Synthesis of (+)-8-deoxyvernolepin and its 11,13-dihydroderivative.: A novel reaction initiated by sulfene elimination leads to the 2-oxa-cis-decalin skeleton
Synthesis of (+)-8-deoxyvernolepin and its 11,13-dihydroderivative.: A novel reaction initiated by sulfene elimination leads to the 2-oxa-cis-decalin skeleton
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DOI：
10.1021/jo0256538
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发表时间：
2002-08-09
影响因子：
3.6
通讯作者：
Rosales, A
中科院分区：
文献类型：
--
作者：
Barrero, AF;Oltra, JE;Rosales, A
标题化合物是抗真菌筛选的有趣候选者。本文描述了从市售提取物中分离的(+)-木香内酯开始，这些化合物的对映体特异性合成。在这项工作中，我们使用了两个新反应作为关键的合成步骤：酸诱导的δ， ε -环氧酯的环化，立体选择性地得到羟基甲基取代的δ -内酯，羟基烷基在期望的-equatorial配置中；反应级联，由碱促进的亚砜消除引发，从trans-fused δ -内酯的甲磺酸中得到10-oxiranyl-2-oxa-顺式十氢化萘。我们还发现二氧化硒与柠檬烯内酯的1,5-二烯体系反应得到类似天然柠檬烯内酯的硒七酸。我们的研究结果证明，基于仿生概念的合成策略是一种有用的方法，可以从可及的大环内酯类化合物中制备(+)-蛇麻素相关的对映体特异性化合物。
The title compounds are interesting candidates for antifungal screening. This paper describes the enantiospecific synthesis of these compounds starting from (+)-costunolide isolated from a commercially available extract. We used two novel reactions as key synthetic steps in this work: the acid-induced cyclization of an delta,epsilon-epoxy ester, which stereoselectively gave a hydroxymethyl-substituted delta-lactone, with the hydroxyalkyl group in the desired beta-equatorial disposition, and a reaction cascade, initiated by a base-promoted sulfene elimination, which led to a 10-oxiranyl-2-oxa-cis-decalin from the mesylate of a trans-fused delta-lactone. We also found that the reaction between selenium dioxide and the 1,5-diene system of elemanolides gave selenadecalins analogous to natural eudesmanolides. Our results prove that the synthetic strategy employed, on the basis of biomimetic concepts, is a useful procedure for the enantiospecific preparation of (+)-vernolepin-related compounds from accessible germacrolides.