α-Lithiation-rearrangement of N-toluenesulfonyl aziridines with sec-butyllithium and (−)-sparteine: opposite sense of asymmetric induction to epoxides

The α-lithiation rearrangement of three cyclic N-toluenesulfonyl (tosyl) aziridines has been carried out using sec-butyllithium/(−)-sparteine. In each case, it was established that preferential lithiation of the S-aziridine stereocentre occurred. This is the opposite sense of asymmetric induction to that observed with epoxides.