4316-35-2Relevant articles and documents
Ring Substituent Effects on Acetophenone Dimethyl Acetal Formation. 1. Dual-Parameter Treatment of Equilibrium Data in Methanol, Water, and Dodecane
Toullec, Jean,El-Alaoui, Mohiedine,Kleffert, Pascal
, p. 4808 - 4816 (1983)
For substituted acetophenones, the ketone to acetal equilibrium constants, Kx, measured by a water concentration jump method, are reported.Ketone and acetal partition coefficients, P, for the water-dodecane and methanol-dodecane solvent systems provide Gibbs free energies of transfer from methanol to dodecane and from methanol to water.Both sets of results make it possible to calculate Kx values in water and dodecane; these values are compared with those directly measured in methanol and with equilibrium constants reported for other reactions involving the trigonal to tetrahedral conversion of the carbonyl carbon atom.Substituent effects tor the three solvents are examined by means of the usual dual-parameter Gibbs free energy relationships.The Young-Jencks modified Yukawa-Tsuno equation, log Kx = ρn?n + ρr(?+-?n) + i, gives ρn = 1.73, 1.81, and 0.99 for methanol, dodecane, and water, respectively, but ρr ca. 1 whatever the solvent.It is concluded that the through-ring conjugation effects are solvent independent.In contrast, the Taft-Lewis equation, log Kx = ρI?I + ρ+R?+R + i, gives ρI and ρ+R values that are both solvent dependent.The substituent effects on relative solubilities in methanol, dodecane, and water are examined by means of the equation ΠX(Y) = log PX(Y) - log PH(Y) where Y is the carbonyl or the acetal group and X is the substituent.It is shown that log PX(Y) deviates from additivity (ΠX(Y) ΠX(H) and is Y dependent) because of the effects of X on carbonyl and acetal solvation.These effects are particularly large for solvation of acetals by water molecules.Therefore, substituent effects on Kx are interpreted as being mainly due to (a) an inductive effects of the sustituted ring on ketone stability, (b) a solvent-independent through-ring conjugation effect within the ketone, and (c) a specific inhibition of acetal solvation by water molecules.
Synthesis and thermal properties of salts comprising cationic bis(oxazoline)-AuIII complexes and fluorinated anions
Miura, Yuji,Mochida, Tomoyuki,Motodate, Satoshi,Kato, Keisuke
, p. 1 - 4 (2016)
Salts comprising cationic bis(oxazoline) (box)-AuIII complexes and fluorinated anions were synthesized and their thermal properties were investigated. Cations that contain box ligands with butyl substituents (butyl-box) were used with either achiral-(R,S) ([1]+) or chiral-(S,S) ([2]+) configurations. [1][Tf2N] (Tf2N- = bis(trifluoromethanesulfonyl)amide) is a solid that can also be classified as an ionic liquid (Tm = 62 °C, Tg = -11 °C). [1]X and [2]X (X = SbF6- and BF4-) exhibit melting points higher than 100 °C, where [1]X exhibits a higher melting point than [2]X. A salt with an ethyl-box ligand ([3][SbF6]) exhibits no melting up to its decomposition temperature of 267 °C. Crystal structure determination revealed that the achiral cation in [1][BF4] has a bent structure. The potential utility of [1][Tf2N] for catalysis was demonstrated by the catalytic formation of an acetal from an alkyne.
P-Anisaldehyde-Photosensitized Sulfonylcyanation of Chiral Cyclobutenes: Enantioselective Access to Cyclic and Acyclic Systems Bearing All-Carbon Quaternary Stereocenters
Pirenne, Vincent,Traboulsi, Iman,Rouvière, Lisa,Lusseau, Jonathan,Massip, Stéphane,Bassani, Dario M.,Robert, Frédéric,Landais, Yannick
supporting information, p. 575 - 579 (2020/01/09)
The photosensitized p-Anisaldehyde-mediated addition of sulfonylcyanides onto the I -system of cyclobutenes is shown to afford highly functionalized cyclobutanes in high yields and diastereocontrol. The homochiral cyclobutene precursors are accessible on multigram scale in two steps through an asymmetric [2 + 2] cycloaddition/vinyl thioether reduction sequence. The enantiopure cyclobutylnitriles can be elaborated further through SmI2-mediated ring opening or converted into new enantiopure cyclobutenes through base-mediated sulfone elimination.
Formation of Acetals and Ketals from Carbonyl Compounds: A New and Highly Efficient Method Inspired by Cationic Palladium
Green, Shawn D.,Kindoll, Tyler,Lazaro-Martinez, Brenda,Mensah, Enoch A.,West, Jesse
, p. 1810 - 1814 (2019/09/09)
The development of a new, highly efficient, and simple method for masking carbonyl groups as acetals and ketals is described. This methodology relies on the nature of the palladium catalyst to direct the acetalization/ketalization reaction. This new protocol is mild and proceed with a very low catalyst loading at ambient temperatures. The method has been extended to a wide variety of different carbonyl compounds with various steric encumbrances to form the corresponding acetals and ketals in excellent yields.