Pyridinium-based fluorosulfonamide reagents enabled photoredox catalyzed radical fluorosulfonamidation

Sulfamoyl fluorides, as a crucial building block of SuFEx, have garnered extensive research interest due to their applications in chemical biology, materials science, and drug discovery. Recently, considerable research has been dedicated to the synthesis of sulfamoyl fluorides. However, the direct radical fluorosulfonamidation process for the synthesis of sulfamoyl fluorides employing fluorosulfonamide radicals has largely been overlooked. We herein disclosed a practical procedure for constructing bench-stable redox-active fluorosulfonamide radical reagent from inexpensive SO2F2, which would provide appropriate solution to the long-standing issue of radical fluorosulfonamidation. Simultaneously, the radical fluorosulfonamidating reagents, namely fluorosulfonyl-N-pyridinium tetrafluoroborate (PNSF), can be readily scaled up and prepared under simple aerobic conditions. These practical and air-stable crystalline salts can effectively facilitate a range of reactions, including the N-(fluorosulfonyl) sulfonamidation of diverse (hetero)arenes, sequential radical stereoselective fluorosulfonamidation, and the 1,2-difunctionalization of various alkenes, enabling the construction of a diverse array of functionalized sulfamoyl fluoride compounds.