Benzenesulfonyl chlorides: new reagents for access to alternative regioisomers in palladium-catalysed direct arylations of thiophenes

The palladium-catalysed coupling of benzenesulfonyl chlorides with thiophene derivatives allows regioselective access to beta-arylated thiophenes. The reaction proceeds with easily accessible catalyst, base and substrates, without oxidant or ligand and tolerates a variety of substituents on both the benzene and thiophene moieties.