Asymmetric hydrogenation of acetophenone catalyzed by cinchonidine stabilized Ir/SiO2 |
| |
Authors: | ChaoFen Yang HeYan Jiang Jian Feng HaiYan Fu RuiXiang Li Hua Chen XianJun Li |
| |
Institution: | aKey Lab of Green Chemistry and Technology, Ministry of Education, Institute of Homogeneous Catalysis, College of Chemistry, Sichuan University, No. 29 Wang Jiang Road, Chengdu, Sichuan 610064, PR China |
| |
Abstract: | A series of silica (SiO2) supported iridium catalysts stabilized by cinchona alkaloids was prepared and applied in the heterogeneous asymmetric hydrogenation of acetophenone. Cinchona alkaloids exhibited a marked ability to stabilize and disperse the Ir particles. In the presence of (1S,2S)-diphenylethylenediamine ((1S,2S)-DPEN)) as chiral modifier, the cinchonidine (CD) stabilized catalyst 5%Ir/2CD-SiO2 exhibited excellent catalytic performance in the asymmetric hydrogenation of acetophenone in MeOH. Under the optimum conditions, the ee value of (R)-phenylethanol achieved 79.8% and no other product was produced, a higher enantioselectivity than that reported up to now for acetophenone hydrogenation catalyzed by the supported metal catalysts modified by chiral reagents. In particular, a synergistic effect between (1S,2S)-DPEN and CD was observed, which significantly accelerated the reaction rate and enhanced the enantioselectivity. The catalyst can be reused several times without a significant loss of activity and enantioselectivity. |
| |
Keywords: | Supported iridium catalyst Stabilizer Heterogeneous asymmetric hydrogenation (1S 2S)-DPEN |
本文献已被 ScienceDirect 等数据库收录! |
|