Copper-Catalyzed Sulfonylation Reaction of NH-Sulfoximines with Aryldiazonium Tetrafluoroborates and Sulfur Dioxide: Formation of N-Sulfonyl Sulfoximines

An efficient and practical SO2 insertion protocol of NH-sulfoximines with aryldiazonium tetrafluoroborates and DABSO toward N-sulfonyl sulfoximines has been developed under mildly basic conditions. This transformation features easy operation, readily available substrates, and mild conditions. A tentative mechanism is proposed, which indicates that the aryldiazonium tetrafluoroborates would be radical donors under standard reaction conditions. The aryl radical produced in situ from diazonium salts would be trapped by SO2 to generate an arylsulfonyl radical and then undergo further transformation to generate the final N-sulfonyl sulfoximines.