Photoredox-catalyzed stereo- and regioselective vicinal fluorosulfonyl-borylation of unsaturated hydrocarbons

There has been considerable research on sulfur(VI) fluoride exchange (SuFEx) chemistry, which is considered to be a next-generation click reaction, and relies on the unique balance between reactivity and stability inherent in high valent organosulfur. The synthetic versatility of the bifunctional handles containing the fluorosulfonyl group presents great synthetic value and opportunity for drug discovery. However, the direct photoredox-catalyzed fluorosulfonyl-borylation process remains unexplored and challenging due to its system incompatibility and limited synthetic strategies. Herein, we developed a sequential photocatalytic radical difunctionalization strategy for the highly efficient stereoselective synthesis of vicinal fluorosulfonyl borides (VFSBs) with an integrated redox-active SO2F radical reagent. The VFSBs acted as orthogonal synthons, and were subjected to a range of convenient transformations via the cleavage of the C–B and S(VI)–F bonds, including halogenation, Suzuki coupling, hydrogenation, and the SuFEX click reaction, which demonstrated the great potential of the VFSB moieties for use in skeleton linkage and drug modification.