An expedient approach for the synthesis of naphthyl dispiro pyrrolidine/pyrrolizidine through 1,3-dipolar cycloaddition reaction

Synthesis of naphthyl pyrrolidine/pyrrolizidine-spirooxindoles has been achieved by a one pot three component 1,3-dipolar cycloaddition (1,3-DC) reaction. The azomethine ylides generated in situ from isatin/N-substituted isatin and secondary amino acids (sarcosine/l-proline) reacted with naphthylidene tetralone as a dipolarophile to give naphthyl dispiro heterocycles, in good yields. However anthrylidene tetralone, failed to react under the same conditions as a dipolarophile to give the products as expected in 1,3-DC reaction possibly due to steric and electronic properties. The structures and stereochemistry of cycloadducts were confirmed by 1H and 13C NMR spectroscopy, mass spectrometry, and single crystal X-ray diffraction studies.