Ionic Environment Controlled Alkyl Transfer Enables Divergent Difunctionalization of Alkenes

Abstract Alkyl group transfer from bifunctional reagents to alkenes remains challenging under transition-metal-free conditions. Here, we report a photoredox strategy that enables alkyl transfer from allyl and benzyl sulfones in alkene difunctionalization under visible light irradiation. This work shows that atom transfer radical addition (ATRA)-type alkene difunctionalization can be coupled to a reductive radical polar crossover manifold to enable transition-metal-free C(sp3)–C(sp3) bond formation. Mechanistic experiments and density functional theory calculations indicate that a sulfinate additive alters the local ionic environment and diverts a common reaction platform into two distinct difunctionalization manifolds, enabling either alkylsulfonylation or desulfonylative alkylheteroarylation.