NOTE: Important charges and non-bonding electrons are shown throughout the animation except during the transition phase
Click the structures and reaction arrows to view the 3D models and animations respectively
Hydroxide opens the aziridinium intermediate at the less hindered end, so the amine migrates from the primary to the secondary position. Primary centres can take part in fast SN2 reactions but cannot undergo SN1. Hydroxide is a good nucleophile and can therefore do fast SN2 reactions, whereas water is a poor nucleophile and cannot.