Hydroxyamide-Functionalized Azolium Anchored on Merrifield Resin for Enantioselective Ir-Catalyzed Reduction of Ketones with Silane

Polystyrene-supported chiral hydroxyamide-functionalized benzimidazolium chloride was synthesized by reacting Merrifield resin with a substituted-azole derived from (S)-leucinol. The combination of [IrCl(cod)]2 and the resulting polymer-supported N-heterocyclic carbene (NHC) ligand precursor catalyzed the enantioselective reduction of ketones using (EtO)2MeSiH under heterogeneous reaction conditions via a pre-mixing reaction procedure. Additionally, the solid-state resin could be easily recovered through simple filtration and the catalyst system’s reusability was evaluated.