研发从仿生合成所启发的氧化自由基串联环化反应及其在天然产物全合成中的应用

天然产物仿生合成（Biomimetic Synthesis）的研究不仅可以加深对生源合成途经及关键酶作用机理的了解，而且可以纠正天然产物结构鉴定上的误差。更重要的是，仿生合成的研究还可以启发新型高效的串联环化反应的开发。本课题组最近从 (±)-Yezo’otogirin C的仿生合成研究中获得启发，研发了氧化自由基串联环化反应，能从简单的原料出发一步构建目标天然产物的碗形氧杂-6,5,5-及-6,6,5-三并环骨架。因此，本课题的目标是把这个氧化自由基串联环化反应发展成一个更加高效和通用的合成方法，用以一步构建多种不同的碗形氧杂三并环骨架，并应用于Picrotoxane及ent-cis/cis-Clerodane家族天然产物的全合成。

The study on biomimetic synthesis of natural products is a very important research topic in organic synthesis since it could provide valuable information about the biosynthetic pathways and the enzymatic mechanisms. More importantly, biomimetic synthesis could lead to the development of new cascade cyclization reactions. Inspired by the biogenetic proposal of (±)-Yezo’otogirin C, our group has recently developed an oxidative free-radical cascade cyclization reaction for construction of the bowl-shape oxa-6,5,5- and -6,6,5- tricyclic fused ring system of (±)-Yezo’otogirin C. The objective of this project is to develop this oxidative free-radical cascade cyclization reaction into a general and efficient synthetic methodology that can establish a variety of bowl-shape oxa-tricyclic fused ring systems in one step and can be applied to the total synthesis of Picrotoxanes and ent-cis/cis-Clerodanes.