- Photoredox-Catalyzed Ring-Opening Addition Reaction between Benzyl Bromides and Cyclic Ethers
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A novel nucleophilic reaction between cyclic ethers and benzyl bromides is achieved under photoredox catalysis. The reaction proceeds through a single-electron-transfer (SET) pathway rather than a common SN2 mechanism. By two steps of reduction and oxidation, a benzyl bromide heterolyzes to give a carbocation and bromide ion under mild conditions, and then a cyclic ether captures both the carbocation and bromide ion to afford the addition product.
- Kuang, Cuiwen,Ni, Chuanfa,Gu, Yucheng,Hu, Jinbo
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p. 1272 - 1286
(2021/12/24)
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- One-Pot Successive Turbo Grignard Reactions for the Facile Synthesis of α-Aryl-α-Trifluoromethyl Alcohols
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A novel straightforward one-pot methodology for two successive turbo Grignard reagent (iPrMgCl·LiCl) reactions, was developed for a facile synthesis of α-aryl-α-trifluoromethyl alcohols, motifs of value in pharmaceutical chemistry. The method displayed broad functional group tolerance, including reducible groups. Dual roles of iPrMgCl·LiCl were exploited in the tandem reaction with commercially available iodoarenes or iodoheteroarenes and 2,2,2-trifluoroethyl trifluoroacetate. The process encompasses three successive reactions in a one-pot process: the iPrMgCl·LiCl-mediated iodine/magnesium-exchange reaction of iodoarenes or iodoheteroarenes; nucleophilic addition of various generated aryl or heteroarylmagnesium reagents to 2,2,2-trifluoroethyl trifluoroacetate; and the reduction of in-situ generated aryl trifluoromethyl ketones with iPrMgCl·LiCl, to produce the corresponding α-aryl or α-heteroaryl-α-trifluoromethyl alcohols bearing various substituents, including reducible functional groups in good to excellent yields.
- Kani, Ryunosuke,Inuzuka, Toshiyasu,Kubota, Yasuhiro,Funabiki, Kazumasa
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supporting information
p. 4487 - 4493
(2020/06/01)
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- Generation of Carbocations under Photoredox Catalysis: Electrophilic Aromatic Substitution with 1-Fluoroalkylbenzyl Bromides
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A novel Friedel-Crafts-type alkylation of arenes to access valuable 1-fluoroalkyl-1,1-biaryl compounds is established under mild conditions. The key to success is the efficient generation of a destabilized benzylic carbocation intermediate via two consecutive single-electron transfer processes by virtue of visible-light photoredox catalysis. This unique activation pattern avoids using strong Lewis acids and high temperatures that are required for generation of destabilized carbocations in traditional Friedel-Crafts reactions. This protocol demonstrates the first example of photoredox-catalyzed heterolysis of electronically deactivated benzylic C-Br bonds for the formation of destabilized carbocation intermediates.
- Gu, Yucheng,Hu, Jinbo,Kuang, Cuiwen,Ni, Chuanfa,Xie, Qiqiang,Zhou, Xin
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supporting information
(2020/11/13)
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- Synthesis and Derivatization of 1,1-[18F]Difluorinated Alkenes
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A general method for the synthesis of 1,1-[18F]difluorinated alkenes from [18F]fluoride is reported. This transformation is highly regioselective giving the desired 18F-fluoroalkenes with radiochemical purities of up to 77 % within 20 minutes and a molar activity (Am) of 1 GBq μmol?1. The transformations are operationally simple to perform and were readily translated onto a commercial automated synthesis unit. The resultant 1,1-[18F]difluorinated alkene motif is prevalent in numerous drug molecules, and this is the first general method to synthesize this motif with fluorine-18. 18F-fluorinated alkenes are excellent building blocks and participate in a number of post-labeling transformations to access a range of 18F-perfluorinated functional groups that have never before been radiolabeled with non-carrier-added [18F]fluoride. This method considerably expands the range of 18F-motifs accessible to radiochemists.
- Frost, Aileen B.,Brambilla, Marta,Exner, Rüdiger M.,Tredwell, Matthew
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p. 472 - 476
(2018/12/13)
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- Palladium-Catalyzed Direct Approach to α-Trifluoromethyl Alcohols by Selective Hydroxylfluorination of gem-Difluoroalkenes
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A novel palladium-catalyzed selective hydroxylfluorination of gem-difluoroalkenes has been developed. By employing easily obtainable gem-difluoroalkenes and NFSI as the fluorine source, the scope, advantages, and limitations of this reaction were investigated. The reaction presents an efficient synthesis to afford a series of α-trifluoromethyl alcohols in good to excellent yields. Furthermore, this reaction probably proceeds via oxidation of Pd0 to PdII fluoride complex by NFSI, followed by fluoropalladation of gem-difluoroalkenes to generate an α-trifluoromethylbenzyl–Pd intermediate. And this strategy offers more possibilities for the construction of other bonds, such as C–C, C–N and C–S.
- Zhang, Bin,Zhang, Xiaofei,Hao, Jian,Yang, Chunhao
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p. 5007 - 5015
(2018/10/05)
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- METHOD FOR PRODUCING TRIFLUOROMETHYL GROUP-CONTAINING ALCOHOLS
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PROBLEM TO BE SOLVED: To provide a method for producing trifluoromethyl group-containing alcohols useful as synthetic intermediates for medicines and agrochemicals. SOLUTION: This invention relates to a method for producing trifluoromethyl group-containing alcohols expressed by a formula (2), comprising: making carbonyl compounds expressed by a formula (1) react with trifluoromethane in an organic solvent in the presence of polyvalent ethers and potassium tert-butoxide, or kalium hexamethyldisilazide. (R1 and R2 are each independently a phenyl group etc.; R2 may combine with R1, to form a ring, and both R1 and R2 are not hydrogen atoms). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0081; 0082; 0093
(2018/04/10)
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- Synthesis of α-CF3 and α-CF2H amines: Via the aminofluorination of fluorinated alkenes
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A novel synthesis of α-CF3 and α-CF2H amines via the aminofluorination of gem-difluoroalkenes and mono-fluoroalkenes, respectively, is reported. The method employs Selectfluor as an electrophilic fluorine source and acetonitrile as a nitrogen source. Mechanistic studies revealed a single-electron oxidation/fluorine-abstraction/Ritter-type amination pathway. The protocol allowed the synthesis of a broad range of fluorinated amines including those bearing quaternary carbon centers with good efficiency and functional group tolerance.
- Yang, Ling,Fan, Wen-Xin,Lin,Tan, Dong-Hang,Li, Qingjiang,Wang, Honggen
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p. 5907 - 5910
(2018/06/14)
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- Visible light-promoted umpolung coupling of aryl tri-/difluoroethanones with 2-alkenylpyridines
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Tertiary alcohols bearing a trifluoromethyl group are of considerable medicinal interest. Using an umpolung strategy, we herein report the first intermolecular reductive cross-coupling of aryl tri-/difluoroethanones with 2-alkenylpyridines with the aid of a Br?nsted acid catalyst upon visible-light irradiation. This metal-free reaction is operationally simple and performed at ambient temperature, allowing access to desired tertiary alcohols with tri-/difluoromethyl groups in moderate to excellent yields. The commercially available and easily handled Hantzsch ester effectively serves as an electron donor, as well as a hydrogen atom source.
- Xu, Xiao,Min, Qing-Qiang,Li, Na,Liu, Feng
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supporting information
p. 11017 - 11020
(2018/10/08)
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- Palladium-Catalyzed Suzuki–Miyaura Cross-Coupling of Secondary α-(Trifluoromethyl)benzyl Tosylates
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A palladium-catalyzed C(sp3)?C(sp2) Suzuki–Miyaura cross-coupling of aryl boronic acids and α-(trifluoromethyl)benzyl tosylates is reported. A readily available, air-stable palladium catalyst was employed to access a wide range of functionalized 1,1-diaryl-2,2,2-trifluoroethanes. Enantioenriched α-(trifluoromethyl)benzyl tosylates were found to undergo cross-coupling to give the corresponding enantioenriched cross-coupled products with an overall inversion in configuration. The crucial role of the CF3 group in promoting this transformation is demonstrated by comparison with non-fluorinated derivatives.
- Brambilla, Marta,Tredwell, Matthew
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supporting information
p. 11981 - 11985
(2017/09/20)
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- Photoinduced additive-free trifluoromethylation of aromatic aldehydes with TMSCF3
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We report herein a new and effective method for additive-free trifluoromethylation of aromatic aldehydes with TMSCF3. Normal acidic hydrolysis for desilylation in the workup process is not required in this transformation. This reaction presents
- Sun, Jing,Peng, Xinhua,Guo, Hao
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supporting information
p. 797 - 800
(2015/01/30)
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- Diversity-oriented approach to CF3CHF-, CF3CFBr-, CF3CF2-, (CF3)2CH-, and CF3(SCF3)CH-substituted arenes from 1-(Diazo-2,2,2-trifluoroethyl)arenes
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Arenes substituted with perfluoroalkyl groups are attractive targets for drug and agrochemical development. Exploiting the carbenic character of donor/acceptor diazo compounds, a diversity-oriented synthesis of perfluoroalkylated arenes, for late stage fluorofunctionalization, is described. The reaction of 1-(diazo-2,2,2-trifluoroethyl)arenes with HF, F/Br, F2, CF3H, and CF3SH sources give direct access to a variety of perfluoroalkyl-substituted arenes presenting with incremental fluorine content. The value of this approach is also demonstrated for radiochemistry and positron emission tomography with the [18F]-labeling of CF3CHF-, CF3CBrF-, and CF3CF2-arenes from [18F]fluoride.
- Emer, Enrico,Twilton, Jack,Tredwell, Matthew,Calderwood, Samuel,Collier, Thomas Lee,Ligault, Benot,Taillefer, Marc,Gouverneur, Vronique
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supporting information
p. 6004 - 6007
(2015/01/09)
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- Magnesium metal-mediated reductive trifluoromethylation of aldehydes with phenyl trifluoromethyl sulfone
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An unprecedented reductive nucleophilic trifluoromethylation of aldehydes by using phenyl trifluoromethyl sulfone is reported. Mercury(II) chloride efficiently activates magnesium metal to induce the desulfonylative trifluoromethylation process. The new r
- Zhao, Yanchuan,Zhu, Jieming,Ni, Chuanfa,Hu, Jinbo
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experimental part
p. 1899 - 1904
(2010/08/19)
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- REVERSIBLE INHIBITORS OF MONOAMINE OXIDASE A AND B
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The instant invention relates to compounds of formula I, diagrammed below, wherein R3, E, D and Y are defined in the application, which are useful as reversible inhibitors of monoamine oxidase-B and/or monoamine oxidase-A, and therefore useful to treat or prevent neurological diseases or conditions in mammals, preferably humans.
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Page/Page column 44; 46; 48
(2008/06/13)
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- METHODS FOR NUCLEOPHILIC FLUOROMETHYLATION
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A novel, convenient and efficient method for trifluoromethylation of substrate compounds is disclosed. Particularly, alkoxide and hydroxide induced nucleophilic trifluoromethylation of carbonyl compounds, disulfides and other electrophiles, using phenyl trifluoromethyl sulfone PhSO2CF3 (or sulfoxide PhSOCF3) is disclosed. A method of both symmetrical and unsymmetrical anti-2,2-difluoropropan-1,3-diols with high diastereoselectivity (up to 94 % de) is disclosed using dufluoromethyl phenyl sulfone. This unusual type of high diastereoselectivity was obtained via an intramolecular charge-charge repulsion effect rather than the traditional steric control (based on the Cram's rule). Thus, difluoromethyl phenyl sulfone can be used as a novel difluoromethylene dianion species (`CF2""), which can couple two electrophiles (such as diphenyl disulfide or non-enolizable aldehydes) to give new difluoromethylenated products.
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- Alkoxide- and hydroxide-induced nucleophilic trifluoromethylation using trifluoromethyl sulfone or sulfoxide
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(Matrix presented) The first alkoxide- and hydroxide-induced nucleophilic trifluoromethylation of carbonyl compounds, disulfides, and other electrophiles, using phenyl trifluoromethyl sulfone 1a (sulfoxide 1b) is reported. The trifluoromethyl sulfone 1a or sulfoxide 1b acts as a CF3 - synthon. Both sulfone 1a and sulfoxide 1b are commercially available and can also be conveniently prepared from trifluoromethane. The new methodology provides a convenient route for efficient trifluoromethylation.
- Prakash, G. K. Surya,Hu, Jinbo,Olah, George A.
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p. 3253 - 3256
(2007/10/03)
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