DESYMMETRISATION OF MESO-ANHYDRIDES UTILIZING (S)-PROLINE DERIVATIVES

meso-Anhydrides derived from norbornanes and norbornenes, undergo an a symmetric ring opening upon treatment with (S)-proline derivatives, to give amido acids with moderate to excellent enantiomeric excesses. A cyclopropane derived anhydride was also desymmetrised in this way, whi lst cyclohexyl derived anhydrides gave a 1 : 1 mixture of diastereomer s. The origin of the desymmetrisation is explained by a model based on steric interactions in the transition state.