- A Carbene Strategy for Progressive (Deutero)Hydrodefluorination of Fluoroalkyl Ketones
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Hydrodefluorination is one of the most promising chemical strategies to degrade perfluorochemicals into partially fluorinated compounds. However, controlled progressive hydrodefluorination remains a significant challenge, owing to the decrease in the stre
- Bi, Xihe,Sivaguru, Paramasivam,Song, Qingmin,Wang, Zikun,Zanoni, Giuseppe,Zhang, Xiaolong,Zhang, Xinyu
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- Double Enzyme-Catalyzed One-Pot Synthesis of Enantiocomplementary Vicinal Fluoro Alcohols
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A double-enzyme-catalyzed strategy for the synthesis of enantiocomplementary vicinal fluoro alcohols through a one-pot, three-step process including lipase-catalyzed hydrolysis, spontaneous decarboxylative fluorination, and subsequent ketoreductase-catalyzed reduction was developed. With this approach, β-ketonic esters were converted to the corresponding vicinal fluoro alcohols with high isolated yields (up to 92percent) and stereoselectivities (up to 99percent). This new cascade process addresses some issues in comparison with traditional methods such as environmentally hazardous reaction conditions and low stereoselectivity outcome.
- Fan, Jiajie,Lin, Xianfu,Peng, Yongzhen,Wang, Anlin,Wu, Qi,Xu, Jian,Xu, Weihua,Yu, Huilei
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supporting information
(2020/07/24)
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- Decarboxylative fluorination of β-Ketoacids with N-fluorobenzenesulfonimide (NFSI) for the synthesis of α-fluoroketones: Substrate scope and mechanistic investigation
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Cesium carbonate (Cs2CO3)-mediated decarboxylative fluorination of β-ketoacids using NFSI in the MeCN/H2O mixed solvent system affords α-fluoroketones with a broad scope. Both electron-rich and electron-deficient α-non-substituted β-ketoacids are amenable to this protocol. The mechanistic study indicates that the reaction proceeds through electrophilic fluorination followed by decarboxylation, which is different from the decarboxylative fluorination of normal carboxylic acids.
- Zhang, Rui,Ni, Chuanfa,He, Zhengbiao,Hu, Jinbo
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p. 166 - 172
(2017/09/18)
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- Α - fluoro acetophenone derivative
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PROBLEM TO BE SOLVED: To provide a new production method of an α-fluoroacetophenone derivative by a simple one-step fluorination reaction with an acetophenone derivative under a mild condition.SOLUTION: An acetophenone derivative represented by formula (I) is reacted with a hydrogen fluoride/amine complex in the presence of a hypervalent iodine compound, (in the formula, a ring A indicates an aromatic ring of 1-3 members; Rindicates a hydrogen atom or an aromatic ring of 1-3 members that may be substituted; Rindicates a hydrogen atom or an alkyl group of 1-6 carbons; and Rindicates a hydrogen atom, an alkyl group of 1-6 carbons, an alkoxy group of 1-6 carbons or a halogen atom). The H part in formula (I) is substituted and fluorinated.
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Paragraph 0029; 0032
(2018/08/28)
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- Synthesis of α-Fluoroketones from Vinyl Azides and Mechanism Interrogation
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An efficient and mild fluorination of vinyl azides for the synthesis of α-fluoroketones is described. The mechanistic studies indicated that a single-electron transfer (SET) and a subsequent fluorine atom transfer process could be involved in the reaction.
- Wu, Shu-Wei,Liu, Feng
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supporting information
p. 3642 - 3645
(2016/08/16)
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- Fluorination of α-bromomethyl aryl ketones with fluorohydrogenate-based ionic liquids
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Fluorination of α-bromomethyl aryl ketones using fluorohydrogenate-based ionic liquids as fluorinating reagent is described. Reaction of various α-bromomethyl aryl ketones (1a-g) with fluorohydrogenate-based ionic liquids such as EMIMF·(HF)2.3, PYR13F·(HF)2.3 or PYR14F·(HF)2.3 as a fluoride ion source in anhydrous THF led to the formation of the corresponding α-fluoromethyl aryl ketones (2a-g) in very good yield. Compared to alternative fluorinating agents for this reaction, fluorohydrogenate-based ionic liquids are safer to handle and have the potential to be less expensive and more selective.
- Singh, Rajendra P.,Martin, Jerry L.
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- Catalytic Promiscuity of Transaminases: Preparation of Enantioenriched β-Fluoroamines by Formal Tandem Hydrodefluorination/Deamination
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Transaminases are valuable enzymes for industrial biocatalysis and enable the preparation of optically pure amines. For these transformations they require either an amine donor (amination of ketones) or an amine acceptor (deamination of racemic amines). Herein transaminases are shown to react with aromatic β-fluoroamines, thus leading to simultaneous enantioselective dehalogenation and deamination to form the corresponding acetophenone derivatives in the absence of an amine acceptor. A series of racemic β-fluoroamines was resolved in a kinetic resolution by tandem hydrodefluorination/deamination, thus giving the corresponding amines with up to greater than 99 % ee. This protocol is the first example of exploiting the catalytic promiscuity of transaminases as a tool for novel transformations.
- Cuetos, Aníbal,García-Ramos, Marina,Fischereder, Eva-Maria,Díaz-Rodríguez, Alba,Grogan, Gideon,Gotor, Vicente,Kroutil, Wolfgang,Lavandera, Iván
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supporting information
p. 3144 - 3147
(2016/03/12)
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- One-Pot Synthesis of α-Fluoroketones and 3-Fluoro-2,4-diaryl-furans from Trifluoromethyl β-Diketones via Decarboxylation
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A facile and mild one-pot protocol via decarboxylation of trifluoromethyl β-diketones has been developed for the construction of α-fluoroketones and 3-fluoro-2,4-diarylfurans which are important units in many biologically active compounds and useful precursors in a variety of functional-group transformations.
- Shao, Tongle,Fang, Xiang,Yang, Xueyan
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supporting information
p. 1835 - 1840
(2015/08/06)
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- Metal-free, efficient oxyfluorination of olefins for the synthesis of α-fluoroketones
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A novel oxyfluorination of olefin reactions has been developed. The reactions involve a metal-free and green catalytic system for the synthesis of α-fluoroketones which is an important building block for organic synthesis. Moreover, this reaction system exhibits great functional group tolerance.
- Yang, Qiang,Mao, Liu-Liang,Yang, Bin,Yang, Shang-Dong
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supporting information
p. 3460 - 3463
(2014/07/21)
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- Hypervalent iodine-promoted α-fluorination of acetophenone derivatives with a triethylamine·hf complex
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The direct fluorination reaction of acetophenone using iodosylarenes and TEA·5HF was conducted under mild conditions except for use of a HF reagent. The fluorination reaction was applied to acetophenone derivatives, acetonaphthones, benzyl phenyl ketone, propiophenone, butyrophenone, 1-indanone, and phenacyl chloride, giving selectively the corresponding α-fluoroketone derivatives in good yields.
- Kitamura, Tsugio,Muta, Kensuke,Muta, Kazutaka
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p. 5842 - 5846
(2014/07/08)
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- Synthesis of α-fluoroketones and α-fluoroenones in aqueous media
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An efficient synthesis of α-fluoroketones via the nucleophilic fluorination of α-bromoketones in water with TBAF·3H2O as the fluorinating agent was developed in this paper. In addition, a simple and efficient synthesis of α-fluoroenones through the condensation of α-fluoroketones with aldehydes promoted by sodium hydroxide in water was also discovered.
- He, Yan,Zhang, Xinying,Shen, Nana,Fan, Xuesen
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- Synthesis of enantiopure fluorohydrins using alcohol dehydrogenases at high substrate concentrations
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The use of purified and overexpressed alcohol dehydrogenases to synthesize enantiopure fluorinated alcohols is shown. When the bioreductions were performed with ADH-A from Rhodococcus ruber overexpressed in E. coli, no external cofactor was necessary to obtain the enantiopure (R)-derivatives. Employing Lactobacillus brevis ADH, it was possible to achieve the synthesis of enantiopure (S)-fluorohydrins at a 0.5 M substrate concentration. Furthermore, due to the activated character of these substrates, a huge excess of the hydrogen donor was not necessary.
- Borzeicka, Wioleta,Lavandera, Ivan,Gotor, Vicente
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p. 7312 - 7317
(2013/08/23)
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- Formation of chiral fluoroalkyl products through copper-free enantioselective allylic alkylation catalyzed by an NHC ligand
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A valuable Cu-free protocol is reported where an NHC ligand has been employed to form quaternary carbon centers bearing fluoroalkyl units. The results obtained, from this allylic substitution, are better in terms of enantioselectivity and regioselectivity compared to the copper catalyzed system.
- Grassi, David,Li, Hailing,Alexakis, Alexandre
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supporting information
p. 11404 - 11406
(2013/01/15)
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- One-pot α-nucleophilic fluorination of acetophenones in a deep eutectic solvent
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Two methods of nucleophilic fluorination to prepare α-fluoroacetophenones from α-bromoacetophenones by using KF with PEG-400 or TBAF with ZnF2 are described. On the fundamental of nucleophilic fluorination, a novel method of one-pot fluorination to prepare α-fluoroacetophenones directly from acetophenones in DES was developed.
- Chen, Zizhan,Zhu, Wei,Zheng, Zubiao,Zou, Xinzhuo
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experimental part
p. 340 - 344
(2010/06/11)
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- Direct electrophilic α-fluorination of imines: Efficient synthesis of mono-and difluoroimines
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(Chemical Equation Presented) A mild and efficient procedure to synthesize α-fluoro- and α,α-difluoroimines was developed. Various N-alkylimines derived from acetophenones were successfully monofluorinated using NFSI (N-fluorobenzenesulfonimide) in a mixture of CH3CN and DMF at 0°C. Alternatively, the same procedure without DMF gave rise to difluorinated imines when performed at room temperature. The obtained α- and α,α-difluorinated imines were subsequently reduced to give the corresponding β-fluoro- and β,β-difluoroamines in good yield.
- Verniest, Guido,Van Hende, Eva,Surmont, Riccardo,De Kimpe, Norbert
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p. 4767 - 4770
(2007/10/03)
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- Compounds and methods which modulate feeding behavior and related diseases
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There are provided compounds, compositions and methods of use thereof in the modulation of feeding behavior, obesity, diabetes, cancer (tumor), inflammatory disorders, depression, stress related disorders, Alzheimer's disease and other disease conditions.
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- Facile preparation of di- and monofluoromethyl ketones from trifluoromethyl ketones via fluorinated enol silyl ethers
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Di- and monofluoromethyl ketones were prepared from the readily available trifluoromethyl ketones in high yields. Magnesium metal mediated reductive defluorination readily generates fluorinated enol silyl ethers, which upon fluoride or acid assisted hydrolysis give the respective ketones in good to excellent yields.
- Surya Prakash,Hu,Olah
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p. 357 - 362
(2007/10/03)
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