Mechanistic Aspects of beta-Bond Cleavage Reactions of Aromatic Radical Cations

The mesolytic cleavage of a alpha-C-X bond is one of the most important reactions of alkylaromatic radical cations. In this Account, our group’s results concerning some fundamental aspects of this process (cleavage mode, structural and stereoelectronic effects, competitive breaking of different alpha-bonds, nucleophilic assistance, possible stereochemistry, carbon vs oxygen acidity in arylalkanol radical cations) are presented and critically discussed for reactions where X = H, CR3, SR, and SiR3. Several examples illustrating how this information was exploited as a tool to detect electron-transfer mechanisms in chemical and enzymatic oxidations are also reported