Cu/AlO(OH)-catalyzed formation of β-enamino ketones/esters under solvent, ligand and base free conditions - Experimental and computational studies

Cu/AlO(OH) has been found to be an efficient catalyst for the formation of β-enamino ketones/esters under solvent, ligand and base free conditions. The catalyst Cu/AlO(OH) is prepared from CuCl ₂·2H ₂O, pluronic P123 and Al(O-sec-Bu) ₃. The prepared catalyst is characterized by HR-TEM, SEM-EDX, XPS and FT-IR spectra. The β-ketoenamine is prepared using Cu/AlO(OH) as catalyst under mild and environmentally benign conditions. The reaction conditions are optimized with different catalyst amounts and temperatures using an acetylacetone and aniline system as a model. The scope of the reaction is extended to different types of diketones and amines. Solvent, ligand and base free and room temperature conditions make the reaction interesting from both an economic and environmental point of view. A mechanism is proposed on the basis of DFT calculations.