Stereoselective Allylic Alkylation of 1-Pyrroline-5-carboxylic Esters via a Pd/Cu Dual Catalysis
作者:Penglin Liu、Xiaohong Huo、Bowen Li、Rui He、Jiacheng Zhang、Tianhong Wang、Fang Xie、Wanbin Zhang
DOI:10.1021/acs.orglett.8b02902
日期:2018.10.19
The asymmetric allylation of 1-pyrroline-5-carboxylic esters has been accomplished through a synergistic Pd/Cu catalyst system under mild reaction conditions. The mechanistic studies suggested that (1) nucleophilic attack is the enantiodiscriminating step; (2) the cooperative action of two chiral reactive species, N-metalated azomethine ylides and π-allylpalladium, is most likely responsible for its
1-吡咯啉-5-羧酸酯的不对称烯丙基化反应是通过在适度的反应条件下通过协同的Pd / Cu催化剂体系完成的。机理研究表明:(1)亲核攻击是对映区分的步骤;(2)两种手性反应物种N-金属化的甲亚胺基化物和π-烯丙基钯的协同作用最有可能归因于其高反应性和出色的对映选择性(高达> 99%ee); (3)烯丙基亲电子试剂和亚氨基酯底物的位阻和电子因子对于线性产物的形成至关重要。一系列3,4-2 H具有高的立体产率和高至极高的区域选择性和对映选择性的合成具有四级立体异构中心的-吡咯衍生物。