Heptacyclic Skeleton Construction in the Total Synthesis of Hetisine‐Type C ₂₀ ‐Diterpenoid Alkaloids

Hetisine‐type C ₂₀ ‐diterpenoid alkaloids (DAs) are a prominent subclass of C ₂₀ ‐diterpenoid alkaloids, renowned for their exceptionally complex N ‐fused caged architecture and bicyclo[2.2.2]octane core. Their highly strained 6/6/6/6/5/5/5 heptacyclic framework features at least 9 contiguous stereocenters, 3 all‐carbon quaternary centers, and a distinctive N–C6 bridge, presenting formidable challenges for chemical synthesis. In this minireview, we provide a comprehensive overview of all reported total syntheses of hetisine‐type DAs, highlighting the strategic innovations that have enabled the efficient assembly of the heptacyclic framework and N ‐fused cage‐like architecture. This minireview provides strategic insights into the synthesis of hetisine‐type DAs and may facilitate the development of efficient synthetic approaches to other complex polycyclic natural products.