Approaches to the Synthesis of (±)-Strychnine via the Cobalt-Mediated [2 + 2 + 2] Cycloaddition: Rapid Assembly of a Classic Framework
作者:Michael J. Eichberg、Rosa L. Dorta、Douglas B. Grotjahn、Kai Lamottke、Martin Schmidt、K. Peter C. Vollhardt
DOI:10.1021/ja016333t
日期:2001.9.1
Five synthetic approaches to racemic strychnine (1), with the cobalt-mediated [2 + 2 + 2] cycloaddition of alkynes to indoles as the key step, are described. These include the generation and attempted cyclization of macrocycle 8 and the synthesis of dihydrocarbazoles 15, 22, and 26 and their elaboration to pentacyclic structures via a conjugate addition, dipolar cycloaddition, and propellane-to-spirofused
描述了外消旋士的宁 (1) 的五种合成方法,其中钴介导的炔烃与吲哚的 [2 + 2 + 2] 环加成反应是关键步骤。这些包括大环 8 的生成和尝试环化以及二氢咔唑 15、22 和 26 的合成,以及它们分别通过共轭加成、偶极环加成和推进烷到螺旋融合骨架重排形成五环结构。最后讨论了1的成功全合成。烯炔基吲哚 40 与乙炔的环化和胺 49 的正式分子内 1,8-共轭加成形成五环 50,突出了短而高度收敛的路线(最长线性序列中的 14 个步骤)的发展。