Ni-Catalyzed Dual C–H Annulation of Benzimidazoles with Alkynes for Synthesis of π-Extended Heteroarenes

Abstract

Transition metal catalyzed dual C–H activation and annulation with alkynes was an attractive protocol to construct polycyclic π-extended structures. However, most of them were dominated by noble metal catalysts. Disclosed herein was the study of base-metal Ni-catalysis for dual C–H annulation of N-aromatic imidazole, which produced a range of desired polycyclic aza-quinolines in 48–95% yields. The use of bifunctional phosphine oxide ligand proved to be critical for success.

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