手性氨基酸衍生物-钌配合物催化的酮不对称氢转移反应  

Chiral Amino-acids Derivatives-Ruthenium Catalyzed Asymmetric Transfer Hydrogenation of Ketones

作　　者：李小娜[1] 王丽华[1] 周宏勇[1] 王家喜[1] 

机构地区：[1]河北工业大学化工学院绿色化工与高效节能重点实验室,天津300130

出　　处：《有机化学》2016年第9期2175-2182,共8页Chinese Journal of Organic Chemistry

基　　金：河北省自然科学基金(No.2011202087)资助项目~~

摘　　要：合成了手性氨基酸衍生的苯并咪唑和二肽衍生的苯并咪唑配体.手性氨基酸衍生的苯并咪唑2与[RuCl_2(p-cymene)]2原位生成的催化剂在苯乙酮的不对称氢转移反应中表现出较好的催化性能,反应的转化速率(TOF)可以达到15400 h-1,产物的对映体选择性达到77%.通过构效关系的研究认为,金属钌与配体可能是通过吡咯烷上的NH和离子化的酰胺部分的N配位.通过动力学计算解释了[RuCl_2(p-cymene)]_2/2在苯乙酮的氢转移反应中表现出的反常温度效应.在二肽衍生的苯并咪唑配体7与[RuCl_2(p-cymene)]2原位生成的催化体系中加入添加剂Li Cl,可以使产物的对映体选择性由38%提高到43%.Benzimidazoles derived from chiral amino acids and benzimidazoles derived from dipeptides were prepared and proved to be efficient ligands in the ruthenium catalyzed asymmetric transfer hydrogenation of acetophenone. Employing ligand 2 in the reduction of acetophenone resulted in better activity and enantioselectivity （with 15400 h-1 TOF and 77% ee）. Through structure-activity correlations, the corresponding metal-ligand bifunctional mechanism was speculated. In addition, the catalytic system of[RuCl2（p-cymene）]2/2 exhibited reversed temperature effects, which explained through kinetics data. The enantioselectivity was increased from 38% to 43% when LiCl was added in dipeptides derived benzimidazoles 7/[RuCl2（p-cymene）]2 catalyzed asymmetric transfer hydrogenation.

关 键 词：不对称催化 对映体选择性 氢转移 

分 类 号：O621.251[理学—有机化学]