Indium(I) iodide-promoted cleavage of dialkyl disulfides and subsequent Michael addition of thiolate anions to conjugated carbonyl compounds

Indium(I) iodide promotes cleavage of dialkyl disulfides generating thiolate anions which then undergo facile addition to alpha,beta-unsaturated ketones, aldehydes, carboxylic esters and nitriles under neutral conditions producing corresponding beta-keto or beta-cyano sulfides in high yields. There are several examples of dialkyl/diaryl disulfides and activated alkenes participating in this reaction.