Benzyl phenyl ketone, from benzil

Ketones are oxidatively cleaved by Cr(VI) or Mn(VII) reagents. The reaction is sometimes of utility in the synthesis of difunctional molecules by ring cleavage. The mechanism for both reagents is believed to involve an enol intermediate.206 A study involving both kinetic data and quantitative product studies has permitted a fairly complete description of the Cr(VI) oxidation of benzyl phenyl ketone.207 The products include both oxidative-cleavage products and benzil, 7, which results from oxidation a to the carbonyl. In addition, the dimeric product 8, which is suggestive of radical intermediates, is formed under some conditions. 

Oxidation of diphenylcyclopropenone with m-chloroperbenzoic acid gave a mixture of benzil, diphenylacetylene and benzophenone, whereas di-r-butylcyclopropenone gave mainly 4,5-epoxy-2,2,4,5-tetramethylhexan-3-one. Alkaline hydrogen peroxide and diphenylcyclopropenone yield the same products along with benzyl phenyl ketone (equation 49). The benzyl phenyl ketone is thought to arise from addition of... 

Recently a complete product study has been carried out for benzil irradiated in cyclohexane.63 A complex mixture containing benzaldehyde, phenyl-cyclohexyl ketone, benzoin benzoate, benzoin, benzoic acid, and smaller amounts of other compounds containing from three to six benzyl groups was obtained. 

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