Density Functional Theory Investigation of the Alkyl-Alkyl Negishi Cross-Coupling Reaction Catalyzed by N-Heterocyclic Carbene (NHC)-Pd Complexes Academic Article uri icon

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abstract

  • A novel mechanism is proposed for the Pd-1,3-(2,6-diisopropylphenyl)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 N-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 (approximately = 2.4 A, rho(b) approximately = 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.

authors

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

publication date

  • April 20, 2009