Selected applications of Meldrum’s acid – A tutorial

Due to its unique structure and the vast array of substituents that can be attached to its core, Meldrum’s acid is a molecule with exceptional chemical properties. In water, it has a remarkably low pka value of about 4.9. Its C5 position is readily involved in electrophilic substitution reactions whereas the C4 and C6 positions are easily attacked by nucleophiles. At elevated temperatures Meldrum’s acid undergoes distinctive decomposition pathways, which can be used in cycloaddition and acylation reactions. In this Tutorial Review, the authors indend to introduce the principles of the synthetic chemistry of Meldrum’s acid and provide the essential knowledge for the design and preparation of compounds with desired properties. For achieving this goal, some recent advances in using Meldrum’s acid derivatives in synthetic scenarios are presented with the hope to further stimulate and promote research leading to additional innovative applications of this synthetically highly relevant molecule.