Reactions of Xenon Difluoride

The reaction of phenol with aqueous xenon difluoride has been investigated at pH 3—4, the primary stable product being p-benzoquinone. Under these conditions, the rate of consumption of XeFg in water is independent of the substrate present. The initial hydrolysis reaction is followed by a series of rapid redox steps depending on the substrate present  

Goncharov and Y. N. Kozlov, Russ. J. Phys. Chem. Engl. TransL), 1978, 52, 539. 

This chapter covers all topics studied by pulse radiolysis which are relevant to this Report. The material is divided into sections, the main themes of which are (i) the reactions of inorganic free radicals, (ii) systems involving non-metallic compounds, (iii) aquo-metal ions in unusual oxidation states, (iv) reactions of transition-metal complexes, and (v) metalloproteins and related systems. 

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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. 

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... 

Investigation of the reaction of xenon difluoride and difluoroiodobenzene with aliphatic 1,3-dienes in the presence of boron trifluoride-diethyl ether complex has shown that under mild conditions this reaction proceeds with kinetic control, to form mainly the products of 1,2-addition of fluorine atoms. The ratio of product is reported in Table 5. 

Reaction of Xenon Difluoride with Butadiene (2, R = H) Typical Procedure 44... 

Reactions of xenon difluoride with various carbanions have been extensively studied by Tselinski and coworkers25-28. They found that the solvent plays the most important role in the transformation reactions in dichloromethane give mixtures of up to four products, while acetonitrile is found to be the most convenient solvent (Scheme 6). Excellent results were established with various substrates, while cationic species do not play a very important role. The authors suggested a one-electron transfer oxidation of the carbanion and further formation of various radicals, which is especially evident in reactions in mixtures of acetonitrile and benzene. 

In contrast with the fluorination process, Patrick and Nadji29 observed only dimerization in low-temperature reactions of xenon difluoride in dichloromethane (Scheme 7), while fluorination is achieved when disubstituted sulfides are present (the yield of substituted fluoromalonates depends on the substituent R = N02,0% R = H, 42%). The authors suggested the formation of [R2SXeF]+ as reacting species, which is supported by the... 

Transfer of a RCOO or R group from FXeOCOR or Xe(OCOR)2 to aliphatic, aromatic and heteroaromatic molecules has been achieved in recent years. Reactions of difluo-ronitro- and fluorochloronitroacetic acids in the presence of xenon difluoride result in alkylation and acylation of the aromatic ring9, while 1-trifluoroacetoxyadamantane is formed in the reaction of xenon difluoride in the presence of trifluoroacteic acid42. The... 

Korytnyk and coworkers have shown that reactions of xenon difluoride with acetylated glycals in the presence of boron trifluoride are a convenient route for the synthesis of 1,2-difluoro sugars, while the addition of fluorine to the double bond occurred predominantly from the less hindered side and cis adducts were mainly formed75, 76. Stereoselective transformation of tri-O-acetyl-D-galactal with xenon difluoride at -20 to +5 °C, without a catalyst in CFC13, after hydrolysis, afforded 2-deoxy-2-fluoro-D-galactose in 63% yield77. 

Bardin and coworkers99"101 studied the reactions of xenon difluoride with fluoro-substi-tuted benzene and naphthalene derivatives and in agreement with earlier investigations96"98, mainly addition products were observed (Scheme 34). 

Anand and Filler123 demonstrated that pyridine reacted with xenon difluoride forming 2-fluoro-, 3-fluoro- and 2,6-difluoropyridine and 8-hydroxyquinoline was converted to 5-fluoro 8-hydroxyquinoline, while nitrogen functionalization was observed by reaction of phthalimide and saccharin in benzene124. A-Fluoroimides were formed in good yields by reactions of xenon difluoride with imides of perfluorinated succinic and glutaric acids125 (Scheme 52). 

The reaction of hexafluoropropene with xenon tetrafluoride gives octafluoropropane (3) in 94 % yield after 15 hours however, the reaction of xenon difluoride with hexafluoropropene... 

This only known stable alkyliodine(III) difluoride is prepared by the reaction of xenon difluoride with excess methyl iodide and hydrogen fluoride at 20°. 

Xenon.—Several studies have been reported by Russian workers on the reactions of xenon difluoride in aqueous solution. The oxidation of phenol to p-benzo-quinone is suggested to involve an intermediate in the hydrolysis of xenon difluoride, possibly xenon monoxide. The rate of disappearance of xenon difluoride in the presence of phenol is the same as the rate of hydrolysis in the absence of the latter. A competition method has been used to study the role of this postulated intermediate. The kinetics of reaction of xenon difluoride with 2,3,6,6-tetramethylpiperidin-l-oxyl have been studied. In a review of recent developments in the chemistry of some electronegative elements there is a brief summary of fluxional behaviour in the proposed tetramer of XeF in solution. ... 

Two characteristic reactions of xenon difluoride need to be mentioned here. One is its action as an oxidizing agent. The standard reduction potential ofXeF2 to Xe is 2.64 V, as shown in Equation (19.12) ... 

The second characteristic reaction of xenon difluoride is its combination with fluoride-ion acceptors such as various pentafluorides. Two typical reactions are represented in Equations (19.15) and (19.16) ... 

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