Key Laboratory of Drug Targeting, Ministry of Education Department of Chemistry of Medicinal Natural Products, West China College of Pharmacy, Sichuan University, Chengdu, 610041, P. R. China.
State Key Laboratory of Oral disease, West China School of Stomatology, Sichuan University, Chengdu, 610041, P. R. China.
Chem Asian J. 2018 Apr 16;13(8):955-958. doi: 10.1002/asia.201800116. Epub 2018 Mar 23.
Franchetine, a unique 7,17-seco type of norditerpenoid alkaloid, possesses a highly congested polycyclic architecture coupled with nine stereogenic centers. Here we present an efficient synthetic approach for the intact hexacyclic framework of franchetine from the known tricyle 16 in 20 steps. The synthesis features a diastereoselective 6-exo-tet radical cyclization for construction of ring A and a unique oxidative Wagner-Meerwein-type rearrangement to realize the functionalized [3.2.1] bridging ring CD.
Franchetine 是一种独特的 7,17- 裂环型二萜生物碱，具有高度拥挤的多环骨架和九个手性中心。在此，我们提出了一种从已知三环 16 经 20 步反应高效合成完整六元环骨架 franchetine 的方法。该合成方法的特点是通过立体选择性 6-endo-四元自由基环化反应构建 A 环，并通过独特的氧化 Wagner-Meerwein 型重排反应实现功能化 [3.2.1] 桥环 CD。
