cis-Selective Acyclic Diene Metathesis Polymerization of alpha,omega-Dienes

摘要

The cis/trans stereochemistryof repeating alkenes in polymers provides a powerful handle to modulatethe thermal and mechanical properties of these soft materials, butsynthetic methods to precisely dictate this parameter remain scarce.We report herein a cis-selective acyclic diene metathesis(ADMET) polymerization of readily available alpha,omega-dienemonomers with high functional group tolerance. Identification of ahighly stereoselective cyclometalated Ru catalyst allowed the synthesisof a broad array of polymers with cis contents upto 99. This platform was leveraged to study the impact of the cis geometry on the thermal and mechanical properties ofpolyalkenamers, including an ABA triblock copolymer synthesized viaextension of a cis-rich telechelic polyoctenamerwith d,l-lactide. These results suggest that cis-selective ADMET affords an efficient strategy to tunethe properties of a variety of polymers.