Asymmetric Total Synthesis of Dendrobatid Alkaloids: Preparation of Indolizidine 251F and Its 3-Desmethyl Analogue Using an Intramolecular Schmidt Reaction Strategy
作者:Aaron Wrobleski、Kiran Sahasrabudhe、Jeffrey Aubé
DOI:10.1021/ja0320018
日期:2004.5.1
allowed for a key intramolecular Schmidt reaction to deliver the tricyclic core of the target molecule. In a second-generation approach, a tandem ring-opening/ring-closing metathesis reaction effected an overall [2.2.1] --> [3.3.0] skeletal rearrangement to deliver diquinane 4a. In similar fashion, 4a was manipulated to an appropriate keto azide, and an intramolecular Schmidt reaction generated the core
生物碱 251F (1)(一种从 dendrobatid 蛙种 Minyobates bombetes 的皮肤提取物中检测到的天然产物)及其外消旋 3-去甲基衍生物 (2) 的全合成已被报道。Diels-Alder 反应引发了两种合成并建立了四个连续的立体中心。对 2 的合成很重要的是将 [2.2.1] 双环酸转化为 [3.3.0] 双环辛烷二喹烷 4b 的第一代臭氧分解/烯烃化/醛醇策略。对合适的酮基叠氮化物的进一步加工允许关键的分子内施密特反应传递目标分子的三环核心。在第二代方法中,串联开环/闭环复分解反应实现了整体 [2.2.1] --> [3.3.0] 骨架重排以提供二喹烷 4a。以类似的方式,