Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (5): 422-428.DOI: 10.6023/A15110736 Previous Articles     Next Articles



杨一诺, 张琪, 石景, 傅尧   

  1. 中国科学技术大学化学系 合肥 230026
  • 投稿日期:2015-11-21 发布日期:2016-03-22
  • 通讯作者: 石景, 傅尧;
  • 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 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).

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