Density functional theory investigation of the Alkyl-aikyl negishi Cross-coupling reaction catalyzed by N-heterocyclic carbene (NHC)-Pd complexes

Gregory A. Chass, Christopher J. O'Brien, Niloufar Hadei, Eric Assen B Kantchev, Wei Hua Mu, De Cai Fang, Alan C. Hopkinson, I. Csizmadia, Michael G. Organ

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Abstract

A novel mechanism is proposed for the Pd-1,3-(2,6-diisopropyl-phenyl) imidazolyl-2-ylidene (1) catalyzed Negishi reaction. DFT computations supported by atoms-in-molecules (AIM) analyses of non-truncated models show that a "steric wall" created by the iV-substituent on the ligand guides reactants to and from the Pd center. Notably, transmetalation and not oxidative addition is found to be rate-limiting. Additionally, a key Pd-Zn interaction (≈2.4 Å, pb ≈ 0.0600 au) is identified in the mechanism. This interaction persists beyond reductive elimination and, in combination with the ligand, facilitates reductive elimination by creating a highly sterically crowded environment in the coordination sphere of the Pd center.

Original languageEnglish
Pages (from-to)4281-4288
Number of pages8
JournalChemistry - A European Journal
Volume15
Issue number17
DOIs
Publication statusPublished - Apr 20 2009

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Keywords

  • Cross-coupling
  • Density functionnl calculations
  • N-hetcro-cyclic carbenes
  • Palladium
  • Zinc

ASJC Scopus subject areas

  • Chemistry(all)

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