Heterocyclic Ketene Aminals: Scaffolds for Heterocycle Molecular Diversity

Heterocyclic ketene aminals (HKAs) have proven to be a class of fascinating and versatile synthetic building blocks for use in the construction of heterocyclic or fused heterocyclic compounds. The bicyclic, tricyclic, and tetracyclic nitrogen‐containing analogues with HKA skeleton widely exist in natural and synthetic drugs. To understand and to master the reaction properties of HKAs and to construct other new fused heterocycles in the future, it is very important and necessary to investigate HKAs. This review covers the relevant contributions of the last twenty years with respect to the developments and applications of HKAs, categorized by reaction type. Heterocyclic ketene aminals (HKAs) have proven to be fascinating and versatile synthetic building blocks for use in the construction of heterocyclic or fused heterocyclic compounds. This review covers the more relevant contributions of the last twenty years with respect to the developments and applications of HKAs according to reaction type.