A convenient synthesis of C-22 and C-25 stereoisomers of cephalostatin north 1 side chain from spirostan sapogenins
A convenient synthesis of C-22 and C-25 stereoisomers of cephalostatin north 1 side chain from spirostan sapogenins
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DOI：
10.1021/ol025580e
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发表时间：
2002-04-18
期刊：
影响因子：
5.2
通讯作者：
Suárez, E
中科院分区：
文献类型：
--
作者：
Betancor, C;Freire, R;Suárez, E
描述了天然螺甾皂苷配基的八碳侧链到头孢菌素north 1螺缩酮部分的简单转化。该方法基于烷氧基促进的分子内夺氢反应，允许合成二氧杂螺[4.4]壬烷头孢菌素环系统的C-22和C-25立体异构体。研究了不同异构体中螺环中心的酸催化异构化反应。
[GRAPHIC]A simple transformation of the eight-carbon side chain of a natural spirostan sapogenin into the cephalostatin north 1 spiroketal moiety is described. This methodology, based on an intramolecular hydrogen abstraction reaction promoted by alkoxy radicals, permits the synthesis of C-22 and C-25 stereoisomers of the dioxaspiro[4.4]nonane cephalostatin ring system. The acid-catalyzed isomerization of the spirocenter in the different isomers is studied.