Benzoate cyclometallation enables oxidative addition of haloarenes at a Ru(II) center

Research output: Contribution to journalArticle

  • Authors:
  • Marco Simonetti
  • Rositha Kuniyil
  • Stuart A. Macgregor
  • Igor Larrosa

Abstract

The first Ru(II)-catalyzed arylation of substrates without a directing group was recently developed. Remarkably, this process only worked in the presence of a benzoate additive, found to be crucial for the oxidative addition step at Ru(II). However, the exact mode of action of the benzoate was unknown. Herein, we disclose a mechanistic study that elucidates the key role of the benzoate salt in the C–H arylation of fluoroarenes with aryl halides. Through a combination of rationally designed stoichiometric experiments and DFT studies, we demonstrate that the aryl–Ru(II) species arising from initial C–H activation of the fluoroarene undergoes cyclometalation with the benzoate to generate an anionic Ru(II) intermediate. The enhanced lability of this intermediate, coupled with the electron-rich anionic Ru(II) metal center renders the oxidative addition of the aryl halide accessible. The role of an additional (NMe4)OC(CF3)3 additive in facilitating the overall arylation process is also shown to be linked to a shift in the C–H pre-equilibrium associated with benzoate cyclometalation.

Bibliographical metadata

Original languageEnglish
Pages (from-to)11836-11847
Number of pages11
JournalJournal of the American Chemical Society
Volume140
Issue number37
Early online date22 Aug 2018
DOIs
Publication statusPublished - 2018