Professor Nancy I. Totah, of the Department of Chemistry at the University of Iowa, is developing new methods for the synthesis of complex natural products with the support of the Organic Synthesis Program. Selective epoxidation of an enamide functionality in ten-membered macrocycles and subsequent transannular addition is explored as an approach to the synthesis of 6-6 fused ring amides with control of up to four stereogenic centers. This methodology will be applied to the enantioselective synthesis of phenanthridone alkaloids such as pancratistatin. Exploitation of the conformational preferences of a tricyclic precursor will provide access to C-ring modified phenanthridone alkaloids. The phenanthridone alkaloids are an important class of natural products, displaying a variety of biological activities that include anticancer, antiviral, growth regulatory, and insect antifeedant activities. With the support of the Organic Synthesis Program, Professor Nancy I. Totah, of the Department of Chemistry at the University of Iowa, is developing new approaches for the synthesis of this class of compounds. These approaches, based on the formation of molecules containing two rings from precursors containing only one larger ring, offer promise for the preparation of compounds available in only small quantities from natural sources as well as modified compounds, not known to occur naturally, which may have potential medicinal and agricultural applications
