The second classification model utilized an 80% N incorporation threshold (Figure ), wherein the computed N-C6 bond length in the triflylated heterocycle serves as an effective criterion for categorizing substrates into those yielding high (> 80%) or lower isotopic yield, achieving an accuracy of 90%. Triflylated substrates with computed N-C6 bond distance exceeding 1.357 Å consistently exhibit N incorporation above 80%. Specifically, the model suggests that as the triflyl N-C6 bond length increases, C6 becomes more electrophilic, rendering this carbon atom more susceptible to nucleophilic attack. The model misclassified compounds 22, 32, and 34, predicting higher isotopic labeling efficiency than what is empirically achieved. The simple model fails to account for additional reaction intricacies (e.g., increased reaction barrier for the 6p electrocyclic ring opening or the 6-exo-trig closure steps), which could potentially explain the observed misclassifications. Nonetheless, this model can be a valuable tool for anticipating substrates that can produce high isotopic yields. The model accuracy in the validation set is 83%, demonstrating robustness.