Non-heme iron catalysis in C=C, C-H, and CH2 oxidation reactions. Oxidative transformations on terpenoids catalyzed by Fe(bpmen)(OTf)2

The oxidation of terpene olefins with hydrogen peroxide in the presence of the non-hemo catalyst 5a afforded mixtures of epoxides whose composition was dependent upon the oxidation protocol used in each case. With terpenoid enones, the mixtures obtained evolved from clean epoxidation of alpha-ionone 23 to the clean allylic oxidation of damascone 28 due to the progressive deactivation of the electron density on the double bonds present in this series. The oxidation of bicyclic and tricyclic terpenoids afforded oxidation products coming from epoxidation, to olefin degradation, methyne and methylene activation products. Probably, the most attractive result was the synthesis of the Magnus lactone 46, from the tricyclic ether 45, with 88% yield and 100% conversion. (C) 2013 Elsevier Ltd. All rights reserved.