Controllable Synthesis of Benzo[b]furo[2,3-d]azepines or Furo[3,2-b]indoles via Intermolecular Oxidative Annulation of 2-(Furan-2-yl)anilines and Propargyl Carbonates versus Intramolecular C–H Amination Reactions

Abstract

Two novel Pd-catalyzed protocols for the controllable synthesis of benzo[b]furo[2,3-d]azepines and furo[3,2-b]indoles have been developed by intermolecular oxidative annulation of 2-(furan-2-yl)anilines and propargyl carbonates versus intramolecular C–H amination reactions. These two protocols feature great scalability, functional group tolerance, and relatively mild reaction conditions. Notably, the robust methodologies could also provide valuable opportunities for assembling azepine-fused benzothiophene, indole-fused benzothiophene, and indole-fused benzimidazole, which may have potential applications in the synthesis of related pharmaceuticals or polymeric materials.