Explanation of Substituent Effects on the Enolization of [beta]-Diketones and [beta]-Ketoesters

This article highlights some of the challenges in explaining simple substituent effects on keto-enol equilibria, particularly to an undergraduate audience. Quantum-chemical calculations were performed to identify the role of intramolecular hydrogen bonding, inductive effects due to electron-withdrawing groups, and cross-conjugation on the enolization of [beta]-diketones and [beta]-ketoesters. These insights could be applied by an instructor in order to enrich undergraduate chemistry students' understanding of this fundamental reaction.