Organocatalytic asymmetric aldol reaction using protonated chiral 1,2-diamines
作者:Jae Ho Shim、Min-Joon Kim、Ji Yeon Lee、Kyoung Hoon Kim、Deok-Chan Ha
DOI:10.1016/j.tetlet.2020.152295
日期:2020.9
Organic-catalyzed stereoselective reactions have gained attention because they avoid the problems associated with metal catalysts, but existing catalysts based on proline have limitations. Therefore, (R,R)-(+)-1,2-diphenylethylenediamine (DPEN) was selectively mono-N-alkylated through reductive alkylation and used as an organic catalyst for the aldol reaction. Using a variety of aldehydes in the catalytic
Direct asymmetric aldol reactions between aldehydes and ketones catalyzed by l-tryptophan in the presence of water
作者:Zhaoqin Jiang、Hui Yang、Xiao Han、Jie Luo、Ming Wah Wong、Yixin Lu
DOI:10.1039/b921460g
日期:——
Primary amino acids and their derivatives were investigated as catalysts for the direct asymmetric aldol reactionsbetween ketones and aldehydes in the presence of water, and L-tryptophan was shown to be the best catalyst. Solvent effects, substrate scope and the influence of water on the reactions were investigated. Quantum chemical calculations were performed to understand the origin of the observed
Highly modular dipeptide-like organocatalysts for direct asymmetric aldol reactions in brine
作者:Xiao-Mu Hu、Dong-Xu Zhang、Sheng-Yong Zhang、Ping-An Wang
DOI:10.1039/c5ra07019h
日期:——
dipeptide-like organocatalysts derived from proline, amino acids and primaryamines have been prepared for directasymmetricaldolreactions between various aromatic aldehydes and acetone to afford aldol products in good yields (up to 82%) and moderate enantioselectivities (up to 67% ee) with only 1 mol% of catalyst-loading in brine. Under the same conditions, the directasymmetricaldolreactions of aromatic
Facile one-pot fabrication of magnetic nanoparticles (MNPs)-supported organocatalysts using phosphonate as an anchor point through direct co-precipitation method
Novel MNP-supported organocatalysts were prepared by one-pot co-precipitation and surface modification using phosphonate as an anchor point, and exhibited excellent performance in aqueous asymmetric aldol reactions.
Highly efficient direct a larger-scale aldol reactions catalyzed by a flexible prolinamide based-metal Lewis acid bifunctional catalyst in the presence of water
prolinamide-based organocatalysts were readily synthesized and applied to the asymmetric direct aldolreactions of ketones and aromatic aldehydes in the presence of water. When TFA was used as an acidic additive, 10 mol % loading of 1c afforded aldol products with good diastereoselectivity of up to 91/9 and enantioselectivity of up to 85%. When ZnCl2 was added as a metal Lewis acid additive, the aldol product