title: C(sp3)-F bond activation of CF3-substituted anilines with catalytically generated silicon cations: spectroscopic evidence for a hydride-bridged Ru-S dimer in the catalytic cycle.
abstract: Heterolytic splitting of the Si-H bond mediated by a Ru-S bond forms a sulfur-stabilized silicon cation that is sufficiently electrophilic to abstract fluoride from CF(3) groups attached to selected anilines. The ability of the Ru-H complex, generated in the cooperative activation step, to intramolecularly transfer its hydride to the intermediate carbenium ion (stabilized in the form of a cationic thioether complex) is markedly dependent on the electronic nature of its phosphine ligand. An electron-deficient phosphine thwarts the reduction step but, based on the Ru-S catalyst, half of an equivalent of an added alkoxide not only facilitates but also accelerates the catalysis. The intriguing effect is rationalized by the formation of a hydride-bridged Ru-S dimer that was detected by (1)H NMR spectroscopy. A refined catalytic cycle is proposed.
authors: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany.
authors: Timo
authors: T
authors: Stahl
authors: Hendrik F T
authors: HF
authors: Klare
authors: Martin
authors: M
authors: Oestreich
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D019281:Dimerization; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D002412:Cations; D009942:Organometallic Compounds; D013455:Sulfur; D012428:Ruthenium; C023650:aniline; D012825:Silicon