Chiral Brønsted Acid-Catalyzed Direct Asymmetric Mannich Reaction
作者:Qi-Xiang Guo、Hua Liu、Chang Guo、Shi-Wei Luo、Yi Gu、Liu-Zhu Gong
DOI:10.1021/ja068236b
日期:2007.4.1
A chiral Bronsted acid-catalyzed direct asymmetric Mannich reaction has been described. Various phosphoric acids, prepared from BINOL and H-8-BINOL derivatives, have been evaluated for catalyzing the direct Mannich reaction. In the presence of a truly catalytic amount of the phosphoric acid, anti-selective Mannich reactions of cyclic ketones with a wide scope of aldimines were obtained in high yields with excellent enantioselectivities (up to 98% ee) and high diastereomeric ratios (up to 98/2 dr). A one-pot Mannich reaction using aromatic ketones as donors proceeded smoothly to give beta-amino carbonyls with fairly good enantioselectivities.
Nanostructured Zirconium Pyrophosphate Catalyzed Diastereoselective Synthesis of β-Amino Ketones via One-Pot Three-Component Mannich Reaction
co-precipitation. Moreover, the ZrP2O7 catalysts were easily recovered and reused several times with only a slight loss of activity. At the conclusion of this study, a possible mechanism of the Mannichreaction over ZrP2O7 catalysts was also proposed and discussed.Graphical abstract
在本研究中,ZrP2O7 催化纳米材料是通过共沉淀和聚乙烯吡咯烷酮辅助的方法制备的。这些纳米材料通过 XRD、N2 吸附/解吸、TGA、SEM 和 TEM 显微技术进行了结构表征。本研究调查了这些纳米材料在醛、酮和胺的一锅三组分缩合合成各种β-氨基羰基化合物中的应用。结果,在室温下在水-乙醇混合溶剂中获得了高效率。在优化条件下,与共沉淀法制备的催化剂相比,PVP 辅助法制备的催化剂表现出更高的催化活性和更高的非对映选择性。此外,ZrP2O7 催化剂很容易回收和重复使用多次,活性只有轻微的损失。