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

• Published in: Journal of physical organic chemistry 2018-11, Vol.31 (11), p.n/a
• Main Authors: Cinar, M. Emin, Lal, Mukul, Deiseroth, Hans‐Jörg, Schlirf, Jens, Schmittel, Michael
• Format: Article
• Language: English
• Subjects: Cations; cyclic voltammetry (CV); Density functional theory; density functional theory (DFT); distonic radical cation, laser flash photolysis (LFP); enol radical cation; Flash photolysis; Oxidation
• ISSN: 0894-3230; 1099-1395
• DOI: 10.1002/poc.3865

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 ion 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. 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.