93131-17-0Relevant articles and documents
Mechanism of Ni-catalyzed oxidations of unactivated C(sp3)-H Bonds
Qiu, Yehao,Hartwig, John F.
supporting information, p. 19239 - 19248 (2020/11/13)
The Ni-catalyzed oxidation of unactivated alkanes, including the oxidation of polyethylenes, by meta-chloroperbenzoic acid (mCPBA) occur with high turnover numbers under mild conditions, but the mechanism of such transformations has been a subject of debate. Putative, high-valent nickel-oxo or nickel-oxyl intermediates have been proposed to cleave the C-H bond, but several studies on such complexes have not provided strong evidence to support such reactivity toward unactivated C(sp3)-H bonds. We report mechanistic investigations of Ni-catalyzed oxidations of unactivated C-H bonds by mCPBA. The lack of an effect of ligands, the formation of carbon-centered radicals with long lifetimes, and the decomposition of mCPBA in the presence of Ni complexes suggest that the reaction occurs through free alkyl radicals. Selectivity on model substrates and deuterium-labeling experiments imply that the m-chlorobenzoyloxy radical derived from mCPBA cleaves C-H bonds in the alkane to form an alkyl radical, which subsequently reacts with mCPBA to afford the alcohol product and regenerate the aroyloxy radical. This free-radical chain mechanism shows that Ni does not cleave the C(sp3)-H bonds as previously proposed; rather, it catalyzes the decomposition of mCPBA to form the aroyloxy radical.
Evidence that steric factors modulate reactivity of tautomeric iron-oxo species in stereospecific alkane C-H hydroxylation
Mitra, Mainak,Lloret-Fillol, Julio,Haukka, Matti,Costas, Miquel,Nordlander, Ebbe
, p. 1408 - 1410 (2014/02/14)
A new iron complex mediates stereospecific hydroxylation of alkyl C-H bonds with hydrogen peroxide, exhibiting excellent efficiency. Isotope labelling studies provide evidence that the relative reactivity of tautomerically related oxo-iron species responsible for the C-H hydroxylation reaction is dominated by steric factors. This journal is The Royal Society of Chemistry.
Highly efficient divanadium(V) pre-catalyst for mild oxidation of liquid and gaseous alkanes
Gupta, Samik,Kirillova, Marina V.,Guedes Da Silva, M. Fátima,Pombeiro, Armando J.L.
, p. 82 - 89 (2013/07/27)
A new binuclear oxovanadium(V) complex bearing an NO2-donor Schiff base ligand, [{VO(EtO)(EtOH)}2(1κ2O,κN: 2κ2O,κN-L)]·2H2O (H4L = bis(2-hydroxybenzylidene)oxalohydrazonic acid) was prepared and fully characterized by IR, 1H NMR and electronic spectroscopies, elemental analysis and single crystal X-ray diffraction. In the presence of 2-pyrazinecarboxylic acid (PCA) or another acid promoter, this compound acts as a highly efficient pre-catalyst towards the oxidation of gaseous and liquid alkanes by aqueous H2O2 under mild conditions, in aqueous MeCN. Total yields of oxygenates up to 45% and overall turnover numbers up to 7.8 × 103 are achieved.
Electronic tuning of iron-oxo-mediated C-H activation: Effect of electron-donating ligand on selectivity
Hitomi, Yutaka,Arakawa, Kengo,Kodera, Masahito
supporting information, p. 14697 - 14701 (2013/11/06)
We have reported previously that an iron(III) complex supported by an anionic pentadentate monoamido ligand, dpaqH (dpaq H=2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamido), promotes selective C-H hydroxylation with H2O2 with high regioselectivity. Herein, we report on the preparation of FeIII-dpaq derivatives that have a series of substituent groups at the 5-position of a quinoline moiety in the parent ligand dpaqH (dpaqR, R: OMe, H, Cl, and NO2), and examine them with respect to their catalytic activity in C-H hydroxylation with H2O2. As the substituent group becomes more electron-withdrawing, both the selectivity and the turnover number increase, but the selectivity of epoxidation shows the opposite trend. Copyright
An iron(III)-monoamidate complex catalyst for selective hydroxylation of alkane C-H bonds with hydrogen peroxide
Hitomi, Yutaka,Arakawa, Kengo,Funabiki, Takuzo,Kodera, Masahito
supporting information; experimental part, p. 3448 - 3452 (2012/06/16)
Selective oxidation: The success of the title reaction (see scheme) is caused by the strong electron donation from the amidate moiety of the dpaq ligand to the iron center (dpaq=2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8- yl-acetamidate). This process facilitates the O-O bond heterolysis of the intermediate FeIIIOOH species to generate a selective oxidant without forming highly reactive hydroxyl radicals. Copyright
Alkane hydroxylation by a nonheme iron catalyst that challenges the heme paradigm for oxygenase action
Company, Anna,Gomez, Laura,Gueell, Mireia,Ribas, Xavi,Luis, Josep M.,Que Jr., Lawrence,Costas, Miquel
, p. 15766 - 15767 (2008/09/19)
A nonheme iron catalyst catalyzed stereoselective oxidation of alkanes with H2O2 with remarkable efficiency and exhibiting an unprecedented high incorporation of water into the oxidized products. The present results challenge the canonical description of oxygenases, the standard oxo-hydroxo tautomerism that applies to heme systems and serves as a precedent for alternative pathways for the oxidation of hydrocarbons at nonheme iron oxygenases. Copyright
METHOD OF DEUTERIZATION
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Page/Page column 12; 14, (2008/06/13)
The present invention relates to a method for deuteration of a compound represented by the general formula [1]:R1―X―R2 ???wherein, R1 represents an alkyl group or an aralkyl group, which may have a carbon-carbon double bond and/or triple bond; R2 represents an alkyl group which may have a carbon-carbon double bond and/or triple bond, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group or a hydroxyl group; X represents a carbonyl group or a hydroxylmethylene group; R1 and R2 may form an alicyclic ring together with a carbon atom contained in X; provided that R2 represents an alkyl group which may have a carbon-carbon double bond and/or triple bond, an aryl group or an aralkyl group when X is a hydroxylmethylene group, comprising reacting the compound represented by the general formula [1] with a heavy hydrogen source in the co-presence of an activated catalyst selected from a palladium catalyst, a platinum catalyst, a rhodium catalyst, a ruthenium catalyst, a nickel catalyst and a cobalt catalyst. The method of the present invention can significantly improve working environment because the deuteration, which has been conventionally carried out under severe conditions such as basic condition, can be carried out under neutral condition. Further, even when the compound represented by the general formula [1] is one having a carbon-carbon double bond or triple bond, the method for deuteration of the present invention enables to efficiently carry out objective deuteration without reduction of said double bond or triple bond.
Ruthenium-catalyzed oxidation of alkanes with tert-butyl hydroperoxide and peracetic acid
Murahashi,Komiya,Oda,Kuwabara,Naota
, p. 9186 - 9193 (2007/10/03)
The ruthenium-catalyzed oxidation of alkanes with tert-butyl hydroperoxide and peracetic acid gives the corresponding ketones and alcohols highly efficiently at room temperature. The former catalytic system, RuCl2(PPh3)3-t-BuOOH, is preferable to the oxidation of alkylated arenes to give aryl ketones. The latter system, Ru/C-CH3CO3H, is suitable especially for the synthesis of ketones and alcohols from alkanes. The ruthenium-catalyzed oxidation of cyclohexane with CH3CO3H in trifluoroacetic acid/CH2Cl2 at room temperature gave cyclohexyl trifluoroacetate and cyclohexanone with 90% conversion and 90% selectivity (85:15). The mechanistic study indicates that these catalytic oxidations of hydrocarbons involve oxo-ruthenium species as key intermediates.
Synthesis of Cyclohexanol by Reduction of Pentachlorophenol using Raney Nickel-Aluminium Alloy in a BaO-D2O Solution under Sonication
Mukumoto, Mamoru,Mashimo, Takuya,Tsuzuki, Hirohisa,Tsukinoki, Takehito,Uezu, Noriko,et al.
, p. 412 - 413 (2007/10/03)
Reduction of pentachlorophenol (1) with Raney nickel-aluminium alloy in saturated BaO-D2O under sonication afforded cyclohexanol (2) in 85percent yield with a high -content (99percent).
On the Mechanism of Carbon-Hydrogen Activation in Gif-type Reactions. Kinetic Isotopic Effects in Pyridine Solution.
Barton, Derek H. R.,Doller, Dario,Geletii, Yurii V.
, p. 3811 - 3814 (2007/10/02)
Kinetic isotopic effects (KIE) were measured for oxidation, bromination and selenylation of c-C6H12/c-C6D12 in pyridine solution for different Gif-type, Fenton and other systems.The comparison of KIE and relative reactivity data for the pair c-C5H10/c-C6H12 proved that the mechanism of activation in Gif-type reactions is different from a hydrogen atom abstraction.
