Synlett 2004(9): 1649-1650  
DOI: 10.1055/s-2004-829539
SPOTLIGHT
© Georg Thieme Verlag Stuttgart · New York

Meldrum’s Acid

Vasco D. B. Bonifácio*
Secção de Química Orgânica Aplicada, Departamento de Química Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829 - Monte de Caparica, Portugal
e-Mail: vasco.bonifacio@dq.fct.unl.pt;
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Publikationsverlauf

Publikationsdatum:
29. Juni 2004 (online)

Introduction

Meldrum"s acid (1, isopropylidene malonate or 2,2-di­methyl-4,6-dioxo-1,3-dioxane), was first synthesized by Meldrum in 1908 [1] and the structure was incorrectly assigned as the b-lactone of b-hydroxyisopropylmalonic acid (b,b-dimethyl-b-propiolactone-a-carboxylic acid). [2] It was only 40 years later that Davidson and Bernhard assigned the correct structure. [2] Meldrum’s acid has attracted considerable attention due to its high acidity (pK a = 4.97) [3] and rigid cyclic structure. Acylated derivatives (synthetic equivalents of mixed ketenes) readily undergo alcoholysis to give b-keto esters. [4] Alkylidene derivatives are strong electrophiles and can undergo Diels-Alder reactions with high diasteroselectivity. [5] This versatile tool is a key intermediate for a large number of important building blocks and there remains much to discover.