To check if the VLAO method can reproduce this ligand engineering, we performed quantum chemical calculations using the VL. First, the VL parameters were tuned to reproduce PPh3 (hereafter, this parameter set is referred as pVL Ph ): Electronic parameters 𝑟 7 and 𝜙 7 were tuned to be 1.606 Å and 64.215°, respectively, to reproduce both LTEP and pyramidalization parameter of PPh3 (2174.5 cm -1 and 7.14 degree 1/2 ). Steric parameters in the ovoid LJ-potential were set to reproduce the steric effect of PPh3, where a1, a2, b1, b2, c1, c2 and d were tuned to fit geometric feature of the phenyl group bonded to a phosphorous atom as shown in Figure . Then, geometry optimizations of transition states for the 1,3-dipolar cycloaddition were performed using thus-tuned VL, and (endo)-TS was calculated to be more stable than (exo)-TS by 0.44 kcal/mol (Figure ). The exo selectivity (𝜉 LMN ) was estimated based on the following equation: