Simple Chiral Derivatization Protocols for 1H NMR and 19F NMR Spectroscopic Analysis of the Enantiopurity of Chiral Diols

Two practically simple chiral derivatization protocols for determining the enantiopurity of chiral diols by (1)H NMR and (19)F NMR spectroscopic analysis are described, involving treatment of the diol with 2-formylphenylboronic acid and alpha-methyl-4-fluorobenzylamine, or its derivatization with 4-fluoro-2-formylphenylboronic acid and alpha-methyl-benzylamine. Both approaches afford mixtures of imino-boronate esters whose diastereomeric ratio may be measured by (1)H NMR or (19)F NMR spectroscopy, the value of which is an accurate reflection of the enantiopurity of the parent diol.