Versatile three-component synthesis of 2′-amino-1,2-dihydrospiro[(3H)-indole-3,4′-(4′H)-pyran]-2-ones

A versatile method for the synthesis of 2′-amino-1,2-dihydrospiro[(3 H )-indole-3,4′-(4′ H )-pyran]-2-ones has been suggested consisting in the three-component reaction of isatins, cyanoacetic acid derivatives, and α-methylenecarbonyl compounds (β-dicarbonyl compounds, activated phenols, and OH-substituted heterocycles) in ethanol in the presence of triethylamine as a catalyst. The reaction proceeds selectively to form spiro[(3 H )-indole-3,4′-(4′ H )-pyrans].