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  • 1
    Electronic Resource
    Electronic Resource
    New Cyclopropyl Building Blocks for Organic Synthesis, 28. Pd(0)-Catalysed Coupling of Cyclopropenylzinc Chlorides and Cyclopropenylstannanes  -  A New Efficient Synthesis of 1-Phenyl-, 1-Ethenyl-, and 1-Ethynyl-1-cyclopropenesDedicated to Professor Christoph Rüchardt on the occasion of his 65th birthday. (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1511-1515 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopropenes, 3,3-dimethyl, 1-substituted ; Cyclopropenylzinc chlorides, coupling reactions of ; Palladium catalysis ; Cyclopropenylstannanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [3,3-Dimethyl-2-(trimethylsilyl)-1-cyclopropen-1-yl]zinc chloride (4) reacts with haloarenes and -alkenes as well as 1-bromo-acetylenes under Pd(0) catalysis to give the corresponding 1-phenyl-, 1-ethenyl-, and 1-ethynyl-1-cyclopropenes 6 in isolated yields ranging from 47 to 99%. The corresponding 1-cyclopropen-1-ylstannane 5 reacts with haloarenes only at higher temperatures, and the yields range from 10 to 98%, depending on the substrate and reaction conditions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270826
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  • 2
    Electronic Resource
    Electronic Resource
    Gas-Phase Kinetics of the Pyrolysis of Some 3,3-Dimethyl-1-(trimethylsilyl)-cyclopropenes  -  Unexpected Product Distribution in the Cyclopropene Rearrangement (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 237-245 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopropenes, 3,3-dimethyl-1-trimethylsilyl-substituted ; Cyclopropene, isomerisation ; Gas-phase kinetics ; Ring opening ; Diradical intermediates ; Cyclopropylidene intermediates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas-phase pyrolyses of 1,3,3-trimethyl-2-(trimethylsilyl)-cyclopropene (9), 3,3-dimethyl-1,2-bis(trimethylsilyl)cyclopropeneTextReactantlog (A/s-1)Ea/kj mol-1(kcal mol-1)913.41 ± 0.22192.1 ± 2.5(45.9 ± 0.6)1013.54 ± 0.19184.4 ± 2.1(44.1 ± 0.5)1112.17 ± 0.38124.6 ± 3.1(29.8 ± 0.7)(10), and 3,3-dimethyl-1-(methylthio)-2-(trimethylsilyl)cyclopropene (11) have been studied, and the pressure-independent Arrhenius parameters listed in the table were obtained. All three rearrangements are homogeneous, first-order and unimolecular reactions. Rather surprisingly all reactions give the corresponding isomeric allenes as the main products. Amongst possible mechanisms discussed, 10 is proposed to react via a cyclopropylidene intermediate, whilst the results for 9 and 11 throw light on the relative importance of the diradical- and vinylcarbene-type intermediates produced by cyclopropene ring opening.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270134
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  • 3
    Electronic Resource
    Electronic Resource
    Gas-Phase Kinetics of Pyrolysis of 3,3-Dimethylcyclopropene and Its 1-Trimethylsilyl Derivative The Effect of Silyl Substitution on Cyclopropene Isomerisation (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 637-642 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopropene, 3,3-dimethyl-1-trimethylsilyl- ; Cyclopropene, isomerisation ; Gas-phase kinetics ; Ring-opening of 3,3-dimethylcyclopropene ; Vinylcarbene intermediates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gas-Phasen-Kinetik der Pyrolyse von 3,3-Dimethylcyclopropen und seinem 1-Trimethylsilyl-Derivat. - Der Effekt der Silyl-Substitution auf die Cyclopropen-IsomerisierungDie Gasphasen-Pyrolyse von 3,3-Dimethylcyclopropen (1) im Temperaturbereich 185-225°C ergibt 3-Methyl-1-butin (2) (91%) und Isopren (3) (9%). Die Gasphasen-Pyrolyse von 3,3-Dimethyl-1-trimethylsilylcyclopropen (4) führt zu 3-Methyl-1-trimethylsilyl-1-butin (5) (99%) und trans-3-Methyl-1-trimethylsilyl-1,3-butadien (6) (1%). Beide Umlagerungen sind homogene, unimolekulare Reaktionen erster Ordnung mit den folgenden druck-unabhängigen Arrhenius-Parametern.Überraschenderweise desaktiviert die Trimethylsilyl-Gruppe das Cyclopropen in bezug auf seine Isomerisierung. Mögliche Mechanismen werden diskutiert.
    Notes: The gas-phase pyrolysis of 3,3-dimethylcyclopropene (1) in the temperature range of 185-225°C gives 3-methyl-1-butyne (2) (91%) and isoprene (3) (9%). The gas-phase pyrolysis of 3,3-dimethyl-1-trimethylsilylcyclopropene (4) in the temperature range of 195-235°C gives 3-methyl-1-trimethylsilyl-1-butyne (5) (99%) and trans-3-methyl-1-trimethylsilyl-1,3-butadiene (6) (1%). Both rearrangements are homogeneous, first-order, unimolecular reactions with the following pressure-independent Arrhenius parameters.Rather surprisingly, the trimethylsilyl group deactivates cyclopropene with respect to its isomerisation. Possible mechanisms are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220409
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  • 4
    Electronic Resource
    Electronic Resource
    On the Effect of 1,2-Disubstitution with Me3M (M = Si, Ge, Sn) Groups upon the Electronic Structure of 3,3-Dimethylcyclopropene (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 169-174 
    Details
    ISSN: 0009-2940
    Keywords: Electronic structure ; Cyclopropenes, 3,3-dimethyl- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: He(I) PE spectra of a series of 3,3-dimethylcyclopropenes bearing Me3Si (1), Me3Ge (2), and Me3Sn (3) groups in the 1- and 2-positions, as well as the He(II) PE spectra of 1 and 3 were recorded. The changes in the lowest energy ionizations along the series are interpreted in terms of inductive and hy-perconjugative interactions. The new compounds were prepared by reaction of lithiated 3,3-dimethylcyclopropene with the corresponding trimethylmetal chlorides.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290210
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