2,2′-Biimidazole as an Efficient Ligand for Copper(I)-Catalyzed C‒N Coupling Reactions

Abstract

An efficient copper(I)-catalyzed system using 2,2′-biimidazole as the ligand was applied to N-arylation of a broad spectrum of nitrogen nucleophiles with aryl halides. The reactions were carried out in relatively mild conditions with good to excellent yields.

Keywords:

• N-Arylation
• 2,2′-biimidazole
• copper-catalyzed
• ligand

ACKNOWLEDGMENTS

We thank the National Natural Science Foundation of China (Nos. 30772652 and 90813026) and Major Projects the National Science and Technology “Creation of major new drugs” (No. 2009ZX09501-010).

Notes

^a Reaction conditions: iodobenzene (1.0 equiv), benzylamine (1.2 equiv), CuI (10 mol%), ligand (20 mol%), Cs₂CO₃ (2 equiv), under N₂ atmosphere at 100°C for 24 h.

^b Isolated yield.

^c DMF:H₂O (1:1) as solvent.

^a Reaction conditions: aryl halide (1.0 equiv), N-containing compound (1.5 equiv), CuI (10 mol%), A (20 mol%), and Cs₂CO₃ (2.0 equiv).

^b Isolated yield.

^c 20 equiv of amine was used to avoid the low yield due to its low boiling point.