American Chemical Society
jo3c02229_si_001.pdf (8.68 MB)

Ru(II)-Catalyzed [4 + 2]-Annulation of 2‑Alkenyl/Arylimidazoles with N-Substituted Maleimides and 1,4-Naphthoquinones: Access to Imidazo-Fused Polyheterocycles

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journal contribution
posted on 2024-02-02, 14:10 authored by Neha Meena, Dhananjay S. Nipate, Prakash N. Swami, Krishnan Rangan, Anil Kumar
Synthesis of imidazo-fused polyheterocyclic molecular frameworks, viz. imidazo[1,2-a]pyrrolo[3,4-e]pyridines, imidazo[2,1-a]pyrrolo[3,4-c]isoquinolines, and benzo[g]imidazo[1,2-a]quinoline-6,11-diones, has been achieved by the ruthenium(II)-catalyzed [4 + 2] C–H/N–H annulation of 2-alkenyl/2-arylimidazoles with N-substituted maleimides and 1,4-naphthoquinones. The developed protocol is operationally simple, exhibits broad substrate scope with excellent functional group tolerance, and provides the desired products in moderate to good yields. The mechanistic studies suggest that the reaction involves the formation of a C–C bond through Ru-catalyzed C(sp2)–H bond activation followed by intramolecular cyclization.