Facile and Selective Synthesis of Imidazobenzimidazoles via a Copper‐Catalysed Domino Addition/Cycloisomerisation/ Coupling Process

Abstract

Ac opper(I)-catalysed domino transformation for the synthesis of tricyclic imidazobenzimidazole derivatives was developed. Using readily available primary propargylic aminesa nd o-haloarylcarbodiimides as the starting materials,avariety of substituted benzo [d]imidazo[1,2-a]imidazoles was efficientlyand selectively assembled. Furtherinvestigations indicated that the domino reaction was likely the result of an ovel addition/cycloisomerisation/coupling process.

Recent Advances in Domino Synthesis of Fused Polycyclic N‐Heterocycles Based on Intramolecular Alkyne Hydroamination under Copper Catalysis

“…[ 42 ] During the recent decade, cross‐coupling (or other sp 2 C—Y bond forming reactions of sp 2 C—X bonds with nucleophiles) and copper‐catalyzed intramolecular alkyne hydroamination have also been elaborately combined in several domino transformations for the convenient and efficient assembly of fused polycyclic N ‐heterocycles. [ 43‐44,46,48,50,52,54,56 ]…”

“…[ 47 ] In 2016, a regioselective copper‐catalyzed domino synthesis of imidazobenzimidazoles was explored by Lv and coworkers (Scheme 23). [ 48 ] Using various o ‐haloaryl carbodiimides and easily accessible primary propargylic amines as the starting materials, a broad range of benzo[ d ]imidazo[1,2‐ a ]imidazoles bearing various substituents were generated efficiently and selectively. It was worth noting that excellent regioselectivity was observed and the desired tricyclic benzo[ d ]imidazo[1,2‐ a ]imidazoles were exclusively obtained without the isolation of their regioisomers.…”

An overview on the copper‐promoted synthesis of five‐membered heterocyclic systems

“…Jacob and co-workers reported the synthesis of 1,3,5-triaryl-4-(organylselanyl)-1H-pyrazoles (95) via copper-catalyzed cyclocondensation and a direct C-H bond selenation reaction from arylhydrazines (92), chalcones (93) and diorganyl diselenides (94). Initially, the reaction between phenylhydrazine, (E)-chalcone and diphenyl diselenide was studied for the search of optimal conditions.…”

A One‐Pot Copper‐Catalyzed 3‐Fold C–N Bond Coupling Strategy to the Synthesis of Substituted Benzimidazoles

“…[11] Very recently, Lv and co-workers have described a domino strategy to make imidazo [1,2-a]benzimidazoles 18 from propargylic amines 16 and o-haloarylcarbodiimides 17 (d). [12] However, the challenge lies in the catalysis that a one-pot sequential couplings followed by C-H amination (vide supra) leading to directly accessing heterocyclic compounds is very elusive in the literature.…”