Facile new method for synthezising N-polyfluoroalkylated heterocycles – molecular structure of N-(bromodifluoromethyl)-4-dimethylaminopyridinium bromide

Abstract

Carbon-bromine bond cleavage is observed when 4-dimethylaminopyridine is treated with CF₂Br₂ and BrCF₂CF₂Br to yield N-(bromodifluoromethyl) and N-(2-bromo-1,1,2,2-tetrafluoromethyl)pyridinium bromides, 1-Br and 2-Br, which are reductively debrominated using Bu₃SnH and fluorinated by anhydrous Me₄N⁺F^–; the molecular structure of 1-Br is determined by single crystal X-ray crystallography to reveal a partial quinoidal character in the pyridine system and a hypervalent Br^–⋯BrCF₂ pairing.