Additive pummerer reactions of vinylic sulphoxides. Synthesis of γ-hydroxy-α,β-unsaturated esters and α-hydroxyketones

Abstract Reaction of α,β-unsaturated sulphoxides with trifluoroacetic anhydride gives α,β-bis(trifluoroacetoxy)thioethers in near-quantitative yields. Subsequent basic methanolysis gives monomeric and dimeric α-hydroxyaldehydes or αhydroxyketones, depending on the nature of the β-R group. The former undergo Wittig olefination with methoxycarbonylmethylenetriphenylphosphorane to give γ-hydroxy-α,β-unsaturated esters in high overall yields.