The total syntheses of the polyhydroxylated macrolactone (+)-aspicilin and a diastereoisomer have been achieved via a concise route, starting from the spatially desymmetrized (R',R',R,S)-2,3-butanediacetal-protected butane tetrol 13. The key steps include a regioselective silyl protection of 13 and a stereoselective Lewis acid mediated addition of allyltributylstannane to the equatorially disposed aldehyde of 4. Macrocyclization is achieved using ring closing metathesis, after which selective hydrogenation and protecting group removal yields the natural product.Key words: aspicilin, butanediacetal, desymmetrization, macrolactone, metathesis.
通过一条简洁的途径,从空间非对称化的(R',R',R,S)-2,3-丁二醛缩醛保护的丁烷四醇13出发,已经成功合成了多羟基大环内酯(+)-aspicilin和一个对映异构体。关键步骤包括对13进行区域选择性硅保护和对4的赤道取向醛基进行立体选择性的路易斯酸介导的烯丙基三丁基锡加成。通过环闭合酯交换反应实现大环化,随后选择性氢化和保护基去除产生天然产物。关键词:aspicilin,丁二醛缩醛,非对称化,大环内酯,酯交换反应。