Progress in Radical Fluorosulfonyl Reagents

Abstract Sulfur(VI) fluoride exchange (SuFEx) chemistry that relies on the unique reactivity–stability balance of high valent organosulfur has emerged as a promising topic for the next-generation click reaction. Sulfonyl fluorides are the most widely used connective hubs of the SuFEx click reaction with widespread applications in the fields of chemical biology, drug discovery, and materials science. Compared with current methods, direct fluorosulfonylation with fluorosulfonyl radicals has emerged as a concise and efficient approach for the production of sulfonyl fluorides. The highly active SO2F radical was an unstable and inaccessible precursor until it was observed in the decomposition of fluorosulfonyl azide, which inspired efforts towards the production of fluorosulfonyl radical precursors for direct radical fluorosulfonylation processes. This review presents and discusses current breakthroughs in the generation of fluorosulfonyl radicals from various radical precursors, as well as their application in the synthesis of diverse functionalized sulfonyl fluorides. 1 Introduction 2 FSO2Cl as a Radical Precursor 3 Benzimidazolium Fluorosulfonates as Radical Precursors 4 Alk-1-ynylsulfonyl Fluorides as Radical Precursors 5 (Diarylmethylene)sulfamoyl Fluorides as Radical Precursors 6 Vinyl Fluorosulfates as Radical Precursors 7 Conclusion and Outlook