Sulfur Oxidation State Controls Radical Smiles–Truce Rearrangements through a Switch in Cyclization Selectivity

The radical Smiles–Truce rearrangement is a powerful strategy for constructing aryl–carbon bonds, although competing ortho addition often limits the utility of conventional S(VI) sulfonamide precursors. Here, we demonstrate that switching to S(IV) sulfinamides enables selective ipso aryl migration while providing a stereochemical handle for asymmetric induction. We report a visible-light-driven nitrogen-centered radical cascade that converts alkene-tethered N-acyl sulfinamides into densely functionalized lactams, fused bicycles, and spirocycles through a desulfinylative Smiles–Truce rearrangement. The transformation accommodates electronically diverse arenes, heteroarenes, and substituted alkenes, affording products in up to 85% yield. Moreover, enantioenriched sulfinamide precursors enable efficient transfer of stereochemical information to the products, with up to 93% enantiospecificity. In contrast to analogous S(VI) sulfonamide reactions, competing ortho dearomatization is not observed. Density functional theory calculations reveal that the S(IV) system disfavors the competing ortho-addition pathway, providing a mechanistic basis for the observed selectivity reversal and establishing sulfinamides as versatile precursors for stereocontrolled radical annulations.