화학공학소재연구정보센터
Journal of Molecular Catalysis A-Chemical, Vol.421, 138-145, 2016
Chiral N-heterocyclic carbene iridium catalyst for the enantioselective hydrosilane reduction of ketones
Enantioselective reduction of ketones with (EtO)(2)MeSiH catalyzed by an in-situ generated N-heterocyclic carbene (NHC) Ir complex at room temperature has been developed. A series of benzimidazolium salts were synthesized and screened in the asymmetric hydrosilylation reaction. As a result, propiophenone was efficiently reduced by the combined catalytic system of [IrCl(cod)](2) and NHC-Ag complex derived from N-(1-naphthalenylmethyl)-substituted benzimidazolium salt L12, affording the corresponding alcohol in 92% yield and with 92% ee. Moreover, the evaluation of an Ir catalyst precursor showed that cationic [Ir(cod)(2)]BF4 complex could be used. Furthermore, the introduction of a chiral hydroxyamide side arm into the benzimidazolium salt was critical for the successful design of the NHC ligand. (C) 2016 Elsevier B.V. All rights reserved.