100-66-3Relevant articles and documents
Efficient aryl-(hetero)aryl coupling by activation of C-Cl and C-F bonds using nickel complexes of air-stable phosphine oxides
Ackermann, Lutz,Born, Robert,Spatz, Julia H.,Meyer, Daniel
, p. 7216 - 7219 (2005)
(Chemical Equation Presented) A couple of couplings: Air-stable diamino-and dioxophosphine oxides are used as preligands in the nickel-catalyzed Kumada cross-coupling reactions of aryl Grignard reagents. A sterically hindered preligand allows for highly efficient cross-coupling of aryl fluorides at ambient temperature (acac = acetylacetonate).
Association Reactions of Trimethylsilyl Ions
Lin, Yi,Ridge, D. P.,Munson, Burnaby
, p. 550 - 558 (1991)
Adduct ions, (1+), were produced by bimolecular association reactions of trimethylsilyl ions, (CH3)3Si(1+), with acetone, cyclohexanone, anisole, dimethyl ether, 2,5-dimethylfuran, 2-methylfuran and furan in ion cyclotron resonance experiments at 300 K and at pressures of ca. 10-7 Torr (1 Torr = 133,3 Pa).The rate constants, ka, for the association reactions varied from 100percent to 2 percent of the collision rate constants, kc.The rate constants were independent of pressure, except for furan.Measurements were also made of bond dissociation energies for these adduct ions, D, from equilibrium measurements.The a ssociation efficiency, ka/kc, increased with increasing bond dissociation energy and with increasing numbers of degrees of freedom, in qualitative aggreement with theoretical predictions.Observations pertinent to the dependence of ka on reactant temperature and relative kinetic energy are discussed.The possibility of determining ion-neutral complex binding energies from radiative association rate constants is considered.
Ortho-selective methylation of phenol catalyzed by CeO2-MgO prepared by citrate process
Sato, Satoshi,Koizumi, Kaoru,Nozaki, Fumio
, p. 264 - 274 (1998)
Vapor-phase alkylation of phenol with methanol was investigated over CeO2-MgO catalysts prepared utilizing a molten mixture of the corresponding nitrates and citric acid. The CeO2-MgO had attractive catalytic performance without decay of activities at the temperature range between 450 and 550°C, and it had excellent selectivities to the sum of o-cresol and 2,6-xylenol higher than 98%. The CeO2-MgO catalysts were found to be mixtures of MgO and an interstitial solid solution of MgxCe1-x/2O2 as a result of XRD measurement. It is confirmed that citric acid used in the preparation heightens the dispersion of the solid solution in the MgO matrix. The pure CeO2, which also exhibited efficient ortho-selectivity, had only weak basic sites in the TPD experiment of adsorbed CO2, while the pure MgO with strong basicity showed very low reaction rate in the methylation. The solid solution of MgxCe1-x/2O2 in the CeO2-MgO catalyst probably provides active centers for the methylation of phenol. In the results of methanol decomposition, methanol was converted into CO, CO2, and CH4 over the CeO2-MgO catalysts, without producing dimethyl ether. The reaction mechanism of the ortho-methylation over the CeO2-MgO catalyst is speculated: the ortho position of phenol adsorbed perpendicularly on weak basic sites on the MgxCe1-x/2O2 solid solution is selectively alkylated by methanol which is possibly activated in the form of formyl or hydroxy methyl group rather than methyl cation.
Dehydrogenative coupling of primary alcohols to form esters catalyzed by a ruthenium N-heterocyclic carbene complex
Solvhoj, Amanda,Madsen, Robert
, p. 6044 - 6048 (2011)
The ruthenium complex [RuCl2(IiPr)(p-cymene)] catalyzes the direct condensation of primary alcohols into esters and lactones with the release of hydrogen gas. The reaction is most effective with linear aliphatic alcohols and 1,4-diols and is believed to proceed with a ruthenium dihydride as the catalytically active species.
Ionic liquids as recyclable and separable reaction media in Rh-catalyzed decarbonylation of aromatic and aliphatic aldehydes
Malcho, Phillip,Garca-Surez, Eduardo J.,Riisager, Anders
, p. 58151 - 58155 (2014)
Ionic liquids (ILs) have been applied as recyclable reaction media in the decarbonylation of aldehydes in the presence of a rhodium-phosphine complex catalyst. The performance of several new catalytic systems based on imidazolium-based ILs and [Rh(dppp)2]Cl (dppp: 1,3-diphenylphosphinopropane) were excellent in the decarbonylation of both aromatic and aliphatic aldehydes providing >99 yield of benzenes and alkanes, respectively. The catalytic performance depended, however, strongly on the employed IL and its thermal stability. In addition, the ILs afforded good catalyst immobilization as well as a biphasic system with the product allowing recovery and reuse of the employed catalyst.
Cationic nickel porphyrinoids with unexpected reactivity
Wicht, Richard,Bahnmüller, Stefanie,Brandhorst, Kai,Schweyen, Peter,Br?ring, Martin
, p. 583 - 588 (2016)
Cationic nickel(ii) complexes of two ring-contracted porphyrinoid ligands distantly related to the corrins were prepared by metal templated macrocyclisation. The compounds show reversible electron transfer processes and were found to be the first porphyrinoid-based catalysts for C-C cross-coupling.
Fluoroform-derived CuCF3 for low-cost, simple, efficient, and safe trifluoromethylation of aryl boronic acids in air
Novak, Petr,Lishchynskyi, Anton,Grushin, Vladimir V.
, p. 7767 - 7770 (2012)
Easy does it: Aryl boronic acids undergo smooth and selective trifluoromethylation with low-cost fluoroform-derived CuCF3 in DMF in non-dried air. The reaction occurs under mild conditions (1 atm, room temperature), exhibits unprecedented funct
Nucleophilic trifluoromethylation of aryl halides with methyl trifluoroacetate
Langlois, Bernard R.,Roques, Nicolas
, p. 1318 - 1325 (2007)
When associated with an alkaline halide, such as cesium fluoride or cesium chloride, and Cu(I) species, methyl trifluoroacetate (MTFA) constitutes a valuable trifluoromethylating agent for substituting aromatic (or heteroaromatic) iodides and bromides. The reaction can be carried out in DMF at 180 °C or, better, in sulfolane which allows he reaction to proceed at a lower temperature (from 140 °C).
PdCl2-catalyzed hydrogenolysis of a C-O bond in monoaryl sulfates by sodium phosphinate in an aqueous alkaline medium
Davydov, D. V.,Beletskaya, I. P.
, p. 573 - 575 (1993)
The hydrogenolysis of the C-O bond in monoaryl sulfates by the action of an excess of NaH2PO2 in the presence of catalytic amounts of PdCl2 and KOH is studied.The reaction proceeds chemoselectively with complete ester conversion to the corresponding arenes.
Gold-catalysis: Reactions of organogold compounds with electrophiles
Hashmi, A. Stephen K.,Ramamurthi, Tanuja Dondeti,Todd, Matthew H.,Tsang, Althea S.-K.,Graf, Katharina
, p. 1619 - 1626 (2010)
Different arylgold(I), one alkynylgold(I), and one vinylgold(I) triphenylphosphane complexes were subjected to electrophilic halogenation reagents. With N-chlorosuccinimid, N-bromosuccinimid, and N-iodosuccinimid as well as the Barluenga reagent, selectively halogenated compounds were obtained. Trifluoroacetic acid, as a source of protons, leads to a clean protodeauration. With N-fluorobenzenesulfonimide or Selectfluor, exclusively a homocoupling was observed. For the precursor of the vinylgold(I) complex, a similar oxidative coupling could be induced by gold(III) chloride. Reactions with silicon or tin electrophiles failed. CSIRO 2010.
