The starting material for this route is a norbornane derivative with a good leaving group in position 2. If the leaving group is on the exo- face, electron density from the σ bond between carbons 1 and 6 is donated into the σ* antibond between carbon 2 and the leaving group (see Figure 8b).
If the leaving group is on the endo- face, the leaving group first leaves on its own. Then electron density from the σ bond between carbons 1 and 6 is donated into the resulting empty atomic orbital on carbon 2. However, this formation route is much slower than that of the exo- isomer because the σ bond cannot provide anchimeric assistance for the first step, making the activation energy to the first transition state much higher. Additionally, if there is a high concentration of reactive electrophiles in the reaction mixture, formation of a newly substituted norbornane derivative may preclude non-classical ion formation.
An example of this formation route is the reaction that led Winstein and Trifan to propose the delocalized structure of the 2-norbornyl cation. 2-norbornyl tosylates and brosylates form the 2-norbornyl cation through this route as an intermediate towards solvolysis.