Radicals masquerading as electrophiles

This work was undertaken to gain insights into mechanistic pathways in radical addition reactions. The multicomponent orbital interactions observed in this study revealed that the radical centre may not be the only or the most reacting centre in the free radical moiety. Contrary to widespread belief, radicals may be subjected to the same driving forces that operate during nucleophile-electrophile reactions. It appears that the charge transfer interaction between the radical and substrate will depend on the electrophilicity of the radical and charges operating during the reaction phase. In the reactions of radicals with strong electrophilic character, where charge separation exists in the transition state, coulombic interactions may dominate. In this instance neglect of charges can lead to misleading results. The orbital interactions observed in this study appear to have a profound effect on the geometry of the reacting systems. Two reacting moieties tend to orient themselves in such a way so as to maximize the energy gained through all possible orbital interactions. This is the principal factor in site specific reactions between electrophiles and nucleophiles.