Mass spectrometric studies–VI: Aziridines

The mass spectra of C-alkylaziridines show that generally β-cleavage is the most important fragmentation, although α-cleavages also occur as do γ-, and δ- and ϵ-cleavages in appropriate examples. A surprising rearrangement of the β-cleavage ions has been explained as the result of a four-centre cyclization followed by fragmentation. Other decompositions occur via transannular cleavages with and without hydrogen transfer. α-Cleavage appears to be the most important fragmentation of N-alkylaziridines. N-Phenylaziridine shows very marked 1,2-phenyl-migration before fragmentation.