It is noteworthy that Q 2 values range between 0 and 1, whereby higher values indicate a more robust explanation for the data. We carried out the initial GPR analysis using the experimental TOF values and pairs of two of the three theoretical parameters (LUMO energy level, Gw°, and GH ‡ ) obtained for the 15 boranes shown in Figure as training data. This GPR analysis resulted in three distinct models, labelled Model I (Gw° vs GH ‡ ; Q 2 = 0.75), II (LUMO level vs GH ‡ ; Q 2 = 0.76), and III (LUMO level vs Gw°; Q 2 = 0.18) (Figure ). Subsequently, we used the theoretical parameters of the other 39 triarylboranes to predict their TOF values using these three models. We found intriguing inconsistencies among the TOF values for the B derivatives that contain meta-CF3 groups predicted using Model I and those predicted using Model II or III (Figure ). For example, when Model I was applied, the TOF values of B 4b , B 4c , and B 4e were predicted to be 3.50, 3.66, and 3.59, respectively; however, using Model II (or III), the corresponding TOF values were predicted to be 0.55 (2.10), 0.23 (2.03), and 0.55 (1.92) respectively (Figures and). A critical difference between Model I and Model II or III is the use of the LUMO energy levels in the GPR analysis. Thus, to evaluate whether the LUMO levels can serve here as a critical parameter for the prediction of the TOF for the production of 3aa, we additionally synthesized B 4b , B 4c , and B 4e , and confirmed that these boranes demonstrate excellent activity for the reductive alkylation of 1a with 2a under the model reaction conditions (Figure ). Subsequently, we evaluated the root mean square errors (RMSE) of Model I, II, and III using the experimental TOF values for B 4b , B 4c , and B 4e as test data; a model with a smaller RMSE value is considered more accurate. The accuracy of Model I (RMSE = acidity of triarylboranes, such as the LUMO energy level, is inappropriate for the prediction of the catalytic activity of triarylboranes under the chosen conditions.