Didymeline is an alkaloid with an azaspiro tricyclic skeleton with various functionalities. Despite the fact that its unique architecture is synthetically attractive, its total synthesis has never been achieved before. Herein, we present synthetic studies on the core structure of Didymeline. Accordingly, a spiro ring system was constructed through dearomatization of a phenol derivative with α-diazoamide unit. Based on the resulting 2-azaspiro[4,5]decane variant, a tricyclic molecule was synthesized via base-promoted intramolecular ring closure. For an asymmetric synthesis, an enantioselective dearomatization was also examined under silver catalysis, which led to the formation of an all-carbon substituted quaternary stereogenic center.

中文翻译：

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具有重氮官能团的苯酚的螺环合成二咪啉的研究

Didymeline是一种生物碱，具有azaspiro三环骨架，具有各种功能。尽管其独特的体系结构在合成上具有吸引力，但它的全面合成以前从未实现过。在这里，我们提出了对双嘧啶核心结构的综合研究。因此，通过使具有α-重氮酰胺单元的苯酚衍生物脱芳香化来构建螺环系统。基于所得的2-氮杂螺[4,5]癸烷变体，通过碱基促进的分子内闭环合成了三环分子。对于不对称合成，在银催化下还检查了对映选择性脱芳香化作用，这导致形成了全碳取代的季立体中心。