Trimethylsulfoxonium iodide

pale yellow crystal, soluble in water and dimethyl sulfoxide, and slightly soluble in methanol.

For the synthesis of methylene transfer reagents for epoxy compound preparation. Strong base treatment can generate ylide, which can undergo addition reaction with the carbonyl of ketone and aldehyde to generate epoxide; it can also preferentially undergo addition reaction with the double bond of α,β-unsaturated ester to generate cyclopropyl ester

Also used in the synthesis of fluconazole.