114336-66-2Relevant articles and documents
DIACYLMETHYLENCYCLOPROPANE ALS ZWISCHENSTUFEN EINER CYCLOPROPANSUBSTITUTION AN AMINOCYCLOPROPANEN
Vilsmaier, E.
, p. 521 - 554 (2007/10/02)
The rapid formation and the stability of cyclopropylidene iminium intermediates 2 allow an easy nucleophilic substitution in aminocyclopropane derivatives 1.It is shown that diacceptor-substituted methylenecyclopropanes 4a, being isoelectronic with 2, may occur as intermediates in nucleophilic cyclopropane substitution, too.Aminocyclopropyl-substituted CH-acidic compounds 1a proved to be suitable starting materials for this new type of substitution.The synthesis of compounds 1a is described.The amino moiety in 1a can be replaced by several nucleophiles such as carbanions, hydride, cyanide oder alkoxide.The poor stability of the diacceptor-substituted methylenecyclopropane intermediate 4a turned out to impose a limitation on the new type of nucleophilic cyclopropane substitution.Decomposition of 4a without added nucleophile is investigated in the thermolysis of the aminocyclopropane derivatives 1a.Thereby, either a Favorski-type ring opening is caused or methylene dihydrofuranes are formed.The latter result from a diacylmethylene cyclopropane intermediate 4a.Methods for the structural assignment of the starting materials 1a and of the products 5a are discussed giving an information about the steric course of the nucleophilic substitution.
