New cyclization mechanism for squalene: a ring-expansion step for the five-membered C-ring intermediate in hopene biosynthesis.
New cyclization mechanism for squalene: a ring-expansion step for the five-membered C-ring intermediate in hopene biosynthesis.
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角鲨烯的新环化机制：希望烯生物合成中五元C环中间体的扩环步骤。
DOI：
10.1271/bbb.63.2038
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
S. Ohashi
中科院分区：
文献类型：
--
作者：
T. Hoshino;M. Kouda;T. Abe;S. Ohashi
从突变的F601A酶的温育混合物中分离出具有6/6/5-融合的三环骨架和6/6/6/5-融合的四环骨架的三种三萜，这些产物符合马尔可夫尼科夫闭包。通过使用具有高度亲核羟基的角鲨烯类似物成功捕获三环阳离子中间体，使我们提出5元C环的扩环过程参与了角鲨烯环化级联。
Three triterpenes having the 6/6/5-fused tri- and 6/6/6/5-fused tetracyclic skeletons were isolated from an incubation mixture of the mutated F601A enzyme, these products being in accordance with a Markovnikov closure. Successful trapping of the tricyclic cationic intermediate by using the squalene analog having a highly nucleophilic hydroxyl group leads us to propose that the ring expansion process of the 5-membered C-ring is involved in the squalene cyclization cascade.