Copper-catalyzed N-arylation of imidazoles can be accomplished using (CuOTf)2·benzene as a copper source and Cs2CO3 as a base in xylenes at 110–125 °C. Addition of 1,10-phenanthroline (phen) and trans,trans-dibenzylideneacetone (dba) was crucial to the success of the process. The products, N-arylimidazoles, were isolated in high yields.
“An efficient copper-catalyzed coupling of aryl halides with imidazoles”, Tet. Lett., 1999, 40(14), 2657-2660.