In Situ Formed Bifunctional Primary Amine-Imine Catalyst for Asymmetric Aldol Reactions of α-Keto Esters
作者:Xi Zhu、Aijun Lin、Ling Fang、Wei Li、Chengjian Zhu、Yixiang Cheng
DOI:10.1002/chem.201100200
日期:2011.7.18
In prime condition: The hydrolysis of a chiral diimine precursor can be carried out by a Brønsted acid to form an in situ primary amine–imine intermediate as a bifunctional primary aminocatalyst, which promoted direct asymmetric aldol reactions between α‐keto esters and ketones in high yields (up to 88 %) and with excellent enantioselectivities (see scheme; R1, R2, R4=alkyl; R3=aryl).
在最佳条件下:手性二亚胺前体的水解可通过布朗斯台德酸进行,形成原位伯胺-亚胺中间体,作为双官能伯氨基催化剂,从而促进α-酮酯与酮之间的直接不对称醛醇缩合反应。产率(高达88%)并且具有优异的对映选择性(参见方案; R 1,R 2,R 4=烷基; R 3=芳基)。