A simple quantitative chiral analysis of amino acid esters by fluorine-19 nuclear magnetic resonance using the modified James-Bull method.

A simple chiral analysis of amino acid esters by fluorine-19 nuclear magnetic resonance (19 F NMR) through the modified James-Bull method is described. Thus, amino acid ester acid salt was treated with 5-fluoro-2-formylphenylboronic acid and (S)-BINOL in the presence of triethylamine (TEA) and MS4A for 10 minutes. The reaction mixture was analysed by 19 F NMR directly to afford good quantifications.