Research on the Efficient Enantioselective Total Synthesis of Useful Bioactive Polycyclic Compounds

Useful bioactive polycyclic natural products are important targets in academic research, wherein their mechanisms of action and total syntheses are commonly investigated. In addition, polycyclic compounds that exhibit highly selective biological activities through multipoint recognition are valuable as biochemical reagents and lead compounds for pharmaceuticals. However, when such compounds are difficult to obtain, their supply depends on appropriate chemical preparations. Unfortunately, polycyclic natural products pose difficult synthetic problems, such as the construction of distorted ring structures, contiguous stereogenic centers, and quaternary asymmetric carbon atoms in their fused ring moieties. Moreover, since polycyclic natural products have a large number of bonds, their total syntheses inevitably become multi-step procedures, and when enantioselective total synthesis is required, the number of steps tends to increase, since such routes require the use of commercially available chiral compounds. Hence, their efficient total synthesis is challenging. In our group, we have demonstrated the preparation of chiral synthetic intermediates, especially those bearing a quaternary stereogenic center, through novel asymmetric catalysis procedures, as well as the incorporation of logically designed cascade reactions to reduce the number of transformations. This route can ultimately lead to the efficient enantioselective total syntheses of useful bioactive polycyclic natural products.