Oxazolone Cycloadducts as Heterocyclic Scaffolds for Alkaloid Construction: Synthesis of (±)-2-epi-Pumiliotoxin C

Intramolecular Diels-Alder cycloaddition of N-substituted oxazolone triene I allows direct entry to the functionalized octahydroquinoline II. Further manipulation of this framework by stereo- and regioselective introduction of the 5-methyl substituent, followed by excision of the carbamate, yields (+/-)-2-epi-pumiliotoxin C.