The first palladium-catalyzed amidation of five-membered heterocyclic bromides with multiple heteroatoms was achieved using the Pd/1 catalyst system. N-Arylated imidazoles, pyrazoles, thiazoles, pyrroles, and thiophenes were synthesized in moderate to excellent yield. Experimental results and DFT calculations point to the need for an electron-rich and sterically demanding biaryl phosphine ligand to promote these difficult reactions.
“A bulky biaryl phosphine ligand allows for palladium-catalyzed amidation of five-membered heterocycles as electrophiles”, Angew. Chem. Int. Ed., 2012, 51, 4710-3.