Bis(cyclotryptamine) alkaloids have been popular topics of study for many decades. Five possible scaffolds for bis(cyclotryptamine) alkaloids were originally postulated in the 1950s, but only four of these scaffolds have been observed in natural products to date. We describe synthetic access to the elusive fifth scaffold, the piperidinoindoline, through syntheses of compounds now termed "dihydropsychotriadine" and "psychotriadine." The latter of these compounds was subsequently identified in extracts of the flower Psychotria colorata. Our synthetic route features a stereospecific solid-state photodecarbonylation reaction to introduce the key vicinal quaternary stereocenters.

中文翻译：

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带有难以捉摸的哌啶二氢吲哚支架的双（环色胺）生物碱的发现和全合成

双（环色胺）生物碱几十年来一直是热门的研究课题。双（环色胺）生物碱的五种可能的支架最初是在 1950 年代提出的，但迄今为止，在天然产物中仅观察到其中四种支架。我们通过合成现在称为“二氢精神三嗪”和“精神三嗪”的化合物，描述了对难以捉摸的第五个支架——哌啶二氢吲哚的合成途径。随后在花Psychotria colorata 的提取物中鉴定出这些化合物中的后者。我们的合成路线采用立体定向固态光脱羰反应来引入关键的邻位四元立体中心。