Zhou Shupeng, Guo Rui, Yang Peng, Li Ang
State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis , Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences , 345 Lingling Road , Shanghai 200032 , China.
J Am Chem Soc. 2018 Jul 25;140(29):9025-9029. doi: 10.1021/jacs.8b03712. Epub 2018 Jul 11.
Septedine (2) is a hetidine type C-diterpenoid alkaloid bearing an oxygenated heptacyclic scaffold. We have accomplished the first and asymmetric total synthesis of 2 and its 7-deoxy analogue 3. A functionalized tricyclic intermediate was prepared with excellent enantiopurity by using Carreira polyene cyclization. An unusual anionic Diels-Alder reaction was responsible for the construction of the bicyclo[2.2.2]octane. The α-methyl ketone was furnished by iridium-catalyzed allylic alcohol isomerization. Sanford Csp-H oxidation was exploited to install the secondary hydroxy group of 2. The oxazolidinopiperidine was assembled by selective reductive amination and spontaneous N, O-ketalization at a final stage.
Septedine（2）是一种具有氧化七环骨架的海替丁型C-二萜生物碱。我们完成了2及其7-脱氧类似物3的首次不对称全合成。通过使用Carreira多烯环化反应制备了具有优异对映体纯度的官能化三环中间体。一个不寻常的阴离子狄尔斯-阿尔德反应负责构建双环[2.2.2]辛烷。α-甲基酮是通过铱催化的烯丙醇异构化反应得到的。利用桑福德Csp-H氧化反应安装了2的仲羟基。恶唑烷并哌啶是在最后阶段通过选择性还原胺化和自发的N，O-缩酮化反应组装而成的。
