 Several of these ligands also seem to enhance the rate of reductive elimination relative to β-hydride elimination via the electron donating arene-palladium interaction.Even electron withdrawn amines and heterocyclic substrates can be coupled under these conditions, despite their tendency to deactivate the palladium catalyst.Ammonia remains one of the most challenging coupling partners for Buchwald–Hartwig amination reactions, a problem attributed to its tight binding with palladium complexes.