During the formation of A4, two intermediates A2 and A3 have the potential to form nitrene intermediates, N1 and N2, as illustrated by the blue and green traces in Figure . While the formation of N1 involves an intramolecular acid-base reaction, both pathways necessitate an oxidative N-O bond cleavage to yield pivalate and nitrene. However, the resulting metal-nitrene intermediates, N1 and N2, exhibit free energies of 2.4 and 1.0 kcal/mol, respectively. These energy levels are even higher than the likely rate determining transition state in the alternative mechanism ( R A5-TS in Figure ). These consistently high energies suggest that the reaction does not proceed via the nitrene intermediate. Additional details are provided in the Supporting Information.