The Condensation Reactions of Bivalent Sulfur Compounds-Copper(II) Complexes with Nucleophiles

It was found that the bivalent sulfur compounds such as benzaldehyde diethylmercaptal, benzophenone diethylmercaptole, ethyl orthotrithioformate and benzyl methylsulfide, react with copper(II) salts of 1,3-dicarbonyl compounds, active methylene compounds or anisole, in the presence of cupric chloride, to give condensation or substitution products in good yields accompanied with carbon-sulfur bond cleavage. On the other hand, in the absence of cupric chloride, the bivalent sulfur compounds underwent no reaction and the starting materials were recovered. These results can be explained by assuming initial formation of active complexes from the bivalent sulfur compounds and copper(II).