The cis/trans (Z/E) 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. Herein, a cis-selective ADMET process of readily available , -diene monomers with high functional-group tolerance is disclosed. Identification of a highly sterereoselective cyclometalated Ru catalyst allowed the synthesis of a broad array of polymers with cis-content up to 99%. This platform was leveraged to study the impact of the cis geometry on thermal and mechanical properties including through the synthesis of ABA triblock copolymers 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.
