Formal [5 + 2] cycloaddition of ortho-indolizinyl anilines with cyclopentenediones: access to planar indolizine-fused azepines

Abstract

An efficient and straightforward approach to planar indolizine-fused azepines via Brønsted acid catalyzed [5+2] cycloaddition of ortho-indolizinyl anilines with cyclopentendiones has been established. This reaction involves a Friedel-Crafts addition/oxidation/Schiff-base condensation...