Imidazolone-activated donor-acceptor cyclopropanes with a peripheral stereocenter. A study on stereoselectivity of cycloaddition with aldehydes

Nucleophilic cyclopropanation of arylideneimidazolones possessing a peripheral chiral center and the subsequent fractional crystallization of diastereomers allows access to the compounds with an enantiomerically uniform configuration of the spirocyclic donoracceptor cyclopropane fragment. They were used to study the mechanism of the cycloaddition reaction with aldehydes; it was demonstrated that stereochemical information from the cyclopropane fragment is lost during the reaction.