N-(aminobenzyliden)phthalimides as a New Redox Mediator Family for the Selective Indirect Reduction of Benzyl or Allyl Halides

The chemical stability of the electrogenerated radical anion of N-(aminobenzyl) phthalimide 1 in aprotic organic media at room temperature is reported in this work. The redox couples 1/1(center dot) and its imine precursor 2/2(center dot) can carry out reductive redox catalysis of benzyl or allyl halides indirectly. This reaction gives easy access to reactive alkyl radicals, which in the presence of diethyl fumarate yields 2-benzylsuccinate diethyl ester in moderate yields; this reaction is unattainable by direct electrochemical reduction. Spin density calculations at the DFT level of theory showed that the spin density of 1(center dot-) and 2(center dot-) is located on the phtalimide ring, and a dimeric association was evidenced (E-int= 23.47 kcal/mol and E-int= 80.42 kcal/mol respectively), via pi-pi stacking interactions. The redox mediators presented here showed good functional group selectivity, redox potential tunability and easy preparation from readily available commercial materials with excellent yields.