Introduction of Perfluoroalkyl Substituents into Heteroarenes via Nucleophilic Substitution of Hydrogen

A summary of research in the area of fluoroalkylation of electron-deficient aromatic compounds is presented. The reaction of dinitroand cyanonitroarenes with trifluoromethyl-trimethylsilane (Me3SiCF3) and tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) and subsequently with DMD provides trifluoromethylated cyanoand nitrophenols via oxidative nucleophilic substitution of hydrogen. Addition of fluorinated carbanions, generated either by addition of F− anions to hexafluoropropene or by activation of Me3SiCF3, to N-alkylazinium salts leads to dihydropyridines, dihydroquinolines etc., oxidation of which affords the respective fluoroalkylated heterocycles. 1,3-Dipolar cycloaddition of azine N-oxides to hexafluoropropene gives 2-heteroaryl-2,3,3,3-tetrafluoropropionic acid fluorides, which react with various protic nucleophiles to give esters and amides of 2-heteroarylperfluoropropionic acids, whereas reaction with water and decarboxylation of the free acids gives azines with a 1,2,2,2-tetrafluoroethyl group at C-2.