The Chalcogeno-Baylis-Hillman Reaction of an α,β-Unsaturated Thioester: A New Approach to α-Methylene-β-hydroxy Carboxylic Acid Derivatives

Abstract

Treatment of aldehydes and an α,β-unsaturated thioester with a catalytic amount of Me2S in the presence of TiCl4 followed by Ti(O-i-Pr)4 or DBU gave α-methylene-β-hydroxy esters or thioesters, respectively, in moderate to good yields. DABCO and Bu3P were ineffective for the Baylis-Hillman reaction of a thioacrylate.