Year 2005, Month 10 (Section Full Articles, Page 2384)
Oxidation of ethers with dimethyldioxirane
S. A. Grabovskiy (a), Q. K. Timerghazin (b), and N. N. Kabal´nova (a)
Oxidation of a series of tertbutyl ethers ButOR (R = Me, Et, CH2CH2Cl, Pri, Bui), diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, diisobutoxymethane, 1,4-dioxane, and tetra-hydrofuran with dimethyldioxirane (DMDO) was studied. The reaction kinetics obeys the second-order equation w = k[DMDO][ether]. The rate constants in a range of 5—50 °C and the activation parameters of the reaction were determined. The solvent effect on the oxidation rate was studied. The oxidation products are the corresponding alcohols and carbonyl compounds. The competition between the nonradical (oxygen insertion) and radical mechanisms of the reaction is discussed. The reactions of the parent dioxirane and DMDO with a series of methyl ethers MeOR´ (R´ = Me, Et, CH2CH2F, Pri) were studied by the density functional theory (DFT). The (U)B3LYP6311G(d,p) method was employed to calculate the geometry and energies of the reactants and transition states. The data obtained indicate a possible increase in the probability of oxidation via the radical route and an increase in the activation barrier for the substrates containing electron-withdrawing substituents.
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