Bifunctional Ionic Liquid Catalyzed Multicomponent Arylsulfonation of Phenols with Aryl Triazenes and DABSO for the Synthesis of Diaryl Sulfones

Abstract

The bifunctional Lewis acidic ionic liquid (LAIL) catalyzed multicomponent arylsulfonation of phenols with aryl triazenes and DABSO was developed. By using LAILs as redox and Lewis acidic catalysts without any additional promoter or ligand through an N2 extrusion/SO2 insertion sequence, various aryl triazenes were transformed into aryl sulfonyl radicals by coupling with DABSO, and these were then coupled with phenoxy radicals to afford the corresponding diaryl sulfones in good yields. The good functional-group tolerance, gram-scale reaction, and avoidance of the use of SO2 gas further demonstrated the practicality of this arylsulfonation reaction.