Abstract A general synthetic method for oxosulfonium salts by oxidation of sulfonium salts with sodium perbenzoate (or sodium m-chloroperbenzoate was developed. In case of the oxidation of aryldimethylsulfonium salts, the corresponding oxosulfonium salts (1e-h) were obtained in 64–91% yields. Diphenymethylsulfonium and triphenylsulfonium salts were also oxidized with sodium perbenzoate to afford the corresponding oxosulfonium salts (1i and ...