Direct Asymmetric Michael Reaction of α,β-Unsaturated Aldehydes and Ketones Catalyzed by Two Secondary Amine Catalysts
作者:Yujiro Hayashi、Nariyoshi Umekubo
DOI:10.1002/anie.201710085
日期:2018.2.12
A direct asymmetric Michael reaction of α,β‐unsaturated aldehydes and ketones proceeded in the presence of two pyrrolidine‐type catalysts, a diphenylprolinol silyl ether and hydroxyproline, to afford synthetically useful δ‐keto aldehydes with excellent diastereo‐ and enantioselectivity. Although there are several iminium ions and enamines in the reaction mixture, the iminium ion generated by the former
α,β-不饱和醛与酮的直接不对称迈克尔反应在两种吡咯烷型催化剂(二苯基脯氨醇甲硅烷基醚和羟脯氨酸)的存在下进行,从而提供了具有优异的非对映异构和对映选择性的合成有用的δ-酮醛。尽管在反应混合物中存在多个亚胺离子和烯胺,但是由前一种催化剂产生的亚胺离子优先与由后一种催化剂产生的烯胺反应。