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 alpha-hydroxylation of beta-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, beta-dicarbonyl compounds can be directly convened 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. (c) 2006 Elsevier B.V. All rights reserved.