Synthesis of spirocyclic benzo[f]quinoline derivatives by cascade heterocyclization of dimedone, 2-naphthylamine, and formaldehyde

The three-component condensation of dimedone, 2-naphthylamine, and formaldehyde in aliphatic alcohols under mild conditions gives in high yields the corresponding N-alkoxymethyl benzof]quinoline derivatives having a substituted 2-azaspiro5.5]undecane fragment. The reaction involves formation of three new carbon-carbon bonds, two carbon-nitrogen bonds, and one carbon-oxygen bond, and the initial β-dicarbonyl system is conserved.