高等学校化学学报 ›› 2021, Vol. 42 ›› Issue (6): 1793.doi: 10.7503/cjcu20210067

• 物理化学 • 上一篇    下一篇

钯催化氧化N—H键羰基化反应合成1,3,4⁃噁二唑⁃2(3H)⁃酮杂环化合物机理的理论研究

任颖(), 李昌华, 王涛, 薛珊珊, 张婷婷, 贾建峰, 武海顺   

  1. 山西师范大学化学与材料科学学院, 磁性分子与磁信息材料教育部重点实验室, 临汾 041004
  • 收稿日期:2021-01-29 出版日期:2021-06-10 发布日期:2021-03-24
  • 通讯作者: 任颖 E-mail:ren.ying1991@163.com
  • 基金资助:
    国家自然科学基金(21501115);山西省高等学校教学改革创新项目(J2020138);山西省师范大学教学改革创新项目(2019JGXM-09)

Theoretical Studies on Pd-catalyzed Oxidative N─H Carbonylation to Synthesis of 1,3,4-Oxadiazole-2(3H)-one Heterocyclic Compounds

REN Ying(), LI Changhua, WANG Tao, XUE Shanshan, ZHANG Tingting, JIA Jianfeng, WU Haishun   

  1. Key Laboratory of Magnetic Molecules and Magnetic Information Materials,Ministry of Education,School of Chemistry and Materials Science,Shanxi Normal University,Linfen 041004,China
  • Received:2021-01-29 Online:2021-06-10 Published:2021-03-24
  • Contact: REN Ying E-mail:ren.ying1991@163.com

摘要:

通过密度泛函理论(DFT)研究了钯催化氧化N—H键羰基化反应合成1,3,4-噁二唑-2(3H)-酮杂环化合物的反应机理. 计算结果表明, 这一反应的催化循环包含N1—H活化、 羰基插入、 N2—H活化和还原消除4个阶段. 反应首先通过协同金属化/去质子化机理活化N1—H键, 然后羰基插入Pd—N1键生成稳定的六元金属环中间体, 随后通过一步反应直接发生N2—H键活化, 最后还原消除. 其中, 羰基插入是整个催化循环的决速步骤, 能垒为102.0 kJ/mol. 研究了配体效应和取代基效应, 其结果与已有的实验结果一致.

关键词: 钯催化, 羰基化反应, 反应机理, 密度泛函理论

Abstract:

A systematic mechanistic investigation was carried out for the Pd-catalyzed oxidative N—H carbonylation to synthesis of 1,3,4-oxadiazole-2(3H)-ones. The calculation results show the preferred cataly-tic cycle proceeds in steps through N1—H activation, CO insertion, N2—H activation, and reductive elimination. The N1—H activation proceeds in a concerted metalation/deprotonation mechanism, and following CO inserts into Pd—N1 bond forming a stable six-membered ring intermediate. Then the metallacycle intermediate undergoes the N2—H bond activation directly through a one-step reaction, and finally reduction and elimination occur to complete the entire catalytic cycle. The rate-determining step is CO insertion with a Gibbs energy of 102.0 kJ/mol. Furthermore, ligand effect and substituent effect are also been elucidated.

Key words: Pd catalysis, Carbonylation, Reaction mechanism, Density functional theory

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