5-Isopropylidene-2,2-dimethyl-1,3-dioxane-4,6-dione (the condensation product of Meldrum's acid and acetone) reacts smoothly with tert-butyl isocyanide in the presence of alcohols-to produce alkyl 1-tert-butyl-4,4-dimethyl-2,5-dioxo-pyrrolidine-3-carboxylate and dialkyl 2-(1-tert-butylcarbamoyl-1-methyl-ethyl)-malonates in good overall yields.