Key points are not available for this paper at this time.
The A/E/F tricyclic system characteristic of C18-, C19-, and denudatine-type C20-diterpenoid alkaloids was constructed via a strategically designed polyene cyclization/Mannich cascade. The configurational inversion of the phenyl group at C7 successfully proceeded through a radical cascade process involving sequential 1,5-HAT and intermolecular HAT, ultimately establishing the desired tricyclic system with an β-oriented phenyl group.
Feng et al. (Thu,) studied this question.