Efficient rhodium catalysts for the hydrogenolysis of thiophenic molecules in homogeneous phase

In the presence of strong bases, the C--S insertion complexes (triphos)Rh[t/3-S(C6H4)CH=CH2] and (triphos)Rh(q3-SCH=CHCH=-CH2) as well as the 7z-alkyne complex [(triphos)Rh0/2-MeO2CC~CCO2 Me)]PF6 are catalyst precursors for the hydrogenation of thiophene (T), benzo[b]thiophene (BT) and dibenzo[b,d]thiophene (DBT) in tetrahydrofuran solution [triphos = MeC(CH2PPh2)3]. Both hydrogenolysis (thiols) and desulfurization (hydrocarbons) products are obtained. Among the substrates investigated, BT is the most reactive, whereas T is the easiest to desulfurize.