ABSTRACT
The utilization of peptide-like therapeutics has not been fully realized due, in large measure, to their generally poor oral bioavailability and short duration of action in vivo. Not surprisingly, the proteolytic enzymes of the gastrointestinal tract are unable to discriminate between peptide drug molecules and nondrug peptides. Inasmuch as peptide molecules possess biochemical information in their primary, secondary, and tertiary structure, one is forced to use chiral isos-teres in order to convey this information. The use of asymmetric catalysis for the preparation of a variety of important organic compounds has experienced unprecedented growth recently. Stereoselective synthesis of either optical antipode is possible by the appropriate choice of ligand absolute configuration. Supplementary illustrations of the application of asymmetric catalysis to the preparation of additional peptide isosteres will be presented in due course.
