Asymmetric allylic substitution–isomerization to axially chiral enamides <i>via</i> hydrogen-bonding assisted central-to-axial chirality transfer
作者:Chao Sun、Xiaotian Qi、Xiao-Long Min、Xue-Dan Bai、Peng Liu、Ying He
DOI:10.1039/d0sc02828b
日期:——
Axially chiral enamides bearing a N–C axis have been recently studied and were proposed to be valuable chiral building blocks, but a stereoselective synthesis has not been achieved. Here, we report the first enantioselective synthesis of axially chiral enamides via a highly efficient, catalytic approach. In this approach, C(sp2)–N bond formation is achieved through an iridium-catalyzed asymmetric allylation
最近已经研究了带有N–C轴的轴向手性酰胺,它们被认为是有价值的手性构件,但尚未实现立体选择性合成。在这里,我们通过高效的催化方法报告了轴向手性酰胺的首次对映选择性合成。在这种方法中,C(sp 2)–N键的形成是通过铱催化的不对称烯丙基化而实现的,然后通过有机碱在初始产物中进行原位异构化,从而促进了1,3-H的转移,从而形成了具有出色的手性从中心到轴向的转移。计算和实验研究表明1,3-H的转移通过手性离子对中间体的逐步去质子化/再质子化途径。与烯酰胺羰基的氢键相互作用在促进逐步1,3-H转移的反应性和立体特异性方面都起着重要作用。温和且操作简单的形式化N-乙烯基化反应提供了一系列构型稳定的轴向手性酰胺,具有良好或优异的收率和对映选择性。