The aryl radical adduct (I1) can then proceed through either a hydrogen atom transfer (HAT) or deprotonation to yield the experimentally observed product, 4-(1methylcyclohexyl)phthalonitrile (Fig. ). In the HAT pathway, hydrogen abstraction by the DABCO radical cation leads to the final reaction product (P) in an overall exergonic process by -53.6 kcal mol -1 , followed by proton exchange between the phthalimide anion and DABCO(H), regenerating the DABCO catalyst (-61.4 kcal mol -1 ). However, this pathway is hindered by a high energy barrier (+29.5 kcal mol -1 ), suggesting a slow reaction at 25 °C.