Table 1. Selected Computed Half-Lives from the Reactions in Figure 6 (CVT/SCT//MP2/cc-pVDZ).

Entry	R =	X =	ΔG(kcal mol–1)	t1/2(comp) (min)
1	H	H	–6.6	2.0 × 10–6
2	H	CN	–7.4	1.3 × 10–7
3	Me	H	–4.2	4.9 × 10–2
4	Me	Cl	–4.4	2.1 × 10–2
5	Me	CN	–4.6	4.7 × 10–3