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A variety of copper species catalyze the allylic oxidation of olefins and the introduction of an ester group at the α-position of a heterocycle. Both transformations are closely related in terms of reaction conditions and radical species involved. This short review highlights the progress made in these two types of oxidations, emphasizing work that has occurred within the last fifteen years. 1 Introduction 2 General Overview of the Copper-Catalyzed Allylic Oxidation of Olefins 3 Mechanistic Considerations 4 Enantioselective Version of the Allylic Oxidation of Olefins 5 Other Landmarks of the Copper-Catalyzed Oxidation of Olefins 6 α-Oxidation of Heterocycles 7 Reactions in Heterogeneous Phase 8 Applications 9 Summary

The use of a copper–iron mixed oxide as a heterogeneous catalyst for the efficient synthesis of α-acyloxy-1,4-dioxanes and 1,4-dithianes employing t-butyl peroxyesters is reported. The preparation and characterization of the catalyst are described. The effect of the heteroatoms and a plausible mechanism are discussed. The method is operationally simple and involves low-cost starting materials affording products in good to excellent yields.

The optimized conditions found for the title reaction can be applied to various substrates.

A strategy for the allylic oxidation of cyclic alkenes with a copper–aluminum mixed oxide as catalyst is presented. The reaction involves the treatment of an alkene with a carboxylic acid employing tert-butyl hydroperoxide as the oxidant. In all cases, the corresponding allylic esters are obtained. When l-proline is employed, the allylic alcohol or ketone is obtained. The oxidation of cyclohexene and valencene has been optimized by design of experiments (DoE) statistical methodology.

The regio- and stereoselective hydroxylation of α,β- or α,β,γ,δ- unsaturated ketones with air in the presence of KOtBu is investigated.

Reaction of cyclohexene with butylpotassium does not give the expected cyclohexanol derivative but 2-butylcyclohexanone.

A stereocontrolled access to the conveniently functionalized homochiral A-ring intermediates including B-seco taxanes is described.

The preparation of 11-hydroxy-eudesmanolides with the stereochemistry found in the Umbelliferae family of plants is described. The decalin system of the eudesmane skeleton is produced by the addition of 5-methyl-2-furyllithium to 3-ethoxycyclohex-2-enone and acidic treatment of the resulting adduct. The stereochemistry of the decalones obtained by this method has been corrected. The α-hydroxy-γ-lactone moiety is obtained by condensation of the appropriate decalone with methyl pyruvate and subsequent reduction under Luche conditions. The usefulness of this procedure has been proven in the synthesis of decipienin A.

α-Hydroxyacids can be enantioselectively prepared by means of a two-step oxidation process, involving first the asymmetric dihydroxylation of a terminal alkene and subsequent oxidation with TEMPO/NaOCl/NaClO 2 in good to excellent yields. No fragmentation of the glycol intermediate was detected.

The enantioselective synthesis of (+)-decipienin A has been carried out. The oxidation of 7-epi-cyperone 2 with molecular oxygen in the presence of methanolic KOH provides de C-6-hydroxylated derivative in quantitative yield. The oxidation of glycols 5a through a Swern oxidation and 14a with TEMPO radical opens up a route to the synthesis of 11-hydroxy sesquiterpenolides. All attempts of oxidation of 5a or 14a with other different oxidation reagents led invariably to fragmentation products.

Three series of trisporins have been prepared using a strategy in which a cross-metathesis is the key step. This reaction has proved to be highly regioselective, allowing the combination of α- or β-ionone derivatives having a 1,1-disustituted olefin with trisubstituted alkenes. The stereochemistry of the newly formed olefins has been established by spectroscopic means.

The direct synthesis of several β- and γ-lactones used as electrophilic sources of chlorine, sodium hypochlorite and a Lewis acid is described. The scope and limitations of the method are discussed.

Four novel and unusual C-19 compounds from Thapsia transtagana, named transtaganolides A−D, have been isolated. Their structures were established by physical methods, including X-ray analysis of transtaganolides A and B. This is the first time that a 7-methoxy-4,5-dihydro-3H-oxepin-2-one ring has been found in a natural product.

The preparation of allylic chlorides by reaction of terminal olefins with sodium hypochlorite in the presence of cerium trichloride heptahydrate is described. The scope, limitations and synthetic perspectives of the reaction are discussed.