Multicomponent access to indolo[3,3a-c]-isoquinolin-3,6-diones: formal synthesis of (±)-plicamine

The complete tetracyclic core structure of plicamine, a novel Amaryllidaceae-type alkaloid, was expeditously prepared by a Ugi four-component condensation reaction, followed by a one-pot sequential phenolic oxidation and intramolecular coupling process. The employment of this strategy resulted in a rapid, formal synthesis of (+/-)-plicamine.