 The lack of an alpha-proton on the acid prevents loss of stereochemical fidelity under the reaction conditions.Thus, using an enantiomerically pure Mosher's acid allows for determination of the configuration of simple chiral amines and alcohols.For example, the ("R")- and ("S")-enantiomers of 1-phenylethanol react with ("S")-Mosher acid chloride to yield ("R","S")- and ("S","S")-diastereomers, respectively, that are distinguishable in NMR.