This article describes the full details of our total syntheses of gephyrotoxin and perhydrogephyrotoxin. Our central strategy toward the total synthesis is based on the use of an N-methoxy group as...
A novel synthetic route to (±)-perhydrogephyrotoxin
作者:Toshiro Ibuka、G.-Namg Chu、Fumio Yoneda
DOI:10.1039/c39840000597
日期:——
Total synthesis of (±)-perhydrogephyrotoxin (3) starting from 1,3-bis (trimethylsiloxy) buta-1,3-diene is presented; an efficient new decarboxylative reduction of γ-carbamoyloxy-α,β-enoate (14) by lithium dibutylcuprate is also presented.
A new stereoselective synthesis of (.+-.)-perhydrogephyrotoxin.
作者:TOSHIRO IBUKA、GIL NAMG CHU
DOI:10.1248/cpb.34.2380
日期:——
A stereoselective synthesis of (±)-perhydorgephyrotoxin (3) starting from 1, 3-bis(trimethyl-siloxy)-1, 3-butadiene and ethyl trans-2-octenoate is described. A crucial step is reductive decarboxylation of the γ-carbamoyloxy-α, β-enoate (6) with lithium dibutylcuprate to yield the β, γ-enoate (40).
numerous synthetic studies. Total syntheses have been reported by Kishi, Hart, Overman, as well as Sato and Chida, and a number of formal syntheses have been described. Smith and co-workers now report an elegant and concise synthesis of gephyrotoxin that relies on an intramolecular enamine/Michael cascade to access the tricyclic scaffold of the natural product. Comment: The synthesis commenced with L-pyroglutaminol
意义:Gephyrotoxin 是一种相对无毒的 dendrobatid 生物碱,具有不寻常的神经学特征。它的特性和复杂的结构使其成为众多合成研究的主题。Kishi、Hart、Overman 以及 Sato 和 Chida 已经报道了全合成,并且已经描述了许多正式的合成。Smith 及其同事现在报告了一种优雅简洁的 gephyrotoxin 合成方法,该合成方法依赖于分子内烯胺/迈克尔级联反应来获取天然产物的三环支架。评论:合成从 L-焦谷氨酰胺 (A) 开始,通过五个简单的步骤将其转化为关键中间体 F。通过用 TFA 处理实现 F 的脱保护,并在氯仿中加热至 40 °C 导致形成亚胺盐 H,其依次进行羟基定向还原以 79% 的产率得到 I。一些官能团相互转化然后导致 K。与炔烃 L 交叉偶联,然后去保护提供合成 gephyrotoxin。H
Stereoselective total synthesis of (.+-.)-perhydrogephyrotoxin. Synthetic applications of directed 2-azonia-[3,3]-sigmatropic rearrangements