At this stage, we proceeded to evaluate a range of other substituted chiral Box ligands with the parent core structure similar to the ligand L1 with 3.0:2.0:1.0 substrate ratio in toluene. The key results are highlighted in Table (Table ), which indicated that structural variations in each benzyl group significantly impact their performance. For instance, ligand L2 with a tert-butyl group in the para-position of the gem-dibenzyl moiety slightly increased the yield, while remarkably improved the enantioselectivity of the product (R)-4a to 84% ee, whereas the more sterically demanding ligand L3 furnished (R)-4a with diminished enantioselectivity (50% ee).