Buttressing effect as a key design principle towards highly efficient palladium/N-heterocyclic carbene Buchwald–Hartwig amination catalysts
| Autor: | Guy Lavigne, Noël Lugan, Yin Zhang, Vincent César |
|---|---|
| Přispěvatelé: | Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Steric effects
010405 organic chemistry Chemistry Stereochemistry Ligand Organic Chemistry Substrate (chemistry) chemistry.chemical_element General Chemistry Buchwald–Hartwig amination 010402 general chemistry 01 natural sciences Medicinal chemistry Catalysis 0104 chemical sciences chemistry.chemical_compound [CHIM.COOR]Chemical Sciences/Coordination chemistry Catalytic efficiency Carbene Palladium |
| Zdroj: | Chemistry-A European Journal Chemistry-A European Journal, Wiley-VCH Verlag, 2017, 23 (55), pp.13792-13801. ⟨10.1002/chem.201702859⟩ |
| ISSN: | 0947-6539 1521-3765 |
| DOI: | 10.1002/chem.201702859⟩ |
| Popis: | International audience; The backbone substitution of the standard 1,3-bis(2,6-diisopropylphenyl)-2H-imidazol-2-ylidene (IPr) ligand by dimethylamino groups was previously shown to induce a dramatic improvement in the catalytic efficiency of the corresponding Pd–PEPPSI (pyridine-enhanced pre-catalyst preparation, stabilization, and initiation) pre-catalysts in N-arylation reactions. Herein, a thorough structure/activity study towards rationalizing this beneficial effect has been described. In addition to the previously reported IPrNMe2 and IPr(NMe2)2 ligands, the new IPrNiPr2 and IPr(NMe2,Cl) ligands, which bear one bulkier diisopropylamino group and a combination of dimethylamino and chloro substituents, respectively, have been designed and analyzed in the study. The influence of the backbone substitution was found to be steric in origin and is related to the well-known buttressing effect encountered in arene chemistry. The usefulness and versatility of this approach was demonstrated through the development of a highly efficient catalytic system for the challenging arylation of bulky α,α,α-trisubstituted primary amines. The optimized system based on the [PdCl(η3-cinnamyl)(IPr(NMe2)2 )] or [PdCl(η3-cinnamyl)(IPrNiPr2 )] pre-catalysts operates under unprecedented mild conditions (catalyst loadings: 0.5–2 mol %, reaction temperatures: 40–60 °C) with a wide substrate scope. |
| Databáze: | OpenAIRE |
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