Oligomerization of negatively-charged amino acids by carbonyldiimidazole.

The carbonyldiimidazole-induced oligomerizations of aspartic acid, glutamic acid and O-phospho-serine are amongst the most efficient reported syntheses of biopolymers in aqueous solution. The dependence of the yields of products on the concentrations of reagents, the temperature and the enantiomeric composition of the substrate amino acids are reported. Catalysis by metal ions, particularly by Mg2+, is described. These reactions do not generate significant amounts of material in the size-range of several tens of residues that are thought to be needed for a polymer to function as a genetic material.