化学学报 ›› 2016, Vol. 74 ›› Issue (5): 422-428.DOI: 10.6023/A15110736 上一篇    下一篇

研究论文

Mn(I)催化亚胺和炔烃脱氢偶联反应的机理研究

杨一诺, 张琪, 石景, 傅尧   

  1. 中国科学技术大学化学系 合肥 230026
  • 收稿日期:2015-11-21 出版日期:2016-05-15 发布日期:2016-03-22
  • 通讯作者: 石景, 傅尧 E-mail:shijing@ustc.edu.cn;fuyao@ustc.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos. 21325208, 21172209, 21361140372, 21202006)、973计划(No. 2012CB215306)、中央高校基础研究经费(Nos. WK2060190025, WK2060190040, FRF-TP-14-015A2)和中国科学院基金(No. KJCX2-EW-J02)资助.

Mechanism Study of Mn(I) Complex-catalyzed Imines and Alkynes Dehydrogenation Coupling Reaction

Yang Yinuo, Zhang Qi, Shi Jing, Fu Yao   

  1. Department of Chemistry, University of Science and Technology of China, Hefei 230026
  • Received:2015-11-21 Online:2016-05-15 Published:2016-03-22
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21325208, 21172209, 21361140372, 21202006), 973 Program (No. 2012CB215306), Fundamental Research Funds for the Central Universities (Nos. WK2060190025, WK2060190040, FRF-TP-14-015A2) and Science Foundation of The Chinese Academy of Sciences (No. KJCX2-EW-J02).

近年来随着过渡金属催化剂的发展和广泛使用, C—H键的活化成为了有机合成中的一大热点, 尤其是在构建有机化合物C—C键中应用广泛. 作为一种储量较大的廉价催化剂, Mn催化的C—H活化表现出巨大的应用价值和研究潜力. 我们采用密度泛函理论(DFT), 对1,4-二氧六环溶液中Mn活化C—H/N—H键实现[4+2]脱氢环化的反应机理进行了系统的研究. 我们发现该反应的催化循环包括溴负离子辅助的催化剂引发、炔烃的插入、双键迁移成环、β-H消除释放产物异喹啉以及催化脱氢循环的C—H键活化等步骤. 旨在深入理解Mn(I)活化C—H键脱氢气的具体过程, 为更多Mn催化的C—H活化反应提供理论依据.

关键词: Mn催化, 密度泛函理论(DFT), C—H活化, 反应机理

With the development and widespread use of transition metal catalysts, C—H activation has become a hot topic in organic synthesis, especially in the construction of C—C bond of organic compounds. As an important and cheap catalyst, manganese complex has shown great potential for catalyzing C—H activation both in academic and industrial applications. In this paper, the mechanism of manganese-catalyzed dehydrogenative [4+2] annulation by C—H/N—H activation was investigated systematically with the aid of density functional theory (DFT) calculations in 1,4-dioxane solvent. In detail, we use M06-L/[SDD:6-311+G(d,p)(SMD)]//M06-L/[LANL2DZ:6-31G(d)] to examine the Gibbs free energy, structure and other properties of possible intermediates and transition states in this catalytic cycle. By comprehensive comparison and discussion, we obtained a favorable pathway consisting of five steps: (1) catalyst initiation occurred with the assistance of bromine anion rather than imide to form active catalyst; (2) alkyne inserted into the active catalyst to generate a seven-membered manganacycle after dissociation of a carbon monoxide; (3) double bond migration happened in this seven-membered manganacycle to form a product precursor; (4) the product precursor would dissociate by β-H elimination and generated product isoquinoline and active Mn—H complex; (5) the active Mn—H complex was subsequently combined with an imine followed by dehydrogenative C—H activation to complete the whole catalytic cycle. In this context, the reason for the highly atom-economical C—H activation by direct dehydrogenation (eliminates the necessity for oxidants or additives) has been clarified by this mechanism. The present study was aimed at further understanding of Mn(I)-catalyzed dehydrogenative C—H activation, and provided more theoretical basis for future more Mn-catalyzed C—H activation.

Key words: manganese-catalyzed, density functional theory (DFT), C—H activation, mechanism