Abstract
It has been shown that the magnetically anisotropic double bond in bicyclic Diels–Alder adducts exerts a paramagnetic effect on protons in an exo configuration and a diamagnetic effect on protons in an endo configuration. Thus the configuration of a proton or proton-bearing substituent can be ascertained by observing the change in its chemical shift when the double bond is removed by hydrogenation. However, caution must be used in applying the method to compounds in which the double bond bears a magnetically anisotropic substituent.