Phenols reactions with xenon difluoride

Vinyltrimethylstannanes react with xenon difluoride in dichloromethane at room temperature in the presence of equimolar (or a 50 Vo excess) of silver trifluoromethanesulfonate and a catalytical (0.1 equiv) quantity of 2,6-di-/e/7-butyl-4-methylpyridine to form the corresponding vinyl fluorides in high to moderate yields.54 57 The substitution reaction is tolerant to various functional groups, such as ketones, esters, carbamates, ketals, ethers, phenol rings and tertiary alcohols. As byproducts corresponding alkenes have been detected due to pro-tiodestannylation. 

Fhiorination of aromatics. The reagent reacts with toluene to form benzyl fluoride as the major product ( 65% yield). It is also useful for fluorination of phenols- and of alkyl ethers of phenols the or/Ao-isomcr is formed as the major product. Reactions with this reagent thus differ from those with xenon difluoride, which generally favors formation of paro-isomers. 

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. ... 

Great differences in product structures and product distributions are obtained by lead(IV) oxide or acetate oxidation of perfluorophenol in different solvents and media. The reaction with the former agent gives a quinoid ether in 22% yield (Table 10).173 The oxidation with lead(IV) acetate has been optimized to such a level as to give perfluoro cyclohexa-2,5-dienone (4) in 65 % yield.174 Treating the phenol with vanadium(V) fluoride or vanadium(III) fluoride as well as xenon difluoride gives a mixture of products,175 therefore, the reactions are only of minor preparative importance. 

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 ... 

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See also in sourсe #XX -- [ , ]

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