Asymmetric transfer hydrogenations of β-N-substituted enamino esters with ammonia borane
作者:Weiwei Zhao、Xiangqing Feng、Jing Yang、Haifeng Du
DOI:10.1016/j.tetlet.2019.03.060
日期:2019.4
β-enamino esters is one of the most efficient approaches for their synthesis. Ammonia borane with low molecular weight, high hydrogen capacity, and good stability, is an ideal hydrogen source for the transfer hydrogenation. However, only a few successful examples have been reported for the asymmetric reduction with ammonia borane. In this work, an asymmetric metal-free transfer hydrogenation of β-N-substituted
旋光性β-氨基酸及其衍生物是合成和药物化学中非常有用的组成部分。β-烯氨基酯的催化不对称还原是最有效的合成方法之一。低分子量,高氢气容量和良好稳定性的氨硼烷是转移加氢的理想氢源。但是,只有少数成功的例子报道了用氨硼烷进行不对称还原。在这项工作中,β-不对称无金属转移氢化Ñ取代与ammoinia硼烷烯酯成功通过使用路易斯受挫对桥墩的硼烷和(实现小号) -叔-丁基亚磺酰胺作为手性催化剂。以51–90%的产率获得了多种β-氨基酸衍生物,ee高达91%。