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  • 2-Silaazetidines  (1)
  • Diels-Alder reactions  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 581-589 
    ISSN: 0009-2940
    Keywords: Silene, dichloroneopentyl- ; Imines ; Cycloaddition reactions ; 2-Silaazetidines ; Thermolysis reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silaheterocycles, XXIII[1]. - Synthesis and Thermolysis Reactions of Si-Functionalized 2-SilaazetidinesDichloroneopentylsilene (1) is formed in situ by the reaction of trichlorovinylsilane with LitBu. The [2 + 2] cycloaddition to imines yields Si, Si1-dichloro-functionalized 2-silaazetidines in a preparative scale. With aldimines as trapping agents for 1, the resulting SiN four-membered ring compounds are isolated as syn/anti1-isomers (e.g. syn/anti-15 and -16; syn/anti ≍ 2:1). Silene 1 is not liberated from the silaazetidines on heating, but the Si, Si1-dichloro-substituted silanimine Cl2Si=NtBu (24) is formed. This can be trapped by Me3SiOMe or Ph2C=NtBu to give the addition products 25 and 26, respectively. The pathways are discussed which lead to stereoisomeric SiN ring compounds by a multiple-step mechanism including zwitterionic intermediates (1,4-dipoles). In addition there is strong evidence for the formation of 1, depending on the trapping reagent used. This fact may be explained by donor→silene interactions. The thermolysis products of silaazetidines support the formulation of a stepwise decomposition to an alkene and Cl2Si=NR derivatives.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 575-580 
    ISSN: 0009-2940
    Keywords: Silaethene derivatives ; Furans ; Cycloaddition reactions ; Rearrangements ; Sila heterocycles ; Diels-Alder reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sila Heterocycles, XXII[1]. - Diels-Alder Reactions of Dichloro(neopentyl)silaethene with Furans and Rearrangement of the Resulting Bicycles into Monocyclic Si - O Seven-Membered Ring compoundsThe reaction of trichloro(vinyl)silane (1) and LitBu (2) initially leads to the α1-lithio adduct Cl3SiCH(Li)CH2tBu (3) which can be trapped by trimethylsilyl triflate yielding the C1-silylated product [Cl3SiCH(SiMe3)CH2tBu (5)]. 1,2-LiCl elimination from 3 gives dichloro(neopentyl)silaethene [Cl2Si=CHCH2tBu (4)] as intermediate. This can be established by insertion of 4 into the Si - O bond of Me3SiOMe to Cl2Si(OMe)CH(SiMe3)CH2tBu (6). 4 is a dienophile of high activity and reacts with the furans 7 - 9 to give the [4 + 2] cycloaddition compounds 10 - 12. These Diels-Alder products are thermally unstable and decompose slowly at room temperature into the starting furans and tetrachlorodisilacyclobutane (15). Under thermolysis conditions (3 d/17°C) they rearrange into the monocyclic Si - O seven-membered ring compounds 16 - 18. A mechanism for the 7-Oxa-2-silabicyclo[2.2.1]hex-5-en → 1-Oxa-2-silacyclohepta-4,6-diene rearrangement is proposed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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