Étard reaction—III Oxidation of N-propylbenzene and methylcyclohexane with chromyl chloride

Étard oxidation of n-propylbenzene yields a number of products among which benzaldehyde, methyl benzyl ketone, propiophenone, 1-chloro-1-phenylpropane, 1-phenylpropan-1-ol, 1-phenyl-1-chloropropan-2-one and 1-phenyl-2-chloropropan-1-one were identified. The same products were obtained by treatment of 1-phenylpropene and 1,2-epoxy-1-phenylpropane with chromyl chloride. Presumably all these compounds result from a common intermediate possessing an epoxide like structure. The oxidation by chromyl chloride of methylcyclohexane also leads to a larger number of products than previously known, namely: 1-methyl-1-cyclohexanol, hexahydrobenzaldehyde, 1-methylcyclopentylaldehyde, 2-methylcyclohexanone and 1-methyl-1-chlorocyclohexan-2-one. The last three compounds were produced also in the reaction of 1-methylcyclohexene with chromyl chloride. The mechanism of these reactions is discussed.