Active esters as acylating reagents in the Friedel–Crafts reaction: trifluoromethanesulfonic acid catalyzed acylation of ferrocene and pyrene

The Friedel–Crafts acylation of electron-rich arenes (ferrocene and pyrene) with N-hydroxysuccinimidyl, 2,3,5,6-tetrafluorophenyl and phenyl esters of benzoic and p-methoxybenzoic acid, activated by superacidic trifluoromethanesulfonic acid is reported. The reactive acylating intermediate in this system is presumably an acyl triflate or its protonated form.