Organocatalysis of asymmetric aldol reaction in water: comparison of catalytic properties of (S)-valine and (S)-proline amides
作者:A. S. Kucherenko、D. E. Siyutkin、R. R. Dashkin、S. G. Zlotin
DOI:10.1007/s11172-013-0132-z
日期:2013.4
(S)-Valine amides containing (S)- or (R)-α-phenylethyl substituents at N1 atom efficiently catalyze asymmetric aldol reactions between cyclic (heterocyclic) ketones and aromatic aldehydes in water, predominantly giving rise to the aldol anti-diastereomers in high yields (up to 98%) and enantiomeric excess (up to 94%).
Chitosan Aerogel Beads as a Heterogeneous Organocatalyst for the Asymmetric Aldol Reaction in the Presence of Water: An Assessment of the Effect of Additives
The catalytic properties of chitosan aerogel for the direct asymmetric aldol reaction in water assisted by various surfactants and acid co-catalysts have been evaluated by employing a range of donor and acceptor systems. A beneficial effect on both the yields and nantioselectivities was observed, and the combination of surfactants and acid co-catalysts has proven particularly useful in the case of
A Green and Efficient Asymmetric Aldol Reaction Catalyzed by a Chiral Anion Modified Ionic Liquid
作者:Yunbo Qian、Xin Zheng、Yongmei Wang
DOI:10.1002/ejoc.201000304
日期:2010.7
A chiral anion modified ionic liquid derivedfrom L -proline proves as a green and efficient asymmetric organocatalyst for direct asymmetric aldolreactions in [BMIm]BF 4 at room temperature. The corresponding aldol products with moderate to good isolated yields (up to 99 %), anti-diastereoselectivities (up to 97:3), and excellent enantioselectivities (up to 99 % ee) were afforded. Recycling of the
Asymmetric aldol condensation in an ionic liquid-water system catalyzed by (S)-prolinamide derivatives.
作者:A. S. Kucherenko、D. E. Syutkin、S. G. Zlotin
DOI:10.1007/s11172-008-0092-x
日期:2008.3
Asymmetric aldol reaction of unmodified aldehydes with ketones catalyzed by 1(R),2(R)-bis((S)-prolinamido)cyclohexane (1) or (Rax)-2,2′-bis((S)-prolinamido)-1,1′-binaphtyl (2) proceeds with high yield (68–99%) and diastereoselectivity (dr ≥ 75/25) in the system (1-butyl-3-methylimida-zolium) tetrafluoroborate ([bmim][BF4])-water. The dependence of ee of the dominating anti-diastereomer of aldol on the percentage of water has a maximum at 50 vol.%. Catalyst 1 can be recycled 5 times without losses in the aldol yield, dr and ee.