title: Synthesis of rhodium(I) and iridium(I) complexes of chiral N-heterocyclic carbenes and their application to asymmetric transfer hydrogenation.
abstract: Rhodium and iridium complexes of chiral NHC-phenolimine and NHC-amine ligands have been prepared and studied for asymmetric transfer hydrogenation. X-ray and NMR spectroscopy show that for NHC-phenolimine complexes abstraction of chloride results in a change in ligand coordination from NHC only to chelating NHC-imine. Complexes of NHC-amines are inactive for transfer hydrogenation, whereas complexes of NHC-phenolimines are active at room temperature for a range of aryl containing ketones. Enantioselectivity is very sensitive to the NHC N-substituent resulting in a switch in the predominant enantiomer.
authors.affiliation: Department of Chemistry, University of York, Heslington, York, UKYO10 5DD.
authors.forename: Gavin
authors.initials: G
authors.lastname: Dyson
authors.forename: Jean-Cédric
authors.initials: JC
authors.lastname: Frison
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Whitwood
authors.forename: Richard E
authors.initials: RE
authors.lastname: Douthwaite
mesh_terms: D000588:Amines / Q000737:chemistry; D002384:Catalysis; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006865:Hydrogenation; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000588:Amines; D006571:Heterocyclic Compounds; D008024:Ligands; D009942:Organometallic Compounds; C030011:carbene; D007495:Iridium; D012238:Rhodium; D008697:Methane