Indium(III) chloride-promoted rearrangement of epoxides: a selective synthesis of substituted benzylic aldehydes and ketones

Abstract

A simple and efficient procedure for the rearrangement of substituted epoxides catalyzed by InCl₃ has been developed. Aryl-substituted epoxides isomerize with complete regioselectivity to form a single carbonyl compound via cleavage of the benzylic C-O bond. The reactions are simple, fast, and high yielding. This procedure is very mild compared to those catalyzed with BF₃ and other Lewis acids and compatible with several acid-sensitive functionalities. This protocol provides a highly selective synthesis of substituted benzylic aldehydes and ketones. However, rearrangement of alkyl-substituted epoxides is not very selective.