CATALYTIC EPOXIDATION OF ALKENES USING MOLECULAR OXYGEN

In the past, oxidation reactions of organic compounds were dominated by reactions involving super-stoichiometric reagents often bringing to formation of huge amounts of wastes, with most of them being poisonous and toxic. Observing the principle of green chemistry, the best approach would involve environment-friendly oxidants.¹ In particular, it would be most advantageous to use molecular oxygen (O₂) as terminal oxidant in presence of a catalyst.

An important example of an oxidation reaction is epoxidation. Epoxides are essential intermediates in the chemical industry due to their wide use in the production of various plastics. However, epoxides are also found in the synthesis of fine chemicals, such as flavors, food additives and pharmaceuticals.²

In this work, the epoxidation of alkenes has been studied using O₂ and polyfluorooxometalates (PFOMs) as catalysts.³ PFOMs are polyoxometalates (POMs) where one or more oxygen atoms have been replaced with fluorine atoms. The PFOMs have been functionalized with a ligand able to exchange an oxygen atom.⁴ Different metal centers, and experimental conditions have been tested as parameters affecting the catalysis.

(1) Sheldon, R. a. Chem. Soc. Rev. 2012, 41 (4), 1437.

(2) Hauser, S. A.; Cokoja, M.; Kühn, F. E. Catal. Sci. Technol. 2013, 3 (3), 552.

(3) Ben-Daniel, R.; Khenkin, A. M.; Neumann, R. Chem. Eur. J. 2000, 6 (20), 3722–3728.

(4) Rubinstein, A.; Jiménez-Lozanao, P.; Carbó, J. J.; Poblet, J. M.; Neumann, R. J. Am. Chem. Soc. 2014, 136 (31), 10941–10948.