Pseudoacid

[1] Unlike the parent (open-form) oxocarboxylic acid, the pseudoacid has a chiral center.

In aliphatic 4- and 5-oxocarboxylic acids, intervening substituents assists in ring closure.

Alkenes with the interacting groups substituted cis to each other also assists in ring closure.

Aryl systems with the interacting groups substituted ortho to each other assists in ring closure.

These include pseudoacyl halides, pseudoesters, endocyclic and exocyclic-N pseudoamides, and pseudoanhydrides.