O-Functionalised NHC Ligands for Efficient Nickel-catalysed C–O Hydrosilylation

Authors

  • Simone Bertini Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
  • Martin Albrecht Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland;, Email: martin.albrecht@dcb.unibe.ch

DOI:

https://doi.org/10.2533/chimia.2020.483

PMID:

32560754

Keywords:

NHC ligands, Nickel catalysis

Abstract

A series of C,O-bidentate chelating mesoionic carbene nickel(ii) complexes [Ni(NHC^PhO)2] (NHC = imidazolylidene or triazolylidene) were applied for hydrosilylation of carbonyl groups. The catalytic system is selective towards aldehyde reduction and tolerant to electron-donating and -withdrawing group substituents. Stoichiometric experiments in the presence of different silanes lends support to a metal–ligand cooperative activation of the Si–H bond. Catalytic performance of the nickel complexes is dependent on the triazolylidene substituents. Butyl-substituted triazolylidene ligands impart turnover numbers up to 7,400 and turnover frequencies of almost 30,000 h-1, identifying this complex as one of the best-performing nickel catalysts for hydrosilylation and demonstrating the outstanding potential of O-functionalised NHC ligands in combination with first-row transition metals.

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Published

2020-06-24