Regiochemical Pathway in the Ring Opening of 2-Acylaziridines †

The aziridine ring bearing electronwithdrawing substituent, so called activated aziridine, is quitelabile to the incoming nucleophiles. Unactivated aziridine isstabilized by the electron-donating substituent at the ringnitrogen with the resistance to the reaction with nucleophilesfor the ring-opening reactions. Thereby, proper activation isneeded to carry out the reaction of unactivated aziridines,and often made through chelation with Lewis acid or bondformation with acyl, trimethylsilyl, protonyl or alkyl grouptoward aziridinium ion.An extensive study on the regiochemical pathways hasbeen carried out with unactivated aziridine since we preparedenantiomerically pure 2-substituted aziridine bearing N-(α-methyl)benzyl group.