Abstract
gem-Difluorination of carbon-carbon triple bonds was conducted using Brønsted acids, such as Tf(2)NH and TfOH, combined with Bu(4)NBF(4) as the fluorine source. The electrochemical oxidation of a Bu(4)NBF(4)/CH(2)Cl(2) solution containing alkyne substrates could also give the corresponding gem-difluorinated compounds (in-cell method). The ex-cell electrolysis method was also applicable for gem-difluorination of alkynes.