Evidence for parallel destructive, and competitive epoxidation and dismutation pathways in metalloporphyrin-catalysed alkene oxidation by hydrogen peroxide

A kinetic and product yield analysis of the F20TPPFeCl-catalysed H2O2 epoxidation of cyclooctene has shown that decomposition is not via either the oxoperferryl intermediate (F20TPP+.)Fe-IV=O or the oxoferryl intermediate F20TPPFeIV=O, but appears to involve direct oxidation of the porphyrin in parallel with the catalytic epoxidation cycle. This is in contrast to the reaction of F20TPPFeCl in the absence of alkene where decomposition is via F20TPPFeIV=O. (C) 2001 Elsevier Science Ltd. All rights reserved.