Carbon-bromine bond cleavage is observed when 4-dimethylaminopyridine is treated with CF2Br2 and BrCF2CF2Br to yield N-(bromodifluoromethyl) and N-(2-bromo-1,1,2,2-tetrafluoromethy1)pyridinium bromides, 1-Br and 2-Br, which are reductively debrominated using Bu3SnH and fluorinated by anhydrous Me4N+F-; the molecular structure of 1-Br is determined by single crystal X-ray crystallography to reveal a partial quinoidal character in the pyridine system and a hypervalent Br-a-BrCF2 pairing.

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The reactivity of bis(trifluoroacetyl)-phenols toward selected

An efficient and reliable method to synthesize 2,6-bis(trifluoroacetyl)phenols bearing various substituents in the 4-position was developed. These valuable fluorinated building blocks were obtained from the corresponding cyclohexanones in a facile and convenient procedure, demonstrated to be superior to the traditional approaches. The application of this methodology to cyclohexane-1,4-dione opened access to 2,5-bis(polyfluoroacyl)-1,4-hydroquinones. Structural peculiarities of the obtained phenols as well as their 1,3-dicarbonyl or 1,3,5-tricarbonyl precursors are discussed on the basis of multinuclear NMR spectroscopy.

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