RAFT Step-Growth polymerization via the Z-group approach using xanthate and vinyl ether

• This study extends the ‘Z-group’ RAFT step-growth polymerization strategy from trithiocarbonates to xanthates, enabling the direct incorporation of thiocarbonylthio groups into polymer backbones using both AB-type and A 2 + B 2 -type monomers. • The polymerizations proceed efficiently under visible light irradiation at room temperature without the need for catalysts, offering a facile synthetic route for producing degradable polymers. • The obtained poly(xanthate)s act as macroRAFT agents for subsequent radical and cationic chain-growth polymerizations, enabling the construction of degradable multiblock copolymers from ‘less activated monomers’ such as vinyl acetate (VAc) and isobutyl vinyl ether (IBVE). The development of degradable vinyl polymers is an urgent challenge in polymer chemistry. Herein, we report a ‘Z-group’ RAFT step-growth polymerization strategy based on xanthate and vinyl ether monomers, enabling the construction of polymers with thiocarbonylthio groups embedded directly into the polymer backbone. These polymers are synthesized under mild conditions such as visible light and catalyst-free, using both AB-type and A 2 + B 2 -type monomers. The step-growth nature of the polymerization is confirmed by 1 H NMR and SEC analyses. The resulting backbones can undergo controlled degradation via phosphine-based reduction, yielding oligomeric fragments. Furthermore, the step-growth polymers serve as macroRAFT agents for subsequent radical or cationic chain-growth polymerizations, enabling the construction of degradable multiblock copolymers using either vinyl acetate (VAc) or isobutyl vinyl ether (IBVE). This work broadens the scope of RAFT step-growth polymerization toward less activated monomers and provides a facile way for the design of degradable functional polymers.