Environmentally benign process for the synthesis of 2,3-disubstituted benzo[b]thiophenes using electrophilic cyclization

We have developed a greener process for the synthesis of 2,3-disubstituted benzo[b]thiophenes using electrophilic cyclization as a key step. Our method not only employs an environmentally friendly solvent ethanol, but also utilizes safe and inexpensive inorganic reagents to furnish the desired products in high yields under mild reaction conditions. In addition to iodo- and bromocyclization, chlorocylization was also successfully accomplished.