Ru-Catalyzed C–H Arylation of Fluoroarenes with Aryl Halides

Research output: Contribution to journalArticle

  • Authors:
  • Marco Simonetti
  • Gregory J. P. Perry
  • Xacobe C. Cambeiro
  • Francisco Julia-Hernandez
  • Jude N. Arokianathar
  • And 1 others
  • External authors:
  • Igor Larrosa

Abstract

Although the ruthenium-catalyzed C–H arylation of arenes bearing directing groups with haloarenes is well-known, this process has never been achieved in the absence of directing groups. We report the first example of such a process and show that unexpectedly the reaction only takes place in the presence of catalytic amounts of a benzoic acid. Furthermore, contrary to other transition metals, the arylation site selectivity is governed by both electronic and steric factors. Stoichiometric and NMR mechanistic studies support a catalytic cycle that involves a well-defined η6-arene-ligand-free Ru(II) catalyst. Indeed, upon initial pivalate-assisted C–H activation, the aryl-Ru(II) intermediate generated is able to react with an aryl bromide coupling partner only in the presence of a benzoate additive. In contrast, directing-group-containing substrates (such as 2-phenylpyridine) do not require a benzoate additive. Deuterium labeling and kinetic isotope effect experiments indicate that C–H activation is both reversible and kinetically significant. Computational studies support a concerted metalation–deprotonation (CMD)-type ruthenation mode and shed light on the unusual arylation regioselectivity.

Bibliographical metadata

Original languageEnglish
Pages (from-to)3596-3606
Number of pages10
JournalAmerican Chemical Society. Journal
Volume138
Issue number10
DOIs
StatePublished - 2016