Photocatalyst-free regioselective sulfonamidation of -(2-hydroxyaryl)amides in visible-light.

In this work, we report a regioselective sulfonamidation of -(2-hydroxyaryl)amides with iminoiodinanes and iodine in visible light at room temperature. The method does not require a strong oxidant, metal or photocatalyst and enables direct functionalization of a C-H bond to a C-N bond. Mechanistic investigations suggest generation of an N-centered radical from ,-diiodo-sulfonamide by homolytic N-I bond cleavage followed by its site-specific addition to -(2-hydroxyaryl)amides to furnish -sulfonamide derivatives.