A new synthesis of 2-sulfanyl allylic alcohols and alpha-sulfanyl ketones from carbonyl compounds and 1-chloroalkyl p-tolyl sulfoxides with carbon-carbon bond-formation

Reaction of lithium alpha-sulfinyl carbanions of 1-chloroalkyl p-tolyl sulfoxides with ketones or aldehydes at low temperature gave adducts in almost quantitative yields. Treatment of the adducts derived from ketones with trifluoroacetic anhydride (TFAA) in the presence of NaI in acetone gave alpha-sulfanyl allylic alcohols in good to quantitative yields. On the other hand, treatment of the adducts derived from aldehydes with TFAA and NaI resulted in the formation of alpha-sulfanyl ketones and/or alpha-sulfanyl allylic alcohols. These reactions offer a good method for the synthesis of the above-mentioned compounds from ketones and aldehydes with carbon-carbon bond-formation in two steps and in good yields.