A High Performance Oxidation Method for Secondary Alcohols by Inductive Activation of TEMPO in Combination with Pyridine-Bromine Complexes.

Abstract A new TEMPO-mediated catalytic oxidation method in combination with Py·HBr 3 (stoichiometric) is developed for oxidation of secondary alcohols to the corresponding ketones. The performance of this oxidizing system is better compared with that of TEMPO method combined with R 4 NBr 3 . Poly(4-vinylpyridine)·HBr 3 can be used in place of Py·HBr 3 . The electron-withdrawing substituent at the C-4 position of TEMPO increases the reactivity of TEMPO significantly in the oxidation of electron-deficient alcohols such as polyhaloalkylmethanols. Inductive effect of the substituent of TEMPO is discussed through the characterization of the redox potential of N–O radical by cyclic voltammetry.