Mosher proposed that the most populated solution-phase conformer placesthe carbinyl proton,
ester carbonyl, and trifluoromethylmoieties in the same plane (6). In this conformation, the L2
signal of the (R)-MTPA ester should appear upfield relative to the L2 signal of the (S)-MTPA ester. Thus, a
pair of NMR-indistinguishable enantiomers is transformed into NMR-distinguishable diastereomers. A
given mixture of enantiomers of a chiral alcohol can then be analyzed by comparing the relative
integrals of their corresponding diastereomers.