Theoretical Analysis of the Mechanism of the 1,3-Dipolar Cycloaddition of Benzodiazepine with N-Aryl-C-ethoxycarbonylnitrilimine

Table 3

Relative energies^a (ΔE) of the low-lying isomers for 1,3-DC of benzodiazepine 1 and dipole D1 at B3LYP/6-31G(d) level.

Approach 1		Approach 2
	ΔE (kcal/mol)		ΔE (kcal/mol)
1-D1	0.00	3-D1	0.00
1-D1-TS1	1.60	3-D1-TS1	2.40
1-D1-Int1	−55.44	3-D1-Int2	−20.50
1-D1-TS2	−52.17	3-D1-TS2	−18.50
3	−76.40	4	−34.70

^aCalculated according to 1-D1 whose E is −1642,38099 ua and to 3-D1 whose E is −2749,05229 ua at B3LYP/6-31G(d).