Fragmentations are controlled by stereochemistry (Trans isomer - Severe interactions)
NOTE: Important charges and non-bonding electrons are shown throughout the animation except during the transition phase
Click the structures and reaction arrows in sequence to view the 3D models and animations respectively
For the trans isomer, only the less stable (severe) conformation fragments. This is because the mesylate group is now anti-periplanar to the correct C-C bond (green bonds). The trans isomer only forms the iminium ion which undergoes hydrolysis in very low yields, this is because the equilibrium lies very much on the side of the more stable (less severe) conformation.