OH + Cyclopropane, according to Gaussian94
This reaction has interested us for years. This image shows the reactants at the transition state. The visualization was produced with an application we are working on, using pixar's renderman. In addition to the simple geometries, it shows molecular orbitals, animates vibrations, and animates reaction coordinates. If you are interested an have NeXTStep/Openstep on your computer, send email and we can get you a copy.