Copper-catalyzed N-arylation of imidazoles and benzimidazoles.
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.
Altman
Ryan A
RA
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Koval
Erica D
ED
Buchwald
Stephen L
SL
D001562:Benzimidazoles / Q000737:chemistry*; D001965:Bromides / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D003300:Copper / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D007454:Iodides / Q000737:chemistry; D008024:Ligands; D008956:Models, Chemical; D011092:Polyethylene Glycols / Q000737:chemistry
D001562:Benzimidazoles; D001965:Bromides; D007093:Imidazoles; D007454:Iodides; D008024:Ligands; D011092:Polyethylene Glycols; D003300:Copper; C032655:2-methylimidazole