title: Synthesis of iridium and rhodium complexes with new chiral phosphine-NHC ligands based on 1,1'-binaphthyl framework and their application in asymmetric hydrogenation.
abstract: The first series of chiral phosphine-imidazole carbene ligands based on a 1,1'-binaphthyl framework were synthesized from (R)-2-amine-2'-(diphenylphosphino)-1,1'-binaphthyl (1) in a four-step pathway. After deprotonation of these phosphine-imidazolium salts with LiO(t)Bu, and subsequent complexation with [Ir(COD)Cl]2 and anion exchange with NaBArF, phosphine-carbene chelated iridium complexes (R)-6a and (R)-6b were obtained. Their structures have been characterized by NMR and X-ray diffraction analysis. The NHC-phosphine rhodium complex (R)-6c has been also obtained by a similar synthetic method. These iridium complexes have been applied to catalyze the asymmetric hydrogenation of alkenes to give the corresponding products in moderate to excellent conversion (up to 99%) and moderate enantioselectivities under mild conditions (up to 61% ee).
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Mei-Long Road, Shanghai 200237, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Gu
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Qin
authors.initials: Q
authors.lastname: Xu
authors.forename: Min
authors.initials: M
authors.lastname: Shi
mesh_terms: D006571:Heterocyclic Compounds / Q000737:chemistry*; D006865:Hydrogenation; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*
chemical_list: D006571:Heterocyclic Compounds; D008024:Ligands; D009281:Naphthalenes; D009942:Organometallic Compounds; D010720:Phosphines; D007495:Iridium; D012238:Rhodium; C044646:phosphine; C412330:1,1'-binaphthyl