(1R,2R)-Bis[(S)-prolinamido]cyclohexane Modified with Ionic Groups: The First C2-Symmetric Immobilized Organocatalyst for Asymmetric Aldol Reactions in Aqueous Media
作者:Sergei V. Kochetkov、Alexandr S. Kucherenko、Sergei G. Zlotin
DOI:10.1002/ejoc.201100707
日期:2011.10
The first C2-symmetric immobilized organocatalyst for asymmetricaldolreactions containing the (1R,2R)-bis[(S)-prolinamido]cyclohexane unit tagged with two imidazolium+/PF6– ion pairs has been synthesized. In its presence, (hetero)aromatic aldehydes reacted with linear or cyclicketones in aqueous media to yield chiral aldols with high diastereo- and enantioselectivities and the catalyst could be
Simple amphiphilic isosteviol–proline conjugates as chiral catalysts for the direct asymmetric aldol reaction in the presence of water
作者:Ya-Jie An、Yun-Xiao Zhang、Ya Wu、Zhao-Min Liu、Chao Pi、Jing-Chao Tao
DOI:10.1016/j.tetasy.2010.04.019
日期:2010.4
activity (up to >99% yield) and stereoselectivity (up to 99:1 dr, >99% ee) for the direct aldolreaction of cyclohexanone and substitutedbenzaldehydes at room temperature in the presence of water. In addition, solventeffects, catalyst loading, substrate scope, temperature, and the influence of water on the reactions were investigated. These results demonstrate that the catalysts with a chiral concave
<scp>l</scp>-Isoleucine in a Choline Chloride/Ethylene Glycol Deep Eutectic Solvent: A Reusable Reaction Kit for the Asymmetric Cross-Aldol Carboligation
作者:Noé Fanjul-Mosteirín、Carmen Concellón、Vicente del Amo
DOI:10.1021/acs.orglett.6b01989
日期:2016.9.2
able to catalyze the cross-aldol reaction between cyclohexanone and aromatic aldehydes in a deep eutectic solvent consisting in choline chloride and ethylene glycol, rendering products with high diatereo- and enantioselectivity. This protocol is straightforward and green: the organocatalyst and the reaction medium can be recycled up to five times, allowing the preparation of different substrates with a
N-Prolinylanthranilic acid derivatives as bifunctional organocatalysts for asymmetric aldol reactions
作者:Anthony J. Pearson、Santanu Panda
DOI:10.1016/j.tet.2011.04.033
日期:2011.6
and tested as bifunctionalorganocatalysts in the direct asymmetric aldolreaction of cyclohexanone with p-nitrobenzaldehyde. It was found that methyl substitution ortho to the carboxylic acid improves enantioselectivity, but substitution ortho to the anilide group does not. The catalyst derivedfrom 2-amino-6-methylbenzoic acid was tested over a range of direct asymmetric aldolreactions and its overall
<i>trans</i>-4-Hydroxy-<scp>l</scp>-proline Hydrazide-Trifluoroacetic Acid as Highly Stereoselective Organocatalyst for the Asymmetric Direct Aldol Reaction of Cyclohexanone
作者:Jian Sun、Chuanling Cheng、Siyu Wei
DOI:10.1055/s-2006-950431
日期:2006.9
Protonated A,-benzyl-N '-L-prolyl-trans-4-hydroxy-L-proline hydrazide has been found to be superior to the L-proline hydrazide counterpart as the catalyst for the asymmetricaldolreaction of cyclohexanone and aromatic aldehydes, resulting in excellent diastereoselectivities (up to > 99:1 dr) and enantioselectivities (up to > 99% ee).