Rearrangement of epoxide to ketone

Scheme 8.7. Mechanism of the electrochemically catalysed rearrangement of epoxides to ketones.

In addition, its proton magnetic resonance spectrum unambiguously supported the 5-ketose structure (69). Rearrangements of epoxides to ketones when dicobalt octacarbonyl is used as the catalyst at temperatures above 100 , or when cobalt hydrocarbonyl is used at lower temperatures, are well known. By applying the technique of double irradiation to a sample of (68), the main component was shown to possess structure (68). Presumably, the free aldehyde group of the hydroformylation product immediately cyclized with the free hydroxyl group on C-3 to give the tricyclic structure (68). A third component (68a) (isolated in less than 5 % yield) was undoubtedly formed by subsequent reduction of the dialdose derivative (68). 

The most widely studied aspect of arene-oxide chemistry is the aromatization reaction to yield phenols. The acid-catalyzed, spontaneous, and thermal rearrangements of epoxides to ketones have a parallel in the isomerization of arene oxides to dienone intermediates with subsequent aromatization to phenols. Prior to their availability by chemical synthesis, arene oxides were postulated as initial inter-... 

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