1636-37-9Relevant articles and documents
Copper-catalyzed homodimerization of nitronates and enolates under an oxygen atmosphere
Do, Hien-Quang,Tran-Vu, Hung,Daugulis, Olafs
, p. 7816 - 7818 (2013/01/16)
A method for copper-catalyzed oxidative dimerization of nitronates and enolates using oxygen as the terminal oxidant has been developed. Cyclization through oxidative intramolecular coupling is also feasible for both nitronates and enolates. The mild reaction conditions lead to good functional group tolerance.
Fast cleavage reactions following electron transfer. Reduction of 1,1-dinitrocyclohexane
Rühl, Janet C.,Evans, Dennis H.,Hapiot, Philippe,Neta, Pedatsur
, p. 5188 - 5194 (2007/10/02)
One-electron reduction of 1,1-dinitrocyclohexane is followed by rapid cleavage of a C-N bond, giving nitrite and 1-nitrocyclohexyl radical. The rate constant has been determined in dimethylformamide by homogeneous redox catalysis (1.6 × 106 s-1) and in aqueous solution by pulse radiolysis (1.1 × 106 s-1). These values are of the order of 106 larger than the rate constant for cleavage of mononitroalkane radical anions. In the case of electrochemical reduction, the electron transfer and bond cleavage are followed by further reduction of the nitroalkyl radical to give the nitronate anion of nitrocyclohexane. For scan rates exceeding about 0.1 V/s in cyclic voltammetry, the 1-nitrocyclohexyl radical is reduced by the anion radical of 1,1-dinitrocyclohexane rather than at the electrode. Controlled potential electrolysis and product analysis showed that about 1.2 electrons were required per molecule of 1,1-dinitrocyclohexane; essentially no nitronate was found, but instead some nitrocyclohexane and substantial amounts of 1,1′-dinitrobicyclohexyl (5) were produced. This latter product arises from the radical chain reaction of nitronate with starting material. A key chain-carrying step in this reaction scheme is the reaction of 1-nitrocyclohexyl radical with the nitronate to give the anion radical of 5. The rate constant for this step was found to be 2.6 × 106 L mol-1 in water by pulse radiolysis. Fitting of fast-scan cyclic voltammograms by digital simulation showed that this rate constant must be about 5 × 108 L mol-11 s-1 in dimethylformamide with a termination reaction (kt = 2 × 104 s-1) of hydrogen atom abstraction by 1-nitrocyclohexyl to produce the nitrocyclohexane found in the electrolyzed solutions.
Correlation of Electron-Transfer Rate Constants of Carbinons with Their Oxidation Potentials and Basicities
Bordwell, Frederick G.,Bausch, Mark J.
, p. 1985 - 1988 (2007/10/02)
Acidity-oxidation-potential (AOP) values for seven 9-substituted fluorenide ions, 9-ArFl(1-), relative to that of fluorene, have revealed the presence of small radical-stabilizing effects for 4-MeO and 4-Me substitutents in the aryl ring and a 3-Me substituent in the fluorene ring and their absence for 3-Cl and 4-MeSO2 substituents in the aryl ring and 2-Br and 2-PhSO2 substituents in the fluorene ring.Measurements of redox potentials have shown that electron-transfer (eT(1-)) reactions of these 9-ArFl(1-) ions with 1,1-dinitrocyclohexane are endergonic by 6.6-13 kcal/mol.A Bronsted-type plot of log kobsd for these reactions vs. pKHA was linear with scatter.A Bronsted-type plot of log kobsd vs.Eox gave an improved plot (β = 1.04; R2 = 0.999) that covered a rate range of >1E5 and an Eox range of 7.3 kcal/mol.Mechanistic schemes are presented to account for the products formed in the eT(1-) reaction and to reconcile the strict linearity of the latter plot with the Marcus equation.
