Total syntheses of the labdane diterpene lactones marrubiin, marrulibacetal, desertine, marrulibacetal A, marrubasch F, cyllenine C, marrulanic acid, and marrulactone are described. The trans-decalin moiety of these molecules was constructed in a stereoselective manner by a Pauson-Khand reaction, and the resultant cyclopentenone was oxidatively cleaved for formation of the lactone ring. Elongation of the side chain at C9 was achieved by an epoxide-opening reaction with a variety of nucleophiles, and the functional group manipulations completed the syntheses of these natural products. Stereochemistries of desertine could be established by the transformations.

中文翻译：

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Marrubiin 和相关拉丹丹二萜内酯的全合成

描述了拉丹二萜内酯 marrubiin、marrulibacetal、desertine、marrulibacetal A、marrubasch F、cylenine C、marrulanic acid 和 marrulactone 的全合成。这些分子的反式萘烷部分是通过 Pauson-Khand 反应以立体选择性方式构建的，所得环戊烯酮被氧化裂解形成内酯环。C9 侧链的延长是通过与各种亲核试剂的环氧化物开环反应实现的，官能团操作完成了这些天然产物的合成。沙漠的立体化学可以通过转化来建立。