Trimethylsulfoxonium iodide is a sulfoxonium salt. It is used to generate dimethyloxosulfonium methylide by reaction with sodium hydride. The latter compound is used as a methylene-transfer reagent, and is used to prepare epoxides. This compound is commercially available. It may be prepared by the reaction of dimethyl sulfoxide and iodomethane: (CH3)2SO + CH3I → (CH3)3SO+I− References Organosulfur compounds Iodides Reagents for organic chemistry