SuFEx Chemistry Enables Sustainable Side-Chain Modification of Renewable Phenylpropanoid Polymers

The development of fully metal-free strategies for the synthesis and functionalization of polymers is crucial for advancing sustainable materials. This study introduces a platform that integrates metal-free reversible addition–fragmentation chain-transfer (RAFT) polymerization with sulfur(VI) fluoride exchange (SuFEx) chemistry to enable the controlled polymerization and postpolymerization side-chain modification of renewable polymers. Silyl-protected poly(vinylphenol) (PSVP)s and poly(vinyl catechol) (PSVC) derived from cinnamic acid analogs were synthesized and subsequently functionalized with a range of sulfonyl fluorides bearing electron-donating or electron-withdrawing substituents. High degrees of modification were achieved for para-substituted PSVP, while meta-substituted PSVP and their corresponding block copolymers exhibited high conversions with minimal side reactions. By contrast, ortho-substituted PSVP and PSVC systems generally exhibited moderate efficiencies, consistent with steric hindrance. This fully metal-free sequence provides a sustainable and versatile strategy for the functionalization of biobased polymers, expanding the scope of SuFEx chemistry and contributing to the development of environmentally sustainable polymer materials.