A facile three-component reaction involving [4+1] cycloaddition leading to furan annulated heterocycles

The in situ generated quinone methides from 4-hydroxycoumarin and 4-hydroxy-6-methylpyrone with various aldehydes underwent facile reaction with cyclohexyl isocyanide to produce furocoumarins in good yields. Quinone methides from 4-hydroxy-1-methylquinolinone afforded furoquinolones. The reaction presumably occurs via a [4+1] cycloaddition followed by a [1,3] H shift.