Hydrogen Atom–Coupled Electron Transfer-Driven Anionic Polymerization under Aerobic Conditions

Radical and anionic polymerizations are two major routes to synthetic macromolecules, yet they have remained largely separate due to their distinct underlying mechanisms. To bridge these traditionally exclusive methods, we report a strategy that combines the complementary strengths of both methods, fueled by Earth-abundant alkali metal Lewis base and hydrosilanes. Central to this approach is a hydrogen atom-coupled electron transfer (HCET) process that transforms radical-driven initiation into anionic propagation. This method enables the synthesis of a broad spectrum of polymers, demonstrated here by polystyrene homopolymers and poly(styrene)-block-poly(methyl methacrylate) copolymers, under user-friendly conditions that tolerate air and use unpurified commodity chemicals. The operational simplicity, oxygen tolerance, and scalability of this method hold promise for sustainable and industrially relevant polymer synthesis.