Iridium-catalyzed reductive sulfonamidation of alkoxy aryl alkynes.

Sulfonamides are valuable structural building blocks, bioactives, and pharmaceuticals. While there have been great achievements in the sulfonamidation of alkyl and alkenyl carbon, the sulfonamidation of alkynyl carbon has not been studied. Herein, we report the synthesis of N-benzylated sulfonamides from alkoxy aryl alkynes and sulfonamides enabled by Ir-catalyzed reductive sulfonamidation using HCO2H as a hydrogen donor. This process was performed under mild conditions, resulting in the transformation of a variety of substituted benzene, heteroaromatic, and aliphatic sulfonamides. Particularly, the structural diversification of valdecoxib and zonisamide showcased the utility of this protocol.