Copper-Catalyzed N-Arylation of Imidazoles and Benzimidazoles
Ryan A. Altman,Erica D. Koval, andStephen L. Buchwald*
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
sbuchwal@mit.edu
Received April 17, 2007
Abstract:
4,7-Dimethoxy-1,10-phenanthroline (L1c) was found to be an efficient ligand for the copper-catalyzed
N-arylation of imidazoles and benzimidazoles with both aryl iodides and bromides under mild conditions.
Further optimization of the system has revealed that the addition of poly(ethylene glycol) accelerates
this reaction. A variety of hindered and functionalized imidazoles, benzimidazoles, and aryl halides were
transformed in good to excellent yields. Heteroaryl halides were also coupled in moderate to good yields.
We also present the results obtained from a series of coupling reactions, which directly compare the use
of L1c with other recently reported ligands.
