Rapid Ullmann-type synthesis of aryl sulfides using a copper(I) catalyst and ligand under microwave irradiation

A rapid and efficient method for C–S bond formation under microwave irradiation is reported. The reaction of both electron-rich and electron-poor aryl halides with thiols using copper(I) iodide as a catalyst is facilitated by the addition of 2 equiv of trans-cyclohexane-1,2-diol as ligand in the presence of K2CO3 as base in 2-propanol. Microwave irradiation at 120 °C for 3 h gives the corresponding aryl sulfide in a procedure amenable to library production.