1112-67-0Relevant articles and documents
EFFECT OF THE NATURE OF SOLID METAL FLUORIDES ON THE ALKYLATION KINETICS OF CH-ACIDS IN THE PRESENCE OF ONIUM SALTS
Esikova, I. A.
, p. 2463 - 2468 (1989)
The selective C-alkylation of ethyl 2-methylacetoacetate by prenyl chloride in the presence of solid metal fluorides proceeds at room temperature with yields of from 2.5 to 87.5percent depending on the nature of the deprotonating agent.The alkylation rate increases in going from LiF to CsF.A linear correlation was found between the activation free energy for thealkylation reaction and the crystal lattice energy of the solid metal fluorides.Ion exchange was not observed between tetrabutylammonium chloride and solid KF, CsF, and CaF2 in acetonitrile.The extent of the exchange with KF*2H2O over 10 h did not exceed 6percent.Deprotonation of ethyl 2-methylacetoacetate by the action of the solid metal fluorides was not observed.Loss of the CH-acid is found in the presence of an onium salt, which varies upon changing the nature of the deprotonating agent; LiF ca.NaF ca.KF (30percent), RbF (54percent), CsF (90percent), CaF2 (35percent).
Anion recognition by a macrobicycle based on a tetraoxadiaza macrocycle and an isophthalamide head unit
Bernier, Nicolas,Carvalho, Silvia,Li, Feng,Delgado, Rita,Felix, Vitor
, p. 4819 - 4827 (2009)
(Chemical Equation Presented) A macrobicycle formed by a tetraoxadiaza macrocycle containing a dibenzofuran (DBF) spacer and an isophthalamide head unit, named DBF-bz, was used as receptor for anion recognition. The molecular structure of DBF-bz was estab
Parker,A.J. et al.
, p. 2228 - 2235 (1972)
Lewis Acidity Scale of Diaryliodonium Ions toward Oxygen, Nitrogen, and Halogen Lewis Bases
Legault, Claude Y.,Mayer, Robert J.,Mayr, Herbert,Ofial, Armin R.
supporting information, (2020/03/13)
Equilibrium constants for the associations of 17 diaryliodonium salts Ar2I+X- with 11 different Lewis bases (halide ions, carboxylates, p-nitrophenolate, amines, and tris(p-anisyl)phosphine) have been investigated by titrations followed by photometric or conductometric methods as well as by isothermal titration calorimetry (ITC) in acetonitrile at 20 °C. The resulting set of equilibrium constants KI covers 6 orders of magnitude and can be expressed by the linear free-energy relationship lg KI = sI LAI + LBI, which characterizes iodonium ions by the Lewis acidity parameter LAI, as well as the iodonium-specific affinities of Lewis bases by the Lewis basicity parameter LBI and the susceptibility sI. Least squares minimization with the definition LAI = 0 for Ph2I+ and sI = 1.00 for the benzoate ion provides Lewis acidities LAI for 17 iodonium ions and Lewis basicities LBI and sI for 10 Lewis bases. The lack of a general correlation between the Lewis basicities LBI (with respect to Ar2I+) and LB (with respect to Ar2CH+) indicates that different factors control the thermodynamics of Lewis adduct formation for iodonium ions and carbenium ions. Analysis of temperature-dependent equilibrium measurements as well as ITC experiments reveal a large entropic contribution to the observed Gibbs reaction energies for the Lewis adduct formations from iodonium ions and Lewis bases originating from solvation effects. The kinetics of the benzoate transfer from the bis(4-dimethylamino)-substituted benzhydryl benzoate Ar2CH-OBz to the phenyl(perfluorophenyl)iodonium ion was found to follow a first-order rate law. The first-order rate constant kobs was not affected by the concentration of Ph(C6F5)I+ indicating that the benzoate release from Ar2CH-OBz proceeds via an unassisted SN1-type mechanism followed by interception of the released benzoate ions by Ph(C6F5)I+ ions.
Distinguishing between pathways for transmetalation in Suzuki-Miyaura reactions
Carrow, Brad P.,Hartwig, John F.
supporting information; experimental part, p. 2116 - 2119 (2011/04/23)
We report a systematic study of the stoichiometric reactions of isolated arylpalladium hydroxo and halide complexes with arylboronic acids and aryltrihydroxyborates to evaluate the relative rates of the two reaction pathways commonly proposed to account for transmetalation in the Suzuki-Miyaura reaction. On the basis of the relative populations of the palladium and organoboron species generated under conditions common for the catalytic process and the observed rate constants for the stoichiometric reactions between the two classes of reaction components, we conclude that the reaction of a palladium hydroxo complex with boronic acid, not the reaction of a palladium halide complex with trihydroxyborate, accounts for transmetalation in catalytic Suzuki-Miyaura reactions conducted with weak base and aqueous solvent mixtures.
