Detection and follow‐up reactions of distonic β,β‐dimesityl enol radical cations containing nitrogen heterocyclic bases

Abstract

β,β-Dimesityl enols E2-E4 containing various nitrogen heterocyclic bases in the α-position were investigated by laser flash photolytic oxidation and density functional theory in order to identify distonic enol radical cations in solution and characterize their immediate follow-up reactions. Enol E1 with a tert-butyl group in the α-position served as a reference. Experimental and computational efforts reveal that one-electron oxidation of enol E1 furnishes the enol radical cation, whereas oxidation of E2-E4 provides distonic radical cations in solution. While the distonic radical cations of E2-E3 undergo intermolecular acid-base reactions, the distonic radical cation of E4 experiences an intramolecular hydrogen abstraction followed by subsequent ring closure and ring-opening steps. As a final product on the laser flash photolysis time scale, the rearranged radical cation E4d-R is generated that is characterized by a dimesitylmethyl radical subunit. KEYWORDS cyclic voltammetry (CV), density functional theory (DFT), distonic radical cation, laser flash photolysis (LFP), enol radical cation

Generation and Radical–Radical Cross-Coupling of Alkenyloxy Radical

“…However, alkene-attached oxygen radicals (alkenyloxy or vinyloxy radicals) , have been rarely used, possibly because of oxygen radicals’ high oxidative power and electrophilicity . As a result, the studies of alkenyloxy were typically limited to spectroscopic and mechanistic ones . The direct radical–radical cross-coupling O radicals are also challenging.…”