Synthesis of unsymmetrical sulfides using ethyl potassium xanthogenate and recyclable copper catalyst under ligand-free conditions.

The synthesis of unsymmetrical sulfides has been achieved in good to excellent yields with inexpensive ethyl potassium xanthogenate via cross-coupling reaction using recyclable CuO nanoparticles under ligand-free conditions.The copper oxide nanoparticles can be recovered and reused up to five cycles without loss of activity.

Nano indium oxide as a recyclable catalyst for C-S cross-coupling of thiols with aryl halides under ligand free conditions.

An efficient ligand-free C-S cross-coupling of aryl halides with aromatic/alkyl thiols has been developed using a catalytic amount of nanocrystalline indium oxide as a recyclable catalyst with KOH as the base in DMSO at 135 degrees C. A variety of aryl sulfides can be synthesized in excellent yields utilizing this protocol.

Copper oxide nanoparticle-catalyzed coupling of diaryl diselenide with aryl halides under ligand-free conditions.

A new, efficient and ligand-free cross-coupling reaction of aryl halides and diaryl diselenides using a catalytic amount of nanocrystalline CuO as a recyclable catalyst with KOH as the base in DMSO at 110 degrees C is reported. This protocol has been utilized for the synthesis of a variety of aryl selenides in excellent yields from the readily available aryl halides and diaryl diselenides.