text: In another case, the stereoelectronic effect can result in an increased contribution of one resonance structure over another, which leads to further consequences in reactivity. For 1,4-benzoquinone monoxime, there are significant differences in the physical properties and reactivities between C2-C3 double bond and C5-C6 double bond.   For instance, in the H NMR, J higher than J The C2-C3 double bond also selectively undergoes Diels–Alder reaction with cyclopentadiene, despite the increased steric hindrance on that side of the molecule. These data illustrate an increased contribution of resonance structure B over structure A. The authors argue that the donation from n to σ*  orbital lengthens the C4–C3 bond (C4 is the carbon bearing the nitrogen substituent), which reduces the p-p overlap between these two atoms.  This in turn decreasing the relative importance of structure A which has a double bond between C4 and C3.