Recent Advances in the Metal-Catalyzed Activation of Amide Bonds.

The amide functional group is commonly found in peptides, proteins, pharmaceutical compounds, natural products, and polymers. The synthesis of amides is typically performed by using classical approaches that involve the reaction between a carboxylic acid and an amine in the presence of an activator. Amides are thought to be an inert functional group, because they are unsusceptible to nucleophile attack, owing to their low electrophilicity. The reason for this resistance is clear: the resonance stability of the amide bond. However, transition metal catalysis can circumvent this stability by selectively rupturing the N-C bond of the amide, thereby facilitating further cross-coupling or other reactions. In this Focus Review, we discuss the recent advances in this area and present a summary of methods that have been developed for activating the amide N-C bond by using precious and non-precious metals.