Synthesis of Carbazole Alkaloids by Ring‐Closing Metathesis and Ring Rearrangement–Aromatization
作者:Kalyan Dhara、Tirtha Mandal、Joydeb Das、Jyotirmayee Dash
DOI:10.1002/anie.201508746
日期:2015.12.21
Aprocess for the assembly of carbazole alkaloids has been developed on the basis of ring‐closing metathesis (RCM) and ringrearrangement–aromatization (RRA) as the key steps. This method is based on allyl Grignard addition to isatin derivatives to provide smooth access to 2,2‐diallyl 3‐oxindole derivatives through a 1,2‐allyl shift. The diallyl derivatives were used as RCM precursors to afford a novel
咔唑生物碱的组装工艺是在关键步骤闭环复分解(RCM)和环重排芳构化(RRA)的基础上开发的。该方法基于烯丙基格利雅(Irally Grignard)除以伊斯丁衍生物之外,从而通过1,2-烯丙基转移可平稳地获得2,2-二烯丙基3-氧吲哚衍生物。二烯丙基衍生物用作RCM前体,以提供一类新的螺环戊烯-3-氧吲哚衍生物,该衍生物经过新颖的RRA反应以提供咔唑衍生物。通过在正交串联催化过程中结合RCM和RRA步骤,缩短了咔唑的合成顺序。咔唑生物碱的直接合成进一步证明了这种方法的实用性,其中包括阿莫konal衍生物,girinimbilol,heptaphylline,