Domino Cyclization Reaction of o-Diisocyanoarenes for the Synthesis of Imidazo[1,2- a]pyridinobenzimidazole Backbones

Org Lett. 2023 Aug 4;25(30):5682-5686. doi: 10.1021/acs.orglett.3c02137. Epub 2023 Jul 24.

Abstract

An efficient procedure to access a variety of connected imidazo[1,2-a]pyridine and benzimidazole skeletons through the C-N bond was described as a new type of Buchwald-Hartwig reaction. Furthermore, the bis(imidazo[1,2-a]pyridin-3-yl)aryl-1,2-diamine scaffolds were obtained by changing the equivalent ratio of the starting materials. Some advantages of the protocol are the formation of four new bonds (C═C, C-N), a transition-metal-free reaction, a broad substrate scope, high yields, and mild reaction conditions. The reaction mechanism was confirmed on the basis of DFT calculations.