- Acyl fluorides from carboxylic acids, aldehydes, or alcohols under oxidative fluorination
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We describe a novel reagent system to obtain acyl fluorides directly from three different functional group precursors: carboxylic acids, aldehydes, or alcohols. The transformation is achieved via a combination of trichloroisocyanuric acid and cesium fluoride, which facilitates the synthesis of various acyl fluorides in high yield (up to 99%). It can be applied to the late-stage functionalization of natural products and drug molecules that contain a carboxylic acid, an aldehyde, or an alcohol group.
- Liang, Yumeng,Zhao, Zhengyu,Taya, Akihito,Shibata, Norio
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supporting information
p. 847 - 852
(2021/02/06)
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- Synthesis method of acyl fluoride
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The invention belongs to the technical field of synthesis of organic compounds, and relates to a synthesis method of acyl fluoride. The invention relates to a synthesis method of acyl fluoride, which is characterized in that carboxylic acid trifluoromethy
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Paragraph 0032-0035
(2021/08/11)
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- METHOD AND REAGENT FOR DEOXYFLUORINATION
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A safe, simple, and selective method and reagent for deoxyfluorination is disclosed. With the method and reagent disclosed herein, organic compounds such as carboxylic acids, carboxylates, carboxylic acid anhydrides, aldehydes, and alcohols can be fluorinated by using the most common nucleophilic fluorinating reagents and electron deficient fluoroarenes as mediators under mild conditions, giving corresponding fluoroorganic compounds in excellent yield with a wide range of functional group compatibility and easy product purification. For example, directly utilizing KF for deoxyfluorination of carboxylic acids provides the most economical and the safest pathway to access acyl fluorides, key intermediates for syntheses of peptide, amide, ester, and dry fluoride salts.
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Paragraph 0111-0112; 0114-0115; 0136
(2021/05/29)
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- Cooperative NHC/Photoredox Catalyzed Ring-Opening of Aryl Cyclopropanes to 1-Aroyloxylated-3-Acylated Alkanes
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Cyclopropanes are an important class of building blocks in organic synthesis. Herein, a ring-opening/arylcarboxylation/acylation cascade reaction for the 1,3-difunctionalization of aryl cyclopropanes enabled by cooperative NHC and organophotoredox catalysis is reported. The cascade works on monosubstituted cyclopropanes that are in contrast to the heavily investigated donor–acceptor cyclopropanes more challenging to be difunctionalized. The key step is a radical/radical cross coupling of a benzylic radical generated in the photoredox catalysis cycle with a ketyl radical from the NHC catalysis cycle. The transformation features metal-free reaction conditions and tolerates a diverse range of functionalities.
- Daniliuc, Constantin G.,Studer, Armido,Zuo, Zhijun
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supporting information
p. 25252 - 25257
(2021/10/29)
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- Deoxyfluorination of Carboxylic Acids with KF and Highly Electron-Deficient Fluoroarenes
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A deoxyfluorination reaction of carboxylic acids using potassium fluoride (KF) and highly electron-deficient fluoroarenes is reported here, giving acyl fluorides in moderate to excellent yield (57-92% based on NMR integration and 34-95% for isolated examples).
- Mao, Siyu,Kramer, Jordan H.,Sun, Haoran
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p. 6066 - 6074
(2021/05/29)
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- Efficient cleavage of tertiary amide bonds: Via radical-polar crossover using a copper(ii) bromide/Selectfluor hybrid system
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A novel approach for the efficient cleavage of the amide bonds in tertiary amides is reported. Based on the selective radical abstraction of a benzylic hydrogen atom by a CuBr2/Selectfluor hybrid system followed by a selective cleavage of an N-C bond, an acyl fluoride intermediate is formed. This intermediate may then be derivatized in a one-pot fashion. The reaction proceeds under mild conditions and exhibits a broad substrate scope with respect to the tertiary amide moiety as well as to nitrogen, oxygen, and carbon nucleophiles for the subsequent derivatization. Mechanistic studies suggest that the present reaction proceeds via a radical-polar crossover process that involves benzylic carbon radicals generated by the selective radical abstraction of a benzylic hydrogen atom by the CuBr2/Selectfluor hybrid system. Furthermore, a synthetic application of this method for the selective cleavage of peptides is described. This journal is
- Maruoka, Keiji,Matsumoto, Akira,Wang, Zhe
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p. 12323 - 12328
(2020/12/08)
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- Synthesis of Acyl Fluorides via DAST-Mediated Fluorinative C-C Bond Cleavage of Activated Ketones
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A new protocol for preparation of acyl fluorides was developed by recognizing activated ketones as starting materials. The method provides a different scope compared with previously reported methods that employ carboxylic acids as substrates. A working hypothesis of pull-and-push-driven fluorinative C-C bond cleavage was successfully demonstrated by the simple addition of diethylaminosulfur trifluoride (DAST) derivatives to α-oximinoketones. The designed reaction system led to a highly efficient and chemoselective reaction. The wide availability of the ketones allowed for a range of synthetically useful aryloyl and aliphatic acyl fluorides including those containing chiral skeletons. The method is mild, fast, scalable, and potentially one-pot operative.
- Kim, Danhee,Lim, Hee Nam
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p. 7465 - 7469
(2020/10/09)
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- Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
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Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp2)-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.
- Ishida, Takumi,Nishihara, Yasushi,Wang, Xiu,Wang, Zhenhua
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p. 7526 - 7533
(2020/06/27)
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- Phosphine-Catalyzed Intermolecular Acylfluorination of Alkynes via a P(V) Intermediate
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We report the phosphine-catalyzed intermolecular carbofluorination of alkynes using acyl fluorides as fluorinating reagents. This reaction promises to be a useful method for the synthesis of highly substituted monofluoroalkene derivatives since acyl fluor
- Fujimoto, Hayato,Kodama, Takuya,Tobisu, Mamoru,Yamanaka, Masahiro
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supporting information
p. 17323 - 17328
(2020/11/02)
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- Nickel-catalyzed decarbonylative stannylation of acyl fluorides under ligand-free conditions
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Nickel-catalyzed decarbonylative stannylation of acyl fluorides under ligand-free conditions was disclosed. A variety of aromatic acyl fluorides are capable of reacting with silylstannanes in the presence of cesium fluoride. A one-pot decarbonylative stannylation/Migita-Kosugi-Stille reaction of benzoyl fluoride, giving rise to the direct formation of the corresponding cross-coupled products, further demonstrated the synthetic utility of the present method. This newly developed methodology with a good functional-group compatibility via C-F bond cleavage and C-Sn bond formation under nickel catalysis opens a new area for the functionalization of acyl fluorides in terms of carbon-heteroatom bond formation.
- Wang, Xiu,Wang, Zhenhua,Liu, Li,Asanuma, Yuya,Nishihara, Yasushi
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- Nickel-catalysed decarbonylative borylation of aroyl fluorides
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The first Ni(cod)2/PPh3 catalyst system has been established for decarbonylative borylation of aroyl fluorides with bis(pinacolato)diboron. A wide range of functional groups in the substrates were well tolerated. The ease of access of the starting aroyl fluorides indicates that these results might become an alternative to the existing decarbonylation events.
- Wang, Zhenhua,Wang, Xiu,Nishihara, Yasushi
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supporting information
p. 13969 - 13972
(2019/01/03)
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- Base-free nickel-catalysed decarbonylative Suzuki–Miyaura coupling of acid fluorides
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The Suzuki–Miyaura cross-coupling of organoboron nucleophiles with aryl halide electrophiles is one of the most widely used carbon–carbon bond-forming reactions in organic and medicinal chemistry1,2. A key challenge associated with these transformations is that they generally require the addition of an exogenous base, the role of which is to enable transmetallation between the organoboron nucleophile and the metal catalyst3. This requirement limits the substrate scope of the reaction because the added base promotes competitive decomposition of many organoboron substrates3–5. As such, considerable research has focused on strategies for mitigating base-mediated side reactions6–12. Previous efforts have primarily focused either on designing strategically masked organoboron reagents (to slow base-mediated decomposition)6–8 or on developing highly active palladium precatalysts (to accelerate cross-coupling relative to base-mediated decomposition pathways)10–12. An attractive alternative approach involves identifying combinations of catalyst and electrophile that enable Suzuki–Miyaura-type reactions to proceed without an exogenous base12–14. Here we use this approach to develop a nickel-catalysed coupling of aryl boronic acids with acid fluorides15–17, which are formed in situ from readily available carboxylic acids18–22. This combination of catalyst and electrophile enables a mechanistic manifold in which a ‘transmetallation-active’ aryl nickel fluoride intermediate is generated directly in the catalytic cycle13,16. As such, this transformation does not require an exogenous base and is applicable to a wide range of base-sensitive boronic acids and biologically active carboxylic acids.
- Malapit, Christian A.,Bour, James R.,Brigham, Conor E.,Sanford, Melanie S.
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p. 100 - 104
(2018/11/25)
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- Synthesis of acyl fluorides via photocatalytic fluorination of aldehydic C-H bonds
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Acyl fluorides are versatile acylating agents owing to their unique stability. Their synthesis, however, can present challenges and is typically accomplished through deoxyfluorination of carboxylic acids. Here, we demonstrate that acyl fluorides can be prepared directly from aldehydes via a C(sp2)-H fluorination reaction involving the inexpensive photocatalyst sodium decatungstate and electrophilic fluorinating agent N-fluorobenzenesulfonimide. This convenient fluorination strategy enables direct conversion of aliphatic and aromatic aldehydes into acylating agents.
- Meanwell, Michael,Lehmann, Johannes,Eichenberger, Marc,Martin, Rainer E.,Britton, Robert
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supporting information
p. 9985 - 9988
(2018/09/11)
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- A O-between the - trifluoromethyl benzoic acid to synthetic method (by machine translation)
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The present invention provides a O-between the - trifluoromethyl benzoic acid to the synthesis method, the method comprises the following steps: (1) between adjacent to methyl benzoic acid acylated preparation between neighbour methyl benzoyl chloride; (2) between the adjacent methyl benzoyl chloride to chlorine light between neighbour trichloromethyl benzoyl chloride is obtained; (3) adjacent to the trichloromethyl benzoyl chloride fluoride obtained between between neighbour trifluoromethyl methyl benzoyle fluoride; (4) adjacent to the trifluoromethyl benzoyle fluoride hydrolysis between the final product is obtained between neighbour trifluoromethyl methyl benzoic acid. The method of the invention cheap raw material, the product yield is high, the process is simple, is favorable for industrial production. (by machine translation)
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- Synthesis method of o-trifluoromethyl methyl benzoate, m-trifluoromethyl methyl benzoate and p-trifluoromethyl methyl benzoate
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The invention provides a synthesis method of o-trifluoromethyl methyl benzoate, m-trifluoromethyl methyl benzoate and p-trifluoromethyl methyl benzoate. The synthesis method comprises the following steps: taking methyl benzoic acid as a raw material, carrying out acylating chlorination to obtain methylbenzoyl chloride, carrying out side-chain chlorination to obtain trichloromethyl benzoyl chloride, carrying out fluorination substitution to obtain trifluoromethyl benzoyl fluoride, and carrying out esterification to obtain a final product which is trifluoromethyl methyl benzoate. The synthesis method can be used for producing the o-trifluoromethyl methyl benzoate, the m-trifluoromethyl methyl benzoate and the p-trifluoromethyl methyl benzoate, is easily available in raw material, mild in reaction mechanism, high in reaction yield, few in reaction by-products, low in yield of three wastes and easy in treatment of three wastes, and is suitable for industrial production.
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- Palladium-catalyzed fluorocarbonylation using N-formylsaccharin as CO source: General access to carboxylic acid derivatives
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N-Formylsaccharin, an easily accessible crystalline compound, has been employed as an efficient CO source in Pd-catalyzed fluorocarbonylation of aryl halides to afford the corresponding acyl fluorides in high yields. The reactions use a near-stoichiometric amount of the CO source (1.2 equiv) and tolerate diverse functional groups. The acyl fluorides obtained could be readily transformed into various carboxylic acid derivatives such as carboxylic acid, esters, thioesters, and amides in a one-pot procedure.
- Ueda, Tsuyoshi,Konishi, Hideyuki,Manabe, Kei
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supporting information
p. 5370 - 5373
(2013/11/06)
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- Synthesis of (E,Z)-1-alkoxy-3-acyloxy-2-methylpenta-1, 3-dienes via danishefsky-type dienes or O-acylation of enones
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(Chemical Equation Presented) 1-Alkoxy-2-methyl-3-acyloxy-(E,E)-penta-1,3- dienes have been prepared applying among others a modified Danishefsky's general method, including chiral, racemic, and achiral derivatives.
- Laclef, Sylvain,Exner, Claudia J.,Turks, Maris,Videtta, Valeria,Vogel, Pierre
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scheme or table
p. 8882 - 8885
(2010/03/01)
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- Elemental fluorine. Part 21. (1) direct fluorination of benzaldehyde derivatives
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Direct fluorination of a range of benzaldehyde derivatives gives mixtures of fluorobenzaldehyde and benzoyl fluoride products in ratios that depend upon the nature of the ring substituent Electron-withdrawing substituents give predominantly benzoyl fluoride derivatives, whereas electron-donating substituents lead to fluoroarene systems. Separation of ring-fluorinated products can be easily accomplished by esterification of the benzoyl fluoride side products. Scale-up of these processes to provide significant quantities of appropriate fluorobenzaldehyde systems has also been achieved using continuous flow techniques.
- Chambers, Richard D.,Sandford, Graham,Trmcic, Jelena,Okazoe, Takashi
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p. 339 - 344
(2013/01/03)
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- Reactions of alcohols with cesium fluoroxysulfate
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The reactions of alcohols with cesium fluoroxysulfate (CsSO4F) in MeCN suspension were studied, and the role of the structure of the alcohol and the reaction conditions on the course of reaction was determined. Secondary benzyl alcohols bearing a nonactivating aromatic ring were selectively oxidized to the corresponding ketones, while the CsSO4F-mediated reaction of phenyl-1-naphthylmethanol resulted in the formation of 1-fluoronaphthalene and benzaldehyde. Cyclic and noncyclic secondary alcohols were readily converted to ketones, as well as 1-hydroxybenzecyclanes to benzocyclanones- 1, without any further fluorination or oxidation under the reaction conditions. On the other hand, reactions of primary alcohols with CsSO4F resulted in the formation of acid fluorides derived from further fluorination of aldehydes. Another type of transformation was observed in the case of alcohols bearing a benzyl functional group attached geminal to a hydroxy group, where decarbanylation of reactive intermediates resulting in the formation of benzyl fluoride derivatives became the main process. 2- Phenylethanol was so converted to benzyl fluoride and phenylacetyl fluoride in a 3:1 relative ratio, while 2-phenyl-1-propanol was selectively transformed to 1-phenyl-1-fluoroethane. The presence of the radical inhibitor nitrobenzene in the reaction mixture considerably inhibited conversion of the starting material. The same effect was observed by lowering the solvent polarity. Hammett correlation analysis of the effect of substituents on the reaction rates of oxidation of a set of substituted 1-phenyl-1-ethanols to acetophenones gave the reaction constant p+ = -0.32, while analysis of analogous data for the transformations of benzyl alcohols to benzoyl fluorides gave the value of -0.54. A mechanism including radical intermediates was proposed for the transformation of alcohols by CsSO4F.
- Stavber, Stojan,Kosir, Iztok,Zupan, Marko
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p. 4916 - 4920
(2007/10/03)
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- Rearrangement and radical mediated decarboxylation of trimethylsilyl benzoates using xenon difluoride
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Treatment of trimethylsilyl benzoates 1 with xenon difluoride in CH2Cl2 or C6F6 results in a novel ester rearrangement and formation of aryl fluoroformates 2: rearrangement is not observed in MeCN solution in wh
- Nongkunsarn, Pakawan,Ramsden, Christopher A.
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p. 121 - 122
(2007/10/03)
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- Reactions of Aldehydes with Cesium Fluoroxysulfate
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Various aromatic and aliphatic aldehydes reacted at 35-40 deg C in CH3CN with CsSo4F giving acid fluorides in a good yield.In some cases formation of fluorohydrocarbons was also observed.Hammett correlation analysis of the transformation of various substituted benzaldehydes (p-OCH3, p-CH3, p-F, p-CF3, m-NO2) gave the reaction constant ρ+ = -0.38.Solvent polarity strongly influenced the conversion of aldehydes into acid fluorides, being in acetonitrile almost quantitative and completely halted in CH2Cl2, n-hexane, or tetrahydrofuran.The presence of nitrobenzene, often used as a radical scavenger, considerably reduced the acid fluoride formation.Based on experimental observations was concluded that the main intermediates involved in the conversion of aldehydes into acid fluorides with CsSO4F must be of a radical nature.
- Stavber, Stojan,Planinsek, Zdenka,Zupan, Marko
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p. 5334 - 5337
(2007/10/02)
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- The Relationship between 19F Substituent Chemical Shifts and Electron Densities: meta- and para-Substituted Benzoyl Fluorides
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The 19F substituent chemical shifts (SCS) of meta- and para-benzoyl fluorides are found to correlate well with substituent parameters using the dual substituent parameter (DSP) equation, indicating that they reflect electronic perturbations induced by the substituent.The direction of the SCS values is such that donating substituents cause upfield shifts whilst acceptors cause downfield shifts.STO-3G calculations indicate that substituents induce only very small changes in ?-electron density about the fluorine atom, but that these changes correlate reasonably well with the observed SCS values.For the para series, the slope of the relationship between Δq?F and 19F SCS is 5000 ppm/electron, indicating the great sensitivity of the fluorine atom to small changes in electron density.
- Brownlee, Robert T. C.,Craik, David J.
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p. 186 - 191
(2007/10/02)
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