1,2,4-Triazole-Based N-Heterocyclic Carb­ene Nickel Complexes - Synthesis and Catalytic Application

• Published in: European journal of inorganic chemistry Vol. 2015; no. 31; pp. 5226 - 5231
• Main Authors: Bheeter, Linus P., Wei, Duo, Dorcet, Vincent, Roisnel, Thierry, Ghosh, Prasenjit, Sortais, Jean-Baptiste, Darcel, Christophe
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-11-2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc; Wiley-VCH Verlag
• Subjects: Aromatic compounds; Bearing; Borylation; Bromides; Carbene ligands; Carbenes; Catalysis; Catalysts; Chemical Sciences; Cross-coupling; Homogenous catalysis; Ligands; Nickel
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201500852

Four nickel complexes bearing 1,2,4‐triazole‐based N‐heterocyclic carbene backbones and a cyclopentadienyl ligand were prepared from the corresponding 1,2,4‐triazolium salts and nickelocene in tetrahydrofuran (THF) under reflux. The obtained complexes were fully characterized, including by X‐ray diffraction analysis. They were then used as catalysts (5 mol‐%) for the borylation of aryl bromide derivatives with bis(pinacolato)diboron in the presence of Cs2CO3 as the base in THF at 70 °C for 20 h to form the corresponding borylated products in moderate yields.
Four new nickel complexes bearing 1,2,4‐triazole‐based N‐heterocyclic carbene backbones and a cyclopentadienyl ligand are prepared, fully characterized, and evaluated in the catalytic borylation of aryl bromides with bis(pinacolato)diboron.