Chapter 9: Ring-opening Polymerization of N-carboxyanhydrides Using Organic Initiators or Catalysts

Ring-opening polymerizations (ROPs) of amino acid-derived N-carboxyanhydrides (NCAs) or N-substituted glycine-derived N-carboxyanhydrides (R-NCAs) are commonly used to produce polypeptides or polypeptoids. These polymers have been increasingly investigated for various biotechnological or biomedical applications, for which the absence of metal residues is often desired. This chapter will be focused on the discussion of recent advances in the development of controlled ROPs of NCAs or R-NCAs using organic initiators/catalysts to access well-defined polypeptides or polypeptoids in the context of historical development. Examples of recent efforts in the development of controlled ROPs of amino acid-derived N-thiocarboxyanhydrides (NTAs) or N-substituted glycine-derived N-thiocarboxyanhydrides (R-NCAs), which are the mercapto analogs of NCAs or R-NCAs, will also be discussed.