Progress in metal-free cooperative catalysis for the ring-opening copolymerization of cyclic anhydrides and epoxides

Recent progress in the design of metal-free Lewis pair catalysts indicates a bright future for the synthesis of various polyesters with broad applications. In the present review, we attempt to highlight the recent advancements and opportunities in the use of metal-free cooperative catalysts or initiators for polymerization reactions. The ring-opening alternating copolymerization (ROAP) of epoxides with cyclic anhydrides is a typical typical polymerization reaction used here to illustrate some of the features of metal-free cooperative catalysts. In addition to the simple simplicity in the structural features of the catalysts and the desirable metal-free polyesters/polycarbonate products, these metal-free catalysts also exhibit impressive catalytic efficiency, molar mass control, and stereo-/regioselectivity. We believe that metal-free cooperative catalysis will continue to drive innovation into polymer chemistry research in the near future.