SEMIQUANTITATIVE FMO ANALYSIS OF SUBSTITUENT EFFECT ON THE REACTION OF PERMANGANATE ION WITH UNSYMMETRICAL ALKENES

The substituent effects on the reactions of permanganate ion with unsy mmetrical alkenes are analyzed on the assumption of a concerted (3 + 2 ) cycloaddition model by using an equation obtained by approximation b ased on the FMO theory in which development and localization of the fr ontier molecular orbitals at the reaction sites with progress of the r eaction are considered. The Hammett plots are successfully reproduced with the newly obtained rate data for the reactions of trans-chalcone and its derivatives and the data for methyl cinnamates, cinnamate ions , and alkyl vinyl ethers taken from the literature using FMO energies and orbital coefficients calculated by the PM3 method. It was indicate d that a factor introduced to the basic equation in order to estimate the extent of localization of the molecular orbitals at the transition state is closely related to the position of the transition state alon g the reaction path.