Ring‐Opening Polymerization and Copolymerization of Propylene Oxide Catalyzed by N‐Heterocyclic Carbenes

Herein, we demonstrate the application of adducts of various N‐heterocyclic carbenes (NHCs) with CO2 (i.e., NHC–CO2) as precatalysts in the ring‐opening homopolymerization of propylene oxide (PO) onto diethylene glycol as a chain starter to give well‐defined polyether diols. The influence of various NHCs on the structure of the polymers and the mechanism of this reaction were investigated both experimentally and through DFT calculations. With this methodology, copolymers of PO and the monomers ε‐caprolactone and (S,S)‐lactide are accessible.