The final states of the reaction show stronger differences in the intrinsic electronic interaction energy for 6-4 (ΔEint(elec) = -422 kJ mol -1 ) compared to 8-4 (-387 kJ mol -1 ). All interaction terms in 6-4 are larger compared to 8-4, regardless of whether it is repulsive or attractive. However, the orbital interaction ΔEorb is the decisive term for the difference of 6-4 and 8-4 in the final state (ΔΔEorb = 46 kJ mol -1 ). The ca. 3% increase in this term is the result of better orbital overlap, which leads to an increase of ΔEorb and ΔEPauli overcompensating the larger steric repulsion. The pEDA of the transition state leads to much smaller values. The higher barrier towards 6-4 found in the last sub-section is reflected in a more positive bonding energy (ΔΔEbond = 8 kJ mol -1 ).