Catalytic systems based on palladium-copper complexes of PPI dendrimers with nitrile terminal groups formed in situ using dendrimer, palladium and copper salts as a catalytic precursor demonstrate high activity in the Wacker-oxidation of terminal alkenes along with good selectivity in respect to methylketone. The study of complexes in solution proved that the selectivity of the formation of methylketone as well as reactivity of alkenes is influenced by the steric parameters of dendrimer aggregates in solutions. (C) 2008 Elsevier B.V. All rights reserved.