Long‐range 1H coupling interactions: Identification of different pathways by 2D NMR δ—δ correlated spectroscopy. Applications in structural analysis

The simplest methods of 2D δ‐δ correlated spectroscopy (COSY and COSY LR) allow the easy observation of long‐range coupling interactions. It is shown how these methods can lead to the discrimination between different pathways across single bonds: 4J through coplanar or gauche arrangement of the bonds and 5J through a zig‐zag pathway or bond proximity. Applications to configurational and conformational analysis of polycyclic compounds, a trimer of isophorone, two natural terpenoids (carotol and daucol) and four steroids, are presented.