ROUTES TO BUILDING-BLOCKS FOR HETEROCYCLIC SYNTHESIS BY REDUCTION OF KETENE DITHIOACETALS

Two general methods have been developed permitting the effective reduc tion of ketene dithioacetals to give substituted dithianes. Reduction with magnesium in methanol is less reliable than reduction with zinc i n acetic acid. The greater inconsistency of magnesium in methanol has been investigated by a cyclic voltammetric study of the substrates. Th e utility of the dithianes has been successfully illustrated by cyclis ations to afford, after deprotection, a variety of heterocyclic aldehy des. (C) 1997 Elsevier Science Ltd.