Replacing the tert-butyl group with fluorine atom (L4) or iso-propyl group (L5) slightly decreased the enantioselectivity compared to ligand L2. In the case of ligand L6 featuring a gem-di(2-quinolyl)methyl group, an obvious decrease of enantioselectivity was observed (63% ee). As shown in the cases of ligand L7 and L8, the benzyl groups in the oxazoline scaffold are critical to the reaction efficiency.