Synthesis and Characterization of Monosaccharide Derivatives and Application of Sugar-Based Prolinamides in Asymmetric Synthesis
作者:Jyoti Agarwal、Rama Krishna Peddinti
DOI:10.1002/ejoc.201200522
日期:2012.11
were converted into the corresponding prolinamide organocatalysts (i.e., 1a, 2a, 3a, and 3b) in high yields. The catalytic activity of these sugar-based prolinamide organocatalysts was demonstrated in asymmetric aldol reactions in various solvents and at different temperatures. The oraganocatalyst 3a was shown to be an efficient and powerful organocatalyst for the enantioselective aldol reaction of various
Highly efficient and solvent-free direct aldol reaction catalyzed by glucosamine-derived prolinamide
作者:Jyoti Agarwal、Rama Krishna Peddinti
DOI:10.1016/j.tetasy.2010.06.009
日期:2010.8
The catalytic activity of novel sugar-based prolinamides in the aldol reaction between ketones and aryl aldehydes has been examined. The prolinamide 1c was found to be an efficient organocatalyst for the asymmetric aldol reaction under solvent-free conditions. A variety of ketones and aldehydes were used as substrates and the corresponding aldol products were obtained in excellent chemical yields with
Highly diastereo- and enantioselective direct aldol reaction under solvent-free conditions
作者:Furen Zhang、Chunmei Li、Chenze Qi
DOI:10.1016/j.tetasy.2013.02.013
日期:2013.4
An efficient, solvent-free protocol for the asymmetric aldol reaction between aldehydes and ketones using prolinamides 1-4 as organocatalysts is reported. Catalysts 2-4, in the presence of TFA (the ratio of catalyst and TFA = 1/1.5), proved to be excellent catalysts, giving the aldol products between aromatic aldehydes and ketones with nearly perfect diastereo- and enantioselectivities (up to >99:1 dr and >99% ee). This catalytic system can also be applied in the cross-aldol reaction of isatin with ketones and the Michael reaction between cyclohexane and nitroalkenes. A mechanism is proposed to account for the formation of the major enantiomer in this reaction. (c) 2013 Elsevier Ltd. All rights reserved.