A series of salen-type ligands ((LH2)-H-1-(LH2)-H-6) with sterically bulky cumyl groups have been synthesized. Reaction of these ligands with AlMe3 yields the mononuclear aluminum complexes [LAlMe] (1-3) or dinuclear species [L2Al2Me4] (4-6), respectively. Further reaction of [LAlMe] (1-3) with benzyl alcohol produces [LAl(OBn)] (1a-3a), respectively. Solid-state structural studies reveal that complexes la and 2a are mononuclear; however, complex 6 is a d.inuclear species. Aluminum alkoxides 1a-3a are highly stereoselective in the ROP of rac-lactide, producing polylactide (PLA) with 94-97% enantiomeric selectivity (P-m) at high conversion. Their high enantioselectivity leads to PLA with high T-m (205 degrees C). The polymerization of L-lactide by these complexes also shows good living features with narrow PDI values (M-w/M-n = 1.06-1.25) signaling less or no transesterification, which can be further verified by MALDI-TOF mass spectrometric analysis

Itaconic acid, a naturally occurring compound mass-produced via fermentation of glucose, was reacted with ethanolamine or ethylene diamine to afford hydroxy-acid or diacid monomers containing the 2-pyrrolidone lactam. Homopolymerization or copolymerization with diols, respectively, yielded polylactam esters with higher glass transition temperatures and faster hydrolytic degradation compared to the commercial polyester polylactic acid (PLA).