Photocatalyst-free visible light mediated cascade sulfonylation/annulation of N-propargyl arylsulfonamides: accessing E- and Z-4-sulfonylmethylidene benzosultams.

Herein, we report visible-light mediated photocatalyst-free stereoselective synthesis of Z- and E-4-sulfonylmethylidene benzosultams via cascade sulfonylation/annulation of N-propargyl arylsulfonamides using iodine as a catalyst. Broad substrate scope and late-stage functionalization of bioactive molecules highlight the method's practicality.