 while significantly expanding the repertoire of possible C–N bond formation.Over the course of its development, several 'generations' of catalyst systems have been developed, with each system allowing greater scope in terms of coupling partners and milder conditions, allowing virtually any amine to be coupled with a wide variety of aryl coupling partners.Because of the ubiquity of aryl C-N bonds in pharmaceuticals and natural products, the reaction has gained wide use in synthetic organic chemistry, with application in many total syntheses and the industrial preparation of numerous pharmaceuticals.