Transition Metal-Catalysed Direct C-H Bond Functionalizations of 2-Pyridone Beyond C3-Selectivity.

2-Pyridone is a ubiquitous motif in natural products, drug molecules, ligands in catalysis and organic materials. There is a necessity of direct step-economic methods for the construction of 2-pyridone based molecules. Strategically, the primary developments have led to the C3-functionalizations due to the inherent reactivity of this center. Despite this, many elegant transition metal-catalysed methods have been established to introduce versatile functional groups at the C4, C5 and C6-position via direct C-H bond functionalizations. This minireview focuses on the categorized introduction of different functional groups at the 2-pyridone scaffolds beyond C3-selectivity and discusses substrate scope, limitations and plausible mechanistic details.