Direct Introduction of Sulfonamide Groups into Quinoxalin-2(1H)-ones by Cu-Catalyzed C3-H Functionalization.

Direct sulfonamidation of quinoxalin-2(1H)-one derivatives has been developed using a readily available Cu salt as the catalyst and inexpensive ammonium persulfate as the oxidant in moderate conditions. Owing to the feature of handy operation and good functional group tolerance, this method provides a convenient and efficient access to curative 3-sulfonamidated quinoxalin-2(1H)-one scaffolds.