Effects of NMR Shift Reagent on Prochiral Groups of Acyclic Alcohols and Diastereomeric Amino Acids

Abstract

The effects of shift reagent [Eu(DPM)₃] on the NMR spectra of alcohols, 3-phenyl-2butanol, 2-phenylpropanol, 3-phenyl-2-methyl-2-butanol, 3-methyl-2-butanol, 4-methyl-2butanol, and 2-methylbutanel, were studied. Two hydrogens er geminal dimethyl groups bonding to prochiral centers, the positions of which and the chiral center are 2 or 3 carbon atoms apart, showed remarkably different chemieal shifts by the addition of this shift reagent. C₄-Methylene protons and C₃-methyl protons of isoleucin methyl ester showed respectively different chemical shift from those of alloiso1eucin ester by the addition of this reagent. These shifts are interpreted in terms of conformational differences.