Oxidative C−H/C−H Cross‐Coupling Reactions between N‐Acylanilines and Benzamides Enabled by a Cp*‐Free RhCl₃/TFA Catalytic System

Abstract

By making use of adual-chelation-assisted strategy, ac ompletely regiocontrolled oxidative CÀH/CÀHc ross-coupling reaction between an N-acylaniline and abenzamide has been accomplished for the first time.T his process constitutes as tep-economic and highly efficient pathwayt o2 -amino-2'carboxybiaryl scaffolds from readily available substrates.A Cp*-free RhCl 3 /TFAcatalytic system was developed to replace the [Cp*RhCl 2 ] 2 /AgSbF 6 system generally used in oxidative CÀH/CÀHc ross-coupling reactions between two (hetero)arenes (Cp* = pentamethylcyclopentadienyl, TFA = trifluoroacetic acid). The RhCl 3 /TFAs ystem avoids the use of the expensive Cp* ligand and AgSbF 6 .Asanillustrative example, the procedure developed herein greatly streamlines the total synthesis of the naturally occurring benzo[c]phenanthridine alkaloid oxynitidine,w hich was accomplished in excellent overall yield.

Simple Access to 3-(Hetero)arylated Derivatives of 2-Furoic Acid via Ru(II)-Catalyzed C3-H Arylation of 2-Furoylimidazole

“…A promising approach for the selective C3-H functionalization of FA derivatives is based on the directing effect of 2-carboxamide and related groups in some transition-metal-catalyzed C–H activation reactions. For example, the selective C3-H (hetero)arylation of furan-2-carboxamides with various arylating agents under Pd, 14 Ir, 15 Rh, 16 Co, 17 Cu, 18 and Ru 19 catalysis has been reported (Scheme 1, a ). However, the carboxamide group is not very suitable as a functional group for further functionalization of C3-H (hetero)arylation products due to its low reactivity.…”