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Silaheterocyclen, XXIII. Synthese und Thermolyseverhalten von Si‐funktionellen 2‐Silaazetidinen
Author(s) -
Auner Norbert,
Weingartner Armin W.,
Bertrand Guy
Publication year - 1993
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19931260306
Subject(s) - chemistry , thermal decomposition , cycloaddition , reagent , aldimine , stereochemistry , medicinal chemistry , ring (chemistry) , catalysis , organic chemistry
Silaheterocycles, XXIII [1] . – Synthesis and Thermolysis Reactions of Si‐Functionalized 2‐Silaazetidines Dichloroneopentylsilene ( 1 ) is formed in situ by the reaction of trichlorovinylsilane with Li t Bu. The [2 + 2] cycloaddition to imines yields Si, Si 1‐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/anti 1‐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, Si 1‐dichloro‐substituted silanimine Cl 2 SiN t Bu ( 24 ) is formed. This can be trapped by Me 3 SiOMe or Ph 2 CN t Bu 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 Cl 2 SiNR derivatives.