Controlled Polymerization of β‑Pinadiene: Accessing Unusual Polymer Architectures with Biomass-Derived Monomers

Biomass-derived polymers are emerging as critically needed alternatives to their petrochemical counterparts. Terpenes, which are among the most abundant natural products, represent particularly fertile chemical space for monomer development (given their inherent structural complexity). Here, we present the living vinyl-addition polymerization of β-pinadiene (the cumulated congener of β-pinene) at room temperature. Employing [(π-allyl)­NiOCOCF₃]₂ as a catalyst afforded the desired polymers with good control over molecular weight and dispersity. Interestingly, the bicyclic pinane core was retained in the isolated materials (which starkly contrasts prototypical pinene polymerizations). Moreover, the reported materials exhibited impressive thermal stability (T_d = 294 °C) and high glass transition temperatures (T_g = 160 °C). As the polymerization of terpene-derived cumulenes can afford scaffolds that defy current synthetic logic, we anticipate our work will unlock additional avenues for sustainable polymer development.