At each stationary point geometry, single-point CCSD(T)-F12a/cc-pVTZ-F12 were performed. Quantum chemistry outputs necessary to reproduce the thermodynamic and kinetic calculations are available in the ESI. Of the 85 calculations performed, over a third had T 1 diagnostic values above 0.02, indicating that many of these structures likely have multireference character. Three of these had T 1 diagnostic values above 0.05, corresponding to the formation of alkoxy radicals from RO 2 . The D 1 values also show similar effects with over a third of structures having a value greater than 0.1. The potential for multireference behavior, as indicated by these diagnostics, is thought to increase the uncertainties in the final energies to approximately 21 kJ/mol.