title: Ru-Catalyzed asymmetric hydrogenation of alpha-ketoesters with CeCl3.7H2O as additive.
abstract: [reaction: see text] An efficient asymmetric hydrogenation of alpha-ketoesters is reported with use of a catalyst prepared from [Ru((S)-3)(benzene)Cl]Cl and CeCl(3).7H(2)O. Alpha-hydroxy esters are obtained in up to 96% ee. The addition of CeCl(3).7H(2)O not only improves the enantioselectivity, but also enhances the stability of the catalyst. As a result, the hydrogenation of methyl benzoylformate affords the product with 92% ee with a substrate/catalyst ratio of 10 000. Hydrolysis of 2 provides the final compound with 83% yield at 99% ee after a single recrystallization from 1,2-dichloroethylene.
authors.affiliation: State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Sun
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wan
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Meng
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
authors.forename: Lijuan
authors.initials: L
authors.lastname: Jiang
authors.forename: Zhaoguo
authors.initials: Z
authors.lastname: Zhang