Aminopyridines are key building blocks for the synthesis of bioactive N-heterocyclic compounds such as azaindoles and imidazopyridines. However, the functionalization of aminopyridines is challenging, due to their electronic properties and coordination with metals. Herein we describe a reactivity study of aminopyridines under palladium-catalyzed reaction conditions. Several aminopyridines underwent a one-pot Pd-catalyzed C–N cross coupling reaction/C–H functionalization sequence affording azaindoles. The role of additives, ligands, and bases was investigated. This work consists of a platform for future studies on aminopyridines involving metal-catalyzed reactions and represents the first report on the direct conversion of non-halogenated aminopyridines into azaindoles via Pd-catalyzed C–H functionalization reactions.
- C–H functionalization
- Pd catalysis