Preparation of alpha-haloacrylate derivatives via dimethyl sulfoxide-mediated selective dehydrohalogenation.

Dimethyl sulfoxide causes alpha,beta-dihalopropanoate derivatives to undergo efficient, selective dehydrohalogenation to form alpha-haloacrylate analogues. A variety of alpha-halo Michael acceptors were prepared in dimethyl sulfoxide under mild, base-free conditions, including the preparation of alpha-bromoacrolein and alpha-chloro- and bromoacrylonitriles. Synthesis of these molecules has been reported in the literature to be difficult. Among all the existing dehydrohalogenation procedures, this protocol is the most facile, practical, and environmentally benign process.