1072-85-1Relevant articles and documents
Exchange of halogens between aromatic compounds in the presence of Cu-HZSM-5 zeolite
Imhaoulne,Imhaoulene,Vivier,Guisnet,Petot,Perot,Gubelmann
, p. 12913 - 12922 (1994)
The reactions between various haloaromatics in binary mixtures which were approximately equimolar, were studied in gas-phase (673 K, atmospheric: pressure) in the presence of a 2 wt % Cu-HZSM-5 zeolite. The exchange of halogens (ipso substitution) between the two compounds was assumed to occur either through a radical mechanism involving an electron transfer between an atom of copper (I) and one aromatic molecule or through a nucleophilic substitution involving arylcopper complexes as intermediates.
Reactions of aromatic compounds with xenon difluoride
Bardin,Adonin, N. Yu.
, p. 1400 - 1407 (2016)
Reactions of substituted benzenes C6H5R (R = Me, F, Cl, Br, CF3, NO2) with xenon difluoride in the presence of boron trifluoride–diethyl ether complex in weakly acidic (1,1,1,3,3-pentafluorobutane) and weakly basic media (acetonitrile) have been studied. These reactions lead to the formation of fluorobenzene derivatives FC6H4R (isomer mixture) together with isomeric difluorobenzenes and fluorinated and non-fluorinated biphenyls. The results have been compared with previously reported data obtained in other solvents using other catalysts.
Hydroxyl radical induced reactions with 1-bromo-2-fluorobenzene in aqueous solutions: Formation of radical cations
Mohan, Hari,Mittal, Jai P.
, p. 263 - 270 (1996)
Hydroxyl radicals are observed to react with 1-bromo-2-fluorobenzene to form C6H4BrF · OH and (C6H4BrF)+· in neutral and acidic solutions respectively. The nature and reactivity of the solute radical cation, (C6H4BrF)+·, formed under different acidic conditions are discussed.
Substrate Selectivity and Orientation in Aromatic Substitution by Molecular Fluorine
Cacace, F.,Giacomello, P.,Wolf, A. P.
, p. 3511 - 3515 (1980)
Direct elemental fluorination of representative aromatic substrates, including PhH, PhCH3, PhF, PhCl, PhBr, PhNO2, PhCN, and PhOCH3, has been investigated in inert solvents, e.g., CCl3F and other fluorocarbons, over the temperature range -154 to 40 deg C.In order to achieve the necessary control of the extremely reactivve electrophile, and to minimize unwanted modifications of the reaction environment, the fluorination has been carried out at extremely low rate and correspondingly low conversions, generally below 0.01percent, using as a reagent gaseous mixtures of F2 highly diluted (+ constants for all the substituents investigated, giving a ρ+ value of -2.45 for aromatic substitution by elemental fluorine with a correlation coefficient of 0.993.These results characterize F2 as a highly reactive, and correspondently unselective, reagent, and support a polar electrophilic substitution mechanism that is discussed and compared with other plausible fluorination pathways.
Radical Decarboxylative Carbometalation of Benzoic Acids: A Solution to Aromatic Decarboxylative Fluorination
Xu, Peng,López-Rojas, Priscila,Ritter, Tobias
, p. 5349 - 5354 (2021)
Abundant aromatic carboxylic acids exist in great structural diversity from nature and synthesis. To date, the synthetically valuable decarboxylative functionalization of benzoic acids is realized mainly by transition-metal-catalyzed decarboxylative cross couplings. However, the high activation barrier for thermal decarboxylative carbometalation that often requires 140 °C reaction temperature limits both the substrate scope as well as the scope of suitable reactions that can sustain such conditions. Numerous reactions, for example, decarboxylative fluorination that is well developed for aliphatic carboxylic acids, are out of reach for the aromatic counterparts with current reaction chemistry. Here, we report a conceptually different approach through a low-barrier photoinduced ligand to metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation strategy, which generates a putative high-valent arylcopper(III) complex, from which versatile facile reductive eliminations can occur. We demonstrate the suitability of our new approach to address previously unrealized general decarboxylative fluorination of benzoic acids.
Fluorination of arylboronic esters enabled by bismuth redox catalysis
Planas, Oriol,Wang, Feng,Leutzsch, Markus,Cornella, Josep
, p. 313 - 317 (2020)
Bismuth catalysis has traditionally relied on the Lewis acidic properties of the element in a fixed oxidation state. In this paper, we report a series of bismuth complexes that can undergo oxidative addition, reductive elimination, and transmetallation in a manner akin to transition metals. Rational ligand optimization featuring a sulfoximine moiety produced an active catalyst for the fluorination of aryl boronic esters through a bismuth (III)/bismuth (V) redox cycle. Crystallographic characterization of the different bismuth species involved, together with a mechanistic investigation of the carbonfluorine bond-forming event, identified the crucial features that were combined to implement the full catalytic cycle.
Palladium-catalysed electrophilic aromatic C-H fluorination
Yamamoto, Kumiko,Li, Jiakun,Garber, Jeffrey A. O.,Rolfes, Julian D.,Boursalian, Gregory B.,Borghs, Jannik C.,Genicot, Christophe,Jacq, Jér?me,Van Gastel, Maurice,Neese, Frank,Ritter, Tobias
, p. 511 - 514 (2018/03/02)
Aryl fluorides are widely used in the pharmaceutical and agrochemical industries, and recent advances have enabled their synthesis through the conversion of various functional groups. However, there is a lack of general methods for direct aromatic carbon-hydrogen (C-H) fluorination. Conventional methods require the use of either strong fluorinating reagents, which are often unselective and difficult to handle, such as elemental fluorine, or less reactive reagents that attack only the most activated arenes, which reduces the substrate scope. A method for the direct fluorination of aromatic C-H bonds could facilitate access to fluorinated derivatives of functional molecules that would otherwise be difficult to produce. For example, drug candidates with improved properties, such as increased metabolic stability or better blood-brain-barrier penetration, may become available. Here we describe an approach to catalysis and the resulting development of an undirected, palladium-catalysed method for aromatic C-H fluorination using mild electrophilic fluorinating reagents. The reaction involves a mode of catalysis that is unusual in aromatic C-H functionalization because no organometallic intermediate is formed; instead, a reactive transition-metal-fluoride electrophile is generated catalytically for the fluorination of arenes that do not otherwise react with mild fluorinating reagents. The scope and functional-group tolerance of this reaction could provide access to functional fluorinated molecules in pharmaceutical and agrochemical development that would otherwise not be readily accessible.
DIRECT PALLADIUM-CATALYZED AROMATIC FLUORINATION
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Paragraph 00186; 00187, (2017/09/27)
Provided herein are palladium complexes comprising a ligand of Formula (Α') and a ligand of Formula (B), wherein R1-R18 are as defined herein. The palladium complexes are useful in methods of fluorinating aryl and heteroaryl substrates. Further provided are compositions and kits comprising the palladium complexes.
Fluorination of aromatic compounds with xenon difluoride in the presence of boron trifluoride etherate
Fedorov,Zubarev,Mortikov, V. Yu.,Rodinovskaya,Shestopalov
, p. 1049 - 1052 (2016/02/09)
Fluorination of benzene with the XeF2 - BF3?Et2O system in acetonitrile at low temperatures affords fluorobenzene in 18% yield, the conversion of benzene being 92%. The rest products are di-, tri-, tetra-, and polyphenyls with different fluorination pattern. Toluene and chloro- and bromobenzenes are fluorinated predominantly at the ortho and para positions. Fluorination of 4-nitroanisole affords 2-fluoro-4-nitroanisole in 73% yield.
Halogen exchange via a halogenation of diaryliodonium salts with cuprous halide
Li, Jian,Liu, Li,Ding, Dong,Sun, Jiang-Tao
, p. 541 - 548 (2014/01/06)
An efficient halogenation reaction has been developed with diaryliodonium salts and cuprous halides. Various diaryliodonium salts 1 could perform the reaction with readily available CuBr or CuCl in CH3CN at 80°C, assembling bromoarenes or chloroarenes in up to 92% yields. This provides us a method for the transformation from iodoarenes to other haloarenes.
