Synthetic study toward the total synthesis of fumigaclavines A–D

In the present study, we developed a novel approach for the synthesis of the tetracyclic core of fumigaclavines A–D. A palladium-catalyzed intramolecular Larock indole synthesis was utilized to assemble the B/C rings of the tetracyclic core in one step. Although all attempts to convert compound 18 to fumigaclavine B failed, this study provided useful information for the total synthesis of fumigaclavines A–D.