Olefin Epoxidation by Methyltrioxorhenium: A Density Functional Study on Energetics and Mechanisms

A spiro attack on a peroxo group is calculated to be the preferred reaction pathway for olefin epoxidation with the catalytic system CH₃ReO₃/H₂O₂ (see picture). This finding is supported by density functional calculations on more than ten transition states for the most probable mechanisms. Hydration has significant effects on various reaction species: it stabilizes the intermediates and destabilizes, with one exception, the transition states.