Trifluoromethylhypofluorite reacts with N-substituted aziridines with ring opening and 1, 3-addition of F on nitrogen and OCF3 on carbon. Three R substituents are discussed. With R benzenesulfonyl or chlorine one mole of CF3OF is added and N-fluorobenzenesulfonamides and N-chloro, N-fluoroamine are obtained. With R 4-nitrobenzoyl two moles of CF3OF are added and a N, N-difluoroamine is isolated.