Selective catalytic oxidation of cyclohexylbenzene to cyclohexylbenzene-1-hydroperoxide: a coproduct-free route to phenol

A method is described for the highly selective oxidation of cyclohexylbenzene to cyclohexylbenzene-1-hydroperoxide. In the presence of 0.5 mol% N-hydroxyphthalimide (NHPI) and 2 mol% of the hydroperoxide product, without solvent, a selectivity of ca. 98% to the desired product was obtained at 32% conversion. The use of NHPI increases the selectivity for initial H-abstraction from the 1-position, vs the other positions in the cyclohexyl ring, suppresses byproduct formation via transannular hydrogen abstraction and increases the overall rate of reaction.