title: Iridium-catalyzed H/D exchange: ligand complexes with improved efficiency and scope.
abstract: Hydrogen isotope exchange (HIE) is one of the most attractive tools for the introduction of deuterium or tritium to an organic compound. Herein, iridium complexes with N,P-ligands, highly active catalysts for asymmetric double bond reductions, have been tested for their HIE capabilities. Electron-rich ligands, containing dicyclohexylphosphines or phosphinites, have been identified as excellent ligands for efficient deuterium incorporation. Substrates with strong directing groups, that is, pyridines, ketones, and amides, as well as weak ligating units, such as, nitro, sulfones, and sulfonamides, could be labeled efficiently. With the addition of tris(pentafluorophenyl) borane to the reaction mixture, also highly deactivating nitrile substituents were well tolerated in the reaction. Based on the excellent results obtained with the chiral ThrePhox ligand, a structurally simpler, achiral ligand was developed. The iridium complex containing this ligand, proved to be a powerful catalyst for HIE reactions.
authors.affiliation: Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel (Switzerland).
authors.forename: Michael
authors.initials: M
authors.lastname: Parmentier
authors.forename: Thomas
authors.initials: T
authors.lastname: Hartung
authors.forename: Andreas
authors.initials: A
authors.lastname: Pfaltz
authors.forename: Dieter
authors.initials: D
authors.lastname: Muri
mesh_terms: D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D007495:Iridium / Q000737:chemistry*; D008024:Ligands
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D007495:Iridium; D006859:Hydrogen; D003903:Deuterium
keywords: CH activation; deuterium; homogeneous catalysis; isotopic labeling; synthetic methods