Improvement of ferrocene acylation. Conventional vs. microwave heating for scandium-catalyzed reaction in alkylmethylimidazolium-based ionic liquids

Acylation of ferrocene-catalyzed by scandium triflate was thoroughly investigated. Reaction time and temperature are important parameters, in that prolonged treatment causes substrate decomposition and/or catalyst deactivation. Hydrophobic alkylmethylimidazolium-based solvents gave best results, in particular 1-butyl-3-methylimidazolium bis(trifluorometansulfonyl) imide. Anhydrides behave as superior acylating reagents with respect to acyl chlorides. MW irradiation allowed to quantitatively acylate ferrocene within minutes.