Design and synthesis of 6-amino-5-oxo-1,2,3,5-tetrahydro-3-indolizinecarboxylic acids as β-sheet peptidomimetics

6-Amino-5-oxo-1,2,3,5-tetrahydro-3-indolizinecarboxylic acid was designed as a novel scaffold that can effectively mimic the extended conformation of a peptide. The key reaction in the synthesis of the scaffold involved a [3+2]-cycloaddition of a dicarbonyl stabilized isomünchnone intermediate. Its effectiveness as a β-sheet mimetic was demonstrated by the preparation of a potent HCV NS3 protease inhibitor.