The inter scoring function follows a similar approach as the ts scoring function, but here the difference in electronic energy between intermediate 2 and the reactants is calculated (intermediate-scoring energy). A template structure of intermediate 2 from Liu et al. is used and the present catalyst is replaced with the catalyst that is to be evaluated. Ten conformers of the catalyst are generated while keeping the atoms of the template fixed to their respective position in the reference structure of intermediate 2. After RMSD pruning, each conformer undergoes optimisation in methanol and the lowest energy conformer is retained. The lowest energy conformer of the catalyst on its own is obtained as previously described and the activation energy is calculated as the difference between the electronic energy of intermediate 2 and the sum of electronic energies of the catalyst, pNBA and MA (∆E