Meldrum’s acid is the trivial name for 2,2-dimethyl-1,3-dioxane-4,6-dione; this amazingly simple, symmetric molecule is a very interesting starting material for many different molecules, from b-ketoacids to natural products. In this review, Aaron M. Dumas and Eric Fillion cover recent advances in the chemistry of this scaffold.

Meldrum’s Acids and 5-Alkylidene Meldrum’s Acids in Catalytic Carbon? Carbon Bond-Forming Processes
Acc. Chem. Res., 2010, 43 (3), pp 440–454.
See: 10.1021/ar900229z