Rummel, F. et. al., Macromolecules, 2025, 58, 5, 2366–2378, https://doi.org/10.1021/acs.macromol.4c03132
A ruthenium-catalyzed hydrogen transfer ester metathesis (HTEM) is reported that allows for the isomerization of different types of linear polyesters such as polylactones without the need for any stoichiometric reagent, forming novel types of copolyesters containing additional alkylene dicarboxylate (AD) repeating units. Poly(butylene succinate) (PBS) is depolymerized to cyclic butyrolactone (BLc) with high yield and high selectivity, whereas cyclic valero- (VLc) and caprolactone (CLc) can be polymerized by HTEM to poly(lactone-alkylene dicarboxylate) copolyesters. Mechanistic investigations show that the formation of the chemically modified polyester relies on a two-fold catalytic reaction: a HTEM via a hydrogen borrowing process and a concomitant transesterification catalyzed by the base cocatalyst. Copyright © 2025 The Authors. Published by American Chemical Society. Open access