Fig. 3. Difference in free energies of activation (ΔG‡B3LYP) between cyclopropane-substituted difluoro-VCP and reference 9j. Green = lower ΔG ^‡ (<25.3 kcal mol^–1), orange = 0–5 kcal mol^–1 higher ΔG ^‡ and red = >5 kcal mol^–1 increase in ΔG ^‡.