Reductive activation of vinyl sulfoxonium ylides enables divergent radical-mediated carbon-carbon bond formation.

Vinyl sulfoxonium ylides are traditionally confined to two-electron cyclization chemistry, limiting their utility in intermolecular C-C bond formation. Herein, we demonstrate that reductive activation of vinyl sulfoxonium ylides under Zn/TiCl4 conditions unlocks a distinct radical reactivity manifold. Depending on the electrophile, the reaction proceeds divergently to furnish dihydropyran-2-ones via formal [4+2] annulation with carbonyl compounds or β-amino acid derivatives from imines. Mechanistic studies support a single-electron-transfer pathway involving ylide-derived radical intermediates.