当前位置: X-MOL 学术Org. Chem. Front. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
The origin of regioselectivity in Cu-catalyzed hydrocarbonylative coupling of alkynes with alkyl halides
Organic Chemistry Frontiers ( IF 5.4 ) Pub Date : 2020-03-25 , DOI: 10.1039/d0qo00214c
Shengnan Liu 1, 2, 3, 4, 5 , Jianbiao Liu 1, 2, 3, 4, 5 , Qiong Wang 1, 2, 3, 4, 5 , Jin Wang 1, 2, 3, 4, 5 , Fang Huang 1, 2, 3, 4, 5 , Wenjuan Wang 1, 2, 3, 4, 5 , Chuanzhi Sun 1, 2, 3, 4, 5 , Dezhan Chen 1, 2, 3, 4, 5
Affiliation  

In recent years, the versatile reactivity of Cu-catalyzed hydrocarbonylative coupling of alkynes with alkyl halides has drawn widespread attention. In this paper, we explore in detail the origin of different regioselectivities for terminal/internal alkynes coupling with primary, secondary and tertiary alkyl halides by using density functional theory (DFT) calculations. The present results reveal that the dominant factor of high Cα-regioselectivity in alkyne insertion is mainly the electron effect for the terminal alkyne, in which the higher electron density of terminal carbon makes electrophilic attack more favorable. For internal alkynes, such as 1-phenyl-1-hexyne, the d orbital in Cu which is able to conjugate with the HOMO of the benzene ring plays a dominant role in Cα-selective formation of alkenyl copper. Moreover, we also confirmed that enones were formed by C–C concerted coupling of alkenyl copper with acyl bromide instead of the oxidative addition suggested in the literature. Notably, the origin of the regioselectivity of 1,2-reduction over 1,4-reduction is mainly the steric effect, whether for the terminal alkyne or the internal alkyne case.

中文翻译:

炔烃与烷基卤化物在铜催化的烃基化偶联反应中区域选择性的起源

近年来,炔烃与烷基卤化物的铜催化的羰基化偶合反应的通用性引起了广泛的关注。在本文中,我们通过使用密度泛函理论(DFT)计算,详细探讨了末端/内部炔烃与伯,仲和叔烷基卤化物偶联的不同区域选择性的起源。本结果表明,高C的主导因素α在炔插入-regioselectivity主要为末端炔,其中末端碳的更高的电子密度使得电攻击更有利的电子效应。对于内部炔烃,如1-苯基-1-己炔,所述d在Cu中的轨道,其能够共轭与苯环的HOMO起着℃的主导作用α烯基铜的选择性形成。此外,我们还证实烯酮是通过烯基铜与酰基溴的CC协同偶联形成的,而不是文献中建议的氧化加成反应。值得注意的是,无论是对于末端炔烃还是内部炔烃,1,2-还原与1,4-还原的区域选择性的起源主要是空间效应。
更新日期:2020-03-25
down
wechat
bug