Overall, the neutral path is the best predictor of β isomers, with an accuracy of 63 %. However, this path also leads to 204 β predictions that are in fact α. The cationic path is a better predictor of α and mix, but with accuracies of only 29 % and 43 %. The accuracy of the cationic path calculations does not improve noticeably for the subset with 153 products that are obtained under cationic conditions as can be seen in Figure (the large percentage increase in false mix predictions for the α isomer is likely due to the small numbers involved). Similarly, the accuracy is relatively unchanged in going to the monodentate subset (Figure and), keeping in mind that the relatively low number of observed α products and mix that can make percentage changes unreliable. So the fact that our calculations are based on the (PPh 3 ) 2 ligand, while the majority of the experimental data is obtained with the DPPP or DPPE bidendate ligands does not appear to be a source of the low predictive accuracies for α and mix.