589-82-2Relevant academic research and scientific papers
Chelating alcohols accelerate the samarium diiodide mediated reduction of 3-heptanone
Dahlén, Anders,Hilmersson, G?ran
, p. 5565 - 5569 (2001)
Initial rate studies of samarium diiodide mediated reduction of 3-heptanone to 3-heptanol are reported. The reduction of 3-heptanone with the polydentate tri(ethylene glycol) methyl ether is 16 times faster than without a proton donor, and 4.3 times faster than methanol. The primary kinetic isotope effect (KIE) was measured as kH/kD ≈ 2, indicating a rate-determining proton transfer. Diols are superior to mono-alcohols as proton donors, the reduction of 3-heptanone is 255 times as fast with di(ethylene glycol) than in the absence of a proton donor. A mechanism of glycol accelerated samarium diiodide reduction is discussed.
Mechanistic Insights into the Aerobic Oxidation of Aldehydes: Evidence of Multiple Reaction Pathways during the Liquid Phase Oxidation of 2-Ethylhexanal
Vanoye, Laurent,Favre-Réguillon, Alain
, p. 335 - 346 (2022/02/10)
The liquid-phase aldehyde oxidation by molecular oxygen (autoxidation) has been known for about 2 centuries and is a critical organic transformation in both industrial applications and academic research. However, the general reaction pathway proposed for the aerobic oxidation of aldehydes into the corresponding carboxylic acid exhibits some inconstancies, in particular, for β-substituted aliphatic aldehydes. Thus, the liquid-phase aerobic oxidation of 2-ethylhexanal was further studied in acetonitrile at 20 °C with O2 at atmospheric pressure. By precisely monitoring the primary intermediate (peracid), product (carboxylic acid), and byproducts as a function of time and catalysts used, we demonstrated the pivotal role of the acylperoxy radical. The direct formation of peracid and carboxylic acid from the latter was highlighted by analyzing the composition of the reaction mixture at low conversion. Peracid could be converted into carboxylic acid by metal catalysts or through reaction workup. Consequently, the commonly accepted pathway of aerobic oxidation of aldehyde via a Criegee intermediate can be overlooked under these conditions.
Iron(III) Complexation with Galactodendritic Porphyrin Species and Hydrocarbons’ Oxidative Transformations
Castro, Kelly A. D. F.,Westrup, Kátia C. M.,Silva, Sandrina,Pereira, Patrícia M. R.,Sim?es, Mário M. Q.,Neves, Maria da Gra?a P. M. S.,Cavaleiro, José A. S.,Tomé, Jo?o P. C.,Nakagaki, Shirley
, p. 2857 - 2869 (2021/07/14)
The iron metalation of the known free-base porphyrins H2P2 and H2P3, obtained by structural modification of the well-known TPPF20 (H2P1) with galactose dendritic units, gave the corresponding iron(III) porphyrin complex FeP2 and the solid hybrid material FeP3S. Their synthesis, characterization and catalytic efficacy toward the oxidation of the organic substrates (Z)-cyclooctene, cyclohexane and heptane, are reported. In this work, the possibility to modulate selectivity and chemical efficiency of the catalytic system by using simple and more sophisticated metalloporphyrins is demonstrated. Furthermore, the presence of the galactose dendrimer units at the meso-porphyrin ring positions can tune the oxidation at the terminal positions in linear alkanes. In addition, the FeP3S material was easily recovered and reused at least 3 times for the cyclooctene oxidation. The catalytic performance of material FeP3S, associated with their possibility of reuse, makes this material a promising catalyst.
Robust Mn(iii): N -pyridylporphyrin-based biomimetic catalysts for hydrocarbon oxidations: heterogenization on non-functionalized silica gel versus chloropropyl-functionalized silica gel
Pinto, Victor Hugo A.,Falc?o, Nathália K. S. M.,Mariz-Silva, Bárbara,Fonseca, Maria Gardennia,Rebou?as, Júlio S.
supporting information, p. 16404 - 16418 (2020/12/03)
Two classes of heterogenized biomimetic catalysts were prepared and characterized for hydrocarbon oxidations: (1) by covalent anchorage of the three Mn(iii) meso-tetrakis(2-, 3-, or 4-pyridyl)porphyrin isomers by in situ alkylation with chloropropyl-functionalized silica gel (Sil-Cl) to yield Sil-Cl/MnPY (Y = 1, 2, 3) materials, and (2) by electrostatic immobilization of the three Mn(iii) meso-tetrakis(N-methylpyridinium-2, 3, or 4-yl)porphyrin isomers (MnPY, Y = 4, 5, 6) on non-modified silica gel (SiO2) to yield SiO2/MnPY (Y = 4, 5, 6) materials. Silica gel used was of column chromatography grade and Mn porphyrin loadings were deliberately kept at a low level (0.3% w/w). These resulting materials were explored as catalysts for iodosylbenzene (PhIO) oxidation of cyclohexane, n-heptane, and adamantane to yield the corresponding alcohols and ketones; the oxidation of cyclohexanol to cyclohexanone was also investigated. The heterogenized catalysts exhibited higher efficiency and selectivity than the corresponding Mn porphyrins under homogeneous conditions. Recycling studies were consistent with low leaching/destruction of the supported Mn porphyrins. The Sil-Cl/MnPY catalysts were more efficient and more selective than SiO2/MnPY ones; alcohol selectivity may be associated with hydrophobic silica surface modification reminiscent of biological cytochrome P450 oxidations. The use of widespread, column chromatography, amorphous silica yielded Sil-Cl/MnPY or SiO2/MnPY catalysts considerably more efficient than the corresponding, previously reported materials with mesoporous Santa Barbara Amorphous No 15 (SBA-15) silica. Among the materials studied, in situ derivatization of Mn(iii) 2-N-pyridylporphyrin by covalent immobilization on Sil-Cl to yield Sil-Cl/MnP1 showed the best catalytic performance with high stability against oxidative destruction and reusability/recyclability.
Regioselective C-H hydroxylation of: N -alkanes using Shilov-type Pt catalysis in perfluorinated micro-emulsions
De Vos, Dirk E.,Janssen, Michiel
, p. 1264 - 1272 (2020/03/23)
Shilov-chemistry inspired catalysis has remained largely overlooked as a tool for establishing the remote hydroxylation of non-polar compounds, such as long linear alkanes, due to the need for an acidic aqueous solution. To circumvent the solubility issue, the concept of micellar catalysis is introduced, using PtII in perfluorinated micro-emulsions. Notably, the terminal C-H activation of n-heptane is demonstrated under an oxygen atmosphere using perfluorooctanoic acid (PFOA) as a surfactant, along with the intrinsic ability of PtII to convert the highly inert primary C-H bonds. Coordination of PtII to the carboxylate groups of PFOA proved to be particularly important for achieving maximum catalyst activity towards the hydrocarbon substrate solubilized inside the micelle interior. Based on these insights, optimization of the reaction parameters allowed a positional selectivity of 60% for 1-heptanol, among the C7 alcohols, to be achieved, using low catalyst and surfactant loadings under acid-free conditions.
Metal-Organic Architectures Assembled from Multifunctional Polycarboxylates: Hydrothermal Self-Assembly, Structures, and Catalytic Activity in Alkane Oxidation
Gu, Jinzhong,Wen, Min,Cai, Yan,Shi, Zifa,Arol, Aliaksandr S.,Kirillova, Marina V.,Kirillov, Alexander M.
, p. 2403 - 2412 (2019/02/28)
A three-component aqueous reaction system comprising copper(II) acetate (metal node), poly(carboxylic acid) with a phenylpyridine or biphenyl core (main building block), and 1,10-phenanthroline (crystallization mediator) was investigated under hydrothermal conditions. As a result, four new coordination compounds were self-assembled, namely, {[Cu(μ3-cpna)(phen)]·H2O}n (1), {[Cu(μ-Hbtc)(phen)]·H2O}n (2), {[Cu(μ3-Hcpic)(phen)]·2H2O}n (3), and [Cu6(μ-Hcptc)6(phen)6]·6H2O (4), where H2cpna = 5-(2′-carboxylphenyl)nicotinic acid, H3btc = biphenyl-2,4,4′-tricarboxylic acid, H3cpic = 4-(5-carboxypyridin-2-yl)isophthalic acid, H3cptc = 2-(4-carboxypyridin-3-yl)terephthalic acid, and phen = 1,10-phenanthroline. Crystal structures of compounds 1-3 reveal that they are 1D coordination polymers with a ladder, linear, or double-chain structure, while product 4 is a 0D hexanuclear complex. All of the structures are extended further [1D a?' 2D (1 and 2), 1D a?' 3D (3), and 0D a?' 3D (4)] into hydrogen-bonded networks. The type of a multicarboxylate building block has a considerable effect on the final structures of 1-4. The magnetic behavior and thermal stability of 1-4 were also investigated. Besides, these copper(II) derivatives efficiently catalyze the oxidation of cycloalkanes with hydrogen peroxide under mild conditions. The obtained products are the unique examples of copper derivatives that were assembled from H2cpna, H3btc, H3cpic, and H3cptc, thus opening up their use as multicarboxylate ligands toward the design of copper-organic architectures.
Heptanuclear Fe5Cu2-Phenylgermsesquioxane containing 2,2′-Bipyridine: Synthesis, Structure, and Catalytic Activity in Oxidation of C-H Compounds
Bilyachenko, Alexey N.,Khrustalev, Victor N.,Zubavichus, Yan V.,Shul'Pina, Lidia S.,Kulakova, Alena N.,Bantreil, Xavier,Lamaty, Frédéric,Levitsky, Mikhail M.,Gutsul, Evgeniy I.,Shubina, Elena S.,Shul'Pin, Georgiy B.
, p. 528 - 534 (2018/01/11)
A new representative of an unusual family of metallagermaniumsesquioxanes, namely the heterometallic cagelike phenylgermsesquioxane (PhGeO2)12Cu2Fe5(O)OH(PhGe)2O5(bipy)2 (2), was synthesized and structurally characterized. Fe(III) ions of the complex are coordinated by oxa ligands: (i) cyclic (PhGeO2)12 and acyclic (Ph2Ge2O5) germoxanolates and (ii) O2- and (iii) HO- moieties. In turn, Cu(II) ions are coordinated by both oxa (germoxanolates) and aza ligands (2,2′-bipyridines). This "hetero-type" of ligation gives in sum an attractive pagoda-like molecular architecture of the complex 2. Product 2 showed a high catalytic activity in the oxidation of alkanes to the corresponding alkyl hydroperoxides (in yields up to 30%) and alcohols (in yields up to 100%) and in the oxidative formation of benzamides from alcohols (catalyst loading down to 0.4 mol % in Cu/Fe).
New oxidovanadium(iv) complex with a BIAN ligand: synthesis, structure, redox properties and catalytic activity
Fomenko, Iakov S.,Gushchin, Artem L.,Shul'pina, Lidia S.,Ikonnikov, Nikolay S.,Abramov, Pavel A.,Romashev, Nikolay F.,Poryvaev, Artem S.,Sheveleva, Alena M.,Bogomyakov, Artem S.,Shmelev, Nikita Y.,Fedin, Matvey V.,Shul'pin, Georgiy B.,Sokolov, Maxim N.
supporting information, p. 16200 - 16210 (2018/10/04)
Reaction of VCl3 with bis[N-(2,6-diisopropylphenyl)imino]acenaphthene (dpp-bian) in air afforded [VOCl2(dpp-bian)] (1). The complex was characterized by IR and UV-vis spectroscopies and elemental analysis. The crystal structure of 1 was determined by X-ray diffraction (XRD) analysis. The vanadium atom is in a square-pyramidal OCl2N4 coordination environment. The cyclic voltammogram (CV) in dichloromethane reveals an irreversible oxidation process at +1.40 V (vs. Ag/AgCl) assigned to the V(iv)/V(v) couple, and two consecutive quasi-reversible one-electron reduction processes at ?0.32 V and ?1.05 V (vs. Ag/AgCl), respectively, assigned to the bian/bian?/ and bian?//bian2? couples, followed by irreversible reduction at ?1.6 V (vs. Ag/AgCl). The EPR spectrum of 1 in toluene shows a single 8-line signal typical for oxidovanadium(iv) complexes with d1 configuration. The magnetic behavior of 1 confirms the presence of one unpaired electron (μeff (330 K) = 1.67 μB), and the isolation of the paramagnetic centers. Application of 1 to oxidation of alkanes documented high catalytic activity under mild conditions. The kinetics and selectivity of alkane oxygenation by the 1/H2O2 and 1/PCA/H2O2 systems (PCA is pyrazine-2-carboxylic acid) were studied. The reaction is more efficient in the presence of PCA.
Mild and selective reduction of aldehydes utilising sodium dithionite under flow conditions
Neyt, Nicole C.,Riley, Darren L.
supporting information, p. 1529 - 1536 (2018/07/05)
We recently reported a novel hybrid batch-flow synthesis of the antipsychotic drug clozapine in which the reduction of a nitroaryl group is described under flow conditions using sodium dithionite. We now report the expansion of this method to include the reduction of aldehydes. The method developed affords yields which are comparable to those under batch conditions, has a reduced reaction time and improved space-time productivity. Furthermore, the approach allows the selective reduction of aldehydes in the presence of ketones and has been demonstrated as a continuous process.
OPEN-FLASK HYDROBORATION AND THE USE THEREOF
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Paragraph 0046; 0049; 0059; 0060; 0061, (2018/03/25)
The present disclosure generally relates to a process for hydroboration of an alkene or alkyne using ammonia borane (AB). In particular, the present invention relates to hydroboration of an alkene or alkyne in the presence of air or moisture, and a clean process for facile preparation of an alcohol by oxidizing the organoborane so formed with hydrogen peroxide. The products, including aminodialkylboranes, ammonia trialkylborane complexes, as well as various alcohols so prepared, are within the scope of this disclosure.
