A non-chiral lithium aluminate reagent for the determination of enantiomeric excess of chiral alcohols

Abstract

Here we illustrate a new method for the rapid determination of ee's of chiral alcohols using the thermally-stable, non-chiral lithium aluminate reagent [EtAl(6-Me-2-py)₃Li] (1). In situ reaction of the alcohols with 1 produces robust dimers in solution, present as diastereomeric pairs (SS/RR and RS) with distinct resonances in their ¹H and ⁷Li NMR spectra. The ee can be calculated simply from integration of the ¹H and/or ⁷Li NMR spectra.