A kinetic study of the Baeyer-Villiger epoxidation of methyleyclohexanone with 35% hydrogen peroxide catalyzed by [(triphos-PO)Pt(CH2Cl2)](2+) is reported based on initial rate analysis. The mechanism suggested involves coordination of the ketone to the coordinatively unsaturated complex, followed by nucleophilic attack of free hydrogen peroxide. The importance of the Lewis acid character of the metal center is crucial in promoting the activation of the substrate as well as its ability to facilitate the leaving of the otherwise bad OH- leaving group from the intermediate quasi-peroxymetallacycle. (c) 2004 Elsevier B.V. All rights reserved.