Asymmetric hydrogenation of N-alkyl and N-aryl ketimines using chiral cationic Ru(diamine) complexes as catalysts: the counteranion and solvent effects, and substrate scope
作者:Fei Chen、Ziyuan Ding、Yanmei He、Jie Qin、Tianli Wang、Qing-Hua Fan
DOI:10.1016/j.tet.2012.03.019
日期:2012.7
Asymmetrichydrogenation of N-alkyl and N-aryl ketimines catalyzed by chiralcationic η6-arene-(N-monosulfonylated diamine) Ru(II) complexes has been investigated. Strong counteranion and solvent effects on the enantioselectivity were observed. The ruthenium catalyst bearing non-coordinating BArF− anion was found to be particularly effective for the hydrogenation of acyclic and exocyclic N-alkyl ketimines
Asymmetric Hydrogenation of N-Alkyl Ketimines with Phosphine-Free, Chiral, Cationic Ru-MsDPEN Catalysts
作者:Fei Chen、Tianli Wang、Yanmei He、Ziyuan Ding、Zhiwei Li、Lijin Xu、Qing-Hua Fan
DOI:10.1002/chem.201002846
日期:2011.1.24
(Solvent) free and easy: A phosphine‐free, chiral, cationicRu–MsDPEN complex [(S,S)‐1] is found to be an efficient catalyst for the enantioselective hydrogenation of a range of often‐problematic N‐alkyl ketimines (see scheme). This new method provides a more practical and greener synthetic approach to optically active amines, particularly N‐alkyl amines, such as Sertraline.
The influence of the alcohol, as the hydrogen donor, on the efficiency and selectivity of the asymmetrictransferhydrogenation (ATH) of imines is reported for the first time. This discovery not only leads to a highly enantioselective access to N‐aryl and N‐alkyl amines, but also provides new insight into the mechanism of the ATH of imines. Both experimental and computational studies provide support