研究小组报道了前所未有的底物导向的，铱催化的三取代烯烃形成一个无环全碳四元立体中心β到氮原子的对映选择性氢炔化反应。烯酰胺的氢炔化反应具有非常规的选择性，有利于阻碍反应的位置。合成了具有β-立体中心的同炔丙基酰胺，具有较高的区域选择性和对映性。结合实验和计算研究揭示了区域选择性和对映选择性的起源。
研究人员表示，全碳季碳中心的立体选择性结构，特别是无环季碳中心的立体选择性结构是有机合成中的一个重要挑战。特别是具有β到氮原子的四元立体中心的同丙基酰胺是一种很有价值的合成中间体，可以通过炔烃转化转化为多种手性结构。然而，高对映选择性合成具有β季元立体中心的同丙基酰胺的方法是极为罕见的。
附：英文原文
Title: Ir-Catalyzed Regio- and Enantioselective Hydroalkynylation of Trisubstituted Alkene to Access All-Carbon Quaternary Stereocenters
Author: Su-Lei Zhang, Wen-Wen Zhang, Bi-Jie Li
Issue&Volume: June 21, 2021
Abstract: The stereoselective construction of all-carbon quaternary stereocenters, especially acyclic ones, represents an important challenge in organic synthesis. In particular, homopropargyl amides with a quaternary stereocenter β to a nitrogen atom are valuable synthetic intermediates, which could be transformed to diverse chiral structures through alkyne transformations. However, highly enantioselective synthetic methods for homopropargyl amides with a β quaternary stereocenter are extremely rare. We report here unprecedented substrate-directed, iridium-catalyzed enantioselective hydroalkynylations of trisubstituted alkenes to form an acyclic all-carbon quaternary stereocenter β to a nitrogen atom. The hydroalkynylation of enamide occurred with unconventional selectivity, favoring the more hindered reaction site. Homopropargyl amides with β-stereocenters were prepared in high regio- and enantioselectivities. Combined experimental and computational studies revealed the origin of the regio- and enantioselectivities.
DOI: 10.1021/jacs.1c04493
Source: https://pubs.acs.org/doi/10.1021/jacs.1c04493
