Construction of Well‐Defined Redox‐Responsive CO2‐Based Polycarbonates: Combination of Immortal Copolymerization and Prereaction Approach

Due to the axial group initiation in traditional (salen)CoX/quaternary ammonium catalyst system, it is difficult to construct single active center propagating polycarbonates for copolymerization of CO₂/epoxides. Here a redox‐responsive poly(vinyl cyclohexene carbonate) (PVCHC) with detachable disulfide‐bond backbone is synthesized in a controllable manner using (salen)CoTFA/[bis(triphenylphosphine)iminium, [PPN]TFA binary catalyst, where the axial group initiation is depressed by judiciously choosing 3,3′‐dithiodipropionic acid as starter. While for those comonomers failing to obtain polycarbonate with unimodal gel permeation chromatography (GPC) curve, a versatile method is developed by combination of immortal copolymerization and prereaction approach, and functional aliphatic polycarbonates having well‐defined architecture and narrow polydispersity can be prepared. The resulting PVCHC can be further functionalized with alkenes by versatile cross‐metathesis reaction to tune the physicochemical properties. The combination of immortal polymerization and prereaction approach creates a powerful platform for controllable synthesis of functional CO₂‐based polycarbonates.