An efficient and direct route to the synthesis of diaryl sulfoxides catalyzed by heteropoly acid

Heteropoly acid tungstophosphoric acid (H₃PW₁₂O₄₀) was found to be an excellent catalyst for the synthesis of symmetrical diaryl sulfoxides. The reaction was carried out in various organic solvents or ionic liquids and under solventfree condition. The reaction exhibited better results in terms of the yield and rate under solventfree condition. The catalyst was efficiently recovered from the reaction mixture and reused. The highlighting features of the present protocol are short reaction times, high yields of the products, ambient conditions, and simple workup.