Mechanistic Studies in the Radical Induced DNA Strand Cleavage—Formation and Reactivity of the Radical Cation Intermediate

In order to understand the heterolytic cleavage of 4′-DNA radical 1 and the regioselective attack of nucleophiles at the intermediate DNA radical cation 3, the chemistry of model radical 8 was studied. It turned out that the heterolytic cleavage in water is favored over homolysis because of the effective solvation of the ions 9 and 10. The regioselectivity of the nucleophilic attack at radical cation 10 can be explained with the valence bond configuration mixing (VBCM) model.