The syntheses of kulkenon and sulfangolide

磺胺内酯和kulkenon是黏菌中新的次生代谢物。磺胺内酯是特殊的，因为它们是粘菌中第一个表现出硫酸盐酯的次生代谢物。通过核磁共振实验和计算机辅助计算对其结构进行了分析。这一结构的阐明为我们合成这两种化合物奠定了基础。在kulkenon的合成过程中，我们意识到这种结构解析并没有描述两个立体中心的正确构型。由于我们在kulkenon上的工作，我们不仅完成了这种天然产物的第一次全合成，而且确定了它的正确构型。我们期望这种改进也适用于磺胺类化合物。磺胺内酯的合成是为了提供这种不寻常的天然产物的合成途径，并提供我们的葡萄树木山醛醇反应的一个例子，并展示如何缩短合成复杂天然产物的步骤。在此之前，这些片段要么是通过标准的醛醇和烯烃协议，要么是通过经典的葡萄醛反应，然后是Mitsunobu转化来构建的。另一个不寻常的转化是分子内Heck反应作为大环化协议。由于我们必须重新研究kulkenon的配置并重新启动它的合成，我们在项目的这一部分使用了比最初计划更多的时间。另外，我们在进行C16和C17之间的aldol连接时遇到了很大的问题。本项目旨在完成磺胺内酯的合成并确定其构型。作为一个额外的方法学方面，我们计划详细调查上述醛醇反应，因为只有很少的例子，其中一些结果似乎是矛盾的。

Sulfangolide and kulkenon are new secondary metabolites from myxobacteria. The sulfangolides are special since they were the first secondary metabolites from myxobacteria that exhibit a sulfate ester. Its structure was analyzed with the aid of NMR experiments and computer aided calculations. This structure elucidation set the background for our synthesis of both compounds. During the synthesis of kulkenon we realized that this structure elucidation was not describing the correct configuration at two stereocentres. Due to our work on kulkenon we could not only complete the first total synthesis of this natural product but also determine its correct configuration. We expect that this refinement will also apply to the sulfangolides. The synthesis of sulfangolide is to provide synthetic access to this unusual natural product and to provide an example of our vinylogous Mukaiyama aldol reaction and to show how this might shorten the number of steps during the synthesis of a complex natural product. Before, these fragments were constructed by either standard aldol and olefination protocols or by a classical vinylogous aldol reaction followed by a Mitsunobu inversion. Another unusual transformation is the intramolecular Heck reaction as macrocyclization protocol. Due to the fact that we had to re-investigate the configuration of kulkenon and restart its synthesis we used more time for this part of the project than initially planned. In addition, we encountered significant problems when performing the aldol connection between C16 and C17. The project is designed to complete the synthesis of sulfangolide and to confirm its configuration. As an additional methodological aspect we plan to investigate the aforementioned aldol reaction in detail since there are only few examples and some of these results seem to be contradictory.