The reaction of 2H-1-benzopyran with several 1, 3-dipoles gives cycloadducts in good yields. The orientation of the cycloaddition is qualitatively interpreted in terms of FMO theory. These heteropolycyclic compounds were also obtained from hydrazones of 3-aroyl-2H-1- benzopyrans, prepared from 3-cyano-2H-1-benzopyran.
