New chiral derivatizing agents: convenient determination of absolute configurations of free amino acids by 1H NMR.

The chiral carbonate reagents 5 allow for the direct and unambiguous determination of the absolute configurations of a wide range of free amino acids using (1)H NMR. By using a approximately 3:1 mixture of (S)-5 and (R)-5, absolute configurations of the corresponding carbamates are determined by only analyzing the nitrogen protons.