1383254-70-3Relevant academic research and scientific papers
Asymmetric hydrogenation of N-Alkyl ketimines with phosphine-free, chiral, cationic Ru-MsDPEN catalysts
Chen, Fei,Wang, Tianli,He, Yanmei,Ding, Ziyuan,Li, Zhiwei,Xu, Lijin,Fan, Qing-Hua
, p. 1109 - 1113 (2011)
(Solvent) free and easy: A phosphine-free, chiral, cationic Ru-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.
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
Chen, Fei,Ding, Ziyuan,He, Yanmei,Qin, Jie,Wang, Tianli,Fan, Qing-Hua
supporting information; experimental part, p. 5248 - 5257 (2012/08/08)
Asymmetric hydrogenation of N-alkyl and N-aryl ketimines catalyzed by chiral cationic 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 in the presence of (Boc)2O in dichloromethane or even under solvent-free conditions, providing chiral amines with up to >99% ee and full conversions. Alternatively, the ruthenium catalyst bearing achiral phosphate anion together with corresponding phosphoric acid as the additive was also efficient for the hydrogenation of N-alkyl ketimines in the absence of (Boc)2O with excellent enantioselectivities and full conversions. For N-aryl ketimines lower enantiomeric excesses were observed by using the ruthenium catalyst bearing BArF- anion. This catalytic protocol thus provides a facile and practical access to optically active amines and has been successfully employed in the gram-scale synthesis of enantiomerically pure (+)-sertraline.
A highly enantioselective organocatalytic method for reduction of aromatic N-alkyl ketimines
Wang, Chao,Wu, Xinjun,Zhou, Li,Sun, Jian
supporting information; experimental part, p. 8789 - 8792 (2009/09/25)
A study has demonstrated the development of a highly enantioselective catalytic method for the reduction of aromatic N-alkyl ketimines by trichlorosilane under mild conditions using the newly designed Lewis base organocatalyst that incorporates C- and S-chirality. The S-chiral sulfinamide group in these catalysts plays a crucial role similar to the carboxamide groups as Lewis base for the activation of HSiCl3, and also serves as a source of chirality that the carboxamide group lacks for the asymmetric induction. The results of the study showed that excellent enantioselectivities of up to 99.6% ee and high yields were obtained for a wide range of substrates. Further works is also in progress to clarify the mechanism of the transformation and explore the full application scope of the present catalyst system.
