Photo-induced copper-catalyzed controllable denitrogenation/SO2 insertion of aryltriazenes: divergent synthesis of aryl sulfonamides and diaryl sulfones†

A photo-induced copper-catalyzed nitrogen extraction/SO₂ insertion of aryltriazenes for controllable synthesis of aryl sulfonamides and diaryl sulfones has been established. Under purple LED irradiation, using CuI as the catalyst and 1,1-dichloroethane as the solvent, a series of aryl sulfonamides were obtained, while diaryl sulfones could be selectively achieved using Cu(NO₃)₂ as the catalyst in acetonitrile. The chemoselectivity can be well controlled by the choice of copper catalyst. In this strategy, aryltriazenes were used as a bifunctional precursor reagent for aryl and amino groups, and 1,4-diazoniabicyclo[2.2.2]octane-1,4-disulfinate (DABSO) was used as a solid SO₂ source. The reactions featured mild reaction conditions, simple operation, readily available reagents, and good functional group tolerance.