The chief objective of our research on the chemistry of small ring heterocycles and intramolecular dipolar cycloaddition chemistry is to open up new synthetic methods for preparation of novel heterocyclic compounds. Intramolecular dipolar cycloadditions of nitrones, nitrile ylides, nitrilimines, diazoalkenes and azides will be studied. By working with an assortment of different 1,3-dipoles and dipolarophiles we hope to achieve an understanding of the basic principles and structural features of the cycloaddition reaction and thus be able to evaluate electronic and stereochemical effects. The development of general synthetic routes leading to unusual small ring heterocycles via intramolecular dipolar cycloaddition will also be examined.