. 2021 Mar 22;26(6):1774. doi: 10.3390/molecules26061774

Table 1.

Regioselectivity in ring opening of nonactivated 2-substituted aziridines either at C2 (pathway “b”) with a substituent or at C3 (pathway “a”) without any substituent depending on the substrate, the electrophile, and the nucleophile.

	Lewis Acid	RCO⁺	H⁺	R⁺	TMS⁺
R¹	Lewis Acid	RCO⁺	H⁺	R⁺	TMS⁺
–CH=CH₂, –CH=CH–COOEt	C2^c	C2	C2 ^c	C2	C2
Aryl	C2	C2	C2	C2 ^c	C2 ^c
COR, COOR, CONH₂	C3	C2	C2	C2	C2
Alkyl	C3	C3 and/or C2 ^a	C3	C3 ^b	C3

^a Depending on the nucleophile (e.g., azide attacks at C2; alcohol attacks at C3). ^b Among halides, only the fluoride ion attacks the C3 position to a major extent. ^c Proposed regioselectivity (no experimental data available).