- N-Fluoro Perfluoroalkylsulphonimides: Efficient Reagents for the Fluorination of 1,3-Dicarbonyl Derivatives
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Fluorination of 1,3-dicarbonyl derivatives with N-fluoro sulphonimides afforded either 2-fluoro or 2,2-difluoro products in high yields.
- Xu, Ze-Qi,DesMarteau, Darryl D.,Gotoh, Yoshihiko
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- N-Fluorobisimides. Efficient reagents for the fluorination of 1,3-dicarbonyl derivatives
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Fluorination of 1,3-dicarbonyl derivatives with N-fluorobisimides, (CF3SO2)2NF (1), results in the formation of 2-fluoro- or 2,2-difluoro-1,3-dicarbonyl analogs, depending on the reaction conditions.High yields are obtained for a variety of structural types.In the case of 1,3-dicarbonyl derivatives with low enol content, only the sodium enolates react with 1.Thus 1 has been demonsrtated to be perhaps the best fluorinating reagent for the fluorination of 1,3-dicarbonyl derivatives.All of the 2-fluoro-1,3-dicarbonyl products exist predominantly as keto tautomers.
- Xu, Ze-Qi,DesMarteau, Daryl D.,Gotoh, Yoshihiko
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- Highly enantioselective Michael addition of 2-fluoro-1,3-diketones to nitroalkenes
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Highly enantioselective Michael addition of 2-fluoro-1,3 diketones to nitroalkenes was developed, and the desired adducts were obtained in good chemical yields with moderate to good diastereoselectivties and excellent enantioselectivities. Subsequent stereoselective reduction of the carbonyl groups led to the preparation of a functionalized fluoroisostere of glycerol that contains four continuous stereogenic centers.
- Kwiatkowski, Jacek,Lu, Yixin
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- Organocatalytic Asymmetric Cascade Michael-acyl Transfer Reaction between 2-Fluoro-1,3-diketones and Unsaturated Thiazolones: Access to Fluorinated 4-Acyloxy Thiazoles
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Quinine derived bifunctional urea catalyzed cascade Michael-acyl transfer reaction of 5-alkenyl thiazolones and monofluorinated β-diketones has been developed. The fluorine containing 4-acyloxy thiazoles were synthesized in high yields and good diastereo-and excellent enantioselectivities. Synthetic transformations, including synthesis of 4-hydroxy thiazoles, have been demonstrated.
- Biswas, Rayhan G.,Ray, Sumit K.,Unhale, Rajshekhar A.,Singh, Vinod K.
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supporting information
p. 6504 - 6509
(2021/08/30)
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- Gold-catalyzed Fluorination of Alkynyl Esters and Ketones: Efficient Access to Fluorinated 1,3-Dicarbonyl Compounds
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We developed an efficient synthesis of 2-fluoro-1,3-dicarbonyl compounds using readily available alkynyl ketones or esters as starting material. The key step is the insertion of hydrogen fluoride (HF) to the gold carbene intermediate generated from cationic gold catalyzed addition of N-oxides to alkynyl ketones or esters. This method gives excellent chemical yields and regioselectivity with good functional group tolerance. (Figure presented.).
- Zeng, Xiaojun,Lu, Zhichao,Liu, Shiwen,Hammond, Gerald B.,Xu, Bo
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p. 4062 - 4066
(2017/11/30)
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- Controlling reactivity through liquid assisted grinding: The curious case of mechanochemical fluorination
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We have identified an example of a mechanochemically milled organic reaction where liquid-assisted grinding controls the selectivity, such a phenomenon has not been reported/observed before. It was found that upon milling dibenzoylmethane with Selectfluor in the absence of any solvent, a 3:1 ratio of monofluorinated:difluorinated product was observed. Whereas, addition of 0.125 mL of acetonitrile (~10% of the total volume of materials present) to the ground reaction mixture afforded 50:1 selectivity. Furthermore, this phenomenon is applicable to a small range of diketone substrates thus far explored. Additionally, we have demonstrated that difluorination can be achieved by simply switching from adding acetonitrile to addition of sodium carbonate. Most notable, in the latter case, is the reduced reaction time compared to a conventional solvent approach, 2 hours in the mill and 24 hours in the flask.
- Howard, Joseph L.,Sagatov, Yerbol,Repusseau, Laura,Schotten, Christiane,Browne, Duncan L.
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supporting information
p. 2798 - 2802
(2017/07/24)
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- Mild and selective α-fluorination of carbonyl compounds (ketones, 1,3-diketones, β-ketoesters, α-nitroketones, and β-ketonitriles) with Selectfluor (F-TEDA-BF4) in imidazolium ILs [BMIM/PF6 or BMIM/NTf2] with Br?nsted-acidic IL [PMIM(SO3H)/OTf] as promoter
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Structurally diverse ketones, 1,3-diketones, and β-ketoesters, were selectively monofluorinated with Selectfluor (F-TEDA-BF4) (1 equiv) in [BMIM][PF6] as solvent and [PMIM(SO3H)][OTf] as promoter under mild conditions. In selected cases, the monofluorinated products were transformed to the gem-difluoro derivatives by employing an additional equivalent of Selectfluor, and gem-difluoro-derivatives were synthesized directly from the substrates by employing 2 equiv of Selectfluor. The method was extended to monofluorination of representative α-nitroketones and β-ketonitriles using [BMIM][NTf2] without the need for promoters. The described method offers the added advantage of recycling and reuse of the IL solvent. (Chemical Equation Presented).
- Reddy, A. Srinivas,Laali, Kenneth K.
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supporting information
p. 5495 - 5499
(2015/09/21)
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- Facile synthesis of 2-fluoro-1,3-dicarbonyl compounds with aqueous hydrofluoric acid mediated by iodosylarenes
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Direct fluorination of 1,3-dicarbonyl compounds including 1,3-diketones, 3-oxo esters, and 3-oxoamides was conducted using aqueous hydrofluoric acid with the aid of iodosylarenes, giving the corresponding 2-fluorinated products in good to high yields. Among the used iodosylarenes, o-iodosyltoluene was found to be the most effective, and the yield of 2-fluorinated products was improved. Georg Thieme Verlag Stuttgart New York.
- Kitamura, Tsugio,Kuriki, Satoshi,Muta, Kensuke,Morshed, Mohammad Hasan,Muta, Kazutaka,Gondo, Keisuke,Hori, Yuji,Miyazaki, Masaya
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p. 3125 - 3130
(2013/12/04)
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- Catalytic fluorination of 1,3-dicarbonyl compounds using iodoarene catalysts
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Catalytic fluorination of 1,3-dicarbonyl compounds with aqueous hydrofluoric acid proceeded efficiently with the aid of iodoarene catalysts in the presence of m-CPBA as a terminal oxidant. o-Iodotoluene, o-iodoanisole, and o-ethyliodobenzene showed a high
- Kitamura, Tsugio,Muta, Kazutaka,Kuriki, Satoshi
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p. 6118 - 6120
(2013/10/22)
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- Reaction of iodonium ylides of 1,3-dicarbonyl compounds with HF reagents
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Reaction of dibenzoylmethane with (diacetoxyiodo)benzene in the presence of KOH in MeCN quantitatively gave the corresponding iodonium ylide, which was treated with a HF reagent to afford the corresponding 2-fluorinated dibenzoylmethane in 14-50% yields.
- Gondo, Keisuke,Kitamura, Tsugio
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experimental part
p. 6625 - 6632
(2012/08/27)
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- Electron-deficient aryl β-diketones: Synthesis and novel tautomeric preferences
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Fluorinated aryl β-diketones were prepared using Claisen and electrophilic fluorination methods. The keto-enol and enol-enol tautomerism of these compounds were examined in the solid state, as neat liquids and in polar, aprotic solution by crystallography and spectroscopy. Neat-liquid spectroscopic measurements as well as single crystal X-ray crystallographic results for selected electron-deficient aryl β-diketones suggest a single, chelated cis-enol isomer that is conjugated with the aryl ring. In polar aprotic solvents, nonfluorinated aryl β-diketones equilibrate rapidly from the chelated cis-enol form to a tautomeric mixture of cis-chelated enol and a substantial proportion of the diketone form, trifluoromethylated aryl β-diketones show only limited equilibration from the chelated cis-enol to the diketone form, with 2-fluoro-1-aryl β-diketones again displaying only the diketonic form.
- Sloop, Joseph C.,Boyle, Paul D.,Fountain, Augustus W.,Pearman, William F.,Swann, Jacob A.
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p. 936 - 941
(2011/04/17)
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- A practical and convenient fluorination of 1,3-dicarbonyl compounds using aqueous HF in the presence of iodosylbenzene
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Chemical equations presented. A simple, practical, and convenient fluorination of 1,3-dicarbonyl compounds was achieved by direct use of aqueous hydrofluoric acid and iodosylbenzene (PhIO). The reaction of ethyl benzoylacetate with the reagent system of a
- Kitamura, Tsugio,Kuriki, Satoshi,Morshed, Mohammad Hasan,Hori, Yuji
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supporting information; experimental part
p. 2392 - 2394
(2011/06/28)
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- Continuous gas/liquid-liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination
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4-Fluoropyrazole systems may be prepared by a single, sequential telescoped two-step continuous gas/liquid-liquid/liquid flow process from diketone, fluorine gas and hydrazine starting materials.
- Breen, Jessica R.,Sandford, Graham,Yufit, Dmitrii S.,Howard, Judith A. K.,Fray, Jonathan,Bhairavi, Patel
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supporting information; experimental part
p. 1048 - 1054
(2011/10/05)
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- Microwave-mediated pyrazole fluorinations using selectfluor
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Microwave-mediated electrophilic fluorinations and a new single-pot condensation en route to ring-fluorinated pyrazoles were examined: chemical equation represented The monofluorination by these methods was successful for a variety of pyrazoles, with yields ranging from 13% to 75%. While electrophilic aromatic fluorination of 3-CF3 pyrazoles proved largely ineffective, development ofa single-pot process overcame this limitation. The microwave-mediated reaction is regioselective; ring fluorination of the heterocycle occurs preferentially over phenyl and alkyl substituents. Alkyl side chain fluorination, when desired, can be modulated by reactant ratios. The single-pot method, which involves acid catalysis by H-TEDA, produces 4-fluoropyrazoles products.
- Sloop, Joseph C.,Jackson, James L.,Schmidt, Robert D.
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scheme or table
p. 341 - 345
(2010/08/05)
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- Regioselective synthesis of fluorinated phenols, biaryls, 6H-benzo[c]chromen-6-ones and fluorenones based on formal [3+3] cyclizations of 1,3-bis(silyl enol ethers)
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A variety of fluorinated phenols, biaryls, 6H-benzo[c]chromen-6-ones and fluorenones were prepared based on regioselective [3+3] cyclizations of 1,3-bis(silyl enol ethers) with 2-fluoro-3-silyloxy-2-en-1-ones. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Hussain, Ibrar,Yawer, Mirza Arfan,Lau, Matthias,Pundt, Thomas,Fischer, Christine,Goerls, Helmar,Langer, Peter
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p. 503 - 518
(2008/09/18)
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- One-pot synthesis of aryl fluorides by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-fluoro-3-silyloxy-2-en-1-ones
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Functionalized aryl fluorides were regioselectively prepared by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-fluoro-3-silyloxy-2-en-1-ones.
- Pundt, Thomas,Lau, Matthias,Hussain, Ibrar,Yawer, Mirza A.,Reinke, Helmut,Langer, Peter
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p. 2745 - 2747
(2008/02/03)
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- Synthesis of fluorinated heterocycles
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Selected 1,3-diketones having a trifluoromethyl group and/or a fluorine in the 2-position were condensed with aromatic hydrazines, hydroxylamine, urea, thiourea, guanidine, and substituted anilines producing pyrazoles, isoxazoles, pyrimidines, and quinolines, respectively, in yields ranging from 27 to 87%.
- Sloop, Joseph C.,Bumgardner, Carl L.,Loehle, W. David
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p. 135 - 147
(2007/10/03)
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- Aldol reactions of acylsilanes and difluoroenoxysilanes. Application to the synthesis of 2-fluoro-1,3-diketones
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We describe the synthesis of new gem-difluoro-C-silylated aldols from acylsilanes and trifluoromethyltrimethylsilane via an aldol reaction. Their defluorosilylation gives aliphatic and alicyclic 2-fluoro-1,3-diketones. The overall reaction sequence can be
- Saleur, Damien,Brigaud, Thierry,Bouillon, Jean-Philippe,Portella, Charles
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p. 432 - 434
(2007/10/03)
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- Selective Monofluorination of β-Diketones
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Treatment of silyl enol ethers of β-diketones with 5percent F2 in N2 results in the formation of 2-fluoro 1,3-diketones.The acyclic derivatives exist as keto tautomers, while the dimedone derivative is enolic.Similarly, the silyl enol ethers of β-keto esters give rise to α-fluoro-β-keto esters.
- Purrington, Suzanne T.,Bumgardner, Carl L.,Lazaridis, Nicholas V.,Singh, Phirtu
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p. 4307 - 4310
(2007/10/02)
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