1-Chloroalkyl p-Tolyl Sulfoxides as Acetylide Anion Equivalent: A Novel Synthesis Including Asymmetric Synthesis of Propargylic Alcohols from Carbonyl Compounds

Addition of the carbanion of 1-chloroalkyl p-tolyl sulfoxide to carbonyl compounds gave the adducts, which were heated in refluxing toluene or xylene to give vinyl chlorides in high overall yield. Dehydrochlorination of the vinyl chlorides with excess n-BuLi afforded propargylic alcohols in high yields. Asymmetric synthesis of both enantiomers of the propargylic alcohols was realized using optically active 1-chloroalkyl p-tolyl sulfoxide and aldehyde.