Synthesis of the bis-spiroacetal moiety of the shellfish toxins spirolides B and D using an iterative oxidative radical cyclization strategy
Synthesis of the bis-spiroacetal moiety of the shellfish toxins spirolides B and D using an iterative oxidative radical cyclization strategy
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DOI：
10.1039/b604334h
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发表时间：
2006-01-01
影响因子：
3.2
通讯作者：
Brimble, Margaret A.
中科院分区：
文献类型：
--
作者：
Meilert, Kai;Brimble, Margaret A.
报道了贝类毒素螺内酯B 1和D2的双螺缩醛片段的对映选择性合成。通过二氢吡喃10与醛11的Barbier反应构建碳框架，然后通过两次氧化自由基环化构建双螺缩醛环系统。甲硅烷基修饰的Prins环化和对映选择性巴豆酰化成功地在环化前体21中安装了立体中心。初始不饱和双螺缩醛9a-d在环氧化成反式环氧化物24期间经历平衡，反式环氧化物24转化成叔醇7。
The enantioselective synthesis of the bis-spiroacetal fragment of the shellfish toxins, spirolides B 1 and D 2, is reported. The carbon framework was constructed via a Barbier reaction of dihydropyran 10 with aldehyde 11, followed by two oxidative radical cyclizations to construct the bis-spiroacetal ring system. A silyl-modified Prins cyclization and enantioselective crotylation successfully installed the stereocenters in the cyclization precursor 21. The initial unsaturated bis-spiroacetals 9a - d underwent equilibration during epoxidation to trans-epoxide 24 that was converted to tertiary alcohol 7.