Construction of Divergent Fused Heterocycles via an Acid-Promoted Intramolecular <i>ipso</i>-Friedel–Crafts Alkylation of Phenol Derivatives
作者:Takuya Yokosaka、Naoki Shiga、Tetsuhiro Nemoto、Yasumasa Hamada
DOI:10.1021/jo500308y
日期:2014.5.2
Two different cascade cyclization processes were developed using aryl group-substituted propargyl alcohol derivatives with a p-hydroxybenzylamine unit as common substrates. Using TFA as an acid promoter, an intramolecular ipso-Friedel–Crafts alkylation of phenol derivatives, formation of an iminium cation via a rearomatization-promoted C–C bond cleavage, an aza-Prins reaction, and a 6-membered ring
使用具有对羟基苄胺单元的芳基取代的炔丙醇衍生物作为常见底物,开发了两种不同的级联环化方法。使用TFA作为酸启动子,分子内本位经由rearomatization促进的C-C键断裂,氮杂普林斯反应酚衍生物的-Friedel-Crafts烷基化,形成亚铵阳离子的,和一个6元环的形成顺序进行,以45–99%的产率生产各种稠合三环二氢喹啉衍生物。此外,使用相同系列的底物检查了一锅法连续乙酸银催化的加氢胺化/醚化-酸促进的骨架重排,从而以66-89%的产率提供了稠合的三环吲哚/苯并呋喃衍生物。