Synthesis of new 2-arylbenzo[b]thiophenes using ‘Heck-type’ technology

Direct 3-substituted benzothiophene arylation using a Heck-type reaction with Pd(OAc)2/n-Bu4NBr as a catalytic system is reported. This reaction was found to perform relatively fast whatever the electron-donating or the electron-withdrawing group at position 3. We also extended this reaction to several aromatic halides, such as benzene, naphthalene and pyridine derivatives, synthesising new 2-arylbenzo[b]thiophenes in moderate to good yields.