Phenols with mercuric trifluoroacetate

Mercuration of aromatic compounds can be accomplished with mercuric salts, most often Hg(OAc)2 ° to give ArHgOAc. This is ordinary electrophilic aromatic substitution and takes place by the arenium ion mechanism (p. 675). ° Aromatic compounds can also be converted to arylthallium bis(trifluoroacetates), ArTl(OOCCF3)2, by treatment with thallium(III) trifluoroacetate in trifluoroace-tic acid. ° These arylthallium compounds can be converted to phenols, aryl iodides or fluorides (12-28), aryl cyanides (12-31), aryl nitro compounds, or aryl esters (12-30). The mechanism of thallation appears to be complex, with electrophilic and electron-transfer mechanisms both taking place. 

Mercuration- Thallation. Mercuric acetate and thallium trifluoroacetate react with benzene to yield phenylmercuric acetate [62-38-4] or phenylthallic trifluoroacetate. The arylthallium compounds can be converted into phenols, nitriles, or aryl iodides (31). 

Oxidation of phenols and hydroqumones. Mercuric oxide in methanol oxidizes these substances to quinones. Mercury(II) trifluoroacetate can also be used, but then an acid scavenger is necessary tO neutralize the trifluoroacetic acid formed. The oxidation is analogous to that with thallium(III) salts. Yields in the oxidation of p-hydroquinones with HgO are in the range 70-95%. 

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