Detalle de: Bis-CF 3 -bipyridine Ligands for the Iridium-Catalyzed Borylation of N -Methylamides

Bipyridine and phenanthroline are well-established neutral ligands for promoting iridium-catalyzed borylations of aromatic C-H bonds. However, their use with aliphatic substrates is almost uncharted. Herein we demonstrate that introducing CF substituents at the 5- and 5'-positions of bipyridine generates ligands that enable an efficient and regioselective iridium-catalyzed borylation of the methyl group in a broad variety of methylamides. The reaction shows broad functional group tolerance and exhibits remarkable selectivity, offering a powerful approach for the borylation of challenging aliphatic C-H bonds. Mechanistic investigations, including computational analysis, suggest that the accelerating effect of the ligand is likely associated with the formation of non-covalent dispersion interactions between the carbonyl amide of the substrates and the trifluoromethylated pyridine rings of the ligand.