Table 1.

Formation and ring opening of aziridinium ions: synthesis of optically active β-haloamines

entry	substrate	halogenating agent	product	#ratio of isomers	yield (%)
1	1a	+DAST	3a/4a	5:1	71
2	1a	NCS/PPh3	5a		70
3	1a	NBS/PPh3	6a		86
4	1b	NBS/PPh3	6b		63
5	1c	NBS/PPh3	6c		44
6	1a	I2/PPh3/imidazole	7a/8a	6:1	73

^#Determined by ¹H NMR;

⁺diethylaminosulfur trifluoride (DAST)