280-33-1Relevant academic research and scientific papers
A Product Study of 1-Adamantyl and 1-Bicyclooctyl Radicals in Hydrocarbon Solvents. An Unusually Large Hydrogen Isotope Effect
Engel, Paul S.,Chae, Woo-Ki,Baughman, Sharon A.,Marschke, Gregor E.,Lewis, Edward S.,et al.
, p. 5030 - 5034 (1983)
1-Adamantyl (ada.) and 1-bicyclooctyl (bo.) radicals have been generated by photolysis of the corresponding azoalkanes in various hydrocarbon solvents.Both radicals abstract hydrogen readily from hydrocarbons and they add to aromatic rings much faster than tert-butyl. does.Despite its reactivity, ada. is remarkably selective in hydrogen atom abstraction, preferring a benzylic hydrogen 25:1 over a cyclohexane hydrogen.The effect of solvent viscosity indicates that formation of the radical dimers biada and bibo occurs in the solvent cage.The most striking result of this work is a deuterium isotope effect of 25 for hydrogen transfer from cyclohexane to ada. at 65 deg C.Steric compression in the transition state is postulated to cause an unusually large tunnel correction and hence a large kH/kD.
Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst
Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett
supporting information, p. 2157 - 2161 (2021/05/21)
The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.
A simple and straightforward approach toward selective C=C bond reduction by hydrazine
Chen, Hao,Wang, Jianmin,Hong, Xuechuan,Zhou, Hai-Bing,Dong, Chune
supporting information, p. 758 - 761 (2012/11/07)
A simple and straightforward method for reducing the C=C double bond with hydrazine is described. A number of representative C=C bonds in various steric and electronic environments were examined. Substituted alkenes can be selectively reduced in EtOH in the presence of hydrazine to give the corresponding products in up to 100% yields.
Accuracy of calculations of heats of reduction/hydrogenation: Application to some small ring systems
Wiberg, Kenneth B.
, p. 10393 - 10398 (2013/01/15)
The enthalpies of reduction of carbonyl compounds and hydrogenation of alkenes have been calculated at the HF, B3LYP, M06, MP2, G3, G4, CBS-QB3, CBS-APNO, and W1BD levels and, in the case of the first four methods, using a variety of basis sets up to aug-cc-pVTZ. The results are compared with the available experimental data, and it is found that the compound methods are generally more satisfactory than the others. Large basis sets are usually needed in order to reproduce experiments. Some C-C bond hydrogenolysis reactions also have been examined including those of bicycloalkanes and propellanes. In addition, the dimerization of the remarkably strained bicyclo[2.2.0]hex(1,4)ene was studied. The reaction forming a pentacyclic propellane was calculated to have ΔH = -57 kcal/mol, and the cleavage of the propellane to give a diene had ΔH = -71 kcal/mol. The strain energies of these compounds were estimated.
Cobalt-catalyzed reductive allylation of alkyl halides with allylic acetates or carbonates
Qian, Xin,Auffrant, Audrey,Felouat, Abdellah,Gosmini, Corinne
supporting information; experimental part, p. 10402 - 10405 (2011/12/03)
An efficient method for the direct allylation of alkyl halides catalyzed by simple cobalt(II) bromide has been developed. This reaction, using a variety of substituted allylic acetates or carbonates, provides the linear product as the major product. It displays broad substrate scope and good functional group tolerance. Copyright
Structure-reactivity correlations in the reactions of hydrocarbons on transition metal surfaces. 2. Hydrogenation of norbornene and bicyclo[2.2.2]octene on platinum(111)
Hostetler, Michael J.,Nuzzo, Ralph G.,Girolami, Gregory S.
, p. 1814 - 1827 (2007/10/02)
The reactivity of two bicyclic alkenes, bicyclo[2.2.2]octene (BOE) and norbornene (NBE), has been studied on Pt(111) in both the absence and the presence of co-adsorbed hydrogen. The inability of these alkenes to rearrange to alkylidyne species on the surface considerably alters their reaction chemistry. At 130 K, the alkenes are bound molecularly to the surface via two interactions: (1) a π di-σ interaction with a C=C double bond, and (2) an apparent agostic interaction with a C-H bond. The geometries of these bicyclic alkenes strongly suggest that they are interacting with three mutually-adjacent surface Pt atoms, but it is not clear from the data whether the alkene group bridges between two Pt atoms and the agostic interaction involves one Pt atom or vice versa. Several reactions ensue upon thermolysis. At ～250 K, the agostic C-H bond is cleaved and a surface-bound alkyl intermediate is formed. The resulting surface-bound hydrogen atoms do not immediately desorb, but some of them transfer to unreacted BOE and NBE molecules to form the alkanes bicyclo[2.2.2]octane (BOA) and norbornane (NBA), respectively. The rate-determining step for this self-hydrogenation reaction is the dehydrogenation of BOE or NBE; these processes appear to follow first-order rate laws with activation energies of ～16 kcal/mol. If the Pt(111) surface is first treated with hydrogen and then dosed with the bicyclic alkene, alkane is formed at lower temperatures (as low as 190 K) and in significantly greater amounts. In the presence of co-adsorbed D2, BOE and NBE are hydrogenated to a distribution of alkane isotopomers with up to four deuterium atoms per molecule; these observations suggest that the surface-bound alkyl intermediates can α-eliminate and reversibly form alkylidenes. Surface carbon atoms, when present at sufficiently high coverages, inhibit the hydrogenation and self-hydrogenation of these bicyclic alkenes due to the reduced ability of the carbonaceous Pt(111) surface to activate H-H or C-H bonds. At higher temperatures (470-520 K), both BOE and NBE eventually decompose to give benzene (part of which desorbs) and surface CxHy fragments. The latter decompose by ～620 K to give a partial carbonaceous overlayer and H2 gas.
Oxidations by Methyl(trifluoromethyl)dioxirane. 2. Oxyfunctionalization of Saturated Hydrocarbons
Mello, Rossella,Fiorentino, Michele,Fusco, Caterina,Curci, Ruggero
, p. 6749 - 6757 (2007/10/02)
The reaction of methyl(trifluoromethyl)dioxirane (1b), a novel dioxirane species, with two open-chain, four cyclic, and five polycyclic saturated hydrocarbons and two aralkyl hydrocarbons in CH2Cl2/1,1,1-trifluoropropanone has been studied; under mild conditions (-22 to 0 deg C), it gives alcohols and/or ketones (deriving from further oxidation of secondary alcohols) in high yields and within very short reaction times.Primary C-H bonds are not appreciably oxidized and high regioselectivities were determined for attack at tertiary over secondary C-H bonds, with theexception of norbornane, which showed opposite regioselectivity.The reaction is also highly stereoselective, since hydroxylations of cis- and trans-decalin and of cis- and trans-1,2-dimethylcyclohexane were found to be in each case stereospecific with retention.From kinetic data, Ea = 14.3 kcal mol-1 and log A = 9.9 were estimated for cyclohexane oxidation.Relative rates change in the order cyclohexane (0.78) octane (9.2) adamantane (146); cis-1,2-dimethylcyclohexane was observed to be 7-fold more reactive than its trans isomer, demonstrating remarkable discrimination for equatorial vs axial C-H attack (also noticed in the case of cis- and trans-decalin).The relative rate of oxidation of cumene vs ethylbenzene was found to be ca. 3.1 (after statistical correction), i.e., in sharp excess over values usually recorded in classical radical H-atom abstraction from benzylic position.Rate constants determined for the reactions of cumene and of ethylbenzene show the title dioxirane (1b) is more reactive than dimethyldioxirane (1a) by factors of ca. 600 and over 700, respectively.The whole of theobservations is better accommodated by an "oxenoid" mechanism, involving concerted O-atom insertion by dioxirane into C-H bonds of hydrocarbons.
HYDROGENOLYSIS OF CUBANE
Stober, Reinhard,Musso, Hans,Osawa, Eiji
, p. 1757 - 1762 (2007/10/02)
On catalytic hydrogenation over Pd-C under normal conditions cubane (10) takes up 3 mol of hydrogen in a few hours.Bicyclooctane (13) is formed as the main product, and tetracyclo2.5.03.8>octane (11, secocubane) and tricyclo2.5>octane (12, nortwistbrendane) have been identified as intermediates.The hydrogenolysis of dimethyl 1,4-cubane dicarboxylate, as well as cuneane derivatives, have also been studied.Results are discussed in terms of strain relief calculated by the molecular mechanics method for cubane-like structures.
Perfume composition
-
, (2008/06/13)
A perfume composition is described, which contains at least one compound of bicyclo[2,2,2]octane and bicyclo[2,2,2]octene derivatives represented by the general formula (I) STR1 wherein the symbols are the same as defined hereinbefore.
Reluctant Azoalkanes: The Photochemical Behavior of Acyclic, Bridgehead-Centered Azoalkanes on 185- and 350-nm Irradiation
Adam, Waldemar,Mazenod, Francois,Nishizawa, Yoshinori,Engel, Paul S.,Baughman, Sharon A.,et al.
, p. 6141 - 6145 (2007/10/02)
Azo-1-adamantane (1a), azobicyclooctanes (1b and 1c), and azo-1-norbornane (1d) isomerize to cis-azoalkanes but are reluctant to lose nitrogen directly upon long-wavelength irradiation.Use of 185-nm light is shown to enhance deazatization quantum yields considerably, though photoisomerization remains an important reaction.In the case of 1a especially, thermolysis of the cis isomer is the dominant decomposition mechanism at long and probably at short wavelength; however, the cis isomer of 1d is thermally stable.It follows that the second excited singlet state is responsible for deazatization of 1d.The products of photolyisis in pentane have been identified, and the amount of bridgehead radical hydrogen abstraction relative to recombination is found to increase under short-wavelength irradiation.
