Modular and Direct Synthesis of γ-Sultines From Simple Unactivated Alkenes

Despite long-standing interest in sultines, their efficient and general synthesis remains elusive. Existing methods typically rely on oxidative or rearrangement pathways or on prefunctionalized homoallylic substrates, thus limiting practicality and scope. For the first time, we demonstrate a visible-light-driven relay that directly converts simple unactivated alkenes into γ-sultines using sulfoxonium ylides and DABSO as an SO₂ source. The reaction involves a highly electrophilic distonic radical cation, generated through polarity inversion, which initiates addition to unactivated alkenes and, acting as an intrinsic leaving-group precursor, orchestrates radical relay and cyclization in a single photochemical sequence. This modular and operationally simple strategy exhibits broad substrate scope and excellent functional-group tolerance and is applicable to late-stage functionalization of complex molecules, opening new avenues for γ-sultine synthesis and diversification.