For the compounds 07, 12 and 13, experimentally protonated only at the C4 carbon atom in HSO3F (with/without SbF5) or CF3SO3H, the MOLPROJ software returned sufficiently high (higher than 0.4) Γ coefficient values only for the HOMO, mainly located at the C4 carbon atom (Figure ). In these compounds, the HOMO is the FERMO of the reaction.