Aminoacids as Chiral Synthons1: Preparation of Enantiomerically Pure (R) and (S) Malic Acids and its Application to the Synthesis of 3-Hydroxy 4-Butanolide

Malic acid has been proved to be an extremely valuable chiral synthon for enantiospecific synthesis of complex molecules such as monensin2, amphotericin B3, variou s hydroxytetrahydrofurans4, lactones5,6 and pheromones7. However the (S) isomer only is easily available8; the (R) isomer is more difficult to obtain and is generally prepared by a synthetic way9.