Highly efficient primary amine organocatalysts for the direct asymmetric aldol reaction in brine
作者:Xiao Ma、Chao-Shan Da、Lei Yi、Ya-Ning Jia、Qi-Peng Guo、Li-Ping Che、Feng-Chun Wu、Jun-Rui Wang、Wei-Ping Li
DOI:10.1016/j.tetasy.2009.05.032
日期:2009.7
amine organocatalysts, derivedfrom natural primary amino acids, in combination with 2,4-dinitrophenol (DNP) have proven to be efficient in the presence of brine without further addition of organic solvents. The system formed by 1f and DNP was the most efficient one; it can catalyze the directaldolreaction with a broad range of ketones and aromatic aldehydes, giving the corresponding aldol products
Catalytic antibody 27C1 bears binding sites for both a substrate-and a functionalized small nonprotein component in the active site. We investigated the possibility of exploiting imine and enamine intermediates using a primary amine molecule into the active site of antibody 27C1. The antibody catalyzed beta-keto acid decarboxylation with a rate enhancement (k(cat)/K-m/k(uncat)) of 140,000, as well as highly regioselective cross-aldol reactions of ketones and p-nitrobenzaldehyde. These studies provide new strategies for the generation of catalytic antibodies possessing binding sites for functionalized components. (C) 2013 Elsevier Ltd. All rights reserved.
Proline-based dipeptides as efficient organocatalysts for asymmetric aldol reactions in brine
Simple N-proline-based dipeptides with two N-H groups in combination with 2,4-dinitrophenol (DNP) catalyze the direct asymmetric aldol reactions of aldehydes with a broad range of ketones to furnish the corresponding aldol products in high yields (up to 99%) and with high enantioselectivities (up to 97%) and diastereoselectivities (up to > 99:1, anti/syn) at room temperature and in brine. (C) 2011 Elsevier Ltd. All rights reserved.