- A Hg(OTf)2-Catalyzed Enolate Umpolung Reaction Enables the Synthesis of Coumaran-3-ones and Indolin-3-ones
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The potential of mercury catalysis has been extended to the arena of enolate umpolung reactions for the first time by the generation of enolonium species via Hg(OTf)2-catalyzed N-oxide addition to alkynes. The enolonium species formed can undergo intramolecular nucleophilic attack by hydroxyl or amino groups, leading to the synthesis of various coumaran-3-ones and indolin-3-ones.
- Dai, Ning,Hu, Weican,Qian, Guoying,Rong, Zhouting
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supporting information
p. 3286 - 3290
(2020/04/21)
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- Catalytic synthesis method of 3-benzofuranone compound
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The invention discloses a catalytic synthesis method of a 3-benzofuranone compound. The catalytic synthesis method comprises the following steps: dissolving a 2-acetenyl phenol derivative into a solvent dichloromethane at normal temperature and normal pressure according to a molar volume ratio of the 2-acetenyl phenol derivative to the dichloromethane of 1:5mmol/mL, so as to obtain a dichloromethane solution of the 2-acetenyl phenol derivative; then adding mercury trifluoromethanesulfonate and pyridine-N-oxide into a dichloromethane solution of the 2-ethynylphenol derivative, wherein the molaramounts of mercury trifluoromethanesulfonate and pyridine-N-oxide are respectively 5% and 120% of the molar amount of the 2-ethynylphenol derivative; and then performing stirring for 1 hour at room temperature, and performing reacting to generate the 3-benzofuranone compound. The market price of the catalyst mercury trifluoromethanesulfonate used in the catalytic synthesis method is lower than 30yuan/g, the cost is low, the operation is simple, the reaction time is short, the reaction conditions are mild, the reaction yield is high, and the yield can reach 91.0-96.0%.
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Paragraph 0014-0017
(2020/05/14)
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- Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation
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The oxygenation of aliphatic and aromatic hydrocarbons using earth-abundant Fe and Cu catalysts and "green" oxidants such as hydrogen peroxide is becoming increasingly important to atom-economical chemical processing. In light of this, we describe that dinuclear CuII complexes of pyrrolic Schiff-base macrocycles, in combination with ferric chloride (FeCl3), catalyze the oxygenation of π-activated benzylic substrates with hydroperoxide oxidants at room temperature and low loadings, representing a novel design in oxidation catalysis. Mass spectrometry and extended X-ray absorption fine structure analysis indicate that a cooperative action between CuII and FeIII occurs, most likely because of the interaction of FeCl3 or FeCl4- with the dinuclear CuII macrocycle. Voltammetric measurements highlight a modulation of both CuII and FeIII redox potentials in this adduct, but electron paramagnetic resonance spectroscopy indicates that any Cu-Fe intermetallic interaction is weak. High ketone/alcohol product ratios, a small reaction constant (Hammett analysis), and small kinetic isotope effect for H-atom abstraction point toward a free-radical reaction. However, the lack of reactivity with cyclohexane, oxidation of 9,10-dihydroanthracene, oxygenation by the hydroperoxide MPPH (radical mechanistic probe), and oxygenation in dinitrogen-purge experiments indicate a metal-based reaction. Through detailed reaction monitoring and associated kinetic modeling, a network of oxidation pathways is proposed that includes "well-disguised" radical chemistry via the formation of metal-associated radical intermediates.
- Pankhurst, James R.,Curcio, Massimiliano,Sproules, Stephen,Lloyd-Jones, Guy C.,Love, Jason B.
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supporting information
p. 5915 - 5928
(2018/05/28)
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- Practical, modular, and general synthesis of 3-coumaranones through gold-catalyzed intermolecular alkyne oxidation strategy
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A gold-catalyzed intermolecular alkyne oxidation for the preparation of 3-coumaranones has been developed. Using 8-isopropylquinoline N-oxides as oxidants, the reactions of o-ethynylanisoles afford versatile 3-coumaranones in moderate to good isolated yields. The synthetic utility of this chemistry is also indicated by the synthesis of the natural product sulfuretin.
- Shu, Chao,Liu, Rongfu,Liu, Shuang,Li, Jian-Qiao,Yu, Yong-Fei,He, Qiao,Lu, Xin,Ye, Long-Wu
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- Synthesis and cyclization of 1-(2-hydroxyphenyl)-2-propen-1-one epoxides: 3-Hydroxychromanones and -flavanones versus 2-(1-hydroxyalkyl)-3-coumaranones
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Competitive α and β cyclization of 2'-hydroxychalcone epoxides affords 2-(α-hydroxybenzyl)-3-coumaranone and/or 3-hydroxyflavanones, which depends on the conditions employed. Epoxidation of 2'-hydroxychalcones by dimethyldioxirane followed by either base- or acid-catalyzed ring closure provides a novel, general, and efficient method for the synthesis of trans-3-hydroxyflavanones, which includes also the naturally occurring derivatives. Extension of this two-step procedure to 1-(2-hydroxyphenyl)-2-alken-1-ones was also accomplished. A strong preference for α cyclization was observed in the case of β-unsubstituted or -monoalkylated α,β-enones, while both 2,2-dimethyl-3-hydroxychromanones and 2-(1-hydroxy-1-methylethyl)-3-coumaranones were obtained from the β,β-dimethylated substrates.
- Patonay, Tamas,Levai, Albert,Nemes, Csaba,Timar, Tibor,Toth, Gabor,Adam, Waldemar
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p. 5375 - 5383
(2007/10/03)
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- Oxidation of ethers to esters by photo-irradiation with benzil and oxygen
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A novel method for the conversion of ethers to esters by photo-oxidation using benzil and molecular oxygen, and its plausible reaction mechanism participated by benzoylperoxy radical are described.
- Seto, Hideharu,Yoshida, Keigo,Yoshida, Shigeo,Shimizu, Takeshi,Seki, Hiroshi,Hoshino, Mikio
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p. 4179 - 4182
(2007/10/03)
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- Synthesis of β-keto-phosphotriesters using functionalized diazoketones
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Convenient substitution (Ac) on the heteroatom in diazo ketones as in compounds 6, 8 or 10, prevents the classical cyclisation reaction and allows intermolecular addition; the reaction is applied to phosphorylation (reaction 1).
- Gefflaut,Perie
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- A convenient and general synthesis of trans-3-hydroxyflavanones from chalcones by dimethyldioxirane epoxidation and subsequent base-catalyzed cyclization
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2'-Hydroxychalcone epoxides were found to give trans-3-hydroxyflavanone and 2-(α-hydroxybenzyl)-3-coumaranone under basic conditions. Epoxidation of 2'-hydroxychalcones with dimethyldioxirane followed by treatment of tetrabutylammonium hydroxide provides a convenient and general method for the synthesis of trans-3-hydroxyflavanones.
- Patonay,Toth,Adam
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p. 5055 - 5058
(2007/10/02)
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- HYPERVALENT IODINE OXIDATION OF 1-TRIMETHYLSILYLOXY,1-(2'-TRIMETHYLSILYLOXYPHENYL)ETHENE. SYNTHESIS OF 3-COUMARANONE AND 2,2'-DIHYDROXYACETOPHENONE
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The oxidation of 1-trimethylsilyloxy,1-(2'-trimethylsilyloxyphenyl)ethene (6) with iodosobenzene, boron trifluoride etherate and water affords two major products, namely, 3-coumaranone (9, 31percent) and 2,2'-dihydroacetophenone (10, 25percent).Formation of 9 is explained by neihgboring group participation by the adjacent hydroxyl group.
- Moriarty, Robert M.,Prakash, Om,Duncan, Michael P.
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p. 1239 - 1246
(2007/10/02)
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- CONTROLLED OXIDATION OF BENZYL ETHERS ON IRRADIATED SEMICONDUCTOR POWDERS
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Irradiation of a suspension of powdered TiO2, a photoactive semiconductor, in oxygen saturated acetonitrile leads to mild selective oxidation of substrates containing a benzylic methylene by conversion of that carbon to a carbonyl group.The method is shown to be synthetically useful for the preparation of esters from ethers and ketones from hydrocarbons.A critical analysis of the products and of the possible intermediates results in a plausible mechanistic pathway for these photooxidations.
- Pincock, James A.,Pincock, Alexandra L.,Fox, Marye Anne
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p. 4107 - 4118
(2007/10/02)
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- Furano Compounds: Part IL - Solvolytic Rearrangement of Ketoximes in Benzofuran Series and PMR Study of Benzofuryl-2-alkyl(aryl) Ketoximes
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Solvolytic rearrangement of tosylates of 3-alkyl(aryl)-benzofuryl-2-alkyl ketoximes and 2-substituted(and unsubstituted)benzofuryl-3-methyl ketoximes with aqueous methanol depends upon their configurations.The tosylates of 2-ethyl(benzyl)benzofuryl-3-methyl ketoximes obtained in alkaline medium do not undergo solvolytic rearrangement under similar conditions.The isomerisation of anti-isomers of the above mentioned ketoximes to syn-forms with hydrogen chloride is unsuccesful.The configurations of syn- and anti-isomers of benzofuryl-2-alkyl(aryl) ketoximes have been studied by PMR spectroscopy.
- Chatterjea, J. N.,Singh, K. R. R. P.
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p. 1053 - 1056
(2007/10/02)
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