cis-Selective Acyclic Diene Metathesis Polymerization of α,ω-Dienes

Abstract

The cis/trans stereochemistry of repeating alkenes in polymers provides a powerful handle to modulate the thermal and mechanical properties of these soft materials, but synthetic methods to precisely dictate this parameter remain scarce. We report herein a cis-selective acyclic diene metathesis (ADMET) polymerization of readily available α,ω-diene monomers with high functional group tolerance. Identification of a highly stereoselective cyclometalated Ru catalyst allowed the synthesis of a broad array of polymers with cis contents up to 99%. This platform was leveraged to study the impact of the cis geometry on the thermal and mechanical properties of polyalkenamers, including an ABA triblock copolymer synthesized via extension of a cis-rich telechelic polyoctenamer with d,l-lactide. These results suggest that cis-selective ADMET affords an efficient strategy to tune the properties of a variety of polymers.

cis-Selective Acyclic Diene Metathesis Polymerization Using Bulky Cyclometalated Ruthenium Carbene Catalysts

“…This may enable the formation of an alternative cis – trans main-chain configuration that is difficult to access conventionally. Here, we report cis -selective ADMET polymerization of terminal acyclic dienes, which exhibits a broad scope among functionalized skeletons and a high cis -selectivity of up to 99% . We also showcased the convenient synthesis of cis -a- trans polyalkenamers from triene monomers and the full degradation of one of these polymers using G2 (Scheme c).…”