ziehende Substituenten (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1847-1852 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes of chromium and tungsten ; Alkenylcarbene complexes, protonation of ; β-(Acylamino)alkenyl complexes of chromium ; Activated aminocarbene complexes ; 1-Metalla-1,3-dienes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 46.  -  Alkenylcarbene Chromium and Tungsten Complexes; Proton Addition and Activation by Electron-Withdrawing SubstituentsAlkenylcarbene complexes LnM=C(OEt)-CH=C(R)NMe2[1, LnM = Cr(CO)5, W(CO)5; R = H, CH3, C6H5] add HBF4 in ether to give novel cationic carbene complexes [Ln M=C(OEt)-CH2-C(R)=NMe2]BF4 (3) by protonation at C-2 of the =C-C=C ligand. The addition of HBF4 to 7 leads to the formation of the cyclic carbene complexes 8. Structures of 3 and 8 are assigned spectroscopically. X-ray data are reported for 8a. Protonation of 1 and 7 results in a strong deshielding of the carbene carbon atoms, which parallels an increase of reactivity at the M=C bonds. An activation of the M=C bond has also been achieved by electron-withdrawing substituents like N-acyl groups. We report on the first synthesis of [β-(acylamino)-alkenyl]carbene complexes 13, which are more reactive than β-(aminoalkenyl)carbene complexes 7.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230916
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  • 4
    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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  • 5
    Electronic Resource
    Electronic Resource
    Kondensation von Methylcarben-Komplexen mit Säureamiden: β-Alkoxyalkenyl- und β-Aminoalkenylcarben-Komplexe von Chrom und Wolfram - Konkurrenz von Kondensation und Insertion (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 611-620 
    Details
    ISSN: 0009-2940
    Keywords: Key Words: Aminoalkenylation of methylcarbene complexes / Carbon = carbon bond, formation by insertion into M = C bonds / Alkenylcarbene complexes, by condensation, by condensation, insertion / Carbene complexes of chromium and tungsten ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 441. - Condensation of Methyl Carbene Complexes with Acid Amides: β-Alkoxyalkenyl- and β-Aminoalkenyl Carbene Complexes of Chromium and Tungsten - Competition of Condensation and InsertionThe condensation of the methyl(ethoxycarbene) complexes LnM = C(OEt)CH3 (4) [LnM = Cr(CO)5, W(CO)5] with acid amides RCONR1R2 (5) under the influence of POCl3/Et3N leads stereoselectively to (E)-β-aminoalkenyl(ethoxycarbene) complexes LnM=C(OEt)CH=C(R)NR1R2 [(E)-6] (R = H, aryl, alkyl). A condensation of 4 can also be achieved via amidium salts 11, which are easily available from 5. In this case, (E)-6 and (E)-β-alkoxyalkenyl(ethoxycarbene) complexes LnM=C(OEt)CH = C(R)OEt[(E)-13] were obtained. Via the cyclic amidium salts 15 and 20 four-to seven-membered lactams (E)-17 and (E)-21a-d are accessible. The reaction of 4 with acid amides RCH2CONR1R2 (2) and POCl3/Et3N yields mainly insertion products LnM=C(NR1R2)C(R)=C(OEt)CH3 [(E)/(Z)-22] and only small amounts of condensation products LnM=C(OEt)CH=C(CH2R)NR1R2 [(E)-23].
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230330
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  • 6
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetall-Komplexen, 63. (β1-Aminovinyl)carben-Komplexe und (Alkinyl)aminocarben-Komplexe von Chrom und Wolfram.  -  Stereochemie und Isomerisierung (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 421-427 
    Details
    ISSN: 0009-2940
    Keywords: Alkynylcarbene complexes of chromium and tungsten ; (β1-Aminovinyl)carbene complexes of chromium and tungsten ; 4-Amino-1-metalla-1,3-dienes ; (3-Aminoalkenyl)carbene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 63[1].  -  (β1-Aminovinyl)carbene complexes and (Alkinyl)aminocarbene Complexes of Chromium and Tungsten.  -  Stereochemistry and Isomerization(Alkinyl)alkoxycarbene complexes LnM=C(OEt)-C≡CR 3 [LnM=Cr(CO)5, W(CO)5; R=Ph, nBu, SiMe3] react with primary amines H2NR1 4 (R1=Me, iPr, allyl, CH2Ph, CHMePh) to give (β1-aminovinyl)carbene complexes LnM=C(OEt)-CH=CR-NHR1 (Z)-5 (by a Michael-type 3-addition) together with (alkinyl)aminocarbene complexes anti-6 (by a 1-aminolysis). The product ratio (Z)-5/anti-6 is strongly influenced by the reaction temperature: at 20°C (Z)-5 is obtained as the main product, while at -78°C mainly anti-6 is formed. Both reactions are stereospecifical; they yield 5 in the (Z), and 6 in the anti configuration only. An anti/syn isomerization is achieved by acidic treatment of anti-6i. The (alkinyl)aminocarbene complex 6a adds EtOH/EtO- albeit much slower than the (alkinyl)alkoxycarbene complex 3a. A NH21-Enamino carbene complexes (CO)5Cr=C(OEt)-CH=C(NH2)Ph [(Z)-8a] is obtained on addition of ammonia to 3a at 90°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260220
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  • 7
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 47. 1-Chroma-1,3-diene durch Aminoalkenylierung von Methylcarben-Chromkomplexen mit sekundären Amiden (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2047-2051 
    Details
    ISSN: 0009-2940
    Keywords: (β-NH-Aminoalkenyl)carbene chromium complexes ; 1-Chroma-1,3-dienes ; Methylcarbene complexes, aminoalkenylation of ; Methylcarbene complexes, condensation with secondary amides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 47.  -  1-Chroma-1,3-dienes by Aminoalkenylation of Methylcarbene Chromium Complexes with Secondary Amides4-(NH-Amino)-1-chroma-1,3-dienes [= β-(NH-Amino)alkenylcarbene chromium complexes] (CO)5Cr=C(OEt)—CH=C-(NHMe)R (Z)-6 (R = Me, Et, iPr, tBu, Ph) have been obtained with high stereoselectivity in 53-69% yields by the aminoalkenylation of (CO)5Cr=C(OEt)Me (1a) with secondary amides O=C(NHMe)R (5, R = Me, Et, iPr, tBu, Ph) in the presence of POCl3/Et3N.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901231016
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  • 8
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetall-Komplexen, 61[1] Pyridine und Pyridinium-Salze aus (β-Aminovinyl)carben-Komplexen (M=Cr, W) und Alkinen über 4(1H)-Pyridinyliden-Komplexe (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2765-2772 
    Details
    ISSN: 0009-2940
    Keywords: β-Aminovinylcarbene complexes of chromium and tungsten ; 4(1H)-Pyridinylidene complexes ; Pyridines via alkenyl carbene complexes and alkynes ; Pyridinium salts via vinyl carbene complexes and alkynes ; Enol ethers from β-aminovinylcarbene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 61[1]. - Pyridines and Pyridinium Salts from (β-Aminovinyl)carbene Complexes (M=Cr, W) and Alkynes via 4(1H)-Pyridinylidene ComplexesPyridines and pyridinium salts were obtained in good yields by the condensation of (β-aminovinyl)carbene complexes with alkynes. The reaction of [(Z)-β-(monoalkylamino)vinyl]carbene complexes [= 4-(monoalkylamino)-1-metalla-1,3-dienes)] LnM=C(OEt)CH=CRNHR1 (Z)-6a-f (R, R1=Ph, Me, iPr, nBu, CH2Ph, CH2OMe) with alkynes R2C≡CH 7a-c (R2 = nBu, Ph, CH2OMe) involves the highly regioselective formation of 4(1H)-pyridinylidene complexes . Protonation of 8 with HBF4 leads to pyridinium salts 13 by the regiospecific substitution of the metal moiety LnM by a proton. The reaction may conveniently be performed in a one-pot procedure. {[(Z)-β-(H2-Amino)vinyl]carbene}chromium complexes, e.g. 14, react with alkynes to give pyridines, e.g. 15. The thermal decomposition of 6 yields enol ethers 11. A regiospecific formation of (E)-11 is observed in the thermolysis of 6 in the presence of pyridine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921251223
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