Lewis Acid Promoted Radical Alternating Polymerization of Simple and Higher α‑Olefins with Maleic Anhydride

The radical copolymerization of ethylene with vinyl acetate and acrylates is an industrialized method to afford branched functional polyolefins under high temperature and high pressure. Herein, we report the Lewis acid B-(C₆F₅)₃ promoted radical copolymerization of a broad range of olefins including simple olefins of ethylene and propylene, higher α-olefins, isobutylene, styrene, and others with maleic anhydride (MAH) with high activity under mild conditions to afford alternating copolymers with high molecular weights (M _w = 32-350 kg mol^-1) and moderate distributions. The anhydride group can be easily transferred to various functionalities. Mechanism investigation reveals that B-(C₆F₅)₃ activates MAH to reduce the energy barrier for generating the initial radical and stabilizes ethylene and MAH ended radical intermediates throughout the procedure. This is attributed to the moderate Lewis acidity and proper steric bulkiness of B-(C₆F₅)₃, allowing it to reversibly chelate to and disassociate from the carboxyl group of MAH. Thus, a radical polymerization system is constructed, and a practically viable platform to access functional polyolefins is built.