Energy barrier (kcal mol⁻¹) for both carboxylation paths and charge analysis parameters evaluated at two different distances between the enolate and the epoxide groups.

Enolate–epoxide distance (Å)	4.0	13.7
Path 1, ΔG‡ (kcal mol−1)	30.7	25.3
Path 2, ΔG‡ (kcal mol−1)	26.8	39.8
Charge on enolate	−0.749	−0.784
Charge on epoxide	−0.607	−0.565