Direct asymmetric aldol reaction of acetone with α-ketoesters catalyzed by primary–tertiary diamine organocatalysts
作者:Zhaoqin Jiang、Yixin Lu
DOI:10.1016/j.tetlet.2010.02.044
日期:2010.4
Novel primary–tertiary diamine organocatalysts derived from l-serine were utilized to promote enantioselective aldolreaction of acetone with α-ketoesters. The desired products were obtained in high yields and with good to excellent enantioselectivities (up to 95% ee).
In prime condition: The hydrolysis of a chiral diimine precursor can be carried out by a Brønsted acid to form an in situprimaryamine–imine intermediate as a bifunctionalprimary aminocatalyst, which promoted direct asymmetricaldolreactions 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)。