Tandem aldol condensation-Diels–Alder-aromatization sequence of reactions: a new pathway for the synthesis of 2-tetralone derivatives

Abstract

A series of new polysubstituted derivatives of 2-tetralones possessing two ester groups were synthesized via a tandem aldol condensation-Diels–Alder-aromatization sequence of reactions. All the three steps took place in one pot and in the presence of aminofunctionalized silica coated Fe3O4 nanoparticles as the catalyst. In situ formed dienes reacted with diethyl acetylenedicarboxylate at room temperature and the process was followed by spontaneous aromatization of the cycloadducts to produce high yields of the final tetralone products. Further studies suggest that the process goes through an initial aldol condensation-cycloaddition sequence followed by oxidation and rearrangement steps. After completion of the reactions, the catalyst could be recycled and reused efficiently in subsequent reactions.