Chem. J. Chinese Universities ›› 2021, Vol. 42 ›› Issue (6): 1793.doi: 10.7503/cjcu20210067

• Physical Chemistry • Previous Articles     Next Articles

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

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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