Ag-Catalyzed Chemoselective Decarboxylative Mono- and gem-Difluorination of Malonic Acid Derivatives.

Malonic acid derivatives have been successfully applied in a Ag-catalyzed decarboxylative fluorination reaction, providing an unprecedented route to either gem-difluoroalkanes or α-fluorocarboxylic acids by the judicious selection of base and solvent. This reaction features the use of readily available starting materials, tunable chemoselectivity and good functional group compatibility as well as gram-scale synthetic capability. The advantage of using malonic acid derivatives in this radical decarboxylative functionalization is further highlighted by the facile transformations of the α-fluorocarboxylic acid to valuable fluorine-containing compounds. Preliminary mechanistic studies suggest that an α-carboxylic acid radical is involved in this reaction.