Structural Revisions/Assignments of Marine Natural Products by Total Synthesis

Marine organisms have yielded a diverse array of biologically active molecules. The small quantities of these marine natural compounds have proven to be a severe obstacle for the development of promising new leads for the development of novel drugs. Structure elucidation of increasingly limited quantities of components from marine natural product extracts heavily rely on advanced nano-scale NMR technologies. Chemical degradation and derivatization were somewhat less involved. However, literature precedent suggested that a large number of structural misassignments were made in relatively recent years. In order to verify the primary structure proposed on the basis of studies of the marine natural products, we have undertaken extensive programs toward the structural revisions/assignments of marine natural products via total synthesis, which also provide materials for biological testing towards pharmaceutical development. The presentation will focus on our work towards the revision/assignment and confirmation of a number of marine natural products, including burkholdac A, lagunamide A, bisebromoamide, yanucamide A, scytonemin A and hoiamide A.