This study focused on synthesizing the tricyclic hexasubstituted spirocyclopropane-core framework 2 of cyclohelminthol X (1), an antifungal cytotoxin isolated from Helminthosporium velutinum yone96 in a stereoselective manner. The synthesis features an S_N2-type cyclopropanation of the quaternary chloride 23 generated via a retro-Michael-type ring-opening reaction of an 8-azatricyclo[4.3.0.1^2,5]deca-3,7,9-trione derivative 22. The successful synthesis confirmed the structure of 1, resolving the ambiguity from the absence of X-ray crystallographic analysis. The prepared models exhibited potent cytotoxicity.

中文翻译：

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环蠕虫醇X的三环六取代螺环丙烷核的立体选择性制备

本研究的重点是合成环蠕虫醇 X ( 1 ) 的三环六取代螺环丙烷核心框架2 ，环蠕虫醇 X 是一种以立体选择性方式从Helminthosporium v​​elutinum yone96中分离出来的抗真菌细胞毒素。该合成的特点是通过 8-氮杂三环[4.3.0.1 ^2,5 ]deca-3,7,9-trione 衍生物的逆迈克尔型开环反应生成季氯化物23的S _{N 2 型环丙烷化反应}22 .成功的合成证实了1的结构，解决了由于缺乏X射线晶体学分析而产生的歧义。制备的模型表现出有效的细胞毒性。