C-F Arylation of Polyfluorophenols by Means of Sigmatropic Dearomatization/Defluorination Sequence.

Selective C-F arylation of polyfluorophenols with aryl sulfoxides has been accomplished by means of a sigmatropic dearomatization/defluorination sequence. This sequence consists of three processes: 1) interrupted Pummerer reaction to form S-O-tethered sulfonium salt; 2) C-C-forming [3,3] sigmatropic rearrangement with dearomatization; and 3) Zn-mediated defluorinative rearomatization. The present biaryl construction provides a facile access to polyfluorinated biaryls that is difficult to synthesize by other methods. The synthetic utility of the strategy is clearly demonstrated by the synthesis of a fluorinated analogue of Maxipost, a potassium channel modulator.