- 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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- Fluorination method
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In order to overcome the problems of high cost and low stability of the existing fluorination reagents for preparing acyl fluoride, sulfonyl fluoride and phosphoryl fluoride compounds, the invention provides a fluorination method, which comprises the following operation steps of: adding a fluorination reagent into a substrate, wherein the fluorination reagent comprises cations M and anions, the anions are selected from one or more of perfluoropolyether chain carboxylic acid anions as shown in the specification: CF3(OCF2)nCO2, wherein n is selected from 1-10; the substrate comprises a carboxylic acid compound, a sulfonic acid compound, a phosphoric acid compound and a phosphine oxide compound; and carrying out fluorination reaction to obtain acyl fluoride, sulfonyl fluoride and phosphoryl fluoride products. According to the fluorination method provided by the invention, the perfluoropolyether chain carboxylate is used as a fluorination reagent, so that the dehydroxylation fluorination reaction of the carboxylic acid compound, the sulfonic acid compound and the phosphoric acid compound and the fluorination reaction of the phosphine oxide compound are realized, the product yield isrelatively high, and the fluorination method has relatively good universality for different substrates.
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Paragraph 0081-0125
(2021/01/12)
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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; 0129
(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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- 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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- Cooperative NHC and Photoredox Catalysis for the Synthesis of β-Trifluoromethylated Alkyl Aryl Ketones
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Despite the great potential of radical chemistry in organic synthesis, N-heterocyclic carbene (NHC)-catalyzed reactions involving radical intermediates are not well explored. This communication reports the three-component coupling of aroyl fluorides, styrenes and the Langlois reagent (CF3SO2Na) to give various β-trifluoromethylated alkyl aryl ketones with good functional group tolerance in moderate to high yields by cooperative photoredox/NHC catalysis. The alkene acyltrifluoromethylation proceeds via radical/radical cross coupling of ketyl radicals with benzylic C-radicals. The ketyl radicals are generated via SET reduction of in situ formed acylazolium ions whereas the benzylic radicals derive from trifluoromethyl radical addition onto styrenes.
- D?ben, Nadine,Meng, Qing-Yuan,Studer, Armido
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supporting information
p. 19956 - 19960
(2020/09/04)
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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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- Direct Access to Acyl Fluorides from Carboxylic Acids Using a Phosphine/Fluoride Deoxyfluorination Reagent System
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A fast and simple method for deoxyfluorination of carboxylic acids is presented. The protocol employs commodity chemicals (PPh3, NBS, fluoride), affording products in excellent yields under mild conditions. Acyloxyphosphonium ion, the key reaction intermediate, was identified by NMR spectroscopic methods. Br?nsted acidic conditions are essential for efficient C-F bond formation. The protocol displays scalability, high functional group tolerance, chemoselectivity, and easy purification of products. Deoxyfluorination of active pharmaceutical ingredients was established.
- Munoz, Socrates B.,Dang, Huong,Ispizua-Rodriguez, Xanath,Mathew, Thomas,Prakash, G.K. Surya
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supporting information
(2019/03/19)
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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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- High-throughput evaluation of in situ-generated cobalt(III) catalysts for acyl fluoride synthesis
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Using a high-throughput experimental procedure, a series of cobalt(iii) complexes of the general formula CpRCo(I)(X)(L) were prepared and screened for their activity towards the catalytic nucleophilic fluorination of benzoyl chloride. A highly active catalyst was identified, and successfully employed in a mild and effective protocol for the synthesis of a group of acyl fluoride compounds.
- Lee, Graham M.,Clément, Roxanne,Baker, R. Tom
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p. 4996 - 5003
(2017/11/09)
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- A convenient, one-pot procedure for the preparation of acyl and sulfonyl fluorides using Cl3CCN, Ph3P, and TBAF(t -BuOH) 4
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Various carboxylic acids were converted into acyl fluorides in excellent yields by treatment with trichloroacetonitrile, triphenylphosphine, and TBAF(t-BuOH)4 at room temperature. The reaction was applicable to the preparation of acid-sensitive amino acid fluorides without deprotection or rearrangement
- Kim, Joong-Gon,Jang, Doo Ok
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experimental part
p. 3049 - 3052
(2011/02/25)
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- Electrochemical fluorination of aromatic compounds in anhydrous HF
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Electrochemical fluorination of anisole furnished 2- and 4-fluoroanisoles in a 3:1 ratio, guaiacol, and 4,4′-dimethoxydiphenyl ether. Phenylacetonitrile alongside the fluorination in the ring suffered the transformation of the cyano group into a trifluoromethyl. 4-Bromobenzamide was fluorinated to a high conversion mostly in the ring to afford predominantly 4-bromo-3,3,6,6-tetrafluoro-1,4-cyclohexadienecarboxamide. 4-Bromonitrobenzene in a low yield gave 4-bromofluoronitrobenzene and 3,4-dibromofluoronitrobenzene. 3-Bromo-nitrobenzene and 1,4-dichlorobenzene did not undergo fluorination. In the course of the electrolysis of the 4-bromobenzamide and 4-bromonitrobenzene in anhydrous HF apart the fluorination occurred also the bromination of the substrates. Pleiades Publishing, Inc. 2006.
- Shainyan,Danilevich
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p. 214 - 219
(2007/10/03)
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- Polymer-Supported Potassium Fluoride - A Versatile Fluorination Reagent
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The nucleophilic reactivity of potassium fluoride was found to be appreciably enhanced via the despersion of KF onto an inert polymeric support.This crosslinked polystyrene was conveniently synthesized with high surface area and porosity.
- Liu, Hanfan,Wang, Ping,Sun, Pengnian
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p. 429 - 434
(2007/10/02)
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