The primary purpose of this research project is to complete efficient total syntheses of the antitumor agents actinobolin and bactobolin from a common bicyclic lactone intermediate. This research should also make available various unnatural analogs of these natural products for antitumor testing by the National Cancer Institute. In addition, the scope, utility and applications of the intramolecular [4+2]-cycloaddition of N-acylimines with alkenes will be explored. This methodology will be applied to synthesis of penem and carbapenem precursors, to the N-terminal Alpha-amino acid components of the nikkomycins and neopolyoxins, and to polyoxamic acid, an Alpha-amino acid component of the polyoxins.