Copper(I)-catalyzed tandem reaction of 2-iodophenols with isothiocyanates in room temperature ionic liquids

A copper(I)-catalyzed tandem reaction of 2-iodophenols with isothiocyanates in hydrophobic [bmim][PF6] ionic liquid was described, which proceeded smoothly and generated a variety of 2-iminobenzo-1,3-oxathioles in good to excellent yields. The tandem reaction that was carried out in [bmim][PF6] has some obvious advantages such as reaction rate acceleration and yield increasing as compared with the reaction run in volatile solvents such as toluene. Furthermore, the CuI/1,10-phenanthroline catalytic system can be reused up to 6 times without loss of activity and efficiency.

Graphical abstractCopper(I)-catalyzed tandem reaction of 2-iodophenols with isothiocyanates was achieved in [bmim][PF6] using 1,10-phenanthroline as a ligand and Cs2CO3 as base at 80–90 °C, yielding a variety of 2-iminobenzo-1,3-oxathioles in good to excellent yields.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The C–S coupling reaction catalyzed by copper was first investigated in ionic liquids. ► A variety of 2-iminobenzo-1,3-oxathioles can been synthesized in high yields. ► Reaction run in RTILs has the advantages of rate acceleration and increase of yield. ► The ionic liquid and catalyst system can be recycled for at least six times.