Highly stereoselective facile synthesis of β-amino carbonyl compounds via a Mannich-type reaction catalyzed by γ-Al2O3/MeSO3H (alumina/methanesulfonic acid: AMA) as a recyclable, efficient, and versatile heterogeneous catalyst

Abstract

Mannich reaction of ketones, aromatic aldehydes, and aromatic amines catalyzed efficiently by γ-Al2O3/MeSO3H (alumina/methanesulfonic acid: AMA) as a heterogeneous catalyst, which were carried out in EtOH at ambient temperature to afford the corresponding β-amino ketones in good yields and high stereoselectivities in favor of the anti isomer, was described for the first time. It was found that this catalyst could be completely recovered and reused without loss of its catalytic activities and is thus environmentally conscious. Furthermore, the use of γ-Al2O3/CH3SO3H (AMA) catalyst is feasible because of its easy preparation, easy handling, stability, easy recovery, reusability, good activity, stereoselectivity, and eco-friendliness. The use of this method provides a novel and improved modification of the three-component Mannich reaction in terms of mild reaction conditions and clean reaction profiles, using a very small quantity of catalyst and a simple workup procedure.