title: Iridium-catalyzed arene ortho-silylation by formal hydroxyl-directed C-H activation.
abstract: A strategy for the ortho-silylation of aryl ketone, benzaldehyde, and benzyl alcohol derivatives has been developed in which a hydroxyl group formally serves as the directing element for Ir-catalyzed arene C-H bond activation. One-pot generation of a (hydrido)silyl ether from the carbonyl compound or alcohol is followed by dehydrogenative cyclization at 80-100 °C in the presence of norbornene as a hydrogen acceptor and the combination of 1 mol % [Ir(cod)OMe]2 and 1,10-phenanthroline as a catalyst to form benzoxasiloles. The synthetic utility of the benzoxasilole products is demonstrated by conversion to phenol or biaryl derivatives by Tamao-Fleming oxidation or Hiyama cross-coupling. Both of these transformations of the C-H silylation products exploit the Si-O bond in the system and proceed by activation of the silyl moiety with hydroxide, rather than fluoride.
authors.affiliation: Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Simmons
authors.forename: John F
authors.initials: JF
authors.lastname: Hartwig
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D007204:Indium / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*
chemical_list: D006841:Hydrocarbons, Aromatic; D006878:Hydroxides; D012821:Silanes; D007204:Indium; D002244:Carbon; D006859:Hydrogen; C031356:hydroxide ion