A theoretical study on the mechanism of the Baeyer-Villiger type oxidation of 7-phosphanorbornene 7-oxides

DFT computations have been performed on selected stationary points of the reaction path (reactants, intermediates, and products) of the Baeyer-Villiger type oxidation of 7-phosphanorbomene 7-oxide derivatives. Our computations justified the relevance of a Criegee-type intermediate forming in the first step, analogously to the Baeyer-Villiger oxidation of ketones. The energy profile indicated a high-energy barrier from the side of the products, supporting the kinetic character of the mechanism. The computations revealed that the mechanism does not include a previously assumed Berry-pseudorotation step in the Criegee-type intermediate. On the basis of the present results, we suggest that the regioselectivity of the Baeyer-Villiger type oxidation of the 7-phosphanorbornene 7-oxide derivatives may be determined by steric interactions between the leaving meta-chlorobenzoate group and substituents on the 7-phosphanorbomene skeleton in the Criegee-type intermediate. (c) 2007 Wiley Periodicals, Inc.