The copper catalyzed regioselective and stereospecific opening of CF3-aziridines is reported. This method focuses on the synthesis of α-CF3-β-arylethylamines, which can be potential key intermediates in the synthesis of synthetic analogues and biologically active molecules. Density functional theory calculations reveal the nature of the active copper species and the role of the LiClMgX2 (X = Cl or I) as a Lewis acid. Further, the computed mechanism accounts for the high regioselectivity of this transformation.