Ring-opening copolymerization of 2-vinyloxirane with anhydride/carbon dioxide: facile access to backbone-editable polymers with tunable lifecycles

Polymer backbone modification (PBM) is an emerging strategy uniquely suited to tuning the intrinsic properties of polymers. However, its utilization in tuning the degradability of polymers is underexplored, and there is no viable route to backbone-editable polyesters and polycarbonates with tunable lifecycles. In this work, we synthesized a series of backbone-editable polyesters and polycarbonate via ring-opening copolymerization (ROCOP) of 2-vinyloxirane (VIO) with anhydrides/CO₂. These polymers feature the specific structure necessary for [3,3]-sigmatropic oxo-rearrangements under a Pd catalyst, in which the terminal olefins can undergo rearrangement to <i>trans</i> internal ones and facilitate backbone modification. After optimizing the rearrangement conditions, we were able to rearrange the polyesters in satisfactory yields (55.2%-72.3%) without affecting the molecular weight. Notably, compared with the original polymers, the rearranged ones exhibit lower hydroboration-oxidation reactivity and glass transition temperature, as well as much faster thermal and hydrolytic degradation profiles, providing a new strategy for the design of polymers with tunable properties and lifecycles.