The overall objective of our research program involves the development of a general, broadly applicable method for the synthesis of novel heterocyclic systems. Emphasis is placed on the use of 1,3-dipolar cycloaddition chemistry for the construction of a variety of biologically interesting heterocycles. Among the reactions to be studied are cycloadditions of carbonyl ylides, azomethine ylides and thiocarbonyl ylides. The project will focus on using the rhodium catalyzed reaction of diazo carbonyl compounds as a general method for generating a variety of 1,3-dipoles. The chemistry to be developed will facilitate the synthesis of complex alkaloids and in so doing provide quantities of material needed for detailed biological assay. Many of the substances to be synthesized are expected to show interesting malignant-growth inhibiting properties and will be tested at the National Cancer Chemotherapy Service Center.