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. (C) 2008 Elsevier B. V. All rights reserved.