Xenon difluoride, reaction

Xenon difluoride reaction with nitro enolates provides a useful entry into a wide variety of fluonnated synthetic intermediates [91 92] (equation 52)... 

The boron trifluoride-diethyl ether complex initiated norbornene/xenon difluoride reaction is much more selective and < xo-2-< . o-5-difluoronorbornane and < M /o-2-e Yo-5-difluoronorbor-nane predominate.116... 

K [14881-07-3], Rb [72151 -96-3], and Cs [72138-72-8]), are prepared by reaction of elemental fluorine, chlorine trifluoride, or xenon difluoride and a mixture of nickel fluoride and alkaH metal fluorides or other metal haHdes (16,17). If the fluorination is carried out using mixed fluorides, a lower temperature can be used, yields are quantitative, and the final products are of high purity. Bis(tetrafluoroammonium) hexafluoronickelate [6310540-8], (NE 2N iF6> prepared from Cs2NiF3 and NE SbE by a metathesis in anhydrous HE, is also known (18). 

Trimethylarsine gives a 98% yield of trimethylarsine difluoride when treated with xenon difluoride [102] in fluorotrichloromelhane. and tnsfpentafluorophen-yl)arsine gives a 94% yield of tris(pentafluornphenyl)arsme difluoride after reaction with dilute fluorine in fluorotnchloromethane at 0 C [106] Other trivalent arsenic compounds have also been fluorinated with xenon difluoride [103] In addition, arsines have been oxidatively fluorinated by iodine pentafluoride [107] or electrochemically in 26-34% yield [108]... 

Xenon difluoride [4, 5, 7, 8,10] is a white crystalline material obtained through the combination of fluorine and xenon m the presence of light The reagent is commercially available and possesses a relatively long shelf-life when stored cold (freezer) Xenon difluoride is very effective for small-scale fluormation of alkenes and activated nucleophilic substrates. The reactions are usually conducted between 0 °C and room temperature in chloroform or methylene chloride solutions Hydrogen fluoride catalysis is sometimes helpful Xenon difluoride reacts in a manner that usually involves some complexation between the substrate and reagent followed by the formation of radical and radical cation intermediates... 

Carboxylic acids react with xenon difluoride to produce unstable xenon esters The esters decarboxylate to produce free radical intermediates, which undergo fluonnation or reaction with the solvent system Thus aliphatic acids decarboxylate to produce mainly fluoroalkanes or products from abstraction of hydrogen from the solvent Perfluoro acids decarboxylate in the presence of aromatic substrates to give perfluoroalkyl aromatics Aromatic and vinylic acids do not decarboxylate [91] (equation 51)... 

Silyl enol ethers are fluonnated in high yields with xenon difluoride [62 93, 94 95] Applications of this reaction to the preparation of fluonnated... 

Xenon difluoride fluorinates adamantane in low yield [45] (equation 22) When the carbon-hydrogen bond is activated by an a-sulfur atom, fliiorination occurs readily The reactions involve intermediates that contain sulfur-fluorine bonds. At-Fluoropyridinium reagents behave similarly [99, 100, 101, 102] (equations 55-57)... 

The interhalogen IFT can be made only by indirect routes. For example, xenon difluoride gas can react with iodine gas to produce 1FV and xenon gas. In one experiment xenon difluoride is introduced into a rigid container until a pressure of 3.6 atm is reached. Iodine vapor is then introduced until the total pressure is 7.2 atm. Reaction is then allowed to proceed at constant temperature until completion by solidifying the IF as it is produced. The final pressure in the flask due to the xenon and excess iodine vapor is 6.0 atm. (a) What is the formula of the mterhalogen (b) Write the chemical equation for its formation. 

CF3OCI has been discussed ), fluorine (F2, diluted with inert gases), xenon difluoride (XeF2), acetyl hypofluorite (MeC02F), and related compounds. As basic aspects of reactions using some of these reagents have been described by Penglis in this Series, developments after 1978 will mainly be described. 

During preparation from perchloric acid and xenon difluoride at —50°C, violent explosions occurred if the reaction mixture was allowed to warm up rapidly [1]. Detonates easily and should be handled with extreme care [2],... 

Though a powerful oxidant, the difluoride is not explosively unstable. Safe procedures for the use of xenon difluoride in fluorination reactions are detailed. Residual traces of the fluoride are rapidly destroyed by dichloromethane at ambient temperatures. 

Xenon difluoride (or the tetrafluoride, or their mixtures) could not be caused to detonate by impact. Xenon difluoride and xenon tetrafluoride both may cause explosion in contact with acetone, aluminium, pentacarbonyliron, styrene, polyethylene, lubricants, paper, sawdust, wool or other combustible materials. Their vigorous reactions with ethanol, potassium iodate or potassium permanganate are not explosive, however. 

In the reaction of the pentaoxide with xenon tetrafluoride oxide to give xenon difluoride dioxide and nitryl fluoride, the xenon tetrafluoride oxide must be used in excess to avoid formation of xenon trioxide, which forms a sensitive explosive mixture with xenon difluoride dioxide. 

Radon difluoride is quantitatively reduced to elemental radon by water in a reaction which is analogous to the reactions of krypton difluoride and xenon difluoride with water. Complex salts of radon also hydrolyze in this fashion. 

Oxidative Fluorination of Nitrones to a-Fluorosubstituted Nitroxyl Radicals Formation of nitroxyl radicals by the radical cation route was observed in reactions of various nitrones with xenon difluoride in dry methylene chloride (520, 523). In this reaction, more than 40 nitrones, including 4H -imidazole N,N -dioxides (219), 4H -imidazole TV-oxides (223) and (224), 2H -imidazole N -oxides (225), 2H -imidazole TV,TV-dioxides (226), 3,3,5,5-tetramethylpyrroline N -oxide (TMPO), derivatives of 3-imidazoline-3-oxides (231) and (232), have been examined. ESR spectra of nitroxyl radicals containing one or two fluorine atoms at a-C have been registered (Scheme 2.108) (523). In the case of... 

Safety precautions applicable to direct liquid phase fluorination of aromatic compounds are discussed [1]. Attention is drawn to the hazards attached to the use of many newer fluorinating agents [2], In a study of fluorination reactions of hafnium and zirconium oxides by the fluoroxidisers xenon difluoride, chlorine trifluoride and bromine trifluoride, reactivity decreased in the order given [3],... 

It has been shown that the thermolysis of arenesulphonyl azides with benzene to yield A-arenesuIphonylazepines (44-80%) is aided by the addition of Adogen [30], Sulphonylazepines have also been obtained from the reaction of tetra-n-butylammo-nium salts of sulphonamides with benzene in the presence of xenon difluoride the reaction probably proceeds via the intermediate nitrene [31 ]. 

O O In the early 1960s, Neil Bartlett, at the University of British Columbia, was the first person to synthesize compounds of the noble gas xenon. A number of noble gas compounds (such as XeF2, XeF4, XeFe, and XeOs) have since been synthesized. Consider the reaction of xenon difluoride with fluorine gas to produce xenon tetrafluoride. 

Xenon difluoride labelled with positron-emitting F has been prepared by reaction of cyclotron produced [ F]p2 with xenon [88]. This low-yielding method requires high pressure. [ F]Xep2 was also obtained by treating sulfuryl chloride fluoride solutions of Xep2 in fluorinated ethylene propylene vessels with Bronst-... 

Also, the tribromides or fluorides of 6-9 and 11 can be quantitatively synthesized by similar one-electron transfer to bromine [20] or xenon difluoride in the solid state [1]. Further inorganic solid-state one-electron redox reactions have also been reported [6]. 

Bartlett prepared xenon difluoride by the reaction of xenon with silver fluoride in hydrofluoric acid in the presence of boron trifluoride ... 

R.E. Ehrenkaufer, R.R. MacGregor, Synthesis of [ F]-perchloryl fluoride and its reactions with functionalized aryllithiums, Int. J. Appl. Radiat. Isot. 34(1983)613-615. R. Chirakal, G. Firnau, J.G. Schrobilgen, J. McKay, E.S. Garnett, The synthesis of [ F]xenon difluoride from [ F]fluorine gas, Int. J. Appl. Radiat. Isot. 35 (1984) 401-404. 

Pyridine is converted into perfluoropiperidine (82) in low yield by reaction with fluorine in the presence of cobalt trifluoride (50JCS1966) quinoline affords (83) under similar conditions (56JCS783). Perfluoropiperidine can be obtained electrochemically. This is useful, as it may be readily aromatized to perfluoropyridine by passing it over iron or nickel at ca. 600 °C (74HC(14-S2)407). Recently, pyridine has been treated with xenon difluoride to yield 2-fluoropyridine (35%), 3-fluoropyridine (20%) and 2,6-difluoropyridine (11%), but it is not likely that this is simply an electrophilic substitution reaction (76MI20500). 

Perfluoropropyl iodide (8) formed difluoroiodoperfluoropropane in 60% yield upon reaction with xenon difluoride at 20 C.21... 

Reaction of Bridgehead Iodides with Xenon Difluoride General Procedure 1617... 

Fluorination of tris(fluorosulfonyl)methane (10) with xenon difluoride in dichlorodifluoro-methane solution gives fluorotris(fluorosulfonyl)methane in quantitative yield.24 In contrast, no fluorination product has been obtained in the reaction of tris(trifluoromethylsulfonyl)meth-ane with xenon difluoride.25... 

The interaction of xenon difluoride with ethene at room temperature was investigated soon after xenon difluoride was discovered.26 The reaction mixture contained 1,2-difluoroethane (45%), 1,1-difluoroethane (35%) and 1,1,2-trifluoroethane (20%). 

Fluorination of propene by xenon difluoride leads to formation of l,2-difluoropropanc(12%), 1,1-difluoropropane (46 %), 2-fluoropropane (24 %) and 1,1-difluoroethane (9 %). The complex composition of the mixture is explained by the radical character of the reaction. 

The reaction of xenon difluoride with a series of cis- and trans-phenyl substituted alkenes was examined in detail. 1,1-Diphenylethene, l,1-diphenyl-2-fluoroethene and 1.1-diphenyl-propene form vicinal 1,2-difluoro derivatives in 65 95% yield in dichloromethane solution with hydrogen fluoride as the catalyst.29-32 Two possible mechanisms were discussed.33... 

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