Sulfonamide Synthesis: Unlocking New Pathways with Aryl Triflates via Photocatalytic Coupling

Abstract

Arylsulfonamides, essential scaffolds in pharmaceuticals and materials science, face synthetic sustainability challenges due to toxic reagents and transition-metal-dependent protocols. The emerging three-component coupling of aryl radicals, SO₂ surrogates, and amines offers a modular alternative; however, aryl radical generation from abundant phenolic precursors remains underexplored. Herein, we report a novel, transition-metal-free photocatalytic strategy for the modular synthesis of structurally diverse arylsulfonamides. This method overcomes longstanding limitations in aryl radical generation by utilizing NaI as a dual-functional catalyst and soft electron donor to directly activate abundant, biomass-derived aryl triflates under mild conditions (room temperature, UV light). The NaI-mediated system enables precise, orbital-oriented electron transfer, overcoming the inherent constraints of traditional SET mechanisms and achieving controlled aryl radical generation where previous methods failed. This novel activation strategy facilitates an efficient three-component cascade coupling with SO₂ surrogates (K₂S₂O₅) and a remarkably broad scope of amines, including aliphatic, aromatic, heterocyclic, and complex pharmaceutically relevant amines, delivering sulfonamide products in good to excellent yields.