Ambimodal reactions involve a single transition state leading to multiple products. To assess the ratio of the bifurcation products, quasiclassical trajectories (QCTs) are propagated from transition states that are randomly sampled using the molecules' zero-point energy (ZPE). However, the influence of ZPE in the resulting bifurcation ratio and time associated with the formation of bonds is not well understood. In this talk, I will discuss the process used to benchmark the effect of varying the percentage of the molecules’ inherent ZPE used in the simulation across three organic reactions with distinct mechanisms that all display post-transition state bifurcation. The three reactions studied include an intramolecular [6+4]/[4+2] cycloaddition, an asynchronous nitrene insertion, and an S<sub>N</sub>2/addition to a carbonyl on an α-bromoketone. These reactions encompass various bond formation and cleavage modes, offering a broad view of the influence of zero-point energy scaling. This work will establish a basis for future computational studies and inform the ZPE scaling used in simulating bifurcating reactions.

Effect of zero-point energy in simulating bifurcating organic reactions

ACS Spring 2022

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