terpinylamine derivative (±)-4 was cyclized in 51% yield to the 19-substituted hobartine derivative (±)-20 upon exposure to anhydrous HCOOH. This pivotal intermediate was further elaborated into the indole alkaloids (±)-serratenone ((±)-22) and (±)-sorelline ((±)-29). In the course of these investigations, a novel rearrangement was uncovered; a Lewis acid-catalyzed 1,3-migration of an arylsulfonyl group from
通过将
吲哚保护的2-(
吲哚-3-基)
乙醛(5)与
萜品胺衍
生物(±)-4缩合而获得的
亚胺在暴露时以51%的产率环化为19-取代的霍巴汀衍
生物(±)-20到无
水HCOOH。该关键中间体被进一步精制为
吲哚生物碱(±)-serratenone((±)-22)和(±)-solineline((±)-29)。在这些调查过程中,发现了一种新颖的重排;一个
路易斯酸催化从
吲哚N原子到苯环的芳基磺酰基的1,3-迁移。合成(±)-aristotelin-19-one((±)-34)的光谱性质与马兜铃内酯截然不同,马兜铃内酯是最近提出的一种代谢产物,导致对后者的结构进行了修改。