Oxidative C−H/C−H Cross‐Coupling Reactions between N ‐Acylanilines and Benzamides Enabled by a Cp*‐Free RhCl 3 /TFA Catalytic System

By making use of a dual‐chelation‐assisted strategy, a completely regiocontrolled oxidative C−H/C−H cross‐coupling reaction between an N ‐acylaniline and a benzamide has been accomplished for the first time. This process constitutes a step‐economic and highly efficient pathway to 2‐amino‐2′‐carboxybiaryl scaffolds from readily available substrates. A Cp*‐free RhCl 3 /TFA catalytic system was developed to replace the [Cp*RhCl 2 ] 2 /AgSbF 6 system generally used in oxidative C−H/C−H cross‐coupling reactions between two (hetero)arenes (Cp*=pentamethylcyclopentadienyl, TFA=trifluoroacetic acid). The RhCl 3 /TFA system avoids the use of the expensive Cp* ligand and AgSbF 6 . As an illustrative example, the procedure developed herein greatly streamlines the total synthesis of the naturally occurring benzo[ c ]phenanthridine alkaloid oxynitidine, which was accomplished in excellent overall yield.