Ruthenium‐Catalyzed Alternating Ring‐Opening Metathesis Copolymerization of Norborn‐2‐ene with Cyclic Olefins

A Grubbs‐type olefin metathesis catalyst bearing a backbone‐substituted unsymmetrical N‐heterocyclic carbene (NHC) ligand has been prepared from readily available reagents using a four‐step synthetic protocol. This catalyst was found able to promote the alternating ring‐opening metathesis copolymerization of norborn‐2‐ene (NBE) with cis‐cyclooctene (COE) or cyclopentene (CPE) with a high degree of chemoselectivity (98% and 95% of alternating diads, respectively) at low comonomers ratios.