Reactions of conjugated arylazocycloalkenes with grignard reagents—4 3: Parallel and antiparallel attacks of grignard hydrocarbon moiety on some arylazocycloalkenes

Abstract

Conjugated phenylazocycloalkenes sterically hindered towards the antiparallel attach react with PhMgBr via parallel attack, to give syn-phenylhydrazones. When such a sterical hindrance is absent in the azoalkenes, the reaction occurs via antiparallel attack even when the arylmagnesium bromide bears a particularly hindering aryl group. The conformation of the syn-phenylhydrazones obtained by the above reactions and those of the corresponding ketones are discussed with the aid of the benzylic proton NMR analysis.