Triazole-assisted ruthenium-catalyzed C-H arylation of aromatic amides

Site-selective ruthenium(II)-catalyzed direct arylation of amides was achieved through C-H cleavages with modular auxiliaries, derived from easily accessible 1,2,3-triazoles. The triazolyldimethylmethyl (TAM) bidentate directing group was prepared in a highly modular fashion through copper(I)-catalyzed 1,3-dipolar cycloaddition and allowed for ruthenium-catalyzed C-H arylations on arenes and heteroarenes, as well as alkenes, by using easy-to-handle aryl bromides as the arylating reagents. The triazole-assisted C-H activation strategy was found to be widely applicable, to occur under mild reaction conditions, and the catalytic system was tolerant of important electrophilic functionalities. Notably, the flexible triazole-based auxiliary proved to be a more potent directing group for the optimized ruthenium(II)-catalyzed direct arylations, compared with pyridyl-substituted amides or substrates derived from 8-aminoquinoline. Assisting activation: Ruthenium(II)-catalyzed C-H arylations of (hetero)arenes and alkenes have been achieved with aryl halides through removable bidentate auxiliaries derived from modular 1,2,3-triazoles (see scheme; TAM=triazolyldimethylmethyl).