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Total Synthesis of Metaphanine and Oxoepistephamiersine |
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| Authors: | Ya-Kui Sun Jin-Bao Qiao Yu-Meng Xin Qin Zhou Zhi-Hua Ma Hui Shao Yu-Ming Zhao |
| Institution: | 1. Key Laboratory of Applied Surface and Colloid Chemistry & School of Chemistry and Chemical Engineering, Shaanxi Normal University, 620 West Chang'an Ave, Xi'an, 710119 China
These authors contributed equally to this work.;2. Key Laboratory of Applied Surface and Colloid Chemistry & School of Chemistry and Chemical Engineering, Shaanxi Normal University, 620 West Chang'an Ave, Xi'an, 710119 China |
| Abstract: | Herein, we report a concise and divergent synthesis of the complex hasubanan alkaloids metaphanine and oxoepistephamiersine from commercially available and inexpensive cyclohexanedione monoethylene acetal. Our synthesis features a palladium-catalyzed cascade cyclization reaction to set the tricyclic carbon framework of the desired molecules, a regioselective Baeyer–Villiger oxidation followed by a MeNH2 triggered skeletal reorganization cascade to construct the benzannulated aza4.4.3]propellane, and a strategically late-stage regio-/diastereoselective oxidative annulation of sp3 C?H bond to form the challenging THF ring system and hemiketal moiety in a single step. In addition, a highly enantioselective alkylation of cyclohexanedione monoethylene acetal paved the way for the asymmetric synthesis of target molecular. |
| Keywords: | Cascade Annulation Hasubanan Alkaloids Late-Stage Oxidation Palladium Catalysis Total Synthesis |