- Controllable Intramolecular Unactivated C(sp3)-H Amination and Oxygenation of Carbamates
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Dual catalyst-controlled intramolecular unactivated C(sp3)-H amination and oxygenation of carbamates merging visible-light photocatalysis and earth-abundant transition metal catalysis have been reported. Useful amino alcohol and diol derivatives could be selectively obtained from readily available tertiary alcohol derivatives. The possible mechanisms have been proposed via a 1,5-HAT process followed by Lewis acid-controlled cyclization. The nickel and zinc catalysts inhibit the formation of oxygenation and amination products, respectively. An interesting phenomenon of chirality transfer is also observed.
- Guo, Qihang,Ren, Xiang,Lu, Zhan
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supporting information
p. 880 - 884
(2019/05/16)
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- METHOD FOR PRODUCING OXIDE
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PROBLEM TO BE SOLVED: To provide a method for producing an oxide capable of easily producing an oxide excellent in substrate selectivity with a high yield, which allows the reaction to proceed without using a solvent under moderate conditions at 100°C or less. SOLUTION: There is provided a method for producing an oxide by oxidizing a substrate (A) in the presence of a compound selected from oxygen, ozone and a radical generator to obtain a corresponding oxide. The radical generator preferably includes at least one compound selected from a nitroxy-based radical generator and an azo-based radical generator. In addition, the oxidation reaction is preferably carried out in the presence of a metal compound containing at least one metal element selected from cobalt, manganese, zirconium and molybdenum. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPO&INPIT
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Paragraph 0090; 0096
(2018/10/16)
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- Alkane oxidation by the system 'tert-butyl hydroperoxide-[Mn 2L2O3][PF6]2 (L = 1,4,7trimethyl-1,4,7-triazacyclononane)-carboxylic acid'
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The kinetics of cyclohexane (CyH) oxygenation with terf-butyl hydroperoxide (TBHP) in acetonitrile at 50°C catalysed by a dinuclear manganese(IV) complex 1 containing 1,4,7-trimethyl-1,4,7-triazacyclononane and co-catalysed by oxalic acid have been studied. It has been shown that an active form of the catalyst (mixed-valent dimeric species 'MnIIIMnIV,) is generated only in the interaction between complex 1 and TBHP and oxalic acid in the presence of water. The formation of this active form is assumed to be due to the hydrolysis of the Mn - O - Mn bonds in starting compound 1 and reduction of one MnIV to MnIII. A species which induces the CyH oxidation is radical tert-BuO generated by the decomposition of a monoperoxo derivative of the active form. The constants of the equilibrium formation and the decomposition of the intermediate adduct between TBHP and 1 have been measured: k = 7.4mol-1dm3 and k = 8.4 × 10 -2s-1, respectively, at [H2O] = 1.5 mol dm -3 and [oxalic acid] = 10-2 mol dm-3. The constant ratio for reactions of the monomolecular decomposition of tert-butoxy radical (tert-BuO → CH3COCH3+ CH3) and its interaction with the CyH (terf-BuO + CyH → fert-BuOH + Cy) was calculated: 0.26 mol dm-3. One of the reasons why oxalic acid accelerates the oxidation is due to the formation of an adduct between oxalic acid and 1 (K ≈ 103 mol-1 dm3). Copyright
- Kozlov, Yuriy N.,Nizova, Galina V.,Shul'pin, Georgiy B.
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p. 119 - 126
(2008/09/20)
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- Hydroperoxidation of alkanes with hydrogen peroxide catalyzed by aluminium nitrate in acetonitrile
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The first example of alkane oxygenation with hydrogen peroxide catalyzed by a non-transition metal derivative (aluminium) is reported. Heating (70 °C) a solution of an alkane, RH, hydrogen peroxide (70% aqueous) and a catalytic amount of Al(NO3)3·9H2O in air for a few hours afforded the corresponding alkyl hydroperoxide, ROOH. With cyclooctane, the hydroperoxide yield attained 31% and the maximum turnover number was 150. It is proposed on the basis of measurements of the selectivity parameters for the oxidation of linear and branched alkanes and a kinetic study that the oxidation occurs with the participation of hydroxyl radicals.
- Mandelli, Dalmo,Chiacchio, Karyna C.,Kozlov, Yuriy N.,Shul'pin, Georgiy B.
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scheme or table
p. 6693 - 6697
(2009/04/07)
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- Oxidations catalyzed by osmium compounds. Part 1: Efficient alkane oxidation with peroxides catalyzed by an olefin carbonyl osmium(0) complex
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A carbonyl osmium(0) complex with π-coordinated olefin, (2,3-η-1,4-diphenylbut-2-en-1,4-dione)undecacarbonyl triangulotriosmium (1), efficiently catalyzes oxygenation of alkanes (cyclohexane, cyclooctane, n-heptane, isooctane, etc.) with hydrogen peroxide, as well as with tert-butyl hydroperoxide and meta-chloroperoxybenzoic acid in acetonitrile solution. Alkanes are oxidized to corresponding alcohols, ketones (aldehydes) and alkyl hydroperoxides. Thus, heating cyclooctane with the 1-H2O2 combination at 70 °C gave products with turnover number as high as 2400 after 6 h. The maximum obtained yield of all products was equal to 20% based on cyclohexane and 30% based on H2O2. The oxidation of linear and branched alkanes exhibits very low regio- and bond-selectivity parameters and this testifies that the reaction proceeds via attack of hydroxyl radicals on C-H bonds of the alkane. The oxygenation products were not formed when the reaction was carried out under argon atmosphere and it can be thus concluded that the oxygenation occurs via the reaction between alkyl radicals and atmospheric oxygen. In summary, the Os(0) complex is much more powerful generator of hydroxyl radicals than any soluble derivative of iron (which is an analogue of osmium in the Periodic System).
- Shul'pin, Georgiy B.,Kudinov, Aleksandr R.,Shul'pina, Lidia S.,Petrovskaya, Elena A.
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p. 837 - 845
(2007/10/03)
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- Alkane oxygenation with H2O2 catalysed by FeCl 3 and 2,2′-bipyridine
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The H2O2-FeCl3-bipy system in acetonitrile efficiently oxidises alkanes predominantly to alkyl hydroperoxides. Turnover numbers attain 400 after 1 h at 60°C. It has been assumed that bipy facilitates proton abstraction from a H2O2 molecule coordinated to the iron ion (these reactions are stages in the catalytic cycle generating hydroxyl radicals from the hydrogen peroxide). Hydroxyl radicals then attack alkane molecules finally yielding the alkyl hydroperoxide.
- Shul'pin, Georgiy B.,Golfeto, Camilla C.,Süss-Fink, Georg,Shul'pina, Lidia S.,Mandelli, Dalmo
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p. 4563 - 4567
(2007/10/03)
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- Oxidations by the system "hydrogen peroxide-[Mn2L 2O3][PF6]2 (L = 1,4,7-trimethyl-1,4, 7-triazacyclononane)-oxalic acid". Part 6. Oxidation of methane and other alkanes and olefins in water
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Oxidation of alkanes with hydrogen peroxide in water solution at 10-50 °C is efficiently catalyzed by the cationic dinuclear manganese (IV) derivative [Mn2L2O3]2+ (1, with L = 1,4,7-trimethyl-1,4,7-triazacyclononane, TMTACN) in the form of the hexafluorophosphate salt ([1][PF6]2) if oxalic acid is present as a co-catalyst. Methane gives methanol and formaldehyde (turnover numbers, TONs, were 7 and 2, respectively, after reduction of the reaction mixture with ascorbic acid) whereas cyclohexane was oxidized with TONs up to 160 affording cyclohexyl hydroperoxide, cyclohexanone and cyclohexanol (the ketone was the main product, although at room temperature almost pure alkyl hydroperoxide was formed). In contrast to the oxidation in acetonitrile, the reaction with linear n-alkanes in water exhibits an unusual distribution of oxygenates. For example, in the oxidation of n-heptane the normalized reactivity of the methylene group in position 4 of the chain is 3-7 times higher than that of the CH2 group in position 2. Dec-1-ene is epoxidized by hydrogen peroxide in water (a biphasic system) catalyzed by [1][PF6] 2 and oxalic acid in the presence of a small amount of acetonitrile with TONs up to 1000 (no epoxidation has been detected in the absence of MeCN).
- Shul'pin, Georgiy B.,Nizova, Galina V.,Kozlov, Yuriy N.,Arutyunov, Vladimir S.,Dos Santos, Ana Cláudia M.,Ferreira, Ana Carolina T.,Mandelli, Dalmo
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p. 4498 - 4504
(2007/10/03)
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- Catalytic oxidation of C-H bonds
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The invention provides a catalytic, chemospecific and stereospecific method of oxidizing a wide variety of substrates without unwanted side reactions. Essentially, the method of the instant invention, under relatively mild reaction conditions, catalytically, stereospecifically and chemospecifically inserts oxygen into a hydrocarbon C—H bond. Oxidation (oxygen insertion) at a tertiary C—H bond to form an alcohol (and in some cases a hemiacetal) at the tertiary carbon is favored. The stereochemistry of an oxidized tertiary carbon is preserved. Ketones are formed by oxidizing a secondary C—H bond and ring-cleaved diones are formed by oxidizing cis tertiary CH bonds.
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- Chemospecific chromium[VI] catalyzed oxidation of C-H bonds at -40 °C
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H5IO6 in the presence of catalytic chromoyl diacetate is a powerful method for oxidation of C-H bonds. Tertiary and oxygen activated C-H bonds are oxidized to tertiary alcohols or ketones at temperatures as low as -40 °C. The putative reagent is neutral dioxoperoxy chromium[VI] which undergoes C-H oxidation with retention of stereochemistry. This reagent appears to be the first reagent capable of oxidation of a C-H bond in the presence of an olefin without concomitant epoxidation. Copyright
- Lee, Seongmin,Fuchs
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p. 13978 - 13979
(2007/10/03)
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- Alkane oxygenation catalysed by gold complexes
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Gold(III) and gold(I) complexes, NaAuCl4 and ClAuPPh3, efficiently catalyse the oxidation of alkanes by H2O2 in acetonitrile solution at 75°C. Turnover numbers (TONs) attain 520 after 144 h. Alkyl hydroperoxides are the main products, whereas ketones (aldehydes) and alcohols are formed in smaller concentrations. It is suggested on the basis of the bond selectivity study that at least one of the pathways in Au-catalysed alkane hydroperoxidation does not involve the participation of free hydroxyl radicals. Possibly, the oxidation begins from the alkane hydrogen atom abstraction by a gold oxo species. The oxidation of cyclooctane by air at room temperature catalysed by NaAuCl4 in the presence of Zn/CH3COOH as a reducing agent and methylviologen as an electron-transfer agent gave cyclooctanol (TON=10).
- Shul'Pin, Georgiy B.,Shilov, Alexander E.,Süss-Fink, Georg
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p. 7253 - 7256
(2007/10/03)
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- Identification of metabolites from the biological transformation of the nonionic surfactant residue octylphenoxyacetic acid and its brominated analog
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The aerobic biological transformation of octylphenoxyacetic acid (OP1EC) and its brominated analog (BrOP1EC) by groundwater enrichment cultures was studied, and persistent metabolites were identified by GC/MS. OP1EC is a representative of the class of alkylphenol ethoxycarboxylates (APEC), formed from alkylphenol polyethoxylate nonionic surfactants during sewage treatment. BrOP1EC is a byproduct formed during chlorine disinfection in the presence of bromide. The metabolite 2,4,4-trimethyl-2-pentanol was detected in stoichiometric quantities in OP1EC-metabolizing enrichment cultures, representing the intact alkyl side chain as a tertiary alcohol. BrOP1EC was transformed by the OP1EC-utilizing cultures only if OP1EC was simultaneously metabolized, suggesting a cometabolic mechanism of transformation. Brominated intermediates were also detected: brominated octylphenol and e compound tentatively identified as 2-aminomethoxy-3-bromo-5-(1,1,3,3- tetramethylbutyl)phenol.
- Fujita, Yoshiko,Reinhard, Martin
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p. 1518 - 1524
(2007/10/03)
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- Substituent Effects of Alkyl Groups on the Decomposition of tert-Alkyl Peroxides
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In order to clarify substituent effects of alkyl groups on the decomposition of various tert-alkyl peroxides (RCMe2OOR'), the decomposition of 1-methoxy-1-(tert-alkylperoxy)cyclohexanes 3 and 1,1-bis(tert-alkylperoxy)cyclohexanes 4 has been studied by use of methods of kinetics and product analysis in cumene with the range of temperatures from 80-110 deg C and compared with those of the corresponding peroxyesters (1; R' = CO-t-Bu) and dialkyl peroxides (2; R' = t-Bu).The decomposition rates for each peroxide series decrease in the following order: 1 >> 3 > 4 >> 2.The decomposition rate for the series of peroxides 1 decreases in the following order: R = t-BuCH2 >> i-Pr >> Et > Pr > Me.But, for the series of peroxides 2, 3, and 4, R = t-BuCH2 >> i-Pr >> Pr > Et >> Me.The decompositon rate is expressed by a modified Taft equation : log kd = ρ*ΣρCH2R* + nh + C, which contains both inductive and C-H hyperconjugation effects of alkyl groups.On the basis of the isokinetic relationship of the activation parameters, the Taft equation, and the decomposition products, the decomposition mechanism via an polar activation complex having a slightly stretched Cα - Cβ bond neighboring to the peroxy oxygen atom is suggested and the abnormal behavior of neopentyl group is discussed.
- Matsuyama, Kazuo,Sugiura, Takashi,Minoshima, Yoshihiko
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p. 5520 - 5525
(2007/10/02)
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- Reaction of Azoalkanes with Isolable Cation Radical Salts
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Three tertiary azoalkanes related in the sense acyclic, cyclic, and bicyclic are shown to evolve nitrogen upon oxidation with stable cation radical salts.Thus azo-tert-octane (ATO), 3,3,6,6-tetramethyl-1,2-diazacyclohexene (TMDAC), and 1,4-dimethyl-2,3-diazabicyclooct-2-ene (Me2DBO) react rapidly with thianthrenium perchlorate (Th(.1+)ClO4(1-)), tris(p-bromophenyl)aminium hexachloroantimonate (TBPA(.1+)SbCl6(1-)), and TBPA(.1+)SbF6(1-).The ether and olefin products, which are formed in high yield in CH2Cl2/MeOH solvent, are not those expected from the usual free-radical decomposition of azoalkanes but instead implicate carbocations.Althrough the reaction stoichiometry clearly requires 2 equiv of cation radical salt to one of azoalkane, the mechanism is not yet clearly defined.A complication in these studies is found in the ability of certain cation radical salts to oxidize more azoalkane than expected based on the 2:1 stoichiometry.
- Engel, Paul S.,Robertson, Donald M.,Scholz, John N.,Shine, Henry J.
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p. 6178 - 6187
(2007/10/02)
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- Substituent Effects in the Decomposition of t-Alkyl t-Butyl Peroxides
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The decomposition rates and products of various t-alkyl t-butyl peroxides were examined in cumene at several temperatures.The decomposition of these peroxides took place homolytically, depending on the structure of the t-alkoxyl moieties (RC(CH3)2-O), and was retarded in the order: R = (CH3)3CCH2 > (CH3)2CH > CH3CH2CH2 > PhCH2 > CH3CH2 > ClCH2 > CH3.The rate constants for the electron-donating alkyl substituents at 150 deg C are correlated very well to a Taft equation (log kd = -10.93Σ?*-6.61 (correlation coefficient of 0.9501)), which is fairly different from the equation log kd = -0.131Σ?*-3.422 for electron-withdrawing polar substituents.From this correlation and a product analysis, the nature of the polar character at the transition state of the decomposition is discussed.
- Matsuyama, Kazuo,Higuchi, Yoshiki
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p. 259 - 265
(2007/10/02)
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- Identification of High-Valent Fluoroiron Porphyrin Intermediates Associated with the Electrocatalytic Functionalization of Hydrocarbons
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The difluoroiron(III) tetraphenylporphyrin complex undergoes a one-electron oxidation at 0.68 V (SCE) in contrast with values of 1.1 V measured for the monofluoroiron(III) porphyrin and the other five-coordinate iron(III) porphyrin complexes.Cyclic voltammetric oxidation of the difluoroiron(III) species in dichloromethane solution is quasi-reversible as a consequence of an EC mechanism.Reversible waves are favored at high scan rates and lower temperatures.Increased water content serves to make the oxidative cyclic voltammetric process irreversible presumably due to a disproportionation process.In the presence of added olefin substrates, this EC process permits efficient electrocatalytic oxidation to the epoxide, allylic alcohol, and enone.Tertiary carbon units are converted to the corresponding alcohol.Utilization of fluoride ion permits generation and low-temperature spectroscopic identification of a highly oxidized iron porphyrin species.The high-valent complex is produced at -78 deg C through addition of m-chloroperbenzoic acid to monofluoroiron(III) tetraarylporphyrins or by fluoride ion promoted disproportionation of the dication radical μ-oxo dimeric iron(III) porphyrin derivative.The oxidized iron porphyrin species is competent to effect olefin epoxidation at -78 deg C.Low-temperature 1H and 2H NMR spectroscopies demonstrate the porphyrin ?-cation radical nature of the high-valent species, in that porphyrin phenyl resonances are drastically shifted in alternating upfield and downfield directions.The electron spin resonance spectrum is consistent with an S = 3/2 ground state, and the high-valent intermediate is assigned a tentative fluorooxoiron(IV) porphyrin ?-cation radical formulation.
- Hickman, David L.,Nanthakumar, Alaganandan,Goff, Harold M.
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p. 6384 - 6390
(2007/10/02)
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- Homolytic Decomposition of t-Alkyl 2,2-Dimethylperoxypropionates
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Decomposition rates and products of t-alkyl 2,2-dimethylperoxypropionates were measured in cumene at several temperatures.The peroxyesters decomposed homolitycally, depending on the structure of the t-alkyl moiety.The relative rates of the t-alkyl moieties to the 1,1-dimethylethyl one were: 1,1-dimethylbutyl (1.14), 1,1-dimethylpropyl (1.19), 1,1,2-trimethylpropyl (1.85), 1,1,3,3-tetramethylbutyl (2.10), and 1,1-dimethyl-2-phenylethyl (2.34).The decomposition showed an isokinetic relationship and the importance of stabilization by hyperconjugation.Based on these data, the decomposition mechanism, which contains a slight stretching of the Cα-Cβ bond to the peroxyl oxygen at the transition state is, discussed.
- Komai, Takeshi,Matsuyama, Kazuo,Matsushima, Masaru
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p. 1641 - 1646
(2007/10/02)
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- ORGANOBORANES FOR SYNTHESIS. 2. OXIDATION OF ORGANOBORANES WITH ALKALINE HYDROGEN PEROXIDE AS A CONVENIENT ROUTE FOR THE cis-HYDRATION OF ALKENES via HYDROBORATION
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Aqueous hydrogen peroxide in the presence of dilute alkali effects the oxidation of organoboranes.The conditions necessary for a clean and quantitative transformation of organoboranes into the corresponding alcohols have been established.Thus, one mole of trialkylborane reacts with three moles of hydrogen peroxide in the presence of one mole of sodium hydroxide to provide three moles of the corresponding alcohol.The concentrations of these reagents or the reaction temperature can be varied widely without affecting the yield significantly.Oxidation proceeds well in water-miscible solvents, such as diglyme and THF.However, the reaction is slow and incomplete in diethyl ether.The addition of ethanol as a cosolvent circumvents this difficulty.Wide variations in the structure of organoboranes do not affect the reaction greatly.A variety of common organic functional groups, such as alkenes, alkynes, esters, ketones, nitriles, etc., are unaffected under the normal oxidation conditions.However, aldehydes are somewhat unstable under these conditions, although they do not interfere with the oxidation of organoboranes
- Brown, Herbert C.,Snyder, Carl,Rao, B. C. Subba,Zweifel, George
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p. 5505 - 5510
(2007/10/02)
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- Thermolabile Hydrocarbons, XIX. Syntheses, Spectra, Structures, and Strain of Highly Branched Pentanes
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The syntheses and spectroscopic properties of eight hydrocarbons R1R2CH-C(CH3)3 (3a-h) and of ten hydrocarbons R1R2R3C-C(CH3)3 (4a-k) (R = alkyl) are described.Their structures and strain enthalpies are discussed on the basis of force field calculations.
- Hellmann, Siegried,Beckhaus, Hans-Dieter,Ruechardt, Christoph
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p. 2219 - 2237
(2007/10/02)
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- Studies on the Autoxidation of Branched-chain Olefins. I. Autoxidation of 2-Methylalk-1-enes and 2-Methylalk-2-enes
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The products of the autoxidation of 2-methylpent-1-ene, 2-methylpent-2-ene, 2-methylhex-1-ene, 2-methylhex-2-ene, 2,4,4-trimethylpent-1-ene, and 2,4,4-trimethylpent-2-ene were analyzed by gas chromatography.The identification of the products corresponding to the individual peaks was possible by comparison with authentic substances or by preparative gaschromatographic separation and n.m.r.-spectroscopy of the isolated samples.In this way not only the epoxides and the products of the oxidative cleavage of the C=C double bond but also the allylic alcohols formed by LiAlH4-reduction of the oxidation mixtures could be identified and analyzed.From the results the compositions of the original oxidation mixtures were calculated.
- Bilas, W.,Hoebold, W.,Pritzkow, W.
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p. 125 - 141
(2007/10/02)
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