Ag-Initiated gem-Difluoromethylenation of the Nitrogen Center of Arenediazonium Salts to gem-Difluoromethylene Azo Compounds.

An efficient method for the synthesis of the thermally stable and pharmaceutically important gem-difluoromethylene azo compounds is developed. This protocol achieved gem-difluoromethylenation of the nitrogen center of arenediazonium salts through in situ generated benzo-1,3-diazolic difluoromethylene radical addition to arenediazonium salts under mild Ag-initiated conditions.