A Novel Synthetic Protocol for the Preparation of Enantiopure 3-, 4-, and 5-Substituted Prolines

Stereochemicaly well-defined 3-, 4-, and 5-monosubstituted prolines can play an important role as probes in search of potent neuroexitatory agents or in the construction of conformationally constrained peptides. Mimicking distinct conformations of excitatory amino acids may lead to a more detailed understanding of the structural requirements for binding of these amino acids to the proteins involved in the process of neurotransmission (1 –3 ). Meanwhile, syntheses of conformationally constrained peptides are emerging as useful means for developing peptide-derived pharmaceutical agents (4 ,5 ). This chapter describes methodology for synthesizing enantiopure 3-, 4-, and 5-monosubstituted prolines starting from the single l -serine-derived chiral derivative (R )-1 (6 –9 ).