Syntheses of Biologically Active Natural Products by Intramolecular Double Michael Reaction

为了发展立体选择性构筑多环化合物的一般方法，研究了分子内双Michael反应。通过以下三种不同的方法有效地实现了目标成环。条件：（A）氨基锂处理，（B）TMSCl、Et_3N、EnCl_2加热，（C）TBSOTF和ET_3N处理。在条件（A和B）下，通过环合反应，全合成了一种二萜（阿替西烯）、一种二萜生物碱（阿替辛）、三醌型倍半萜（并环戊二烯、并环戊二烯酸和脱氧并环戊二烯酸）和雌甾烷型甾体化合物。另外，在（B和C）条件下，通过环合反应合成了生物碱（Epilupinine和Eschophorine）。在条件（C）下也成功地进行了不对称合成。

In orber to develop a general methodology for the stereoselectione construction of polycyclic compounds, the intramolecular double Michael reation was investigated. The objective annulation was effectively achieced by the following three different. conditions:(A)treatment with lithium amide,(B)heating with TMSCl,Et_3N,EnCl_2,(C) treament with TBSOTF and ET_3N. A Diterpene (atisirene),a diterpene alkaloid (atisine),triquinene sesquiterpenes (pentalenene, pentalenic acid and deoxypentalenic acid) and estrane type steroids were totally synthesized via the annulation under conditions(A and B). On the ther hand , syntheses of alkaloids (epilupinine and tylophorine) were accomplished through the cyclisation under the conditions (B and C). Asymmetric synthesis was also successfully carried out under the condition (C).