Asymmetric anionic polymerization of chiral (R)-(+)-N-alpha methylbenzylmaleimide with chiral ligand/organometal complex

Asymmetric anionic polymerizations of chiral (R)-(+)-N-alpha-methylbenzylma leimide (MBZMI) were performed with (-)-sparteine [Sp) or (S, S)-(1-ethylpr opylidene)bis(4-benzyl-2-oxazoline) (Bnbox)/organometal complexes in toluen e or tetrahydrofuran (THF). All polymers obtained were optically active. Sp ecific optical rotations ([alpha](435)(25)) of the polymers initiated by Et 2Zn/Sp and Et2Zn/Bnbox were - 113.5 degrees to - 195.7 degrees and + 56.0 d egrees to + 170.2 degrees, respectively. Number-average molecular weights ( (M) over bar(n)) of the polymers were from 7.2 x 10(3) to 2.9 x 10(4). Chir ality of the polymers was attributed not only to chirality of optically act ive MBZMI units but also to stereogenic centers (S, S) and (R, R), in the m ain chain induced by the polymerization, judging from the results of circul ar dichroism (CD), H-1 and C-13 NMR spectra, and GPC curves obtained with p olarimetric and UV detectors. Anionic polymerizability of MBZMI using organ ometal with and without chiral ligand, and chiroptical properties of the po lymers are discussed.