Palladium-Catalyzed Aminosulfonylation of ortho -Iodoanilines with the Insertion of Sulfur Dioxide for the Synthesis of 3,4-Dihydro-benzothiadiazine 1,1-Dioxides.

A simple and efficient Pd-catalyzed oxidative cyclization system is developed for the chemo- and regioselective synthesis of 3,4-dihydro-benzothiadiazine 1,1-dioxides, which are formed through aminosulfonylation of ortho -iodoanilines with SO 2 . DABSO is utilized as the source of SO 2 , and the organic compound O 2 acts as an oxidant. This direct C-S, S-N, and C-N functionalization is highly efficient, and broad functional group tolerance is observed, resulting in moderate to excellent yields of 3,4-dihydro-benzothiadiazine 1,1-dioxides. Furthermore, this method is amenable to gram-scale synthesis.