- Asymmetric Epoxidation of Enones Promoted by Dinuclear Magnesium Catalyst
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Asymmetric synthesis with cheaper and non-toxic alkaline earth metal catalysts is becoming an important and sustainable alternative to conventional catalytic methodologies mostly relying on precious metals. In spite of some sustainable methods for enantioselective epoxidation of enones, the development of a well-defined and efficient catalyst based on magnesium complexes for these reactions is still a challenging task. In this perspective, we present the application of chiral dinuclear magnesium complexes for asymmetric epoxidation of a broad range of electron-deficient enones. We demonstrate that the in situ generated magnesium-ProPhenol complex affords enantioenriched oxiranes in high yields and with excellent enantioselectivities (up to 99% ee). Our extensive study verifies the literature data in this area and provides a step forward to better understand the factors controlling the oxygenation process. Elaborated catalyst offers mild reaction conditions and a truly wide substrate scope. (Figure presented.).
- Jaszczewska-Adamczak, Joanna A.,Mlynarski, Jacek
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supporting information
p. 4247 - 4255
(2021/07/17)
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- Facile epoxidation of α, β-unsaturated ketones with urea-2,2-dihydroperoxypropane as a new oxidant
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Abstract: Various aromatic α, β-unsaturated ketones were successfully transformed into their corresponding epoxides using urea-2,2-dihydroperoxypropane as the oxygen source for the first time. The reactions were carried out under mild alkaline conditions at room temperature in high yields and short reaction times. Graphical Abstract: [Figure not available: see fulltext.]
- Khosravi, Kaveh,Naserifar, Shirin
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p. 323 - 328
(2017/01/10)
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- Metal-Free and Efficient Epoxidation of α,β-Unsaturated Ketones with 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as a Powerful Solid Oxidant
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1,1,2,2-Tetrahydroperoxy-1,2-diphenylethane was used for the efficient and metal-free epoxidation of various α,β-unsaturated ketones, carried out under mild alkaline conditions at room temperature.
- Khosravi, Kaveh,Naserifar, Shirin,Mahmoudi, Boshra
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p. 683 - 689
(2017/06/19)
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- One approach to cyclic carbonates via a three-component cyclization of phenacyl bromide, CO2, and aldehyde
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A three-component cyclization reaction was designed for synthesizing cyclic carbonates in a single operation from phenacyl bromide, CO2, and aldehyde in the presence of lithium diisopropylamide (LDA). These novel reactions were achieved under extremely mild conditions to generate the target products in moderate to good yields within 10 min.
- Yan, Peng,Tan, Xueqin,Jing, Huanwang,Duan, Shuhui,Wang, Xiaoxuan,Liu, Zhongli
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experimental part
p. 2459 - 2464
(2011/05/14)
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- Intramolecular Friedel-Crafts alkylation of chalcone epoxides using indium(III) chloride as an efficient catalyst
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Indium(III) chloride catalyzes the ring opening of chalcone epoxides followed by intramolecular Friedel-Crafts alkylation under mild conditions at room temperature to afford highly functionalized 3-aryl-2-hydroxy-2,3-dihydro- 1H-inden-1-ones in excellent yields (81-95%). Georg Thieme Verlag Stuttgart, New York.
- Ahmed, Naseem,Babu, B. Venkata,Kumar, Harendra
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experimental part
p. 2471 - 2477
(2011/09/19)
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- Facile epoxidation of α,β-unsaturated ketones with trans -3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as an efficient oxidant
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Application of trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as an efficient oxygen source has been explored in the epoxidation of trans-chalcones. The reactions proceed under mild conditions at room temperature in alkaline solution to afford the corresponding epoxides in excellent yields.
- Azarifar, Davood,Khosravi, Kaveh
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scheme or table
p. 2755 - 2758
(2010/12/25)
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- Ring opening of α,β-epoxy phenyl ketones with eerie ammonium nitrate (CAN) and potassium bromide
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Ring-opening reaction of α,β-epoxy phenyl ketones was achieved cooperatively using cerium ammonium nitrate (CAN) and potassium bromide. The reaction occurred regioselectively at the β-C to afford syn-β-bromo-α-hydroxyl ketones as main outcomes.
- Lu, Zhou,Wu, Wentao,Peng, Lijun,Wu, Longmin
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p. 142 - 145
(2008/09/18)
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- Ionic liquid-grafted Mn(III)-Schiff base complex: A highly efficient and recyclable catalyst for the epoxidation of chalcones
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A new Mn(III)-Schiff base complex with imidazolium phase tag was synthesized and employed as an efficient and recyclable catalyst for the epoxidation of chalcones with MCPBA/NMO. It can be recovered and reused (at least five times) without any loss of activity. Georg Thieme Verlag Stuttgart.
- Peng, Yanqing,Cai, Yueqin,Song, Gonghua,Chen, Jing
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p. 2147 - 2150
(2007/10/03)
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- Michael-type addition of hydroxide to alkynylselenonium salt: Practical use as a ketoselenonium ylide precursor
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A novel synthetic method of ketodiphenylselenonium ylide from alkynylselenonium salt is described. A reaction of alkynylselenonium salt, hydroxide ion, and aldehyde in the presence of silver triflate and triethylamine gave oxiranylketones just as a trans-
- Watanabe, Shin-Ichi,Asaka, Shinsuke,Kataoka, Tadashi
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p. 7459 - 7463
(2007/10/03)
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- Kinetics of oxidation of styryl ketones by pyridinium chlorochromate
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The kinetics of oxidation of substituted styryl phenyl ketones and of substituted styryl methyl ketones by pyridinium chlorochromate (PCC) have been studied in 90percent acetic acid-10percent water (v/v) containing perchloric acid and NaClO4, at 30 deg, 40 deg, 50 deg and 60 deg C.The two reactions are first order each in ketones and PCC.The rate constants are well correlated with ?+ constants.The effects of varying and the percentage of acetic acid on the reaction rate have also been studied.A suitable mechanism has been proposed.
- Mithula, M. Chandra,Murugesan, V.,Ananthakrishnanadar, P.
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- Enhanced Nucleophilicity of Tris(2,6-dimethoxyphenyl)bismuthane as Studied by X-ray Crystallography, 17O NMR Spectrometry and Theoretical Calculations. X-Ray Molecular Structure if Tris(2,6-dimethoxyphenyl)bismuthane and of Trimesitylbismuthane
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In marked contrast to previously studied triarylbismuthane, tris-(2,6-dimethoxyphenyl)bismuthane 1f showed itself to be a nucleophile strong enough to react with some activated alkyl halides via the probable formation of a bismuthonium intermediate.On the basis of X-ray crystallographic and 17O NMR studies, as well as theoretical considerations, the origin of this uniqueness has been attributed to the through-space interaction between the bismuth centre and neigbouring oxygen atoms working favourably toward the stabilization of the bismuthonium intermediate.
- Ogawa, Takuji,Ikegami, Tohru,Hikasa, Tetsuya,Ono, Noboru,Suzuki, Hitomi
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p. 3479 - 3484
(2007/10/02)
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- CATALYTIC ASYMMETRIC DARZENS CONDENSATION IN THE PRESENCE OF BOVINE SERUM ALBUMIN.
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Darzens condensation of aromatic aldehydes with phenacyl halides in the presence of a catalytic amount of bovine serum albumin afforded the corresponding epoxyketones in up to 62percent e.e.
- Annunziata, Rita,Banfi, Stefano,Colonna, Stefano
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p. 2471 - 2474
(2007/10/02)
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- SYNTHESIS OF cis-5-ARYL-4-AROYL-1,3-DIOXOLANES
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The reaction of trans-3-aryl-2-aroyloxiranes containing electron-acceptor substituents in the aryl group with acetone under acid-catalysis conditions gives the corresponding cis-1,3-dioxolanes.
- Bubel, O.N.,Tishchenko, I.G.,Grinkevich, O.A.,Stasevich, G.Z,Shavnya, A.V.
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p. 1076 - 1078
(2007/10/02)
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- Kinetics of Epoxidation of α,β-Unsaturated Ketones in Methanol Medium
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The kinetics of epoxidation of α,β-unsaturated ketones by alkaline H2O2 in methanol in the temperature range 25-40 deg C has been studied.The addition follows second order kinetics.The results indicate that the concentration of NaOH has a significant effect on the reactivity.The effect of various substituents in these reactions show that electron-releasing groups attached to the β-carbon atom in the olefin diminish the rate and electron-attracting groups enhance it.The oxidative cleavage of a few substituted epoxychalkones by hydroperoxide anion has also been studied in methanol at 30 deg C.Adherence to second order kinetics is excellent in every case and the rates are slower than those of the corresponding chalkones.The stability of epoxides depends on the substituents; electron-releasing groups diminish the rate and electron-attracting groups enhance it as observed in the case of epoxidation.The reaction obeys the Arrhenius equation and the respective activation parameters have been calculated.The effect of solvent polarity on the rate of epoxidation has been studied.The differences in the rates in methanol and water as solvents have been explained on the basis of solvent-solute interaction.
- Rama Rao, D. Sri
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p. 786 - 789
(2007/10/02)
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