Novel zinc complexes supported by aminophenolate ligands of multiple stereogenic centers have been diastereoselectively synthesized via the variation of the ortho-substituent of phenoxy moiety and the N-alkyl group of chiral pyrrolidinyl ring in the ligand framework. The X-ray diffraction studies revealed the molecular structures of two diastereoisomers of 1 and the enantiopure complex 4. The enantiopure complex 4 displayed excellent isooselectivity in the ring-opening polymerization of rac-lactide, representing the first example of highly isoselective (Pm
= 0.84) zinc initiating system. An enantiomorphic site control pathway was proposed based on the preliminary kinetic stydies. Complexes 1 to 4 showed interesting stereoselectivity variation from heterotactic bias to highly isotactic selectivity, likely a benefit of enhanced content of one specific diastereomer resulted from the increased steric bulkiness of the aminophenolate ligands.
