title: Oxidation of alcohols and activated alkanes with Lewis acid-activated TEMPO.
abstract: The reactivity of MCl3(η(1)-TEMPO) (M = Fe, 1; Al, 2; TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) with a variety of alcohols, including 3,4-dimethoxybenzyl alcohol, 1-phenyl-2-phenoxyethanol, and 1,2-diphenyl-2-methoxyethanol, was investigated using NMR spectroscopy and mass spectrometry. Complex 1 was effective in cleanly converting these substrates to the corresponding aldehyde or ketone. Complex 2 was also able to oxidize these substrates; however, in a few instances the products of overoxidation were also observed. Oxidation of activated alkanes, such as xanthene, by 1 or 2 suggests that the reactions proceed via an initial 1-electron concerted proton-electron transfer (CPET) event. Finally, reaction of TEMPO with FeBr3 in Et2O results in the formation of a mixture of FeBr3(η(1)-TEMPOH) (23) and [FeBr2(η(1)-TEMPOH)]2(μ-O) (24), via oxidation of the solvent, Et2O.
authors.affiliation: Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States.
authors.forename: Thuy-Ai D
authors.initials: TA
authors.lastname: Nguyen
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Wright
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Page
authors.forename: Guang
authors.initials: G
authors.lastname: Wu
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Hayton