Oxidation of sulfides to sulfoxides with 1, 3-dibromo-5, 5-dimethylhydantoin in the presence of hydrated silica gel

Chemo selective oxidation of sulfides to sulfoxides with 1,3-dibromo-5,5-dimethylhydantoin in dichloro-methane in the presence of hydrated silica gel has been developed. Decomposition of the bromosulfonium salt intermediate produced in this reaction to the product is facilitated by the water present in hydrated silica gel. Hydrated silica gel, as the source of necessary water, expanded the scope of oxidation reactions of sulfides to sulfoxides with N-halogenated reagents by allowing a wider range of protic and aprotic solvents. Also, the heterogeneous nature of this oxidation procedure made the product isolation easy. The procedure presented here is very simple, fast, and oxidizes a wide variety of sulfides that were difficult to achieve by many N-halo reagents in the past.