Total Synthesis of (±)-Cephanolides B and C via a Palladium-Catalyzed Cascade Cyclization and Late-Stage sp3 C–H Bond Oxidation

Lun Xu, Chao Wang, Ziwei Gao, Yu-Ming Zhao

Index: 10.1021/jacs.8b03015

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Abstract

Herein, we report the first total syntheses of complex cephalotaxus diterpenoids cephanolide B and C from commercially available 5-bromo-2-methylanisole. Key to the success of this synthetic route is a palladium-catalyzed cascade cyclization reaction, which allowed us to efficiently forge the 6–5–6 cis-fused tricyclic ring systems found in the entire family of cephalotaxus diterpenoids. Additionally, site-selective late-stage sp3 C–H bond oxidation served as a key strategic element in the chemical synthesis of cephanolide C.