Bioinspired Cobalt Amino Acid Complexes for Synthesis of Polyester Polyols from Epoxide and Cyclic Anhydride

The design of bioinspired catalysts offers a promising route to sustainable polyester synthesis. Herein, a series of chiral cobalt(III) amino acid complexes are introduced as highly efficient catalysts for epoxide/cyclic anhydride ring‐opening copolymerization (ROCOP). Structure–activity studies reveal that complex 2 , featuring a polar organosoluble side chain, exhibits exceptional catalytic performance, achieving turnover frequency (TOF) = 1151 h −1 in CHO/PA ROCOP at 100 °C with DMAP‐comparable to state‐of‐the‐art Cr(III)‐salen catalysts. Furthermore, complex 3 , which features a lysine‐derived ligand, shows improved reactivity at elevated anhydride ratios, indicating an influence from the outer coordination sphere on catalysis. Mechanistic analysis reveals a zero‐order dependence on anhydride concentration, confirming that the propagation step saturates the catalyst. Further, complex 2 maintains high TOF (1164 h −1 ) even in the presence of a chain transfer agent, enabling precise molecular weight control. This work illustrates tuning by an amino acid ligand as a powerful strategy for developing efficient, selective, and sustainable ROCOP catalysts, bridging the gap between bioinspired design and high‐performance polymerization.