Phainanoid家族分子是2015年从叶下珠属植物——海南叶下珠中分离得到的三萜类天然产物，该家族化合物都具有显著的生理活性，Phainanoid F更是具有明显的免疫抑制活性，其免疫抑制能力是环孢霉素Ａ(CsA)的数倍。Phainanoid F分子中含10个环系和15个手性中心，其中8个是四取代的手性中心，且含有新颖的5/4/6螺环并环结构和紧凑的6/3/5并环体系。Phainanoid 家族化合物复杂新颖的化学结构与良好的生物活性引起了我们的合成兴趣。我们拟通过分子内的[2+2]反应、羰基插入-螺环内酯化反应、分子间氧化偶联反应和环丙烷化反应等关键反应，高效地构建分子中的骨架结构和手性中心。在完成Phainanoid F和该家族其他天然产物全合成的同时，丰富和完善方法学内容，并进一步探究构效关系，为药物应用和研发打下基础。

Phainanoids A-F are highly modified triterpenes iosolated from Phyllanthus hainanensis by Jian-Min Yue, 2015. All those six triterpenes exhibited excepetionally popent activities in vitro against the ConA-induced proliferation of T lymphocytes and the LPS-induced proliferation of B lymphocytes. The most potent one, Phainanoid F, exhibited much higher activity than cyclosporin A (CsA). Phainanoid F possesses 10 cyclo skeletons and 15 chiral centers including 8 quaternary centers. The unprecedented 5/4/6 and 6/3/5 cyclo skeletons are challenging for synthesis. Their excellent bioactivity combined with intriging structures make Phainanoids family, especially Phainanoid F an ideal target for synthesis study. To efficiently construct the cyclo skeletons and chiral centers, we propose to synthesize Phainanoid F and other molecules in this family through several key steps including intramolecular [2+2], carbonylative spirolactonization, intermolecular oxidative coupling and cyclopropanation. More method would be developed during the syhthesis, so as further structure-activity relationship, laying fundations for medical research.