The combined magnetic anisotropic effects generated by two auxiliary moieties of 2-methoxy-2-phenylacetic acid (MPA), introduced on two families of terminal 1,2-amino alcohols (prim/sec and sec/prim), determine the signs of the Deltadelta(RS) parameters-the differences in chemical shifts between the bis-(R)-MPA and the bis-(S)-MPA esters-of the hydrogen atoms placed at both sides of the stereogenic carbon atoms, thereby allowing the determination of the absolute configuration of those heterobifunctional compounds. Theoretical (AM1, B3LYP) and experimental (CD, (3)J, low-temperature NMR spectroscopy, isotopic labeling) studies, together with testing with a number of representative compounds, permit one to establish the foundations of this methodology.