Concise Total Synthesis of Ambiguine P

Ambiguine P ( 5 ) is a synthetically challenging representative of the hapalindole-type natural products. Inspired by the biosynthesis of this indole terpenoid family, we developed a Cope/Prins/Friedel–Crafts cascade, achieving a six-step synthesis of 5 from 2,2-dimethylcycloheptanone. Altered from the biosynthetic pathway, this cascade strategically commenced with a tricyclic indolenine derivative bearing a seven-membered ring, enabling efficient construction of the pentacyclic scaffold of 5 . The oxidation state was elevated through chlorination and hydroxylation in the final stage.