Development of a New Lewis Acid-Catalyzed [3,3]-Sigmatropic Rearrangement: The Allenoate-Claisen Rearrangement
作者:Tristan H. Lambert、David W. C. MacMillan
DOI:10.1021/ja028090q
日期:2002.11.1
A new Lewis acid-catalyzed Claisen rearrangement has been developed that allows the stereoselective construction of beta-amino-alpha,beta,epsilon,zeta-unsaturated-gamma,delta-disubstituted esters from simple allylic amines and allenoate esters. This reaction, which is contingent upon the use of Lewis acid, can be conducted with a range of metal salts (Yb(OTf)3, AlCl3, Sn(OTf)2, Cu(OTf)2, MgBr2.Et2O
已开发出一种新的路易斯酸催化克莱森重排,它允许从简单的烯丙胺和烯丙酸酯中立体选择性地构建 β-氨基-α、β、ε、zeta-不饱和-γ、δ-二取代酯。该反应取决于使用路易斯酸,可以使用一系列金属盐(Yb(OTf)3、AlCl3、Sn(OTf)2、Cu(OTf)2、MgBr2.Et2O、FeCl3、Zn (OTf)2) 的催化剂负载量低至 5 mol%。这种催化过程可以高产率地获得各种β-氨基-α、β、ε、zeta-不饱和-γ、δ-二取代酯,并且对一系列烯丙基吡咯烷(R1 = H, Me、i-Pr、Ph、NR2 = 吡咯烷、哌啶、NMe2;>/=81% 产率,>/=94:6 顺式:抗)和烯丙酸酯(R2 = H、Me、i-Pr、Ph、烯丙基, NPht, Cl; >/=75% 的产率,>/=91:9 同步:反)。这种新的克莱森重排为难以捉摸的结构基序提供催化途径的能力也已在由香叶基和橙花基吡咯烷