Total Synthesis of Epilupinine: Synthetic Strategy of Fused Bicyclic Skeleton Containing Nitrogen

The total synthesis of polycyclic natural products is often characterized by methods for constructing fused ring systems, in which there are many examples such as stepwise synthesis, cascade cyclization, rearrangement of spirocycles, and so on. In this highlight review, we focus on the total synthesis of epilupinine as the simplest natural product with a fused ring system. Due to the simple fused ring system, total synthesis of epilupinine has been attempted by various different approaches, and various methods for constructing the octahydro-2H-quinolizine (quinolizidine) skeleton have been developed.