219665-75-5Relevant academic research and scientific papers
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
Ito, Yoshihiko,Miyake, Toshiyuki,Hatano, Seiji,Shima, Ryoto,Ohara, Takafumi,Suginome, Michinori
, p. 11880 - 11893 (2007/10/03)
Aromatizing polymerization of 1,2-diisocyanobenzene derivatives was mediated by optically active organopalladium(II) complexes bearing 1,1'- binaphth-2-yl groups to give optically active poly(quinoxaline-2,3-diyl)s with varying screw-sense selectivities, which crucially depended upon the substituents on the binaphthyl groups. The most effective catalyst, which has 7'-methoxy-1,1'-binaphthyl group, induced the formation of a single screw- sense. Isolation and structural analyses (single-crystal X-ray diffraction and 1H NMR spectroscopy) of intermediary [oligo(quinoxalinyl)]palladium complexes revealed that the screw-sense selection in the polymerization may be decisively governed by the diastereomeric ratios of the (terquinoxalinyl)palladium(II) complex intermediate.
