Stereochemical Effects in Mass Spectrometry 7. Determination of Absolute Configuration of Some Organic Molecules by Reaction Mass Spectrometry

Article abstract of DOI:10.1002/oms.1210231205

It was found that in the chemical ionization (isobutane) mass spectra of some asymmetric secondary alcohols and α-amino acids, when a pair of enantiomers (such as R- and S-2-phenylbutyric anhydride, R- and S-mandelic acid, R- and S-2-methylbutanoic acid or R- and S-α-phenyl ethyl amine) were used as reaction reagents, the relative abundances of characteristic ions formed by the stereoselective reaction between sample and reagent of the same configuration were much higher than those ions formed by the sample and a reagent of a different configuration. The absolute configuration of the sample molecule may be predicted by examination of mass spectra of the sample measured with R- and S-reagent respectively.This approach proved to be a convenient way for determination of the absolute configurations of organic molecules on a micromole level by mass spectrometry.