Highly active cobalt(II) and copper(II) complexes supported by aminomethylquinoline mediating stereoselective ring‐opening polymerization of rac‐lactide

Cobalt(II) and copper(II) complexes supported by 4‐(quinolin‐2‐ylmethyl)morpholine (L) were characterized, and their reactivity toward the ring‐opening polymerization (ROP) of rac ‐lactide ( rac ‐LA) was studied. The use of [LMCl 2 ]/LiO i Pr and [LMCl 2 ]/LiMe (M = Co, Cu) resulted in over 95% conversion within 10 min at 25 °C. The effect of the initiating group and geometry of the metal complexes steered the heterotactic enchainment of the resultant polylactide(PLA). The Co(II)/LiMe system represents the first example of the ROP of rac ‐LA with high heterotactic enchainment ( P r = 0.92) with 98% conversion at 0 °C.