Level 2 – Case 18
124
N
CO 2 Me
NO 2
N
CO 2 Me
Ph
HOMO
N
CO 2 Me
CO 2 Et
5
6
10.51 eV
0.85 eV
inverse Diels Alder
1
0.61 eV
9.44 eV
LUMO
10.13 eV
1.60 eV
Figure 18.5
In Summary
The unusual reactivity of azadiene 1, characterized by the participation in both the
normal and the inverse Diels-Alder reactions can be explained by the fact that the
HOMO and the LUMO of 1 are very close in energy. The study of the FMO energies in other substituted 2-azadienes structurally related to 1 justifies their behavior either in HOMO-controlled (normal) or in LUMO-controlled (inverse) DielsAlder cycloadditions.
A Ad dd di it ti io on na al l C Co om mm me en nt ts s
This problem is based on the work by Pinho e Melo TMVD, Fausto R, d’A Rocha
Gonsalves AM, Gilchrist TL (1998) J. Org. Chem. 63:5350-5355.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
Cycloadditions: effect of the substituents on the energy of the FMO.
124
N
CO 2 Me
NO 2
N
CO 2 Me
Ph
HOMO
N
CO 2 Me
CO 2 Et
5
6
10.51 eV
0.85 eV
inverse Diels Alder
1
0.61 eV
9.44 eV
LUMO
10.13 eV
1.60 eV
Figure 18.5
In Summary
The unusual reactivity of azadiene 1, characterized by the participation in both the
normal and the inverse Diels-Alder reactions can be explained by the fact that the
HOMO and the LUMO of 1 are very close in energy. The study of the FMO energies in other substituted 2-azadienes structurally related to 1 justifies their behavior either in HOMO-controlled (normal) or in LUMO-controlled (inverse) DielsAlder cycloadditions.
A Ad dd di it ti io on na al l C Co om mm me en nt ts s
This problem is based on the work by Pinho e Melo TMVD, Fausto R, d’A Rocha
Gonsalves AM, Gilchrist TL (1998) J. Org. Chem. 63:5350-5355.
S Su ub bj je ec ct ts s o of f R Re ev vi is si io on n
Cycloadditions: effect of the substituents on the energy of the FMO.