Bipolar Electrochemical Fluorination of Triphenylmethane and Bis(phenylthio)diphenylmethane Derivatives in a U-shaped Cell

Electrochemical fluorination of triphenylmethane derivatives and bis(phenylthio)diphenylmethane derivatives by using a split bipolar electrode is described. The reaction conditions for the fluorination of triphenylmethane were further optimized from the previous report to obtain the desired product in quantitative yields. Fluorination reaction cleanly proceeded under a wide range of voltage applied between the driving electrodes, from 25 to 100 V. Use of lower voltage is preferable in terms of energy efficiency, whereas higher voltage shortened the reaction time. The optimized conditions were applicable to the fluorination of other triphenylmethane derivatives and bis(phenylthio)diphenylmethane derivatives to give the corresponding fluorinated products.