Control of helical chirality of poly(quinoxaline-2,3-diyl)s based on postpolymerization modification of the terminal group by small chiral molecules

摘要

Poly(quinoxaline-2,3-diyl)s having a terminal formyl or boronyl group were prepared by living polymerization of 1,2-diisocyanobenzenes using organopalladium initiators bearing a protected formyl or boronyl group. Poly(quinoxaline-2,3-diyl)s were successfully deracemized by reacting them with small optically active molecules at their terminal formyl or boronyl group, leading to the induction of optically active helical structures. Poly(quinoxaline-2,3-diyl) having terminal formyl groups was converted to one-handed helical polymer, in which the screw-sense excess was 68% (84:16). The helix sense of the boronyl-terminated poly(quinoxaline-2,3-diyl) was reversibly controlled by attaching and removing the chiral group.