"On water" sp3-sp2 cross-couplings between benzylic and alkenyl halides

Organic-solvent-free cross-couplings between benzylic and alkenyl halides have been developed. Various alkenyl halides can be efficiently benzylated by combining the precursor halides in the presence of Zn dust and a Pd catalyst at room temperature, in water as the only medium.     

Hydroxyl-containing imidazolium ionic liquids

A number of imidazolium ionic liquids with bis(trifluoromethylsulfonyl)imide anion containing a ω-hydroxyalkyl substituent of different lengths in the cation (n_С = 2–8) were synthesized. The properties of the obtained liquids were investigated by DSC, TGA, IR, and NMR spectroscopy. Their thermal stability was studied; melting points, viscosity, and volatility in vacuum were measured. The possibility of using synthesized ionic liquids as heat carriers under high vacuum conditions is demonstrated.     

Variable-temperature x-ray structural investigation of [Fe[HC(3,5-Me2pz)3]2](BF4)2 (pz= pyrazolyl ring): observation of a thermally induced spin state change from all high spin to an equal high spin-low spin mixture, concomitant with the onset of nonmerohedral twinning

The complex [Fe[HC(3,5-Me(2)pz)(3)](2)](BF(4))(2) (pz = pyrazolyl ring) undergoes a phase transition that occurs concomitantly with a thermally induced spin conversion between the high-spin (HS, S = 2) and low-spin (LS, S = 0) states. Above 204 K the compound is completely HS with the structure in the C2/c space group with Z = 4. A crystal structure determination of this phase was performed at 220 K yielding the cell constants a = 20.338(2) A, b = 10.332(1) A, c = 19.644(2) A, beta = 111.097(2) degrees, and V = 3851.5(6) A(3). There is one unique iron(II) site at this temperature. Below 206 K the compound converts to a 50:50 mixture of HS and LS. The radical change in the coordination sphere for half of the iron(II) sites, most notably a shortening of the Fe-N bond distances by ca. 0.2 A, that accompanies this magnetic transition causes a phase transition. The crystal system changes from C-centered monoclinic to primitive triclinic with Z = 2 with two half-molecules on independent inversion centers. A crystal structure determination was performed at 173 K in space group P1 with a = 10.287(2) A, b = 11.355(3) A, c = 18.949(4) A, alpha = 90.852(4) degrees, beta = 105.245(4) degrees, gamma = 116.304(4) degrees, and V = 1892.3(8) A(3). All specimens investigated below the phase transition temperature were determined to be nonmerohedral twins. Temperature cycling between these two forms does not appear to degrade crystal quality. Previous magnetic susceptibility measurements indicate a second, irreversible increase in the magnetic moment the first time the crystals are cooled below 85 K. A crystal structure determination at 220 K of a specimen precooled to 78 K was not significantly different from those not cooled below 220 K.     

Ozonation of Decalin as a Model Saturated Cyclic Molecule: A Spectroscopic Study

Ozonolysis is used for oxidation of a model cyclic molecule-decalin, which may be considered as an analog of saturated cyclic molecules present in heavy oil. The conversion of decalin exceeds 50% with the highest yield of formation of acids about 15–17%. Carboxylic acids, ketones/aldehydes, and alcohols are produced as intermediate products. The methods of UV-visible, transmission IR, attenuated total reflection IR-spectroscopy, NMR and mass-spectrometry were used to identify reaction products and unravel a possible reaction mechanism. The key stage of the process is undoubtedly the activation of the first C-H bond and the formation of peroxide radicals.     

Preparation of cyclic alkenylmagnesium reagents via an iodine/magnesium exchange

The reaction of various cyclic alkenyl iodides with i-PrMgCl.LiCl produces the corresponding alkenylmagnesium reagents under mild conditions. After reaction with various electrophiles, like allylic halides, disulfides, aldehydes and acid chlorides, the expected products are obtained in 53-91% yield. Remarkably, the mild conditions of the I/Mg-exchange tolerate the presence of sensitive diene functionalities.     

Dicationic disiloxane ionic liquids as heat transfer agents in vacuo

Russian Chemical Bulletin - Bis(trifluoromethylsulfonyl)imidic dicationic liquids containing a disiloxane linker between the imidazole cations have been synthesized. Their thermal stability was...     

The Mg-oppenauer oxidation as a mild method for the synthesis of aryl and metallocenyl ketones

Magnesium alkoxides undergo a hydride-transfer oxidation with benzaldehyde as the oxidant. This magnesium variant of the Oppenauer oxidation was used for the synthesis of polyfunctional biaryl ketones. LiCl was found to promote this reaction by enhancing the solubility of magnesium alkoxides. This mild oxidation method was especially useful for preparing ketones bearing a metallocenyl unit as well as various new ferrocenyl ketones and tricarbonylchromium complexes. This last class of ketones was reduced with the CBS catalyst (CBS=Corey-Bakshi-Shibata, diphenyl oxazaborolidine) to chiral benzhydrol complexes with high enantioselectivity enabling an asymmetric synthesis of electron-rich or -poor benzhydryl alcohols (up to 94 % ee).