Recent Developments in General Methodologies for the Synthesis of α-Ketoamides

The alpha-ketoamide motif is widely found in many natural products and drug candidates with relevant biological activities. Furthermore, alpha-ketoamides are attractive candidates to synthetic chemists due to the ability of the motif to access a wide range of functional group transformations, including multiple bond-forming processes. For these reasons, a vast array of synthetic procedures for the preparation of alpha-ketoamides have been developed over the past decades, and the search for expeditious and efficient protocols continues unabated. The aim of this review is to give an overview of the diverse methodologies that have emerged since the 1990s up to the present. The different synthetic routes have been grouped according to the way the alpha-ketoamide moiety has been created. Thus, syntheses of alpha-ketoamides proceeding via C(2) oxidation of amide starting compounds are detailed, as are amidation approaches installing the alpha-ketoamide residue through C(1)-N bond formation. Also discussed are the methodologies centered on C(1)-C(2) sigma-bond construction and C(2)-R/Ar bond forming processes. Finally, the literature regarding the synthesis of alpha-ketoamide compounds by palladium-catalyzed double-carbonylative amination reactions is discussed.