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
作者:Yoshihiko Ito、Toshiyuki Miyake、Seiji Hatano、Ryoto Shima、Takafumi Ohara、Michinori Suginome
DOI:10.1021/ja982500m
日期:1998.11.1
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
1,2-二异氰基苯衍生物的芳构化聚合由带有 1,1'-联萘-2-基团的旋光有机钯 (II) 配合物介导,得到旋光性聚 (quinoxaline-2,3-diyl)有义选择性,这主要取决于联萘基团上的取代基。最有效的催化剂具有 7'-甲氧基-1,1'-联萘基团,可诱导形成单螺旋。中间体 [oligo(quinoxalinyl)] 钯配合物的分离和结构分析(单晶 X 射线衍射和 1H NMR 光谱)表明,聚合中的螺旋感选择可能决定性地受(terquinoxalinyl)的非对映体比例控制钯 (II) 络合物中间体。