Table 3. Reaction Barriers (ΔG^⧧) for the Attack of Cp to the CIP and Their Decomposition Based on the DLPNO-CCSD(T)/LED Scheme (eq 4)^a.

	TS
	RA			RB
	3a	3a′	3a′ – 3a	3b	3b′	3b′ – 3b
ΔG⧧b,c	16.7	19.3	2.6 (exp 1.1d)	16.9	18.8	1.9 (exp 1.6d)
ΔE⧧	–3.4	0.0	3.4	4.6	7.3	2.7
ΔEgeo-prep⧧	27.3	28.4	1.1	36.2	37.1	0.9
ΔEint⧧	–30.7	–28.4	2.3	–31.6	–29.8	1.8
ΔEdisp⧧	–34.7	–29.6	5.1	–37.7	–37.0	0.7
ΔEno-disp⧧	4.0	1.2	–2.8	6.1	7.2	1.1

^aAll energies are in kcal mol^–1. The free energy difference between the TSs is also reported (and decomposed) and compared with available experimental data.

^bReaction RA at 25 °C.¹⁵

^cReaction RB at −40 °C.¹⁶

^dObtained from the experimental er^15,16 according to the Curtin–Hammett principle.