Transition metal- and solvent-free synthesis of unsymmetrical diaryl sulfides and selenides under ball-milling

A transition metal- and solvent-free procedure for the reaction of aryl diazonium tetrafluoroborates and thiols or selenols over alumina surface under ball-milling at ambient temperature, has been developed for the synthesis of unsymmetrical diaryl or aryl-alkyl sulfides and selenides. A wide range of functionalized diaryl or aryl-alkyl sulfides and selenides were obtained in high yields and high purity within a short reaction time (5-8 min.) by this protocol.