Stereoselective Synthesis of β-Amino Ketones via Direct Mannich-Type Reactions, Catalyzed with ZrOCl2·8H2O under Solvent-Free Conditions

At room temperature, zirconium oxychloride (ZrOCl2·8H2O) efficiently catalyzes the direct Mannich-type reaction of a variety of in situ generated aldimines using aldehydes and anilines with ketones in a three-component reaction under solvent-free conditions. The reaction proceeds rapidly and affords the corresponding β-amino ketones in good to high yields with good to excellent stereoselectivities. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)