A Protocol for NMR Analysis of the Enantiomeric Excess of Chiral Diols Using an Achiral Diboronic Acid Template

A practically simple derivatization protocol for determining the enantiopurity of chiral diols by H-1 NMR spectroscopic analysis is described. Diols were treated with 0.5 equiv of 1,3-phenyldiboronic acid to afford mixtures of diastereomeric boronate esters whose homochiral/heterochiral ratios are an accurate reflection of the diol's enantiopurity.