Diastereoselective Approach to an HIV Protease Inhibitor Intermediate Using a Cation-Exchange Resin Mediated Mannich-Type Reaction

-Mannich-type reaction of ketene silyl acetals with a chiral imine proceeded smoothly to give β-amino esters in good yields with high diasetereoselectivity under the influence of a cation-exchange resin, and the subsequent functional group transformations gave an HIV protease inhibitor intermediate.