Visible-Light-Promoted Radical Cyclization of N-Arylvinylsulfonamides: Synthesis of CF3/CHF2/CH2CF3-Containing 1,3-Dihydrobenzo[c]isothiazole 2,2-Dioxide Derivatives

Abstract A photocatalyzed and highly efficient trifluoromethylation of N -arylvinylsulfonamides using commercially available CF 3 SO 2 Cl as the trifluoromethyl radical source under blue LEDs is reported. The reaction proceeds through radical cyclization under mild conditions. An investigation of the substrate scope is performed to establish a general, synthetically useful protocol for the synthesis of novel trifluoromethylated 1,3-dihydrobenzo[ c ]isothiazole 2,2-dioxides in moderate to high yields. This method is also successfully applied for the synthesis of difluoromethylated and trifluoroethylated 1,3-dihydrobenzo[ c ]isothiazole 2,2-dioxides in good to excellent yields.