Overcoming the limitations of the Morita-Baylis-Hillman reaction: a rapid and general synthesis of alpha-alkenyl-beta'-hydroxy thioesters.

Acryloyl chlorides, aldehydes, and PhSLi undergo a direct aldol cascade sequence in the presence of MgBr2 x OEt2 via in situ derived thioester enolates, which is followed by oxidative elimination to give alpha-alkenyl-beta'-hydroxy thioesters. Overall, the procedure is rapid, efficient, and generally applicable, even to beta-substituted acryloyl chlorides, thus providing an alternative to the Morita-Baylis-Hillman reaction with substantially greater synthetic scope and utility.