Related Experiment Video
Updated: Jun 1, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Autocatalysis for C-H bond activation by ruthenium(II) complexes in catalytic arylation of functional arenes
Emmanuel Ferrer Flegeau1, Christian Bruneau, Pierre H Dixneuf
1Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, 75231 Paris Cedex 5, France.
Abstract:
Kinetic data for the C-H bond activation of 2-phenylpyridine by Ru(II)(carboxylate)(2)(p-cymene) I (acetate) and I' (pivalate) are available for the first time. They reveal an irreversible autocatalytic process catalyzed by the coproduct HOAc or HOPiv (acetonitrile, 27 °C). The overall reaction is indeed accelerated by the carboxylic acid coproduct and water. It is retarded by a base, in agreement with an autocatalytic process induced by HOAc or HOPiv that favors the dissociation of one carboxylate ligand from I and I' and consequently the ensuing complexation of 2-phenylpyridine (2-PhPy). The C-H bond activation initially delivers Ru(O(2)CR)(o-C(6)H(4)-Py)(p-cymene) A or A', containing one carboxylate ligand (OAc or OPiv, respectively). The overall reaction is accelerated by added acetates. Consequently, C-H bond activation (faster for acetate I than for pivalate I') proceeds via an intermolecular deprotonation of the C-H bond of the ligated 2-PhPy by the acetate or pivalate anion released from I or I', respectively. The 18e complexes A and A' easily dissociate, by displacement of the carboxylate by the solvent (also favored by the carboxylic acid), to give the same cationic complex B(+) {[Ru(o-C(6)H(4)-Py)(p-cymene)(MeCN)](+)}. Complex B(+) is reactive toward oxidative addition of phenyl iodide, leading to the diphenylated 2-pyridylbenzene.
Related Concept Videos
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Catalysis
Catalysis
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Olefin Metathesis Polymerization: Overview
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...

