Fine-Tuning the Oxidative Ability of Persistent Radicals: Electrochemical and Computational Studies of Substituted 2‑Pyridylhydroxylamines

• Published in: Journal of organic chemistry Vol. 78; no. 12; pp. 6344 - 6349
• Main Authors: Bogart, Justin A, Lee, Heui Beom, Boreen, Michael A, Jun, Minsik, Schelter, Eric J
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 21.06.2013; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Electrochemical Techniques; Free Radicals - chemistry; Halogens - chemistry; Hydroxylamines - chemical synthesis; Magnesium - chemistry; Magnetic Resonance Spectroscopy; Nitroso Compounds - chemistry; Oxidation-Reduction; Physical Sciences; Pyridines - chemistry; Quantum Theory; Science & Technology; ARYLMAGNESIUM; CHELATE LIGAND; NITROXIDE RADICALS; ELECTRON-TRANSFER KINETICS; CHEMISTRY; NICKEL(II) COMPLEXES; REAGENTS BEARING; REDUCTION POTENTIALS; REDOX MEDIATORS; EXCHANGE
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo400944r

N-tert-Butyl-N-2-pyridylhydroxylamines were synthesized from 2-halopyridines and 2-methyl-2-nitrosopropane using magnesium–halogen exchange. The use of Turbo Grignard generated the metallo-2-pyridyl intermediate more reliably than alkyllithium reagents. The hydroxylamines were characterized using NMR, electrochemistry, and density functional theory. Substitution of the pyridyl ring in the 3-, 4-, and 5-positions was used to vary the potential of the nitroxyl/oxoammonium redox couple by 0.95 V. DFT computations of the electrochemical properties agree with experiment and provide a toolset for the predictive design of pyridyl nitroxides.