A DFT Mechanistic Study of the Regio-, Chemo-, and Stereo- Selectivities of the (3 + 2) Cycloaddition of Diarylnitrone Derivatives with 1-(4-Nitrophenyl)-5H-Pyrrolin-2-One

Table 2

Activation and reaction energies corresponding to transition states and products for the 32CA reaction of 1-(4-nitrophenyl)-5H-pyrrolin-2-one A2 and A1 (para, R=CH_3, OCH₃, (CH₃)₂N, Br, and NO₂) at the M06/6-311G (d, ) level of the theory in the gas phase for path A. All energies are in kcal/mol.

Para
Substituents	TS1A-EXO	TS2A-ENDO	TS3A-EXO	TS4A-ENDO	P1A-EXO	P2A-ENDO	P3A-EXO	P4A-ENDO
H	4.5	10.6	9.6	7.6	−23.4	−20.4	−19.7	−20.3
ERGs
CH3	3.1	10.6	8.3	7.6	−23.5	−20.1	−19.5	−19.9
OCH3	9.2	17.9	14.7	15.5	−15.9	−12.1	−11.7	−12.1
(CH3)2N	3.9	10.2	4.9	7.2	−24.2	−19.0	−18.3	−19.0
EAGs
Br	4.2	11.2	9.8	8.2	−23.3	−19.8	−19.0	−19.8
NO2	5.1	12.0	15.6	9.2	−22.6	−19.6	−18.2	−19.2