Dioxygen insertion into element hydride bond

The aerobic oxidation of alcohols catalysed by low-valent late-transition-metal ions, particularly those of group VIII elements, involves an oxidative dehydrogenation mechanism. In the catalytic cycle (Fig. 5) ruthenium can form a hydridometal species by /1-hydride elimination from an alkoxymetal intermediate, which is reoxidized by dioxygen, presumably via insertion of 02 into the M-H bond with formation of H202. Alternatively, an alkoxymetal species can decompose to a proton and the reduced form of the catalyst (Fig. 5), either directly or via the intermediacy of a hydridometal intermediate. These reactions are promoted by bases as cocatalysts, which presumably facilitate the formation of an alkoxymetal intermediate and/or /1-hydride elimination. 

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