Accessing Diverse N-Centered Peri Fused Cycles (NCPCs): Rh(III) Catalyzed Generation of Triazaacenaphthylenes through C-5(H) Activation of Imidazo[1,2-a]pyridine

Abstract

Ortho-and peri-fused triazaacenaphthylenes containing a central nitrogen atom are rare. In this work, a general strategy for the construction of 5,6,6 N-centered peri-fused cycles (NCPCs) has been described. Departing from traditional methodologies which rely on multiple sequential synthesis, this protocol employs directed C-H activation to functionalize the C-5 position of imidazo[1,2-a]pyridine (IMP) using N-methoxyamide as directing group, catalyzed by Rh(III), to form triazaacenaphthylenes via tandem C-C and C-N bond formation. The reaction mechanism has been established through control experiments and quantum chemical analysis. The procedure is scalable to gram level and allows for versatile postsynthetic modification.