that rehybridization induced by bond angle compression enhances the electrophilicity of cyclopropane C-C bonds by lowering the energy of the s* orbitals. On the other hand, Houk invoked an 'orbital interactions through-bonds' (OITB) argument in which transition state (TS) aromaticity stabilizes ring-opening reactions of cyclopropane, whereas equivalent reactions of cyclobutane are destabilized due to an antiaromatic TS. While these explanations qualitatively explain the reactivity differences in these systems, a comprehensive predictive model connecting bonding to reactivity has yet to emerge.