5-Diazo-2,2-dimethyl-1,3-dioxane-4,6-dione, also known as diazo Meldrum's acid, is a versatile diazo reagent primarily used in organic synthesis. It serves as a key intermediate for generating carbenes and in 1,3-dipolar cycloaddition reactions, facilitating the construction of cyclopropane and other heterocyclic structures essential in pharmaceutical and agrochemical applications. Its reactivity enables efficient formation of complex carbon frameworks, making it valuable for developing new synthetic methodologies in research. This compound is particularly noted for its role in decarboxylative transformations and as a synthon for beta-ketoester equivalents.