An efficient palladium-catalyzed synthesis of unsymmetrical diaryl sulfones from aryl bromides/triflates and arenesulfinates

The palladium-catalyzed coupling of arenesulfinate salts and aryl bromides or triflates provides a simple and extremely efficient route to unsymmetrical diaryl sulfones. The reaction was found to be strongly influenced by the presence of n-Bu4NCl. The ammonium salt tends to favor the formation of sulfones with neutral, electron-rich and slightly electron-poor aryl bromides or triflates and to hamper the reaction with electron-poor aryl bromides or triflates.