物理化学学报 >> 2015, Vol. 31 >> Issue (10): 1864-1871.doi: 10.3866/PKU.WHXB201508281

理论与计算化学 上一篇    下一篇

铜催化内炔的硅羧基化反应机理及区域选择性的密度泛函理论研究

赵义*(),周晋,刘会,禚淑萍   

  • 收稿日期:2015-07-01 发布日期:2015-10-10
  • 通讯作者: 赵义 E-mail:zhaoyichem@sina.com
  • 基金资助:
    国家自然科学基金(51302156, 21302057);山东省自然科学基金联合专项(ZR2014BL012)

Reaction Mechanism and the Regioselectivity of Cu-Catalyzed Silacarboxylation of Internal Alkynes: a Density Functional Theory Study

Yi. ZHAO*(),Jin. ZHOU,Hui. LIU,Shu-Ping. ZHUO   

  • Received:2015-07-01 Published:2015-10-10
  • Contact: Yi. ZHAO E-mail:zhaoyichem@sina.com
  • Supported by:
    the National Natural Science Foundation of China(51302156, 21302057);Combined with Shandong ProvincialNatural Science Foundation, China(ZR2014BL012)

摘要:

用CO2作为原料,在过渡金属催化下生成新的碳碳键是很重要的.在这类反应中,杂原子官能团和CO2同时与不饱和的底物被催化生成高功能化的羧酸衍生物已经越来越受到人们的关注.本文采用密度泛函理论(DFT)方法,研究了金属铜催化剂催化内炔的硅羧基化反应机理.根据炔烃上甲基和苯环两个取代基的相对位置,提出了两条反应路径(path I:甲基和path II:苯环).计算结果表明炔烃插入Cu-Si键既是速率决速步骤也是区域选择决速步骤.在path I中,炔烃插入Cu-Si键的自由能为112.8 kJ·mol-1,而在path II中为127.6kJ·mol-1.显然, path I比path II在动力学上更有利,这与实验上两条路径对应产物的产率97: 3是一致的.分析表明区域选择性是由炔烃取代基甲基和苯环的电子效应决定的.

关键词: 区域选择性, 炔烃, 硅羧基化, CO2, 密度泛函理论

Abstract:

Transition metal-catalyzed carbon-carbon bond formation utilizing CO2 is of great importance. The heteroatom functionality and CO2 are simultaneously and catalytically incorporated into unsaturated substrates to form highly functionalized carboxylic acid derivatives. Here, density functional theory (DFT) is used to study the reaction mechanisms of the Cu-catalyzed silacarboxylation of internal alkynes. Two possible paths were proposed depending on the relative positions of the substituents (path I: methyl and path II: phenyl). The calculations reveal that the initial alkyne insertion into the Cu―Si bond determined both the rate and the selectivity. In path I, the calculated free energy barrier for alkyne insertion is 112.8 kJ·mol-1, while that in path II is 127.6 kJ·mol-1. Thus, path I is more kinetically favorable than path II, which is consistent with the experimentally observed product ratio of 97 : 3. Our analysis revealed that the electronic effects of the alkyne substituents dominated the observed regioselectivity.

Key words: Regioselectivity, Alkyne, Silacarboxylation, Carbon dioxide, Density functional theory

MSC2000: 

  • O643