Frontiers in Chemistry (Mar 2019)

Key Mechanistic Features in Palladium-Catalyzed Methylcyclopropanation of Norbornenes With Vinyl Bromides: Insights From DFT Calculations

  • Fang Ying,
  • Fang Ying,
  • Yutong Zhang,
  • Chuyue Xiang,
  • Zhijun Song,
  • Hujun Xie,
  • Weiliang Bao

DOI
https://doi.org/10.3389/fchem.2019.00169
Journal volume & issue
Vol. 7

Abstract

Read online

DFT calculations were performed to elucidate mechanistic details of an unusual palladium-catalyzed methylcyclopropanation from [2 + 1] cycloadditions of (Z)-2-bromovinylbenzene and endo-N-(p-tolyl)-norbornenesuccinimide. The reaction proceeds via oxidative addition (OA), intermolecular alkene insertion, deprotonation/protonation, intramolecular alkene insertion, β-H elimination and reductive elimination (RE). Protonation is the rate-limiting step and requires an overall barrier of 28.5 kcal/mol. The sources of two protons for protonation and exchange have also been clarified and the calculations agree with experimental observations.

Keywords