Ultrasound-promoted aromatic nucleophilic substitution of dichlorobenzene iron(II) complexes

The nucleophilic aromatic substitution under ultrasound irradiation of a dichlorobenzene iron η6-complex with various secondary amines is reported. The reaction time at moderate temperatures is considerably shortened (15 min) compared to non sonicated reaction conditions at room temperature (several days) or at solvent refluxing temperature (12–48 h). Controlled mono- or di-substitution was achieved by the tuning of the amine nucleophilicity and the solvent polarity. The method was successfully applied to the synthesis of differently substituted phenylenediamines.