(S)-1-(Ethoxycarbonyl)ethyl(2R,5S)-2,5-dimethyl-1,3-dioxolan-4-one-2-carboxylate

The title compound was obtained in low yield in the condensation of ethyl pyruvate and lactic acid. Its structure is determined by NMR methods and x-ray diffraction and the mechanism for formation of this 1:2 adduct from the initial 1:1 adduct is considered.