One-pot synthesis of unsymmetrical benzils from aryl methyl ketones and arenes in the presence of selenous acid catalysed by p-toluenesulfonic acid monohydrate

A modified one-pot method for the synthesis of unsymmetrical and heteroaryl benzils from substituted acetophenones and unactivated or weakly activated arenes by the use of H₂SeO₃ and p-TsOH·H₂O as catalysts at 35 °C is established. The present method is regioselective and avoids the use of p-TsOH·H₂O in stoichiometric amount in the presence of H₂SeO₃ and afforded unsymmetrical benzils in good yields.