Metal catalysis in oxidation by peroxides. Sulfide oxidation and olefin epoxidation by dilute hydrogen peroxide, catalyzed by molybdenum and tungsten derivatives under phase-transfer conditions

A procedure is described which allows the oxidation of nucleophilic substrates such as organic sulfides or alkenes, under phase-transfer conditions, by employing dilute hydrogen peroxide, Mo(VI) and W(VI) catalysts, and a neutral lipophilic monodentate ligand as extracting agent. The yields and selectivities observed are generally rather high, thus establishing the synthetic relevance of the method. The success of this procedure, and particularly the efficiency of monodentate ligands, is also discussed from a mechanistic point of view.