SYNTHETIC STUDIES AIMED AT THE DOLASTANES - AN ATTEMPTED A + C -] ABC APPROACH
SYNTHETIC STUDIES AIMED AT THE DOLASTANES - AN ATTEMPTED A + C -] ABC APPROACH
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DOI：
10.1021/jo00221a027
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发表时间：
1985-01-01
影响因子：
3.6
通讯作者：
PAQUETTE, LA
中科院分区：
文献类型：
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作者：
BELMONT, DT;PAQUETTE, LA
多拉石烷是一种海洋二萜，其6-7-5脂环的分子排列是独特的。作为这些生物活性天然产物代表的合成计划的一部分，研究了通过分子内环化形成中心七元环来详细阐述其框架的可能性。开发了一种方便的两步法制酮酯8。该中间体被证明对烯丙基溴化镁和[(E)-2-（三甲基硅基）乙烯基]锂的铜促进共轭加成有接受性。随后由这些加合物衍生的缩醛21可以方便地制成高度功能化的2-环戊烯酮27。合成策略的核心是需要在27内形成分子内的C-C键。因为我们在达到预期的最终结果方面非常不成功，所以这种特殊的方法似乎不适合获得白云石。
The dolastanes are marine diterpenes whose molecular array of fused 6-7-5 alicyclic rings is distinctive. As part of a program directed toward the synthesis of representatives of these bioactive natural products, the possibility of elaborating their framework by intramolecular cyclization to form the central seven-membered ring has been examined. An expedient two-step route to keto ester 8 was developed. This intermediate proved receptive to cooper-promoted conjugate addition of allylmagnesium bromide and [(E)-2-(trimethylsilyl)vinyl]lithium. The acetal 21 to be subsequently derived from these adducts could be conveniently crafted into the highly functionalized 2-cyclopentenones 27. Central to the synthetic strategy was the need for intramolecular C-C bond formation within 27. Because we were singularly unsuccessful in achieving the desired end result, this particular approach appears unsuited for gaining access to the dolastanes.