La structure de la cétone C15H16O formée par la réaction entre le norbornadiène et le pentacarbonyle de fer

The value of the spin‐spin coupling constant between vicinal protons is known to vary as cos2 φ, where φ is the dihedral angle between the carbon‐hydrogen bonds. A method, based on this relationship, for distinguishing between the exo‐endo isomers of bicycloheptane derivatives is proposed and tested on five such compounds of known structure. In this way, the configuration of I is determineed as exo‐trans‐exo, in contrast to the endo‐trans‐endo configuration proposed by Cookson.