Practical Route for Catalytic Ring-Opening Metathesis Polymerization

Norbornene derivatives are typical monomers for ring-opening metathesis polymerization (ROMP) for synthesizing highly functional polymers. However, the lack of catalytic methods, that is, the lack of readily available chain transfer agents (CTAs) for these monomers has been a significant cost limitation when large-scale syntheses are required. Here, we report commercially available styrene and its derivatives as efficient regioselective CTAs for the catalytic synthesis of metathesis polymers requiring up to 1000 times less ruthenium than in classical ROMP experiments. The molecular weight of the synthesized polymers was controlled by the monomer-to-CTA ratio. Low molecular weight ROMP polymers known for their antimicrobial properties were also synthesized on a gram scale in this report. Polymers were characterized by SEC, ¹H NMR spectroscopy, and isotopically resolved MALDI-TOF MS. This approach describes a greener, more cost-effective, and eco-friendly methodology for the preparation of metathesis-based materials on the multigram scale.