[3,3] and [5,5] Sigmatropic Shifts of Polycyclic Dibutadienylcyclopropanes: Computational Explorations of Concerted and Stepwise Mechanisms and “Negative Activation Energies”

2026-01-14 | [3,3] and [5,5] Sigmatropic Shifts of Polycyclic Dibutadienylcyclopropanes: Computational Explorations of Concerted and Stepwise Mechanisms and “Negative Activation Energies” – J. Am. Chem. Soc. Nathan C. Incandela, Qingyang Zhou, K. N. Houk*.