### 树状分子BINAP膦配体的合成及其在不对称氢化中的应用: 结构与性能关系探究

1. a 中国科学院化学研究所 中国科学院分子识别与功能重点实验室 北京分子科学国家实验室 北京 100190;
b 湘潭大学化学学院 环境友好化学与应用教育部重点实验室 湘潭 411105
• 投稿日期:2013-01-31 发布日期:2013-02-20
• 通讯作者: 范青华 E-mail:fanqh@iccas.ac.cn
• 基金资助:

项目受国家自然科学基金(No. 21232008)、国家重点基础研究发展计划(973 计划) (No. 2010CB833300)资助.

### Synthesis of Dendritic BINAP Ligands and Their Applications in the Asymmetric Hydrogenation: Exploring the Relationship between Catalyst Structure and Catalytic Performance

Ma Baodea, Deng Guojunb, Liu Jia, He Yanmeia, Fan Qinghuaa

1. a Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190;
b Key Laboratory for Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105
• Received:2013-01-31 Published:2013-02-20
• Supported by:

Project supported by the National Natural Science Foundation of China (No. 21232008), the National Basic Research Program of China (973 Program) (No. 2010CB833300).

Series of chiral dendritic BINAP ligands of different generations and with varied structures have been designed and synthesized through incorporation of BINAP unit into the core (disubstituted ligand) or the focal point (monosubstituted ligand) of the Fréchet’s polyether dendrimers. The relationship between catalyst structure and catalytic behavior was explored by choosing the Ru-catalyzed asymmetric hydrogenation of 2-aryl acrylic acid and Rh-catalyzed asymmetric hydrogenation of acetamidocinnamic acid as model reactions together with CD spectra analysis. It was found that the disubstituted dendritic catalysts showed obvious higher activity than the small molecular catalyst, and the reaction rate increased with the increase of the generation. This rate enhancement became more significant when changing the solvent from toluene/methanol (1/1, V/V) to neat toluene. While the monosubstituted dendritic catalysts showed similar performance with the small molecular catalyst, which was due to that the catalytic center located away from the dendritic support. In addition, the disubstituted dendritic BINAP ligands showed different Cotton effect in CD spectra with regard to the monosubstituted dendritic BINAP ligands and BINAP itself, suggesting that the microenvironment inside the disubstituted BINAP-cored dendrimer might be influenced by the sterically demanding dendritic wedges. These results indicated that the microenvironment around the catalytic center created by the dendritic support played an important role in promoting catalytic activity. This positive dendritic effect was further observed in the Rh-catalyzed asymmetric hydrogenation of acetamidocinnamic acid. Finally, the dendritic catalyst could be easily recycled by solvent precipitation at least three times without any loss of activity and selectivity.