157.Stereoselective Synthesis of (±)-Cephanolide B

Anding Li, Ziru He, Bingyan Liu, Zhen Yang*, and Zichun Zhang*

Org. Lett. 2021, 23,(23), 9237–9240

A concise and stereoselective total synthesis of (±)-cephanolide B was achieved in 15 steps. The key steps in the synthesis were as follows: (i) an intermolecular Diels–Alder reaction followed by lactonization to form the oxabicyclo[2.2.2]octane DE ring; (ii) a tandem reaction, featuring an intramolecular Pauson–Khand reaction, a 6π-electrocyclization, and an oxidative aromatization by O₂, to construct the ABC-tricyclic rings (6-5-6); and (iii) a phthaloyl peroxide-mediated arene oxygenation to install the C-13 phenol group.