Total Synthesis of Aurantoside G, an<i>N</i>-β-Glycosylated 3-Oligoenoyltetramic Acid from<i>Theonella swinhoei</i>
作者:Markus Petermichl、Sebastian Loscher、Rainer Schobert
DOI:10.1002/anie.201604912
日期:2016.8.16
The first synthesis of a natural N‐glycosylated 3‐acyltetramic acid is reported. Aurantoside G (1 g), a deep‐red metabolite of the marine sponge Theonella swinhoei, is highly delicate in the pure state. It features a chlorinated dodecapentaenoyl side chain at an l‐asparagine‐derived tetramic acid, the ring nitrogen atom of which is linked to a β‐configured d‐xylose. The side chain was built through
报道了天然的N-糖基化的3-酰基四氢呋喃酸的首次合成。Aurantoside G(1 g)是海洋海绵Theonella swinhoei的深红色代谢产物,在纯净状态下非常细腻。它在l-天冬酰胺衍生的四酸上具有氯化的十二碳五烯酰基侧链,其环氮原子与β-构型的d相连。木糖。侧链是通过连续的Wittig和HWE反应建立的,用于N-酰化已通过Fukuyama-Mitsunobu反应N-木糖基化的天冬酰胺的氨基。此N-酰化步骤可固定木糖的β-构型,这对于抗真菌活性至关重要,但前提是糖带有庞大的,富含电子的保护基团(如PMB)。在最后一步中,通过完全未保护的前体的基本Lacey-Dieckmann缩合将杂环定量关闭。