The course of acid-catalyzed liquid-phase fluorination of methyl-substituted benzene derivatives with xenon difluoride depends strongly on the structure and concentration of the substrate, ita molar ratio to xenon dffluoride, and the catalyst. HF-catalyzed fluorination of 1, 2, 4, 5-tetramethylbnzene (1) with an equimolar amount of xenon difluoride gave a small amount of l&difluoro product 2, while reaction with 2 equiv of xenon difluoride, besides ...
