59512-47-9Relevant articles and documents
Asymmetric aldol reaction catalyzed by modularly designed organocatalysts
Sinha, Debarshi,Mandal, Tanmay,Gogoi, Sanjib,Goldman, Joshua J.,Zhao, John Cong-Gui
, p. 2624 - 2630 (2013/01/15)
The self-assembly of the precatalyst modules, which are amino acids and cinchona alkaloid derivatives, leads to the direct formation of the desired organocatalysts without any synthesis. These modularly designed organocatalysts (MDOs) may be used for cata
Acyclic amino acids catalyzed direct asymmetric aldol reactions in aqueous media assisted by 2,4-dinitrophenol
Deng, Dongsheng,Liu, Ping,Ji, Baoming,Fu, Weijun,Li, Long
experimental part, p. 163 - 170 (2010/11/04)
The catalytic capabilities of acyclic amino acids for the direct asymmetric aldol reactions assisted by 2,4-dinitrophenol in aqueous media were investigated. Several acyclic amino acids catalyzed asymmetric aldol reactions with excellent stereoselectivity, and afforded the corresponding β-hydroxy ketones in high yields and up to 99% ee. Our result suggested that the L-isoleucine was the most effective one. Springer Science+Business Media, LLC 2010.
Water versus solvent-free conditions for the enantioselective inter- and intramolecular aldol reaction employing l-prolinamides and l-prolinethioamides as organocatalysts
Almasi, Diana,Alonso, Diego A.,Balaguer, Andrea-Nekane,Najera, Carmen
supporting information; scheme or table, p. 1123 - 1131 (2009/12/07)
Organocatalysts 1, derived from L-proline and (1S,2R)-cis-l-aminoindan-2-ol or (R)-l-aminoin-dane, are evaluated as promoters in the direct asymmetric aldol reaction between ketones and aromatic aldehydes in the presence of water and under solvent-free reaction conditions. L-Prolinethioamides 1c and 1d exhibited higher enantioselectivity than the corresponding prolinamides 1a and 1b in the model aldol reaction between cyclohexanone and 4-nitro-benzaldehyde in the presence of 4-nitrobenzoic acid as cocatalyst. In particular, L-prolinethioamide 1d (5 mol%), derived from L-proline and (R)-1-amino-indane, is shown as the most efficient organocatalyst studied promoting the direct aldol reaction of cyclo-alkyl, alkyl, and a-functionalized ketones with aromatic aldehydes in the presence of water and under solvent-free reaction conditions employing only 2 equivalents of nucleophile. Generally, anft-aldol products are obtained in high yields and excellent diastereo- and enantioselectivities (up to > 98/2 until syn, up to 98% ee). Solvent-free conditions give slightly higher dr and ee than using water as solvent. In addition, organocatalyst Id can be easily recovered by extractive work-up and reused. Prolinethio-amide Id (5 mol%) in combination with 4-NO2C6H4CO2H (5 mol%) is also a very effective or-ganocatalytic system for the asymmetric solvent-free intramolecular Haj os-Parrish-Eder-Sauer-Wiechert reaction with comparable or higher levels of enantioselectivity (up to 88% ee) to other reported catalysts in organic solvents.
