Conformationally rigid cyclic α-amino acids in the design of peptidomimetics, peptide models and biologically active compounds

A class of conformationally rigid cyclic α-amino acids that can be used in the synthesis of peptidomimetics, peptide models and biologically active compounds is surveyed. The rigid frameworks of such amino acids enable "fixation" of strictly defined torsion angles and hence prediction and deliberate tuning of the conformation of a polypeptide chain. Recent data on the structures and methods of the synthesis of such amino acids are presented.