The direction of rearrangement depends on the nucleophile

The important difference between the following two reactions is the nucleophile used in the reaction. Both reactions go through a very similar aziridinium intermediates, so the difference must be due to the regioselectivity with which the three-membered ring opens in each case. CLICK the nucleophiles below to view each 3D animation respectively.



F. Durrat, M. V. Sanchez, F. Couty, G. Evano and J. Marrot, European J. Org. Chem., 2008, 2008, 3286–3297.