67215-69-4Relevant academic research and scientific papers
Characterization of the isochromen-4-yl-gold(I) intermediate in the gold(I)-catalyzed glycosidation of glycosyl ortho-alkynylbenzoates and enhancement of the catalytic efficiency thereof
Zhu, Yugen,Yu, Biao
, p. 8329 - 8332 (2011/10/18)
Gold standard: The title gold complex (see scheme) was characterized unambiguously as an important intermediate in the title reaction. Protonolysis of this vinyl gold(I) complex was critical for regeneration of the active gold(I) species for the catalytic
Gold(I)-Catalyzed Conia-Ene Reaction of β-Ketoesters with Alkynes
Kennedy-Smith, Joshua J.,Staben, Steven T.,Toste, F. Dean
, p. 4526 - 4527 (2007/10/03)
The intramolecular addition of β-ketoesters to unactivated alkynes under neutral conditions and at room temperature is described. The method employs triphenylphosphinegold(I) cation as a catalyst for the formation of exo-methylenecycloalkanes. Both monocyclic and bicyclic cyclopentanes and cyclohexanes can be formed in excellent yields and with good diastereoselectivity. Copyright
Organometallic gold(III) compounds as catalysts for the addition of water and methanol to terminal alkynes
Casado, Raquel,Contel, Maria,Laguna, Mariano,Romero, Pilar,Sanz, Sergio
, p. 11925 - 11935 (2007/10/03)
Different inorganic and organometallic gold(III) and gold(I) complexes have been tested in the addition of water and methanol to terminal alkynes. Anionic and neutral organometallic gold(III) compounds can efficiently mediate these reactions in neutral media in refluxing methanol. The compounds are added in catalytic amounts (1.6-4.5 mol% with respect to the alkyne), Thus, compounds of the general formula Q[AuRCl3], Q[AuR2Cl2], [AuRCl2]2, and [AuR2Cl]2, (Q = BzPPh3+, PPN: N(PPh3)2+ or N(Bu)4+; R = C6F5 or 2,4,6-(CH3)3C6H2) seem to behave as Lewis acids in nucleophilic additions to triple bonds. Some intermediates could be detected in the stoichiometric reaction between [Au(C6F 5)2Cl]2 and phenylacetylene that was followed by variable temperature 1H, 19F{1H}, COSY 19F{1H}-19F{1H}, and 2H{1H} NMR experiments. Compound [Au(C6F 5)2Cl]2 is also able to catalyze the hydration of phenylacetylene at room temperature. A plausible mechanism for the hydration reaction has been proposed.
H+/AuPPh3+ Exchange for the Hydride Complexes CpMoH(CO)2(L) (L = PMe3, PPh3, CO). Formation and Structure of [Cp(CO)2(PMe3)Mo(AuPPh3)2] +[BF4]-
Galassi, Rossana,Poli, Rinaldo,Quadrelli, E. Alessandra,Fettinger, James C.
, p. 3001 - 3007 (2008/10/09)
The reaction of CpMoH(CO)2L with AuPPh3 +BF4- in THF at -40 °C proceeds directly to the MoAu2 cluster compounds [CpMo(CO)2L(AuPPh3)2]+BF 4- (L = PMe3 (1), PPh3 (2)) with release of protons. A 1:1 reaction leaves 50% of the starting hydride unreacted. At lower temperature, however, the formation of a [CpMo(CO)2-(PMe3)(μ-H)(AuPPh3)]+ intermediate is observed. This compound evolves to the cation of 1 and CpMoH(CO)2-(PMe3) upon warming and is deprotonated by 2,6-lutidine to afford CpMo(CO)2(PMe3)(AuPPh3). The X-ray structure of 1 can be described as a four-legged piano stool with the PMe3 and the η2-(AuPPh3)2 ligands occupying relative trans positions. [Cp(CO)2(PMe3)Mo(AuPPh3)2] +[BF4]- (Mr = 1298.41): monoclinic, space group P21/ n, a= 18.1457(13) A?, b = 9.7811(7) A?, c = 26.096(2) A?, β= 105.086(5)°, V = 4472.0(5) ?3, Z = 4. The reaction of CpMoH(CO)2(PMe3) with 3 equiv of AuPPh3+ affords a MoAu3 cluster, [CpMo(CO)2(PMe3)-(AuPPh3)3] 2+ (3), in good yields under kinetically controlled conditions. Under thermodynamically controlled conditions, 3 dissociates extensively into 1 and free AuPPh3+.. It is proposed that the hydride ligand helps build higher nuclearity Mo - Au clusters. The difference in reaction pathways for the interaction of AuPPh3+ with CpMoH(CO)2L when L = PR3 or CO and for the interaction of CpMoH(CO)2(PMe3 with E+ when E = H, Ph3C or AuPPh3 is discussed. The lower acidity and greater aurophilicity of the [CpMo(CO)2L(μ-H)(AuPPh3)]+ intermediate when L = PMe3 favor attack by AuPPh3+ before deprotonation.
