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  

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

作　　者：任颖 李昌华 王涛 薛珊珊 张婷婷 贾建峰[1] 武海顺[1] REN Ying;LI Changhua;WANG Tao;XUE Shanshan;ZHANG Tingting;JIA Jianfeng;WU Haishun(Key Laboratory of Magnetic Molecules and Magnetic Information Materials,Ministry of Education,School of Chemistry and Materials Science,Shanxi Normal University,Linfen 041004,China)

机构地区：[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

出　　处：《高等学校化学学报》2021年第6期1793-1800,共8页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21501115);山西省高等学校教学改革创新项目(批准号:J2020138);山西省师范大学教学改革创新项目(批准号:2019JGXM-09)资助。

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.A systematic mechanistic investigation was carried out for the Pd-catalyzed oxidative N—H carbonylation to synthesis of 1,3,4-oxadiazole-2(3 H)-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 of102.0 kJ/mol. Furthermore,ligand effect and substituent effect are also been elucidated.

关 键 词：钯催化 羰基化反应 反应机理 密度泛函理论 

分 类 号：O641[理学—物理化学]