Base-free reduction of ketones using a bpy-iridium catalyst. Focus on the synthesis of γ-valerolactone

Abstract

Several [Cp*Ir(N⌒N)SO4] complexes have been prepared and used for the efficient reduction of various ketones in water without any additives, using formic acid as the hydrogen donor. The best catalyst incorprating a bis-dimethylaminopyridine ligand was further used for the base-free reduction of levulinic acid into γ–valerolactone (GVL). This catalyst loaded at 0.1 mol% and used under neat conditions led to quantitative conversion of levulinic acid at 30 °C.