C−H and C−S Activation of Thiophene by Rhodium Complexes: Influence of the Ancillary Ligands on the Thermodynamic Stability of the Products

Abstract

The reaction of thiophene with the rhodium compound [Tp*Rh(C2H4)(PMe3)] (1a; Tp* = hydrotris(3,5-dimethyl-1-pyrazolyl)borate) leads to a mixture of the C−H and C−S activation products [Tp*Rh(H)(2-C4H3S)(PMe3)] (2a) and [Tp*Rh(CHCHCHCHS)(PMe3)] (3a), respectively. In contrast to previous observations, the former is the thermodynamically preferred isomer. For the PEt3 derivative [Tp*Rh(C2H4)(PEt3)] (1b), an even higher selectivity toward C−H activation is observed.