The Heck coupling of haloarenes with various alkenes was successfully performed in the presence of mol% PdCl2 and mol% biphenyl-4-yl-[4(5)-(biphenyl-4-yl)-1H -imidazol-2-yl]ketone 2f as a ligand with Na2CO3 as optimal base, in a 1:1 mixture of H2O/DMF as the reaction solvent at 80◦C for 8 h. Imidazole 2f was found to be an inexpensive, air-stable, easily available, and efficient ligand in the palladium-catalyzed Heck reactions of aryl iodides (76%–94%), bromides (52%–79%), and chlorides (40%–70%). |
