Oxidations by a H2O2-VO3 −-pyrazine-2-carboxylic acid reagent

Alkanes (cyclohexane, hexane, heptane isomers) are effectively oxidized in CH₃CN at 20–70°C by hydrogen peroxide when catalyzed by a Bu₄NVO₃-pyrazine-2-carboxylic acid system. Alkyl hydroperoxide is the main product; an alcohol and a ketone or an aldehyde are also formed. Under these conditions benzene is oxidized to give phenol, while alkyl benzenes yield oxygenation products both of the ring and the side chain. It has been assumed that the interaction of H₂O₂ with VO₃ ^– gives rise to generation of HO radicals and other radical-like vanadium containing species that abstract a hydrogen atom from an alkane, RH. The radical R^. formed reacts with O₂ to produce ROO^. which is then transformed to alkyl hydroperoxide.Presented at the VIII International Symposium on Homogeneous Catalysis (Amsterdam, 1992).Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 64–68, January, 1993.     

Hydrogen peroxide oxidation of hydrocarbons catalyzed by Cr(VI) oxo compounds

>CrO₃, (NBu₄)₂CrO₄, (NBu₄)₂Cr₂O₇, and (NBu₄)Cr₄O₁₃ catalyze the hydrogen peroxide oxidation of cyclohexane, ethylbenzene, and styrene in acetonitrile. The active species is apparently a Cr(VI) peroxo complex.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 210–211, January, 1990.     

Photoinduced reactions of organic compounds with transition metals 22. Polychromate-catalyzed photooxygenation of alkanes and other compounds by O2 OF air in CH2Cl2

Irradiation by light with >520 nm of solutions of cyclohexane, n-hexane, and ethylbenzene in CH₂Cl₂ in air in the presence of the complexes (Bu₄N)₂. Cr₂O₇, (Bu₄N)₂Cr₃O₁₀, or (Bu₄N)₂Cr₄O₁₃ results in formation (after GLC) of the corresponding alcohols and ketones. Under these conditions, styrene epoxide, benzaldehyde, and acetophenone are produced from styrene; alcohols are oxidized to carbonyl compounds; and triphenylphosphine forms triphenylphosphine oxide.For previous communication, see [1]. Preliminary reports have been published [2, 3].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2463–2468, November, 1991.     

Hydrogen-Peroxide Epoxidation of Natural Olefins Catalyzed by a Dinuclear Manganese Complex

The complex of Mn(IV) with the macrocyclic N-containing ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (L) [L₂Mn₂O₃](PF6)2 catalyzes epoxidation of (+)-limonene in CH₃CN solution at room temperature. Adding CH₃COOH accelerates the reaction. The products are isomers of limonene epoxide with predominance of that with an epoxified ring double bond. Epoxidation of - and -pinene by this system is less effective, apparently due to extensive steric shielding of the double bonds in the pinenes.     

Formation of the σ-acetonyl Pt(IV) complex in the reaction of iodoacetone with PtCl 4 2− in aqueous solution

Conclusions The reaction of K₂PtCl₄ with iodoacetone in aqueous solution at about 20C gives the -acetonyl Pt(IV) complex which is more stable to the action of nucleophilic reagents than the analogous methyl and ethyl complexes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1657–1660, July, 1984.     

Photochemical oxidation of hydrocarbons by atmospheric oxygen in acetonitrile catalyzed by cyclopentadienyliron complexes

[(-ArH)Fe(-C₅H₅)]⁺BF₄ ^–, where ArH is benzene or toluene, catalyzes the photochemical oxidation of hydrocarbons by oxygen in acetonitrile. Cyclohexane and ethylbenzene are oxidized to the alcohol and ketone derivatives, which are formed in different amounts (after gas-liquid chromatography); benzaldehyde is obtained from styrene. The proposed mechanism involves the formation of a peroxide radical from the organometallic complex, which is capable of hydrogen atom abstraction from the alkane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1680–1683, July, 1991.     

Oxidation of mesitylene by PtCl6 2− ions in trifluoroacetic acid

Conclusion The reaction of PtCl₆ ^2– ions with mesitylene in aqueous CF₃CO₂H leads to the formation of 2,4,6,3,5-pentamethyl)diphenylmethane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 935–937, April, 1987.