(1S,2S)-Diphenylethylenediamine Modified Ir/SiO2 Catalyst for Asymmetric Hydrogenation of Acetophenone and Its Derivatives

Abstract

An efficient and highly dispersed 5%Ir/SiO 2 catalyst for the asymmetric hydrogenation of acetophenone and its derivatives were prepared under basic conditions without the use of any stabilizer. The effects of different reaction parameters, namely, catalyst preparation, base used, chiral modifier, and concentration of (1 S ,2 S )-diphenylethylenediamine ((1 S ,2 S )-DPEN), were evaluated. Under optimum conditions with 5%Ir/SiO 2 modified by (1 S ,2 S )-DPEN, a high ee value of 70.0% was obtained for the asymmetric hydrogenation of acetophenone. It is noteworthy that this highest ee value was obtained with a supported metal catalyst without any stabilizer. The catalyst preparation is simple and there was no loss of enantioselectivity when the catalyst was reused several times. 不添加任何稳定剂, 在碱性条件下制备了 5%Ir/SiO 2 催化剂, 并用于催化苯乙酮的不对称加氢反应中, 详细考察了碱和手性修饰剂种类、氢气压力、反应温度、(1 S ,2 S )-1,2-二苯基乙二胺 ((1 S ,2 S )-DPEN) 浓度对反应的影响. 在优化反应条件下, 5%Ir/SiO 2 催化剂表现出较好的反应活性和对映选择性. 其中, 苯乙酮不对称加氢反应的对映选择性达 70%. 该催化剂不需要任何稳定剂, 制备方法简单, 催化性能稳定, 通过简单的离心分离即可循环使用. 5%Ir/SiO 2 prepared under basic conditions exhibited good catalytic performance in the asymmetric hydrogenation of acetophenone and its derivatives.