Transition-Metal Free Photocatalytic Synthesis of Acylsulfonamides.

We have developed a transition-metal-free photocatalytic S-N coupling reaction utilizing sodium organosulfinate and hydroxamic acid to synthesize acylsulfonamides. Employing 2,3,5,6-tetra(9H-carbazol-9-yl)benzonitrile (4CzBN) as a photocatalyst, this method enables the preparation of a wide range of acylsulfonamides from arylhydroxamic acids or -hydroxycarbamates. Mechanistic studies indicate that the generation of singlet oxygen (O) via the Energy Transfer Process (EnT) is crucial for facilitating the reaction. This approach offers a sustainable and efficient pathway for acylsulfonamide synthesis under mild conditions.