Ligation state of nickel during C-O bond activation with monodentate phosphines

TETRAHEDRON

卷:74

Article

Hooker, Leidy V.¹  Neufeldt, Sharon R.¹ 

[1] Montana State Univ, Dept Chem & Biochem, 103 Chem & Biochem Bldg, Bozeman, MT 59717 USA

关键词: DFT;    Dispersion;    Oxidative addition;    Cross coupling;    Phosphine ligands;   

DOI  :  10.1016/j.tet.2018.10.025

来源: Elsevier

【 摘 要 】

The oxidative addition of phenolic electrophiles at Ni(0) in the presence of monodentate phosphine ligands was studied with both dispersion-free and dispersion-containing DFT methods. With the popular bulky ligand PCy3, consideration of dispersion has a striking effect on the predicted ligation state of nickel during oxidative addition of aryl sulfa mates. Dispersion-containing methods such as M06L indicate a clear preference for a bis-phosphine ligated transition state (TS), while dispersion free methods like B3LYP strongly favor a mono-phosphine ligated TS. This discrepancy in predicted ligation state is also found with small phosphines (PMe3) in combination with some aryl electrophiles (carbamates, acetates, pivalates, chlorides), but a bis-PMe3-ligated TS is predicted regardless of dispersion for other electrophiles (sulfamates, mesylates, tosylates). DFT calculations that include dispersion also offer a possible explanation for the observed poor efficacy of (PBu3)-Bu-t as a ligand in Ni-catalyzed cross-coupling reactions. (C) 2018 Elsevier Ltd. All rights reserved.

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