Cerium-catalyzed oxidative C–C bond forming reactions

With respect to economical and ecological considerations, molecular oxygen is the oxidant of choice for functionalization of organic substrates. On the basis of our cerium-catalyzed α-hydroxylation of β-dicarbonyl compounds, we have developed an oxidative process for C–C bond formation in the presence of simple olefins like styrene. Products of these reactions, which are isolated as endoperoxidic 1,2-dioxane derivatives with potential anti-malaria activity, are hydroperoxides. These peroxides are disproportionated to 1,4-dicarbonyl compounds in a Kornblum–DeLaMare fragmentation. Actually, β-dicarbonyl compounds can be directly converted in a two-step one-pot procedure to give the 1,4-diketones in high yield. Compounds with 1,4-dicarbonyl structural motif are important intermediates for the synthesis of heterocyclic compounds and commonly only accessible by an Umpolung strategy.