Chiral arylnickel complexes as highly active initiators for screw-sense selective living polymerization of 1,2-diisocyanobenzenes

Optically active chiral organonickel complexes served as efficient chiral initiators for living aromatizing polymerization of 1,2-diisocyanobenzene derivatives, which afford optically active helical poly(quinoxaline-2,3-diyl)s up to 84% s.e. (screw-sense excess). In comparison with asymmetric polymerization with the corresponding organopalladium initiators, the nickel initiators show a much greater polymerization rate, while the selectivity remains high. The organonickel initiators can be generated in situ from nickel(0) precursors with the corresponding enantiopure (S,S)-2-(4,5-diphenylimidazolin-2-yl)phenyl chloride, leading to the convenient synthesis of highly stereo-controlled poly(quinoxaline-2,3-diyl)s.