350-50-5Relevant articles and documents
C?F Bond Activation by Silylium Cation/Phosphine Frustrated Lewis Pairs: Mono-Hydrodefluorination of PhCF3, PhCF2H and Ph2CF2
Mallov, Ian,Ruddy, Adam J.,Zhu, Hui,Grimme, Stefan,Stephan, Douglas W.
, p. 17692 - 17696 (2017)
Single defluorination of aryl polyfluoromethyl functionalities is achieved by both intra- and intermolecular silylium cation/phosphine Lewis pairs. Phosphine-captured aryl fluoromethyl cations are then treated with Br?nsted base to complete the first mono
Catalytic Formation of C(sp3)-F Bonds via Heterogeneous Photocatalysis
Tarantino, Giulia,Hammond, Ceri
, p. 10321 - 10330 (2018)
Due to their chemical, physical, and biological properties, fluorinated compounds are widely employed throughout society. Yet, despite their critical importance, current methods of introducing fluorine into compounds suffer from severe drawbacks. For example, several methods are noncatalytic and employ stoichiometric equivalents of heavy metals. Existing catalytic methods, on the other hand, exhibit poor activity, generality, selectivity and/or have not been achieved by heterogeneous catalysis, despite the many advantages such an approach would provide. Here, we demonstrate how selective C(sp3)-F bond synthesis can be achieved via heterogeneous photocatalysis. Employing TiO2 as photocatalyst and Selectfluor as mild fluorine donor, effective decarboxylative fluorination of a variety of carboxylic acids can be achieved in very short reaction times. In addition to displaying the highest turnover frequencies of any reported fluorination catalyst to date (up to 1050 h-1), TiO2 also demonstrates excellent levels of durability, and the system is catalytic in the number of photons required; i.e., a photon efficiency greater than 1 is observed. These factors, coupled with the generality and mild nature of the reaction system, represent a breakthrough toward the sustainable synthesis of fluorinated compounds.
New fluoride ion reagent from pentafluoropyridine
Murray, Christopher B.,Sandford, Graham,Korn, Stewart R.,Yufit, Dmitrii S.,Howard, Judith A.K.
, p. 571 - 576 (2005)
A new nucleophilic fluorinating agent, derived from reaction of dimethylaminopyridine (DMAP) with pentafluoropyridine, has been synthesised and assessed in various carbon-fluorine bond forming processes.
Acceleration of the Fluorination of Benzyl Halide by the Combination of Lead Fluoride and Sodium Salt
Ichihara, Junko,Hanafusa, Terukiyo,Takai, Yoshio,Ito, Yoshiaki
, p. 1161 - 1164 (1992)
A new composite reagent, a combination of lead fluoride (PbF2) and a small amount of sodium salt (NaX, X=F, Br etc.) was found to be useful for facilitating heterogeneous fluorination of substituted benzyl halides in acetonitrile.
Tetraphenylphosphonium Hydrogendifluoride: a New Source of Fluoride Ion
Brown, Stephen J.,Clark, James H.
, p. 672 - 673 (1985)
Tetraphenylphosphonium hydrogendifluoride, a soluble and thermally stable reagent, acts as a source of fluoride ion in a variety of organic reactions.
Swain,Spalding
, p. 6104 (1960)
SUBSTRATE DEPENDENT SOLVENT EFFECTS IN NUCLEOPHILIC FLUORINE TRANSFER REACTIONS
Clark, J. H.,MacQuarrie, D.
, p. 591 - 596 (1987)
The rate of fluorination of organic substrates by potassium fluoride in aprotic solvents is subject to substrate dependent solvent effects.
Bethell et al.
, p. 1447 (1977)
Reaction evolution of a solvate fluoride ionic liquid induced fluorination process probed by Raman spectroscopy
Chen, Zhengfei,Deng, Meng,Gao, Zhanghua,Jiang, Zhijiang,Li, Lichun,Tang, Haodong
, (2020)
Currently, about 30% of new approved drugs contained fluorine atoms and most of them are made through fluorination reactions using various kinds of fluorinating reagents. In the current work, we report a facile and more accessible way to probe the fluorination evolution at different stages using a newly developed fluorinating reagent (1-ethyl-3-methylimmidazolium fluoride-ethylene glycol, [C2C1im]F-EG). Benzyl bromide was converted to benzyl fluoride using this fluorinating reagent under mild conditions. A more accessible Raman method, compared to NMR, was used to probe the reaction process due to the products having their own characteristic Raman vibrational frequencies because of the formation of different C-X bonds. Thus the yield of the product at different time scales could be then quantified based on their relative intensities, providing a fresh insight into the fluorination process. This method could be applied in other reactions to reflect the important fluorination process, which methodologically reports a facile way to probe reaction processes.
METHOD AND REAGENT FOR DEOXYFLUORINATION
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Paragraph 0148-0150; 0152; 0160, (2021/05/29)
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.
Copper-Catalyzed Functionalization of Benzylic C-H Bonds with N-Fluorobenzenesulfonimide: Switch from C-N to C-F Bond Formation Promoted by a Redox Buffer and Br?nsted Base
Buss, Joshua A.,Golden, Dung L.,Stahl, Shannon S.,Vasilopoulos, Aristidis
supporting information, p. 5749 - 5752 (2020/10/02)
A copper catalyst in combination with N-fluorobenzenesulfonimide (NFSI) has been reported to functionalize benzylic C-H bonds to the corresponding benzylic sulfonimides via C-N coupling. Here, we reported a closely related Cu-catalyzed method with NFSI that instead leads to C-F coupling. This switch in selectivity arises from changes to the reaction conditions (Cu/ligand ratio, temperature, addition of base) and further benefits from inclusion of MeB(OH)2 in the reaction. MeB(OH)2 is shown to serve as a "redox buffer"in the reaction, responsible for rescuing inactive Cu(II) for continued promotion of fluorination reactivity.
C(sp3)-H Fluorination with a Copper(II)/(III) Redox Couple
Bower, Jamey K.,Cypcar, Andrew D.,Henriquez, Brenda,Stieber, S. Chantal E.,Zhang, Shiyu
supporting information, p. 8514 - 8521 (2020/05/28)
Despite the growing interest in the synthesis of fluorinated organic compounds, few reactions are able to incorporate fluoride ions directly into alkyl C-H bonds. Here, we report the C(sp3)-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, LCuF, along with its chloride and bromide analogues, LCuCl and LCuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized with single-crystal X-ray diffraction, X-ray absorption spectroscopy, UV-vis spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Quantum chemical calculations reveal significant halide radical character for all complexes, suggesting their ability to initiate and terminate a C(sp3)-H halogenation sequence by sequential hydrogen atom abstraction (HAA) and radical capture. The capability of HAA by the formally copper(III) halide complexes was explored with 9,10-dihydroanthracene, revealing that LCuF exhibits rates 2 orders of magnitude higher than LCuCl and LCuBr. In contrast, all three complexes efficiently capture carbon radicals to afford C(sp3)-halogen bonds. Mechanistic investigation of radical capture with a triphenylmethyl radical revealed that LCuF proceeds through a concerted mechanism, while LCuCl and LCuBr follow a stepwise electron transfer-halide transfer pathway. The capability of LCuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.
