ASYMMETRIC-SYNTHESIS OF HELICAL POLY(QUINOXALINE-2,3-DIYL)S BY PALLADIUM-MEDIATED POLYMERIZATION OF 1,2-DIISOCYANOBENZENES - EFFECTIVE CONTROL OF THE SCREW-SENSE BY A BINAPHTHYL GROUP AT THE CHAIN-END

Aromatizing polymerization of 1,2-diisocyanobenzene derivatives was me diated by optically active organopalladium(II) complexes bearing 1,1'- binaphth-2-yl groups to give optically active poly(quinoxaline-2,3-diy l)s with varying screw-sense selectivities, which crucially depended u pon the substituents on the binaphthyl groups. The most effective cata lyst, which has 7'-methoxy-1,1'-binaphthyl group, induced the formatio n of a single screw-sense. Isolation and structural analyses (single-c rystal X-ray diffraction and H-1 NMR spectroscopy) of intermediary [ol igo(quinoxalinyl)]palladium complexes revealed that the screw-sense se lection in the polymerization may be decisively governed by the diaste reomeric ratios of the (terquinoxalinyl)-palladium(II) complex interme diate.