N-[3-Acetyl-5-(pentafluorosulfanyl)phenyl]-2,2,2-trifluoro-N-methylacetamide (O2.075; 1.03 g) was dissolved in a mixture of methanol (20 ml) and THF (20 ml). Phenyltrimethylammonium tribromide (1.05 g) was added while stirring. After stirring at RT for 5 h, the mixture was left to stand overnight, then further phenyltrimethylammonium tribromide (100 mg) was added and the mixture was heated to 60° C. for 2 h. After cooling, the reaction mixture was added to 2 N sulfuric acid and stirred for 10 min. Then the aqueous phase was extracted three times with EA. The combined organic phases were dried over magnesium sulfate and, after the desiccant had been filtered off, dried under reduced pressure. 1.2 g of the title compound were obtained, which had sufficient purity for the next reactions.
