After establishing the preferred dual activation mode (i.e., the new Wynberg ion-pair-hydrogen bonding model with 2-naphthol as additive), we subsequently explored the origin of stereoinduction in this reaction. In order to shed light on the source of energy differences between TSwyn2A(S) and TSwyn2A'(R), we performed a form of energy decomposition analysis (EDA) for the two transition state (TS) structures (see Fig. below). We note here that this same approach for EDA analysis has recently been adopted for the electrophilic trifuloromethylthiolation of β-keto ester with N Trifluoromethylthiophthalimide by Xue and coworkers. The activation energy ΔE # of the TSs can be written as ΔE # = ΔEdef + ΔEint, where the terms ΔEdef and ΔEint are the deformation and interaction energies, respectively. The deformation energy ΔEdef is the energy difference that arises from structural changes toward the TS formation. The interaction energy ΔEint corresponds to the energy difference between the sum of the cationic catalyst, the anionic oxinidole substrate, the neutral N-thiocyanatophthalimide substrate and the 2-naphthol additive, minus the complex at the TS structure. The results are presented in Table . Both ΔΔEint and ΔΔEdef are positive, meaning that the two components contribute synergistically to the overall energy difference between TSwyn2A(S) and TSwyn2A'(R).