Key Laboratory of Drug Targeting and Drug Delivery Systems of the Ministry of Education, Department of Chemistry of Medicinal Natural Products, West China School of Pharmacy, and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu 610041, China.
Org Lett. 2014 May 2;16(9):2299-301. doi: 10.1021/ol500726x. Epub 2014 Apr 4.
A synthetic strategy for the modeling construction of the highly bridged azatetracyclic ABEF ring system of numerous lycoctonine-type C19-diterpenoid alkaloids bearing a characteristic oxygenated quaternary center at C-7 has been successfully developed. The tetracyclic core was constructed rapidly from a readily prepared 6,7-bicyclic AB ring precursor through a 13-step sequence via an advanced tetracyclic N,O-acetal intermediate, which belong to another core structure of natural 7,17-seco-type alkaloids. The key step involves an SmI2-promoted intramolecular radical coupling reaction of an N,O-acetal with a carbonyl group, mimicking a plausible biogenetic transformation.
已经成功开发出一种用于模拟构建具有特征性含氧季碳中心的 C-7 位的大量 Lycoctonine 型 C19-二萜生物碱的高度桥连的 AZA 四环 ABEF 环系统的综合策略。四环核心是通过 13 步序列从容易制备的 6,7-双环 AB 环前体快速构建的，通过先进的四环 N,O-缩醛中间体，属于天然 7,17-去甲型生物碱的另一种核心结构。关键步骤涉及 SmI2 促进的 N,O-缩醛与羰基的分子内自由基偶联反应，模拟了一种可能的生物发生转化。
