Recent Advances in Ring-Opening Polymerization of O-Carboxyanhydrides

Poly(α-hydroxy acids) are important biodegradable polymers with wide applications. Recently O-carboxyanhydrides (OCAs) have emerged as promising monomer equivalents of lactides to synthesize poly(α-hydroxy acids). We will highlight recent advances in controlled ring-opening polymerization of OCAs catalyzed by organocatalysts, enzymes, or organometallic complexes. 1 Introduction 2 Organocatalysts for O-Carboxyanhydride Polymerization 2.1 Synthesis of O-Carboxyanhydride Monomers 2.2 Ring-Opening Polymerization of O-Carboxyanhydrides Catalyzed by 4-Dimethylaminopyridine 2.3 Epimerization in the Ring-Opening Polymerization of O-Carboxyanhydrides Catalyzed by the Pyridine Base 2.4 N-Heterocyclic Carbenes for Ring-Opening Polymerization of O-Carboxyanhydrides 3 Enzymes for O-Carboxyanhydride Polymerization 4 Organometallic Catalysts for O-Carboxyanhydride Polymerization 4.1 Early Efforts 4.2 Ring-Opening Polymerization Catalyzed by Zn Complexes 4.3 Photoredox Ring-Opening Polymerization Catalyzed by Zn/Ni Complexes 5 Conclusion and Perspective