Liquid-phase metal-centred autoxidation of cyclo-octene promoted by rhodium species

Abstract

The rhodium(I)-promoted autoxidation of cyclo-octene, in benzene at 74 °C, gives non-catalytic yields of cyclo-oct-1-en-3-one and cyclo-octanone by a route independent of radical chains and a Wacker cycle. With added styrene, or in NN-dimethylacetamide, the oxidation is catalytic (6 mol of products per mol Rh). The oxidation is interpreted in terms of a rate-limiting metal-centred insertion of oxygen into an allylic carbon–hydrogen bond and subsequent reactions of the resulting cyclo-oct-1-en-3-ol.