Table 2.

Summarization of the imaginary frequencies (i) and the distances between the carbon atom of the benzyl group and the oxygen atom in TS, as well as the activation energies of the formation of o-QMR[4]A from ABR[4]A and HBR[4]A ($\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{F}}$) and the activation energies of the backward reaction ($\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{B}}$).

R	imaginary mode (i)	distance H2C..OR	GFN2-xTB (kcal mol−1)		B97-3c (kcal mol−1)		wB97XD (kcal mol−1)
	(cm−1)	(A)	$\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{F}}$	$\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{B}}$	$\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{F}}$	$\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{B}}$	$\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{F}}$	$\mathrm{\Delta }{\mathrm{E}}_{\mathrm{a}}^{\mathrm{B}}$
H	i338.77	1.981	40.63	7.38	22.26	9.64	32.29	13.92
Me	i255.66	2.027	41.29	5.12	21.86	6.18	31.58	10.38
Et	i228.21	2.047	40.67	4.10	20.59	5.44	30.12	9.33
nPro	i238.16	2.029	40.55	3.56	20.50	6.20	30.05	10.40
iPro	i205.37	2.046	39.45	3.72	20.32	5.38	29.92	9.20
nBut	i237.69	2.027	40.53	4.56	20.52	6.28	29.87	10.22
tBut	i218.17	2.017	39.89	5.19	21.63	9.06	30.82	12.71