The reactive atoms of the reactant and product, together with their neighboring atoms out to a specific graphical distance (d g , Fig. ), are retained and the termini are hydrogenated at a level that conserves the hybridization of the retained atoms. The model reaction obtained in this way represents the simplest reaction that exhibits both the corresponding reaction centers and the Lewis structures of the reactive parts of both the reactant and the product. Once a model reaction is generated, the TS of this model reaction can be localized using an arbitrary transition state localization package (Fig. ). In this study, this step is carried out by Yet Another Reaction