Synthesis of novel tetradentate ligands with helical chirality and their application to catalytic asymmetric reactions

1，2-二异氰苯衍生物的芳构化聚合是在含有1，1-联萘-2-基的光学活性有机钯(II)配合物的催化下进行的，得到具有不同螺杆选择性的光学活性聚(2，3-喹恶啉-2，3-二基)S，其选择性主要取决于联萘上的取代基。最有效的催化剂是含有7-甲氧基-1，1-联萘基的催化剂，它诱导了单螺杆的形成。相反，具有2-甲氧基-L、L-联萘基的催化剂只能得到低于20%的螺旋选择性。在母体L、L‘-联萘和2’-叔丁基二甲基硅氧基-L、L-联萘衍生物中，选择性为63%ee~84%ee分离和中间体[喹恶啉]钯配合物的结构分析(单晶X-射线衍射和1H核磁共振波谱)表明，聚合中螺杆的选择可能由(叔喹恶啉)钯(II)络合物中间体的非对映异构体比例决定。[低聚(喹恶啉)]钯配合物与二苯基磷化锂反应，以合理的产率得到相应的[低聚(喹恶啉)]二苯基膦。旋光活性的螺旋三膦与钯(II)发生配位反应，生成相应的单(膦)氯(烯丙基)钯(II)配合物。

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. In contrast, a catalyst with 2 methoxy-l, l -binaphthyl group only afforded polymers with less than 20% screw-sense selectivity. In the cases of parent l, l'-binaphthyl and 2'-tert-butyldimethylsiloxy-l, l -binaphthyl derivatives, the selectivities ranged from 63% ee to 84% ee 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. The [oligo(quinoxalinyl)]palladium complexes were reacted with lithium diphenyiphosphide to give the corresponding [oligo(quinoxalinyl)]diphenylphosphine in reasonable yields. The optically active, helical tertiary phosphine was found to coordinate to palladium(II) in the reaction with allylpalladium chloride dimer to give the corresponding mono(phosphine)chloro(allyl)palladium(II) complexes.