节点文献
一种新型2,5-二甲基-2,4-己二烯不对称环丙烷化原位催化体系
A NEW KIND OF Cu(Ⅰ)-CHIRAL SCHIFF BASE CATALYTIC SYSTEM FOR ASYMMETRIC CYCLOPROPANATION OF2,5 DIMETHYL-2,4-HEXADIENE
【摘要】 以( - )1 R,2 S2氨 基1 ,2二苯 基乙 醇 作为 手性 源, 与取 代 水杨 醛 缩合 制 备 了系 列 手性 Schiff 碱配 体,考察 了该类配体的二价铜配合物及配体与 Cu( C H3 C N)4 Cl O4 组成的原位 体系对2 ,5二甲基2 ,4己二烯与 重氮乙酸 L薄 荷酯的环丙烷化反应的催化作用. 结果表明, Cu(Ⅱ) 配合物尽管具有较高的催化活性,但几乎没有光 学选择性,而原 位体系 则表 现出极 高的 催化活 性和 一定的 光学选择性,化学收率为903 % , 顺 式体e .e .值达到30 %
【Abstract】 A new kind of copper(Ⅰ) chiral Schiff base complex, formed in situ by Cu(CH 3CN) 4ClO 4 and the Schiff bases derived from (-) (1 R ,2 S ) 2 amino 1,2 diphenyl ethanol and substituted salicylaldehyde, was employed in the catalytic asymmetric cyclopropanation of 2,5 dimethyl 2,4 hexadiene with L menthyl diazo acetate, and 90% of yield and 30% of e.e.( cis ) were obtained. Compared with copper(Ⅱ) complex catalyst, this catalysis system showed better enantiomeric excess and higher activity. And in the system, Cu(CH 3CN) 4ClO 4 gave far higher activity than Cu(Ⅰ)OTf and was believed to be a good reagent for the title reaction.
【Key words】 asymmetric cyclopropanation; chiral Schiff base ligand; 2; 5 dimethyl 2; 4 hexadiene;
- 【文献出处】 催化学报 ,CHINESE JOURNAL OF CATALYSIS , 编辑部邮箱 ,1999年03期
- 【被引频次】6
- 【下载频次】141