Table 1. Relative energies (in kcal mol⁻¹) for the species involved in Steps 1 in terms of enthalpies (ΔH) and free energies (ΔG) in aqueous solution at 298.15 K.

Site/face	Unimolecular barrier		Bimolecular barrier		Reaction energy
	ΔH	ΔG	ΔH	ΔG	ΔH	ΔG
Ns 4-endo	−0.30	−0.18	−6.4	3.0	−28.2	−30.8
No 4-endo	3.0	3.9	0.58	8.9
Ns 5-endo	−0.30	0.73	−7.0	3.1	−34.1	−32.0
No 5-endo	3.3	2.7	−0.09	8.7
Reference values for C atoms taken from reference [21]
C2 4-endo	1.1	1.2	−1.5	6.9	−20.1	−22.3
C3s 4-endo	1.7	2.0	−5.1	4.6	−20.1	−22.6
C3o 4-endo	−0.9	−0.3	−3.0	6.2
C4s 4-endo	1.6	1.5	−5.1	4.1	−20.1	−22.8
C4o 4-endo	1.0	2.3	0.0	8.9
C5s 4-endo	3.9	5.2	−3.3	6.7	−18.5	−20.7
C5o 4-endo	1.3	0.9	−0.9	7.3