Description:
<jats:title>Abstract</jats:title><jats:p>The NMR spectra of the cycloaddition adducts between tetracyanoethylene oxide (TCNEO) and norbornadiene derivatives have been studied. It was shown that there was significant long‐range coupling between 7‐<jats:italic>anti</jats:italic> and <jats:italic>endo</jats:italic> hydrogens in the adducts and that this long‐range coupling was solvent dependent. Based on the present study it is concluded that the long‐range coupling between <jats:italic>endo</jats:italic> and <jats:italic>anti</jats:italic> hydrogens can be as high as 4·1 Hz when an electronegative substituent is attached to the carbon which bears <jats:italic>endo</jats:italic> hydrogen.</jats:p>