Syntheses of Biologically Active Natural Products by Intramolecular Double Michael Reaction

为了建立多环化合物立体选择结构的一般方法，研究了分子内双迈克尔反应。通过以下三种不同的方法有效地实现了目标环封。条件：(A)用锂酰胺处理，(B)用TMSCl、Et_3N、EnCl_2加热，(C)用TBSOTF和Et_3N处理。在条件（A和B）下，通过环化完全合成了二萜（atisirene）、二萜生物碱（atisine）、三醌倍半萜（pentalene、pentalenic acid和deoxpentalenic acid）和甾烷型类固醇。另一方面，在条件（B和C）下通过环化合成了生物碱（epilupinine和tylophorine）。在(C)条件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).