Yoshikai M, Ishibashi R, Yamada Y, Hanamoto T * Saga University, Japan
TiF
4-Mediated Regioselective Cycloaddition of 2-(Trifluoromethyl)-
N-tosylaziridine to Nitriles.
Org. Lett. 2014;
16: 5509-5511
Significance
The authors describe a mild and efficient [3+2] cycloaddition of 2-(trifluoromethyl)-N-tosylaziridine to various nitriles using TiF4 as a Lewis acid, to give the corresponding 4-(trifluoromethyl)-1,3-imidazolines in
good yields and excellent regioselectivity.
Comment
From a mechanistic point of view, the authors assume that the aziridine is activated
by TiF4, which is then attacked by the nitrile to afford the betaine intermediate, which
collapses to form the 1,3-imidazole.
