二倍半萜bipolarolide C和D的合成研究

萜类化合物一直以来都是全合成领域的研究热点。bipolarolide C和D是一类结构新颖的二倍半萜，具有前所未有的5-5-5-5非线性并环结构，并且具有重要的生理活性。关于他们的合成研究还没有报道。我们拟通过不对称环加成反应和自由基加成反应作为关键步骤完成这两个复杂分子的高效合成。其中线型的5-5-5并环的构建拟利用小分子催化的不对称[6+2]环加成反应实现，同时引入季碳手性中心。期望烷基化立体选择性地引入烯基碘，再通过底物控制的5-exo-trig自由基环化构建另外一个含两个季碳中心的5-5并环。我们希望通过该合成探索富烯参与的环加成反应和自由基环化反应，为高效合成类似的环系提供高效的合成策略。另外希望可以通过合成大量目标化合物，推动该类分子的生物活性研究。

Terpene is a popular research area of total synthesis. Bipolarolide C and D are two sesterterpenes possessing unprecedented 5-5-5-5 fused-ring system, which exhibit considerable bioactivities. So far, total synthesis of these two natrual products has not been reported. We plan to exploit asymmetric cycloaddition and radical cyclization as key steps to accomplish the total synthesis of these two targets efficiently. Linear 5-5-5 fused ring could be constructed by asymmetric [6+2] cycloaddition, introducing the chiral quaternary carbon center. We expect alkylation would be a practical way to install the vinyl iodide which proceeds 5-exo-trig radical cyclization to furnish 5-5 fused ring containing two quaternary carbon centers. We will explore fulenve-invovled cycloaddition and radical cyclization, providing an efficient strategy to synthesize this kind ring system. Highly efficient and scalable synthesis is expected to be achieved, promoting the investigation of their biological activities.