Addition of Azomethine Ylides to Aldehydes: Mechanistic Dichotomy of Differentially Substituted α-Imino Esters
作者:Brinton Seashore-Ludlow、Staffan Torssell、Peter Somfai
DOI:10.1002/ejoc.201000377
日期:——
of azomethine ylides and aldehydes is explored, as hydrolysis of the resulting oxazolidine product gives facile access to valuable syn-β-aryl-β-hydroxy-α-amino esters. The use of using benzaldehyde-derived imines as the ylide precursor results in 1,3-dipolar cycloaddition with high conversions but low diastereoselectivity. In contrast, the employment of benzophenone-derived imines as the ylide precursor
探索了偶氮甲碱叶立德和醛的正式 1,3-偶极环加成反应,因为所得恶唑烷产物的水解可以轻松获得有价值的顺-β-芳基-β-羟基-α-氨基酯。使用苯甲醛衍生的亚胺作为叶立德前体导致 1,3-偶极环加成反应具有高转化率但非对映选择性低。相比之下,使用二苯甲酮衍生的亚胺作为叶立德前体会导致羟醛反应,从而产生具有高非对映选择性的中间体恶唑烷,并且需要弱酸催化剂来实现更高的转化率。