Hydrogen-bonding catalysis of sulfonium salts

Although quaternary ammonium and phosphonium salts are known as important catalysts in phase-transfer catalysis, the catalytic ability of tertiary sulfonium salts has not yet been well demonstrated. Herein, we demonstrate the catalytic ability of trialkylsulfonium salts as hydrogenbonding catalysts on the basis of the characteristic properties of the acidic a hydrogen atoms on alkylsulfonium salts.