Cover Picture: An Efficient Mixed-Ligand Pd Catalytic System to Promote CN Coupling for the Synthesis of N-Arylaminotriazole Nucleosides (Chem. Eur. J. 8/2012)

A mixed-ligand system of Pd/Synphos/Xantphos promotes effective CN coupling in the synthesis of various N-arylaminotriazole and N-arylaminopurine nucleoside analogues. This catalytic system is strikingly powerful and efficient, allowing for unparalleled substrate scope and high product yields as well as promotion of CCl bond activation for CN coupling. ³¹P NMR investigations provided useful evidence favoring a mechanism in which the catalytic reactions are mediated by ligand exchange during both Pd catalyst formation and oxidative insertion. For more details see the Communication by L. Peng et al. on page 2221 ff.