Palladium asymmetric reduction of β-carboline imines mediated by chiral auxiliaries assisted by microwave irradiation
作者:Marlene Espinoza-Moraga、Ana Gloria Caceres、Leonardo Silva Santos
DOI:10.1016/j.tetlet.2009.09.181
日期:2009.12
An alternative synthetic approach for the introduction of chirality in β-carboline moiety through in situ reduction of N-acyliminium ion intermediates generated from imine 2 and chloroformate of 8-phenylmenthyl as chiral auxiliary was achieved. The method applied microwave-assisted irradiation and used PdCl2/Et3SiH protocol as a mild reducing agent, which decreased reaction times to minutes when compared
通过原位还原由亚胺2和8-苯基薄荷基的氯甲酸酯作为手性助剂生成的N-酰基亚胺离子中间体,实现了另一种在β-咔啉部分中引入手性的合成方法。该方法采用微波辅助辐射,并使用PdCl 2 / Et 3 SiH协议作为温和的还原剂,与常规的热反应相比,该方法将反应时间缩短至数分钟。还原产生的R-胺的非对映选择性(4-12:1),与从Noyori不对称氢化催化剂获得的产物相比,在手性辅助去除和光谱数据后将其分配。