Low Temperature, High Conversion, Liquid-Phase Benzylic Oxidation with Dioxygen by Metal/NHPI-Catalyzed Co-Oxidation with Benzaldehyde

摘要

A new liquid-phase catalytic oxidation system for the low temperature, high conversion benzylic mono-oxyfunctional-ization of 10,11-dihydrocarbamazepine (1) into oxcarbazephine (4) with dioxygen has been developed. The method is based on a co-oxidation of 1 with benzaldehyde in the presence of a four-component catalyst system consisting of Co(OAc)_2, Ni(OAc)_2, Cr(NO_3)_3, and N-hydroxyphthalimide (NHPI). The influence of the catalyst system on the formation and decomposition of the crucial hydroperoxide intermediate 2 has been investigated. Based on these results, the role of each of the components in the catalyst system is discussed. The scope of this method for the oxidation of other substrates has been studied, and the results are compared with those obtained by Co/NHPI catalyzed oxidation of these substrates.