Proline-Glycine Dipeptidic Derivatives of Chiral Phosphoramides as Organocatalysts for the Enantiodivergent Aldol Reaction of Aryl Aldehydes and Isatins with Cyclohexanone in the Presence of Water
(S)-proline-glycine dipeptides and incorporating a chiral phosphoramide fragment was accomplished. These chiral compounds catalyze the enantioselective aldol addition reaction of cyclohexanone to prochiral aryl aldehydes and isatins in the presence of water. These chiral organocatalysts represent some of the few proline-derived compounds capable to catalyze aldol-type addition of cyclohexanone to isatins, a C–C
Synthesis of a new chiral organocatalyst derived from (S)-proline containing a 1,2,4-triazolyl moiety and its application in the asymmetric aldol reaction. Importance of one molecule of water generated in situ
作者:Omar Sánchez-Antonio、Eusebio Juaristi
DOI:10.1016/j.tetlet.2019.151128
日期:2019.10
yield. Our triazolyl-containing heterocycle was evaluated as organocatalyst (10 mol% load, under neat reaction conditions) in the enantioselective aldolreaction between four different types of ketones and a variety of aryl aldehydes. Good results in terms of enantioselectivity and chemical yield were observed under solvent-free reaction conditions and in the absence of any additive. Evidence is provided
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
New Mesoporous Silica-Supported Organocatalysts Based on (2S)-(1,2,4-Triazol-3-yl)-Proline: Efficient, Reusable, and Heterogeneous Catalysts for the Asymmetric Aldol Reaction
作者:Omar Sánchez-Antonio、Kevin A. Romero-Sedglach、Erika C. Vázquez-Orta、Eusebio Juaristi
DOI:10.3390/molecules25194532
日期:——
their efficiency was assessed in the asymmetric aldol reaction. These materials were fully characterized by FT-IR, MS, XRD, and SEM microscopy, gathering relevant information regarding composition, morphology, and organocatalyst distribution in the doped silica. Careful optimization of the reaction conditions required for their application as catalysts in asymmetric aldol reactions between ketones and
基于最近开发的 (S)-脯氨酸衍生物 (2S)-[5-(苄基硫基)-4-苯基-(1,2,4-三唑)-3-基]-吡咯烷负载在介孔二氧化硅上的新型有机催化系统是制备并在不对称醛醇反应中评估它们的效率。这些材料通过 FT-IR、MS、XRD 和 SEM 显微镜进行了全面表征,收集了有关掺杂二氧化硅中的组成、形态和有机催化剂分布的相关信息。仔细优化它们在酮和醛之间的不对称醛醇反应中用作催化剂所需的反应条件,提供了预期的醛醇产物,具有优异的产率和适中的非对映选择性和对映选择性。推荐的实验方案简单、快速、高效,提供对映体富集的醛醇产品,通常不需要特殊的后处理或纯化方案。这种方法构成了基于异质(S)-脯氨酸的有机催化领域的显着改进;特别地,本文所述的固相二氧化硅键合催化系统允许显着减少溶剂使用。此外,与新合成的有机催化剂相比,此处描述的支撑系统可以回收、重新激活和重复使用多次,催化效率损失有限。
Multifunctional phosphoramide-(<i>S</i>)-prolinamide derivatives as efficient organocatalysts in asymmetric aldol and Michael reactions
作者:Carlos Cruz-Hernández、José M. Landeros、Eusebio Juaristi
DOI:10.1039/c9nj00300b
日期:——
The synthesis and evaluation of three novel chiral organocatalysts derived from (S)-proline and containing a bis-amidophosphoryl amine fragment are reported. The structure and conformation of the new compounds were determined by NMR spectroscopy and X-ray crystallographic analysis. The present study represents an effort directed to enhance the performance of (S)-proline-derived organocatalysts in asymmetric