Concise Enantioselective Total Synthesis of Daphenylline Enabled by an Intramolecular Oxidative Dearomatization.

Daphenylline is a structurally unique member of the triterpenoid natural alkaloids, which exhibit intriguing biological activities. Six total syntheses have been reported, five of which utilize aromatization approaches. Herein, we report a concise protecting-group-free total synthesis by means of a novel intramolecular oxidative dearomatization reaction, which concurrently generates the critical seven-membered ring and the quaternary-containing vicinal stereocenters.