Bathocuproine-coordinated palladium(0) complexes, (bc)Pd-0(alkene) (bc = 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) undergo facile oxygenation in the presence of molecular oxygen to produce the eta(2)-peroxopalladium(II) complex, (bc)Pd-II(O-2). The same Pd(0)-alkene complexes undergo self- and cross-exchange reactions with exogenous alkenes. Mechanistic studies highlight distinct similarities between the oxygenation and alkene-substitution reactions: kinetic studies reveal that both reactions proceed via an associative addition/substitution pathway, and electronic effects reveal that the transition states for both reactions feature removal of electron density from (i.e., oxidation of) the palladium(0) center. These results have important implications for the reactivity of dioxygen and benzoquinone (an electron-deficient alkene) as stoichiometric oxidants in palladium-catalyzed oxidation reactions. (c) 2006 Elsevier B.V. All rights reserved.