Ligand-Enabled C–CF3 coupling at tetracoordinated Au(III)

The formation of C–CF3 bonds is an important challenge in organofluorine chemistry. Understanding the factors governing this process is key to develop new synthetic strategies. Here, we report ligand-enabled C–CF3 coupling at tetracoordinate Au(III) centres supported by hemilabile P^N ligands. A series of well-defined Au(III) trifluoromethyl complexes bearing aryl, vinyl or alkynyl groups were prepared and shown to undergo thermal reductive elimination, affording the corresponding C–CF3 coupling products in high yields (86% on average of 17 examples). The reaction accommodates sterically hindered aryl groups and functional groups. Kinetic experiments support a first-order process, while density functional theory calculations identify a concerted reductive elimination pathway involving a three-centre transition state. The calculations further highlight the role of the hemilabile nitrogen donor, which partially dissociates during C–CF3 bond formation. The coupling also extends to a related perfluoroethyl Au(III) complex, demonstrating the potential to forge C–C2F5 bonds. Together, these findings establish P^N-chelated Au(III) complexes as a platform for studying and promoting C–CF3 bond formation, providing mechanistic insight into reductive elimination at gold and a basis for exploring new ligand-enabled transformations.