Pyridones - Powerful Precursors for the Synthesis of Alkaloids, Their Derivatives, and Alkaloid-Inspired Compounds

2-Pyridone is characterized by a very wide range of reactivity of a different nature, ranging from electrophilic aromatic substitution, CH-metal-mediated reactions, and NH/OH functionalization of both possible lactam/lactim tautomers, through cycloaddition, to nucleophilic addition and transformation of the tautomeric C=O/C-OH moiety. The high availability of 2-pyridones and the possibility of their far-reaching functionalization additionally increased their values. Therefore, they are very useful building blocks for the synthesis of structurally diverse piperidine and pyridine compounds, including naturally occurring 2-pyridones. This review reports on the use of simple 2-pyridones in the synthesis of alkaloids and alkaloids-inspired compounds based on the piperidine or pyridine framework.