- Visible-Light-Driven Dehydrogenative Coupling of Primary Alcohols with Phenols Forming Aryl Carboxylates
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A preparative method for obtaining aryl esters from aliphatic primary alcohols and phenols was developed. The reaction proceeds under the irradiation of visible light at ambient temperature, dispensing with any oxidant or hydrogen acceptor. Primary alcohols having a variety of functional groups are successfully esterified with phenols. The produced esters can be utilized as the precursor of various carbonyl compounds.
- Ishida, Naoki,Kawasaki, Tairin,Murakami, Masahiro,Tosaki, Tomohiro
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supporting information
p. 7683 - 7687
(2021/10/12)
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- Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
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The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
- Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
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- Mechanically induced solvent-free esterification method at room temperature
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Herein, we describe two novel strategies for the synthesis of esters, as achieved under high-speed ball-milling (HSBM) conditions at room temperature. In the presence of I2 and KH2PO2, the reactions afford the desired esterification derivatives in 45% to 91% yields within 20 min of grinding. Meanwhile, using KI and P(OEt)3, esterification products can be obtained in 24% to 85% yields after 60 min of grinding. In addition, the I2/KH2PO2 protocol was successfully extended to the late-stage diversification of natural products showing the robustness of this useful approach. Further application of this method in the synthesis of inositol nicotinate was also discussed. This journal is
- Zheng, Lei,Sun, Chen,Xu, Wenhao,Dushkin, Alexandr V.,Polyakov, Nikolay,Su, Weike,Yu, Jingbo
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p. 5080 - 5085
(2021/02/05)
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- Photoinduced Specific Acylation of Phenolic Hydroxy Groups with Aldehydes
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A convenient method is reported to specifically acylate phenolic hydroxyl groups through a radical pathway. When a mixture of an aldehyde and a phenol in ethyl acetate is irradiated with blue light in the presence of iridium and nickel bromide catalysts at ambient temperature, phenoxyl and acyl radicals are transiently generated in situ and cross-couple to furnish an ester. Aliphatic hydroxy groups remain untouched under the reaction conditions.
- Ishida, Naoki,Kawasaki, Tairin,Murakami, Masahiro
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supporting information
p. 18267 - 18271
(2020/08/21)
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- Photo-Fries rearrangement in flow under aqueous micellar conditions
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A flow edition of photo-Fries rearrangement for the synthesis of 2-acylphenols in an aqueous micellar medium has been described. We take advantage of a narrow channel reactor and micelle-induced confinement effect to refine both the efficiency and selectivity of the parent photoreaction. This journal is
- Chen, Chun-Jen,Chien, Chia-Chen,Kao, Shih-Chieh,Wu, Yen-Ku
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supporting information
p. 15470 - 15472
(2020/12/25)
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- Selectivity in the photo-fries rearrangement of some aryl benzoates in green and sustainable media. Preparative and mechanistic studies
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Irradiation of a series of p-substituted aryl benzoates under N2 atmosphere in homogeneous and micellar media was investigated by means of steady-state condition and of time-resolved spectroscopy. A notable selectivity in favor of the 2-hydroxybenzophenone derivatives was observed in micellar media. The benzophenone derivatives were the main photoproduct. On the other hand, in homogeneous media (cyclohexane, acetonitrile, and methanol) the observed product distribution was entirely different, viz. substituted 2-hydroxybenzophenones, p-substituted phenols, benzyl and benzoic acid were found. The binding constants in the surfactant were also measured and NOESY experiments showed that the aryl benzoates were located in the hydrophobic core of the micelle. Laser flash photolysis experiments led to the characterization of both p-substituted phenoxy radical and substituted 2-benzoylcyclohexadienone transients in homogeneous and micellar environment.
- Siano, Gastón,Bonesi, Sergio M.,Crespi, Stefano,Mella, Mariella
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p. 4338 - 4352
(2019/05/01)
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- Enol Ester Intermediate Induced Metal-Free Oxidative Coupling of Carboxylic Acids and Arylboronic Acids
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A facile, efficient and environmentally friendly methodology for the preparation of phenolic esters is realized via metal-free coupling of carboxylic acids and arylboronic acids. This sequential one pot reaction, employing methyl propiolate as an activating reagent, proceeds through the formation of enol ester intermediate, followed by a nucleophilic attack on the C-O bond under the oxidation of hydrogen peroxide. These studies display that enol esters, despite previously being overlooked as synthetic intermediates, would be the valuable building blocks for developing carbon–carbon and carbon–heteroatom bond-forming reactions.
- Xu, Xianjun,Feng, Huangdi,Li, Huiqiong,Huang, Liliang
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p. 3921 - 3928
(2019/06/24)
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- Transition-Metal-Free Poly(thiazolium) Iodide/1,8-Diazabicyclo[5.4.0]undec-7-ene/Phenazine-Catalyzed Esterification of Aldehydes with Alcohols
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Poly(3,4-dimethyl-5-vinylthiazolium) iodide was used as a polymer precatalyst in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and phenazine for the oxidative esterification of aldehydes with alcohols. Selective functionalization of OH groups was achieved in the presence of NH2 groups. The poly(thiazolium) iodide/DBU/phenazine system exhibited excellent catalytic activity and could be reused five times without loss of activity.
- Chun, Supill,Chung, Young Keun
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supporting information
p. 3787 - 3790
(2017/07/26)
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- Palladium-Catalyzed Oxidative Carbonylation of Aryl Hydrazines with CO and O2 at Atmospheric Pressure
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Palladium-catalyzed aerobic oxidative aminocarbonylation and alkoxycarbonylation reactions with aryl hydrazines as coupling partners have been developed. The oxidative carbonylation of aryl hydrazines proceeded smoothly at atmospheric pressure CO, employi
- Tu, Yongliang,Yuan, Lin,Wang, Tao,Wang, Changliu,Ke, Jiamei,Zhao, Junfeng
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p. 4970 - 4976
(2017/05/12)
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- Thiophosphoramides as cooperative catalysts for copper-catalyzed arylation of carboxylates with diaryliodonium salts
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A thiophosphoramide-based co-catalyst was found to significantly accelerate copper(ii) trifluoromethanesulfonate-catalyzed arylation of potassium carboxylates with diaryliodonium salts. This effect could be attributed to counterion activation of diaryliodonium salts or organocopper intermediates by thiophosphoramides. Inclusion of thiophosphoramides permits achieving significantly milder reaction conditions and expands the scope of solvents and diaryliodonium counterions that could be used for the arylation of carboxylate nucleophiles.
- Bhattarai, Bijay,Tay, Jia-Hui,Nagorny, Pavel
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supporting information
p. 5398 - 5401
(2015/03/30)
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- Alkoxycarbonylation and phenoxycarbonylation reactions catalyzed by a palladium(II) organometallic complex encaged in y zeolite
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Catalytic routes for synthesis of alkyl benzoates by alkoxycarbonylation reactions and aryl benzoates by phenoxycarbonylation reactions of aryl iodides are described using a palladium-1,10-phenanthroline complex encaged in Y zeolite. Moderate to excellent yields (40-99 %) of various benzoates were obtained at low Pd loadings of 0.6 mol%. The catalyst could be effectively removed from the reaction mixture by a simple filtration process and was reused four times with only minor loss of activity. Furthermore, its catalytic activity was further highlighted by a comparison with another two supported Pd catalysts. The protocol has the advantages of easy handing, moderate to excellent yield, and catalyst recyclability. Graphical Abstract: [Figure not available: see fulltext.]
- Mei, Hui,Xiao, Se,Zhu, Tianwu,Lei, Yizhu,Li, Guangxing
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p. 443 - 450
(2014/05/20)
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- Palladacycle-catalyzed carbonylation of aryl iodides or bromides with aryl formates
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An efficient palladacycle-catalyzed aromatic carbonylation reaction of aryl formates with aryl iodides or bromides has been developed. Commercially available and easily prepared aryl formates were employed as carbonyl sources without the use of external carbon monoxide. The present catalytic system shows broad functional group tolerance and affords aryl benzoate derivatives in good to excellent yields. Copyright
- Chen, Guangwei,Leng, Yuting,Yang, Fan,Wang, Shiwei,Wu, Yangjie
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p. 1488 - 1494
(2014/01/06)
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- Selective mono-acylation of 1,2- and 1,3-diols using (α,α- difluoroalkyl)amines
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In the reaction of N,N-diethyl-α,α-difluorobenzylamine (DFBA) with 1,2- or 1,3-diols, selective mono-benzoylation occurs to afford mono-esters of the diols in good yield. The reaction is completed under mild conditions in a short reaction time. Further, prim-, sec-, and tert-diols and catechol can be converted to the corresponding mono-benzoates. DFBA is used for the protection of the hydroxy group in sugars. The selective mono-nicotinylation, formylation and pivaloylation of diols are also performed by using the corresponding difluoroalkylamines.
- Wakita, Natsumi,Hara, Shoji
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experimental part
p. 7939 - 7945
(2010/10/19)
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- A simple and efficient recyclable phosphine-free catalytic system for alkoxycarbonylation and carbonylative Sonogashira coupling reactions of aryl iodides
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Using palladium on charcoal (Pd/C) and triethylamine as a novel, efficient, versatile, recyclable, and phosphine-free catalytic system, we carried out the alkoxycarbonylation of aryl iodides (alcohols or phenols as nucleophiles) and the carbonylative Sonogashira coupling reaction of aryl iodides with terminal alkynes, affording the corresponding aryl esters and α, β-alkynyl ketones in good to excellent yields under mild conditions. We found that both electron-withdrawing and electron-donating substituents on phenol enhanced the phenoxycarbonylation of iodobenzene. The recyclability of Pd/C was also demonstrated.
- Liu, Jianhua,Chen, Jing,Xia, Chungu
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