Radical-Polar Crossover Enabled Photoredox 1,2-Carbosulfinylation of Alkenes with N-Sulfinyltritylamine

The alkylation of <i>N</i>-sulfinylamines has emerged as a straightforward and promising platform for the construction of sulfinamides. Nevertheless, extant strategies─whether through two-electron nucleophilic addition or single-electron radical pathways─remain confined to two-component reactions, exhibiting intrinsic constraints in terms of carbon nucleophile diversity, synthetic efficiency, and structural variety of the products. Herein, we have successfully developed a photocatalytic radical-polar crossover process that addresses these challenges by enabling a three-component coupling reaction of Tr-NSO, alkenes and alkyl/aryl trifluoroborate salts. Despite the difficulty in controlling chemoselectivity among competing pathways, this strategy affords highly functionalized sulfinamides that are otherwise inaccessible through conventional means. Furthermore, mechanistic investigations, involving the trapping of radical and carbanionic intermediates along with fluorescence quenching studies, offer compelling support for the proposed reaction pathway.