Faculty of Pharmaceutical Sciences, Hokkaido University.
Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University.
Chem Pharm Bull (Tokyo). 2024;72(6):547-558. doi: 10.1248/cpb.c24-00190.
Iridoids, which are a class of monoterpenoids, are attractive synthetic targets due to their diversely substituted cis-fused cyclopenta[c]pyran skeletons. Additionally, various biological activities of iridoids raise the value of synthetic studies on this class of compounds. Here, our synthetic efforts toward 11-noriridoids; (±)-umbellatolide B (6), (±)-10-O-benzoylglobularigenin (9) and 1-O-pentenylaucubigenin (34) are described. For the efficient synthesis of target compounds, common synthetic intermediates (tricyclic enones 17 and 26) were prepared by the Pauson-Khand reaction. The cleavage of the acetal bond on the tricyclic enones and 1,2-reduction introduced the two hydroxy groups on the cyclopentane ring of the core scaffold. Furthermore, the C3-C4 olefin part was constructed by the syn-elimination of a thiocarbonate moiety to obtain 34. The developed synthetic routes for 6, 9, and 34 will be useful for the preparation of iridoid analogs that have a polyfunctionalized core skeleton.
由于其具有多样化取代的顺式稠合环戊[c]吡喃骨架，裂环环烯醚萜类化合物是一类具有吸引力的合成目标物。此外，裂环环烯醚萜类化合物的各种生物活性提高了对这一类化合物的合成研究的价值。在这里，我们描述了对 11-去甲裂环环烯醚萜类化合物；（±）-umbellatolide B（6）、（±）-10-O-苯甲酰基 globularigenin（9）和 1-O-戊烯基 aucubigenin（34）的合成努力。为了有效地合成目标化合物，通过 Pauson-Khand 反应制备了常见的合成中间体（三环烯酮 17 和 26）。在三环烯酮和 1,2-还原上裂解缩醛键，在核心支架的环戊烷环上引入了两个羟基。此外，通过硫代碳酸盐部分的顺式消除构建了 C3-C4 烯烃部分，得到了 34。用于 6、9 和 34 的开发的合成途径对于制备具有多官能化核心骨架的裂环环烯醚萜类化合物的类似物将是有用的。
