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Density Functional Theory Investigation of the Alkyl–Alkyl Negishi Cross‐Coupling Reaction Catalyzed by N‐Heterocyclic Carbene (NHC)–Pd Complexes |
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| Authors: | Gregory?A Chass Dr Christopher?J O'Brien Dr Niloufar Hadei Dr Eric?Assen?B Kantchev Dr Wei‐Hua Mu De‐Cai Fang Prof Alan?C Hopkinson Prof Imre?G Csizmadia Prof Michael?G Organ Prof |
| Institution: | 1. School of Chemistry, University of Wales, Bangor, LL57 2UW (UK), Fax: (+44)?1248‐370528;2. Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J?1P3 (Canada), Fax: (+1)?416‐736‐5936;3. College of Chemistry, Beijing Normal University, Beijing, 100875 (China), Fax: (+86)?10‐58805422;4. Department of Chemistry, University of Toronto, ON, M5G?2E8 (Canada) |
| Abstract: | Why bigger is better : A “steric wall” created by the N‐(2,6‐diisopropylphenyl) substituent on the bulky NHC ligand IPr (1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) guides the reactants to and from the Pd center through weak, fleeting (IPr)H–Pd interactions that help the oxidative addition intermediate escape “the anti‐trap”. The alternative “side” approach leads to transmetalation (the rate‐limiting step) for which a novel Pd–Zn interaction was identified.  |
| Keywords: | cross‐coupling density functional calculations N‐heterocyclic carbenes palladium zinc |