A practical Pd(PPh3)4/DBU catalytic system for the synthesis
of pharmaceutically relevant aminopyridine nitrile intermediates,
as well as a variety of other aryl nitriles using non-toxic
K4[Fe(CN)6] has been developed. The key features of our new
protocol for cyanation lie in that the reaction can be carried out
with readily available Pd(PPh3)4 under mild and green conditions,
even without the assistance of other ligands.