A study of cyclic dialkylamides and an alkyl halide as mechanistic probes in potential electron transfer reactions

Abstract

The elucidation of electron transfer as a pathway in organic reactions is usually difficult. The products from such a mechanistic pathway may be the same as those resulting from a beta hydride transfer or from simple nucleophilic attack upon a substrate. A method used to study these types of reaction mechanisms is that of utilizing molecular probes. Of specific interest are molecular probes which undergo a characteristic skeletal rearrangement if a radical intermediate is formed in the course of the reaction under study. Product analysis of reaction systems incorporating such a probe may indicate the presence or absence of radical intermediates in the reaction mechanism. We extended this methodology to the area of potential electron transfer reactions involving lithium dialkylamides and alkyl halides. We developed and studied a series of N-alkylcyclobutylamine systems which undergo ring fission to give acyclic imines if aminyl radicals are generated in the course of reactions of the lithium amide analogues. In the course of these studies ambiguities came to light in reported reactions which utilized hexenyl halide probes. A new alkyl halide probe was designed and synthesized in order to alleviate some of these ambiguities. The characterization and initial studies utilizing this probe are presented.