(Chemical equation presented). Substituents on both the nucleoside arylsulfonate as well as the aryl amine component have a significant impact on their coupling to form 2,6-diaminopurine-2′-deoxyribonucleosides (see scheme). A systematic study of ligands for the Pd catalysts in amination and C-C cross-coupling reactions gives insight into the structural elements that lead to effective catalysis.