- CYP505E3: A Novel Self-Sufficient ω-7 In-Chain Hydroxylase
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The self-sufficient cytochrome P450 monooxygenase CYP505E3 from Aspergillus terreus catalyzes the regioselective in-chain hydroxylation of alkanes, fatty alcohols, and fatty acids at the ω-7 position. It is the first reported P450 to give regioselective in-chain ω-7 hydroxylation of C10–C16 n-alkanes, thereby enabling the one step biocatalytic synthesis of rare alcohols such as 5-dodecanol and 7-tetradecanol. It shows more than 70 percent regioselectivity for the eighth carbon from one methyl terminus, and displays remarkably high activity towards decane (TTN≈8000) and dodecane (TTN≈2000). CYP505E3 can be used to synthesize the high-value flavour compound δ-dodecalactone via two routes: 1) conversion of dodecanoic acid into 5-hydroxydodecanoic acid (24 percent regioselectivity), which at low pH lactonises to δ-dodecalactone, and 2) conversion of 1-dodecanol into 1,5-dodecanediol (55 percent regioselectivity), which can be converted into δ-dodecalactone by horse liver alcohol dehydrogenase.
- Maseme, Mpeyake Jacob,Opperman, Diederik Johannes,Pennec, Alizé,Smit, Martha Sophia,van Marwijk, Jacqueline
-
supporting information
p. 10359 - 10362
(2020/04/23)
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- Additive-Free Isomerization of Allylic Alcohols to Ketones with a Cobalt PNP Pincer Catalyst
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Catalytic isomerization of allylic alcohols in ethanol as a green solvent was achieved by using air and moisture stable cobalt (II) complexes in the absence of any additives. Under mild conditions, the cobalt PNP pincer complex substituted with phenyl groups on the phosphorus atoms appeared to be the most active. High rates were obtained at 120 °C, even though the addition of one equivalent of base increases the speed of the reaction drastically. Although some evidence was obtained supporting a dehydrogenation–hydrogenation mechanism, it was proven that this is not the major mechanism. Instead, the cobalt hydride complex formed by dehydrogenation of ethanol is capable of double-bond isomerization through alkene insertion–elimination.
- Spiegelberg, Brian,Dell'Acqua, Andrea,Xia, Tian,Spannenberg, Anke,Tin, Sergey,Hinze, Sandra,de Vries, Johannes G.
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supporting information
p. 7820 - 7825
(2019/05/22)
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- Manganese PNP-pincer catalyzed isomerization of allylic/homo-allylic alcohols to ketones-activity, selectivity, efficiency
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We report the first manganese catalyzed isomerization of allylic alcohols to produce the corresponding carbonyl compounds. The ligand plays a decisive role in the efficiency of this reaction. Very high conversions could be obtained using a solvent-free reaction system. A detailed DFT study reveals a self-dehydrogenation/hydrogenation reaction mechanism which was verified by the isolation of the α,β-unsaturated ketone as intermediate and a deuterium labeling experiment. It also provided a rationale for the observed selectivity and the higher efficiency of phenyl over isopropyl substitution.
- Xia, Tian,Spiegelberg, Brian,Wei, Zhihong,Jiao, Haijun,Tin, Sergey,Hinze, Sandra,De Vries, Johannes G.
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p. 6327 - 6334
(2019/11/20)
-
- Selective Visible Light Aerobic Photocatalytic Oxygenation of Alkanes to the Corresponding Carbonyl Compounds
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The aerobic, selective oxygenation of alkanes via C-H bond activation is an important research challenge. Photocatalysis offers the potential for the introduction of additional concepts for such reactions. Visible light photoactive semiconductors such as bismuth oxyhalides (BiOX, X = Cl and Br) used in this research typically oxidize organic compounds through photocatalyzed formation of strongly oxidizing holes. The reactive oxygen species formed react with organic compounds in one-electron processes, leading to radical intermediates and nonselective oxidation. Such oxidation reactions generally lead to total oxidation. Here, impregnation of BiOX with a polyoxometalate, H5PV2Mo10O40, as a strong electron acceptor changed the reactivity of BiOX, leading to Mars-van Krevelen-type reactivity, that is, photoactivated oxygen donation from BiOX to the organic substrate followed by reoxidation by O2 and catalysis. This conclusion was supported by mechanistic studies involving isotope labeling studies. In this way, ethane was selectively oxidized to acetaldehyde in a flow reactor with a turnover number (24 h) of 415.
- Somekh, Miriam,Khenkin, Alexander M.,Herman, Adi,Neumann, Ronny
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p. 8819 - 8824
(2019/09/30)
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- Acylation of Alkenes with the Aid of AlCl3 and 2,6-Dibromopyridine
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Friedel-Crafts-type acylation of alkenes with acyl chlorides has been successfully conducted with a wide substrate scope by the combined use of AlCl3 and 2,6-dibromopyridine. Trisubstituted alkenes afford allylketones or vinylketones depending on the presence or absence of hydrogen atom(s) at the β-position to the acylation site, while monosubstituted alkenes exclusively afford vinylketones.
- Tanaka, Shinya,Kunisawa, Tsukasa,Yoshii, Yuji,Hattori, Tetsutaro
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supporting information
p. 8509 - 8513
(2019/11/03)
-
- Synthesis, structural characterization and C–H activation property of a tetra-iron(III) cluster
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A non-heme tetra-iron cluster, [Fe4 III(μ-O)2(μ-OAc)6(2,2′-bpy)2(H2O)2](NO3 ?)(OH?) (1), [OAc = acetate; 2,2′-bpy = 2,2′-bipyridine] containing oxido- and acetato-bridges was synthesized and structurally characterized by different spectroscopic methods including single crystal X-ray diffraction studies. X-ray crystal structure analysis of 1 revealed that tetra-iron complex was crystallized in monoclinic system with C2/c space group. Each of the Fe centres in 1 was found to exist in octahedral geometry and interconnected by oxido- and acetato-bridges. Bond valence sum (BVS) calculation recommended the existence of iron centres in +3 oxidation state. Variable temperature magnetic measurement authenticated the dominating antiferromagnetic ordering among the iron centres in the solid state of 1. This tetra-iron cluster was also evaluated as an efficient catalytic system towards the oxidation of both linear & cyclic alkanes without production of primary C–H bond oxidation products. Oxidation of secondary C–H bonds attested the formation of both the corresponding alcohols & ketones in 27–900 TONs. The tetra-iron catalytic system with Alcohol/Ketone values 0.2–1.7 indicated the involvement of freely diffusing carbon-centered radicals rather than metal based oxidant.
- Dey, Dhananjay,Patra, Moumita,Al-Hunaiti, Afnan,Yadav, Hare Ram,Al-mherat, Afrah,Arar, Sharif,Maji, Milan,Choudhury, Angshuman Roy,Biswas, Bhaskar
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p. 220 - 226
(2019/01/05)
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- Isomerization of Allylic Alcohols to Ketones Catalyzed by Well-Defined Iron PNP Pincer Catalysts
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[Fe(PNP)(CO)HCl] (PNP=di-(2-diisopropylphosphanyl-ethyl)amine), activated in situ with KOtBu, is a highly active catalyst for the isomerization of allylic alcohols to ketones without an external hydrogen supply. High reaction rates were obtained at 80 °C, but the catalyst is also sufficiently active at room temperature with most substrates. The reaction follows a self-hydrogen-borrowing mechanism, as verified by DFT calculations. An alternative isomerization through alkene insertion and β-hydride elimination could be excluded on the basis of a much higher barrier. In alcoholic solvents, the ketone product is further reduced to the saturated alcohol.
- Xia, Tian,Wei, Zhihong,Spiegelberg, Brian,Jiao, Haijun,Hinze, Sandra,de Vries, Johannes G.
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supporting information
p. 4043 - 4049
(2018/01/27)
-
- Rational Design of a Metallocatalytic Cavitand for Regioselective Hydration of Specific Alkynes
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The synthesis of a functionalized supramolecular cavitand with inwardly oriented AuI and P=O moieties was explored, including its catalytic proclivity in the selective hydration of internal alkynes. The cavitand works as a supramolecular flask device: AuI coordinates to the triple bond, the P=O moiety connects with a H2O molecule, and the cavity favors folding of a single alkynyl side chain. Several tests of different substrate patterns indicated that the cavity was substrate specific, similar to enzymatic catalysis.
- Endo, Naoki,Inoue, Mami,Iwasawa, Tetsuo
-
supporting information
p. 1136 - 1140
(2018/03/13)
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- Site-selective C-H arylation of primary aliphatic amines enabled by a catalytic transient directing group
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Transition-metal-catalysed direct C-H bond functionalization of aliphatic amines is of great importance in organic and medicinal chemistry research. Several methods have been developed for the direct sp 3 C-H functionalization of secondary and tertiary aliphatic amines, but site-selective functionalization of primary aliphatic amines in remote positions remains a challenge. Here, we report the direct, highly site-selective γ-arylation of primary alkylamines via a palladium-catalysed C-H bond functionalization process on unactivated sp 3 carbons. Using glyoxylic acid as an inexpensive, catalytic and transient directing group, a wide array of γ-arylated primary alkylamines were prepared without any protection or deprotection steps. This approach provides straightforward access to important structural motifs in organic and medicinal chemistry without the need for pre-functionalized substrates or stoichiometric directing groups and is demonstrated here in the synthesis of analogues of the immunomodulatory drug fingolimod directly from commercially available 2-amino-2-propylpropane-1,3-diol.
- Liu, Yongbing,Ge, Haibo
-
-
- From DNA to catalysis: A thymine-acetate ligated non-heme iron(III) catalyst for oxidative activation of aliphatic C-H bonds
-
A non-heme, iron(iii)/THA(thymine-1-acetate) catalyst together with H2O2 as an oxidant is efficient in oxidative C-H activation of alkanes. Although having a higher preference for tertiary C-H bonds, the catalyst also oxidizes aliphatic secondary C-H bonds into carbonyl compounds with good to excellent conversions. Based on the site selectivity of the catalyst and our mechanistic studies the reaction proceeds via an Fe-oxo species without long lived carbon centered radicals.
- Al-Hunaiti, Afnan,R?is?nen, Minn?,Repo, Timo
-
p. 2043 - 2046
(2016/02/05)
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- Ligand Effects in the Gold Catalyzed Hydration of Alkynes
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In the gold(I) (e. g. L-Au-OTf) catalyzed hydration of alkynes, the steric hindrance of ligands has a significant influence on the kinetics of the reaction, whereas their electronic effects are less influential. Very low loadings (ppm levels) of a gold catalyst containing a highly sterically hindered phosphine ligand (e. g. L4-Au-OTf) (L4=Me3(OMe)tBuXPhos) is able to catalyze the hydration of a wide range of alkyne substrates in good yields, at relatively low temperature.
- Ebule, Rene E.,Malhotra, Deepika,Hammond, Gerald B.,Xu, Bo
-
supporting information
p. 1478 - 1481
(2016/05/19)
-
- Rhodium-on-carbon catalyzed hydrogen scavenger- and oxidant-free dehydrogenation of alcohols in aqueous media
-
The efficient and catalytic dehydrogenation of alcohols is a clean approach for preparing carbonyl compounds accompanied only by the generation of hydrogen gas. We have accomplished the heterogeneous rhodium-on-carbon catalyzed dehydrogenation of secondary, as well as primary, alcohols to the corresponding ketones and carboxylic acids in water under basic conditions. This journal is the Partner Organisations 2014.
- Sawama, Yoshinari,Morita, Kosuke,Yamada, Tsuyoshi,Nagata, Saori,Yabe, Yuki,Monguchi, Yasunari,Sajiki, Hironao
-
supporting information
p. 3439 - 3443
(2014/07/08)
-
- Mn(ii) acetate: An efficient and versatile oxidation catalyst for alcohols
-
A homogeneous catalytic system consisting of Mn(ii) acetate (18 μmol), tert-butylhydroperoxide (2.5 mmol), acetonitrile (1.5 mL) and trifluoroacetic acid (91 μmol) was developed for efficient and selective oxidation of various alcohols (1 mmol). The system yielded good to quantitative conversions (42-100%) of various secondary alcohols, such as 2-octanol, fenchyl alcohol and borneol, to their corresponding ketones. Primary alcohols, for example 1-octanol and differently substituted benzyl alcohols, were mainly converted to their corresponding carboxylic acids. Studies with a selection of hydrocarbons, tertiary amines and a cyclic ether isochroman showed that besides alcohols, other substrates can be oxidised as well.
- Raeisaenen, Minna T.,Al-Hunaiti, Afnan,Atosuo, Elisa,Kemell, Marianna,Leskelae, Markku,Repo, Timo
-
p. 2564 - 2573
(2014/07/22)
-
- A novel P450-based biocatalyst for the selective production of chiral 2-alkanols
-
A P450 monooxygenase from Nocardia farcinica (CYP154A8) catalyses the stereo- and regioselective hydroxylation of n-alkanes, still a challenging task in chemical catalysis. In a biphasic reaction system, the regioselectivity for the C2-position of C7-C9 alkanes was over 90%. The enzyme showed strict S-selectivity for all tested substrates, with enantiomeric excess (ee) of up to 91%. This journal is the Partner Organisations 2014.
- Von Bühler, Clemens J.,Urlacher, Vlada B.
-
supporting information
p. 4089 - 4091
(2014/04/03)
-
- Co6(μ3-OH)6 cluster based coordination polymer as an effective heterogeneous catalyst for aerobic epoxidation of alkenes
-
A new hexaprismane Co(ii)6(μ3-OH)6 cluster-based three-dimensional coordination polymer ({Co(μ3-OH) (HCOO)0.72(CH3COO)0.28}n, Co6-CP) was successfully synthesized and characterized with single-crystal XRD, IR spectra, TGA spectra and elemental analysis. Co6-CP was used as an effective heterogeneous catalyst for the aerobic epoxidation of various alkenes. For the catalytic epoxidation of trans-stilbene, the conversion and selectivity towards the epoxide reached 98.6 and 98.0%, respectively. Also, an average TOF of 22 h-1 was obtained for the reaction. The results indicated that Co6-CP displayed excellent aerobic epoxidation activity among the reported coordination polymer materials, even rivaling the traditional heterogeneous cobalt catalysts. The influence of the reaction parameters such as temperature and oxygen flow rate for the epoxidation of the trans-stilbene were also studied in detail.
- Gao, Junkuo,Bai, Linlu,Zhang, Qian,Li, Yongxin,Rakesh, Ganguly,Lee, Jong-Min,Yang, Yanhui,Zhang, Qichun
-
p. 2559 - 2565
(2014/02/14)
-
- HYDROCARBON SYNTHESIS METHODS, APPARATUS, AND SYSTEMS
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Embodiments of the invention include apparatus and systems for hydrocarbon synthesis and methods regarding the same. In an embodiment, the invention includes a process for creating a hydrocarbon product stream comprising reacting a reaction mixture in the presence of a catalyst inside of a reaction vessel to form a product mixture, the reaction mixture comprising a carbon source and water. The temperature inside the reaction vessel can be between 450 degrees Celsius and 600 degrees Celsius and the pressure inside the reaction vessel can be above supercritical pressure for water. In an embodiment, the invention includes an extrusion reactor system for creating a hydrocarbon product stream. The temperature inside the extrusion reactor housing between 450 degrees Celsius and 600 degrees Celsius. Pressure inside the reaction vessel can be above supercritical pressure for water. Other embodiments are also included herein.
- -
-
Page/Page column 32
(2014/01/18)
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- Copper-catalyzed aerobic oxidative functionalization of C-H bonds of alkanes in the presence of acetaldehyde under mild conditions
-
Copper-catalyzed oxidative functionalization of C-H bonds of alkanes with molecular oxygen has been performed in the presence of Cu(OAc)2 catalyst and acetaldehyde in acetonitrile at 70 C with extremely high turn-over numbers.
- Hayashi, Yukiko,Komiya, Naruyoshi,Suzuki, Ken,Murahashi, Shun-Ichi
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p. 2706 - 2709
(2013/06/26)
-
- α,β-Unsaturated imines via Ru-catalyzed coupling of allylic alcohols and amines
-
A convenient synthesis of α,β-unsaturated imines requiring only an allylic alcohol, an amine and a Ru catalyst has been developed. The use of large excesses of oxidant and the purification of sensitive intermediates can be avoided.
- Rigoli, Jared W.,Moyer, Sara A.,Pearce, Simon D.,Schomaker, Jennifer M.
-
supporting information; experimental part
p. 1746 - 1749
(2012/04/23)
-
- Low-temperature aerobic oxidation of decane using an oxygen-free radical initiator
-
The direct selective oxidation of long chain alkanes by O2 is a highly demanding reaction. We have shown that it is possible to oxidise n-decane in the presence of the oxygen-free radical initiator azobisisobutyronitrile. Formation of a range of oxygenated products has been observed under relatively mild conditions (70 °C in air). Although the presence of a catalyst is not essential when the initiator is used, ceria-based catalysts have been found to increase the selectivity to alcohols by modifying the oxyfunctionalisation of decane.
- Lloyd, Rhys,Jenkins, Robert L.,Piccinini, Marco,He, Qian,Kiely, Christopher J.,Carley, Albert F.,Golunski, Stanislaw E.,Bethell, Donald,Bartley, Jonathan K.,Hutchings, Graham J.
-
scheme or table
p. 161 - 167
(2011/11/30)
-
- Hydroformylation of alkenes using heterogeneous catalyst prepared by intercalation of HRh(CO)(TPPTS)3 complex in hydrotalcite
-
Intercalation of HRh(CO)(TPPTS)3 complex into the interlayer space of hydrotalcite was carried out to prepare an eco-friendly heterogeneous hydroformylation catalyst. Intercalated catalyst was characterized by 31P NMR, P-XRD, FT-IR, SEM and surface area measurements. Catalytic activity of intercalated catalyst [HT(3.5)-INT] was evaluated for hydroformylation of linear alkenes of varied carbon number from C5 to C13 as well as cyclic alkenes. Selectivity of the aldehydes was observed to decrease with increase in the carbon chain length of linear alkenes. Effect of reaction parameters on catalytic activity of intercalated catalyst was studied by varying the catalyst amount, 1-hexene concentration, reaction temperature, partial pressure of carbon monoxide and hydrogen for hydroformylation of 1-hexene. The catalyst was re-cycled up to five times without significant loss in the alkene conversion and selectivity of aldehydes.
- Sharma, Sumeet K.,Parikh, Parimal A.,Jasra, Raksh V.
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experimental part
p. 153 - 162
(2010/05/01)
-
- Regio- And stereoselective subterminal hydroxylations of n-decane by fungi in a liquid-liquid interface bioreactor (L-L IBR)
-
This article may be the first report to describe the excellent regio- and stereoselective subterminal hydroxylations of n-alkane with microorganisms. Approximately 2000 fungal strains were screened for the regioselective hydroxylation of n-decane with a s
- Oda, Shinobu,Isshiki, Kunio,Ohashi, Shinichi
-
experimental part
p. 105 - 109
(2009/04/10)
-
- Efficient synthesis of γ-Keto esters through neighboring carbonyl group-assisted regioselective hydration of 3-Alkynoates
-
The Au(III)-catalyzed hydration of 3-alkynoates led to a practical one-step synthesis of γ-keto esters in high yields, through a carbonyl group participation enabled by a favored 5-endodig cyclization. This mild-aqueous ethanol, room temperature, and atom
- Wang, Weibo,Xu, Bo,Hammond, Gerald B.
-
supporting information; experimental part
p. 1640 - 1643
(2009/07/01)
-
- O3/Pb(OAc)4: a new and efficient system for the oxidative cleavage of allyl alcohols
-
Allyl alcohols undergo oxidative cleavage, affording the corresponding carbonyl compounds in good yields, when treated with ozone-lead(IV) acetate under mild conditions.
- Alvarez-Manzaneda,Chahboun,Cano,Cabrera Torres,Alvarez,Alvarez-Manzaneda,Haidour,Ramos López
-
p. 6619 - 6622
(2007/10/03)
-
- Reversal of regioselectivity in Wacker-Type oxidation of simple terminal alkenes and its paired interacting orbitals (PIO) analysis
-
The trend of aldehyde selectivity observed in the oxidation of 1-decene with PdCl2(CH3CN)2/CuCl2 in alcohol (ROH) under O2 can be evaluated by the overlap populations for Pd-C and C-OR bonds in the oxypalladation step with paired interacting orbitals (PIO) analysis. The use of t-BuOH affords decanal in 84% regioselectivity.
- Ogura, Toshihiko,Kamimura, Ryuichiro,Shiga, Akinobu,Hosokawa, Takahiro
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p. 1555 - 1557
(2007/10/03)
-
- Temperature-dependent isomerisation versus net fragmentation of secondary allylic alcohols with Grubbs' catalyst
-
Secondary allylic alcohols with 10 mol% of Grubbs catalyst in refluxing toluene/1,2-dichloroethane undergo isomerisation to ethyl ketones whereas with 100 mol% of Grubbs catalyst at room temperature, a net fragmentation reaction with the loss of a carbon atom occurs, to provide a methyl ketone. Probable mechanisms are described.
- Gurjar, Mukund K.,Yakambram, Pedduri
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p. 3633 - 3636
(2007/10/03)
-
- Ruthenium-catalyzed oxidation of alkanes with tert-butyl hydroperoxide and peracetic acid
-
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.
- Murahashi,Komiya,Oda,Kuwabara,Naota
-
p. 9186 - 9193
(2007/10/03)
-
- Alkane oxidation with manganese substituted polyoxometalates in aqueous media with ozone and the intermediacy of manganese ozonide species
-
Manganese substituted polyoxometalates (POMs), such as Li12[MnII2ZnW(ZnW9O 34)2] were effective catalysts for the oxidation of alkanes to ketones with ozone in an aqueous reaction medium; a green intermediate compound observable by UV-VIS and ESR at -78 °C was postulated to be a reactive manganese ozonide species.
- Neumann, Ronny,Khenkin, Alexander M.
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p. 1967 - 1968
(2007/10/03)
-
- Direct Oxidation of Methyl Ethers to Carbonyl Compounds with a Combination of Nitrogen Dioxide and Water in the Presence or Absence of Ozone
-
A combination of nitrogen dioxide and water has been found to provide a new agent for the transformation of various alkyl methyl ethers 1 (R = Me) to carbonyl compounds 2 under mild conditions. The oxidation can be achieved successfully in dichloromethane, but hexafluoro-2-propanol was found to be most satisfactory as the solvent. The reaction was generally clean, and simple evaporation gave the expected oxidation product 2 in moderate to good yield. In the presence of ozone, but without water, the similar oxidation was observed only after prolonged reaction time, suggesting that some initial minor reaction with a strong oxidant, possible nitrogen trioxide, afforded an acidic promoter, which then worked as a catalyst similar to that involved in the reaction with a nitrogen dioxide and water system.
- Suzuki, Hitomi,Takeuchi, Toyomi,Mori, Tadashi
-
p. 3111 - 3115
(2007/10/03)
-
- Lewis Acid-Promoted Coupling Reactions of Acid Chlorides with Organoaluminum and Organozinc Reagents
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An efficient synthesis of α,α-unsaturated ketones by the reaction of acid chlorides with trialkyl-aluminum (1/3 mole equiv) in the presence of AlCl3 (1 mol equiv) is described. Dialkylzincs were also useful and are easier to prepare than trialkylaluminum. Reaction of RCOCl with R′AlCl3 or R′2AlCl gave R′COR, without AlCl3, in high yield.
- Arisawa, Mitsuhiro,Torisawa, Yasuhiro,Kawahara, Michiaki,Yamanaka, Masamichi,Nishida, Atsushi,Nakagawa, Masako
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p. 4327 - 4329
(2007/10/03)
-
- Selective cleavage of ketals and acetals under neutral, anhydrous conditions using triphenylphosphine and carbon tetrabromide
-
A convenient method for the selective removal of ketal and acetal protection under mild, neutral, anhydrous conditions using PPh3 and CBr4 is described.
- Johnstone, Craig,Kerr, William J.,Scott, James S.
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p. 341 - 342
(2007/10/03)
-
- A Novel Ru(VII)/Ru(IV) Mediatory System for Electrooxidation of Primary and Secondary Alcohols, Leading to Aldehydes and Ketones
-
A soluble Ru(VII)/Ru(IV) redox system in MeCN/H2O(9/1 v/v)-Bu4NOH-(Pt/Pt) was found to be a mild oxidizing method for the electrochemical conversion of primary and secondary alcohols into their corresponding aldehydes and ketones under basic conditions.
- Torii, Sigeru,Yoshida, Akihito
-
p. 369 - 370
(2007/10/02)
-
- Hindered organoboron groups in organic chemistry. 27. Preparations and some properties of alkylbis(2,6-dimethyl-4-methoxyphenyl)boranes ((DMP)2BR)
-
Akylbis(2,6-dimethyl-4-methoxyphenyl)boranes ((DMP)2BR) have been synthesized in an attempt to overcome the limitations of the steric hindrance approach to the production of boron stabilised carbanions. Anion production from (DMP)2BR, followed by alkylations and condensations with aldehydes are reported. Reduction of (DMP)2F with potassium hydride yields the corresponding hydroborate. Attempts to isolate (DMP)2BH were unsuccessful but the borane was readily trapped with alkynes, yielding alkenylboranes. The allyl derivative, (DMP)2BAllyl, was made and some of its reactions were investigated.
- Pelter, Andrew,Drake, Robert
-
p. 13775 - 13800
(2007/10/02)
-
- Selective homologation of ketones and aldehydes with diazoalkanes promoted by organoaluminum reagents
-
Organoaluminum-promoted single homologation or ring expansion of ketones and aldehydes with diazoalkanes has been described, and among various organoaluminium reagents, exceptionally bulky methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD) is found to be highly effective for the selective homologation of various ketones and aldehydes.
- Maruoka,Concepcion,Yamamoto
-
p. 1283 - 1290
(2007/10/02)
-
- Ruthenium-Catalyzed Oxidation of Alkanes with Peracids
-
The ruthenium-catalyzed oxidation of alkanes with peracids under mild conditions gives the corresponding ketones and alcohols highly efficiently.Similar treatment of alkanes in trifluoroacetic acid gives alkyl trifluoroacetates.
- Murahashi, Shun-Ichi,Oda, Yoshiaki,Komiya, Naruyoshi,Naota, Takeshi
-
p. 7953 - 7956
(2007/10/02)
-
- Hindered organoboron groups in organic chemistry. 24. The condensation of aliphatic aldehydes with dimesitylboron stabilised carbanions to give ketones
-
The condensation of boron stabilised carbanions, MeS2BCHLiR1, (R1≠H) with aliphatic aldehydes, R2CHO, followed by treatment with trifluoroacetic anhydride (TFAA) or N-chlorosuccinimide (NCS) is an unique, broadly applicable redox process that yields ketones, R1CH2COR2, directly and in high yields. The anion MeS2BCH2Li (MeS2BCHLiR1, R1=H) gives high yields of alkenes, R2CH=CH2 in the same conditions.
- Pelter, Andrew,Smith, Keith,Elgendy, Said M. A.,Rowlands, Martin
-
p. 7104 - 7118
(2007/10/02)
-
- Indirect Electrooxidation of Alcohols by a Double Mediatory System with Two Redox Couples of +=O>/R2NO. and . or Br+>/Br- in an Organic-Aqueous Two-Phase Solution
-
An indirect electrooxidation method for alcohol to aldehyde or ketone conversion has been developed.This method, applicable to chemoselective oxidation, employs two redox couples, consisting of 2,2,6,6-tetramethylpiperidine-1-oxyl derivatives 6 and active bromine species.The former is required for the chemical process and recycled, whereas the latter is to be involved in the electrochemical process.Three chemical events play an important role in this system: (1) the formation of . or Br+> from bromide ion by discharge on the anode in an aqueous solution, (2) the reaction of N-oxyl compounds 6 with active bromine species to generate N-oxoammonium ion 7, and (3) the oxidation of alcohols with 7 in an organic phase.Optimum conditions were established as follows: an aqueous 25percent NaBr solution buffered at pH 8.6 in a binary system, the use of 1-10 mol percent of 4-(benzoyloxy)piperidine derivatives 6, and adjustment of an electric current at 10-100 mA/cm2.The successful applications of the present method to the oxidation of a variety of primary and secondary alcohols including 1,n-diols, giving the corresponding carbonyl compounds, have delineated its synthetic utility.The chemoselective oxidation of a primary hydroxy group in the presence of secondary one has been achieved with a high selectivity by the present procedure.
- Inokuchi, Tsutomu,Matsumoto, Sigeaki,Torii, Sigeru
-
p. 2416 - 2421
(2007/10/02)
-
- Improved Method for the Wacker Oxidation of Cyclic and Internal Olefins
-
An improved method for palladium(II)-catalyzed Wacker oxidation of cyclic and internal olefins is described.Addition of perchloric, sulfuric, nitric, or tetrafluoroboric acid to a chloride free solution of the Pd(II) catalyst gives rate enhancements of up to a factor of 50.The oxidation of cyclohexene to cyclohexanone, which was previously reported to give a 97percent yield after 5 h, is now accomplished in 1 h quantitatively, with only one-third of the amount of Pd(II) used.Limitations of the method are also discussed.
- Miller, D. G.,Wayner, D. D. M.
-
p. 2924 - 2927
(2007/10/02)
-
- Catalysis of Pd(II)-catalyzed acetalization of alkenes with diols
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Alkenes bearing electron-withdrawing substituents are catalytically acetalized with 1,3-propanediol only by the use of PdCl2(MeCN)2 catalyst under O2 atmosphere. When a combination of BiCl3 and LiCl is used as co-catalyst, the acetalization proceeds effectively. These results indicate that a hydroperoxopalladium(II) species is most likely an active catalyst in the present reaction.
- Hosokawa,Ataka,Murahashi
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p. 166 - 169
(2007/10/02)
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- HINDERED ORGANOBORON GROUPS IN ORGANIC SYNTHESIS. 13. THE DIRECT PRODUCTION OF KETONES FROM ALIPHATIC ALDEHYDES BY A UNIQUE VARIANT OF THE BORON-WITTIG REACTION
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In the presence of trifluoroacetic anhydride or N-chlorosuccinimide, aliphatic aldehydes react with dimesitylboron stabilised carbanions to give after work up, the corresponding ketones, a process wich is unique among Wittig type reactions.Yields of ketones are satisfactory in all cases except those involving the anion derived from the parent compound dimesitylmethylborane, wich give the corresponding alkenes.
- Pelter, Andrew,Smith, Keith,Elgendy, Said,Rowlands, Martin
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p. 5643 - 5646
(2007/10/02)
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- Oxidation of Secondary Alcohols with t-Butyl Hypochlorite in the Presence of Pyridine
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When treated with t-butyl hypochlorite and pyridine in methylene dichloride, secondary alcohols give the corresponding ketones in very high yield.The relative reactivities of a number of p-substituted 1-phenylethanols containing electron-donating and -withdrawing substituents were investigated.Oxidation of cis- and trans-4-t-butylcyclohexanol, as well as some other cycloalkanols, proceeds with the same relative rate.On the basis of this and other data a cyclic transition state and loss of α-hydrogen of the starting alcohols as hydride ion are proposed as characteristics of the reaction mechanism.
- Milovanovic, Jovan N.,Vasojevic, Miorad,Gojkovic, Svetislav
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p. 533 - 536
(2007/10/02)
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- A SIMPLE WAY TO SOME KETONE HOMOENOLATES
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Under basic conditions 1-alkene-3-ols were converted into ketone homoenolates which led to β-alkylated ketones.
- Cuvigny, Therese,Julia, Marc,Jullien, Ludovic,Rolando, Christian
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p. 2587 - 2590
(2007/10/02)
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- AZO ANIONS IN SYNTHESIS. PT 1. t-BUTYLHYDRAZONES AS ACYL-ANION EQUIVALENTS
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The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides, crotonates) to form C-trapped t-butylazo-compounds; tautomerisation and hydrolysis gave α-hydroxy ketones, ketones, and γ-keto esters in good yield, thereby providing a convenient new acyl-anion equivalent.Reaction of these lithium salts with aldehydes and ketones, followed by elimination provided a new route to azo alkenes.
- Baldwin, Jack E.,Adlington, Robert M.,Bottaro, Jeffrey C.,Kolhe, Jayant N.,Perry, Matthew W. D.,Jain, Ashok U.
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p. 4223 - 4234
(2007/10/02)
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- Conditions for the Microbial Oxidation of Various Higher Alcohols in Isooctane
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The substrate specifities and reaction conditions for the microbial oxidation of higher alcohols in isooctane were investigated using Rhodococcus equi cells grown on n-tetradecane as the sole carbon source.Primary alcohols, C4ca.C14 (even numbers), were oxidized to the corresponding carboxylic acids, with which the substrate alcohols further combined to form esters, and various kinds of secondary decanols were oxidized to the corresponding ketones, suggesting that the substrate specifities of R. equi were not so restricted in isooctane.As to the the reaction conditions, water was positively required for the oxidation of higher alcohols such as 1-tetradecanol in organic solvents such as isooctane, although the amount of water required represented only a small portion of the reaction mixture.On the other hand, ester formation took place in isooctane practically free from water, and the rates of ester formation from 1-tetradecanol and tetradecanoic acid by dried cells increased with an increase in temperature up to 70 deg C in isooctane, while ester formation hardly occured at deg C when intact cells were used in place of dried cells.It was thus suggested that microbial ester formation is less susceptible to the thermal inactivation in the absence of water than in the presence.
- Ueda, Makoto,Mukataka, Sukekuni,Sato, Seigo,Takahashi, Joji
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p. 1533 - 1538
(2007/10/02)
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- PALLADIUM CHLORIDE AND POLYETHYLENE GLYCOL PROMOTED OXIDATION OF TERMINAL AND INTERNAL OLEFINES
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Both terminal and internal olefins can be efficiently converted to ketones in polyethylene glycol and water using palladium chloride as the catalyst.
- Alper, Howard,Januszkiewicz, Krysztof,Smith, David J. H.
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p. 2263 - 2264
(2007/10/02)
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- REACTIVITE DES DERIVES ORGANOMANGANEUX-VIII; PREPARATION DE CETONES PAR ACYLATION D'ORGANOMANGANEUX. INFLUENCE DE LA NATURE DE L'AGENT ACYLANT, DES SOLVANTS ET DES LIGANDS
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The influence of the nature of acylating reagents, solvents and ligands on the preparation of ketones by acylation of organomanganous reagents is studied.Thus acid chlorides in ether, symmetrical acid anhydrides in ether or THF and mixed carboxylic-carbonic anhydrides (R'COOCOOEt) in ether are compared, they lead to the corresponding ketones with good or excellent yields.Some problems of reproductibility are encountered and discussed when mixed anhydrides R'COOCOOEt are used in THF.The addition of a great variety of cosolvents (e.g.C6H6, AcOEt, CO3Et2, CH3CN, CH2Cl2...) to the reaction mixture before addition of the acylating reagent does not affect the yield of ketones.In comparison the complexation of organomanganous reagents by several ligands (e.g.Me2S or Ph3P) has no subsequent effect on their acylation.The main limitation for the choice of solvents or ligands is the use of amino derivatives which generally lead to a very low yield of ketones (e.g.C5H5N, TMEDA, Et3N) or unreproducible yields (e.g.HMPA).Two applications of these studies are described: -The stabilization of s or t-alkyl manganous derivatives by complexation which leads to the best yield of the corresponding ketones -The use of a cosolvent in order to increase the yield when mixed anhydrides R'COOCOOEt are used in THF.
- Friour, G.,Alexakis, A.,Cahiez, G.,Normant, J.
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p. 683 - 694
(2007/10/02)
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- Azo Anions in Synthesis. t-Butylhydrazones as Acyl-anion Equivalents
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The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides) to form C-trapped t-butylazo compounds; isomerisation and hydrolyse gave α-hydroxy ketones and ketones in good yields, thereby providing a convenient new acyl-anion equivalent.
- Adlington, Robert M.,Baldwin, Jack E.,Bottaro, Jeffrey C.,Perry, Matthew W. D.
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p. 1040 - 1041
(2007/10/02)
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- SYNTHESIS AND DECOMPOSITION OF E- AND Z-3,3,5-TRISUBSTITUTED 1,2-DIOXOLANES.
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The reactions of a number of ozonides and olefins in the presence of boron trifluoride-diethyl ether gave the corresponding mixtures of (E)- and (Z)-1,2-dioxolanes in 12-70% yield. The decomposition of the E-Z isomeric 1,2-dioxolanes 3a-c was undertaken under a variety of conditions, i. e. , thermal, TiCl//4-mediated, FeSO//4-catalyzed, and LiAlH//4-mediated decompositions.
- Yoshida,Miura,Nojima,Kusabayashi
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p. 6279 - 6285
(2007/10/02)
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- Catalytic Double Bond Isomerization by Polystyrene-Anchored RuCl2(PPh3)3
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Dichlorotris(triphenylphosphine)ruthenium has been anchored to diphenylphosphinated styrene-divinylbenzene copolymer.The resulting leaching-resistant catalyst was employed successfully for the isomerization of allylbenzenes and allyl alcohols in numerous turnovers.The stability of the catalyst was examined in different media, and its performances were compared with those of homogeneous RuCl2(PPh3)3 and with those of polymer-bound as well as of free RhCl(PPh3)3 and IrCl(CO)(PPh3)2
- Zoran, Amikam,Sasson, Yoel,Blum, Jochanan
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p. 255 - 260
(2007/10/02)
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