• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.207-212
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• 2001

DFT calculations have been performed on several substituted 1,4-diaza-1,3-butadienes (1,4-DABs) with electron donating and withdrawing groups at the terminal two nitrogens to investigate the reactivity of Diels-Alder reaction with acrolein. The calculated FMO (Frontier Molecular Orbital) energies for the optimized 1,4-disubstituted-1,4-DABs have been used to explain both normal and inverse electron demand Diels-Alder reactions. It is shown that the electron donating and withdrawing substituents lead to the normal(HOMO diene controlled) and inverse electron demand (LUMO diene controlled) Diels-Alder reactions, respectively.

• Bulletin of the Korean Chemical Society
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• v.29 no.11
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• pp.2093-2094
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• 2008

• Journal of the Korean Chemical Society
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• v.23 no.5
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• pp.286-295
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• 1979

In order to predict the effect of Lewis acid catalysis on the regioselectivity of the Diels-Alder reactions between unsymmetrically substituted dienes and dienophiles, the frontier orbital theory applied to the theoretical model of the Lewis acid complexed dienophile was studied by means of CNDO/2 MO. In the majority of reactions, CNDO/2 calculations gave good results in accordance with experimental orientation. Also, it was shown that the secondary orbital interaction played an important role in the regioselectivity of the Diels-Alder reaction between unsymmetrically substituted dienes and dienophiles. Although ANH's treatment is mathematically simpler than other methods, ANH's method which laid emphasis on dissymmetrical transition state gave good results on decision of regioselectivity.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2527-2530
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• 2010

The stereoselectivity of the intramolecular Diels-Alder reactions of 1 and its derivatives were investigated by ab initio calculations. The stereoselectivity mainly originates from the steric repulsion and the orbital interactions. The additional s-cis and s-trans conformations by introducing the carbonyl group at the neighbor of diene or dienophile may change the stereoselectivity, hence this kind of substitution can be utilized for stereoselectivive asymmetric synthesis.

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.448-452
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• 1994

2-Hydroxymethyl-2,5-dihydrothiophene 1,1-dioxide (1) was prepared from thiophene-2-carboxylic acid by consecutive reactions involving the Birch reduction, esterification, reduction with lithium aluminum hydride, and oxidation with Oxone$^{\circledR}$. The esterification of alcohol 1 with various unsaturated carboxylic acids provided the precursors 8 for the intramolecular Diels-Alder reaction. The cheletropic expulsion of sulfur dioxide from the esters 8 followed by intramolecular Diels-Alder reaction furnished bicyclic ${\gamma}$-and ${\delta}$-lactones.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.1021-1022
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• 2002

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.487-490
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• 2008

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1307-1308
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• 2004

• Journal of the Korean Chemical Society
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• v.19 no.4
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• pp.218-224
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• 1975

The ground state SCF IMO theory was applied to the Diels-Alder reactions of cyclopentadiene with 2-substituted acrylonitriles. The CNDO/2 MO of the separate systems, including both $\sigma$ and $\pi$ electrons, was used as starting point. The qualitative prediction of the relative reactivity was made with the calculated primary interaction energies. Here the calculated activation energies appeared to be realistic. The stereoselectivity determined by the calculated secondary interaction energies represented the endo-selectivity for all the substituents. The reason for the slightly unsymmetrical ring closure at the transition state was discussed in terms of valence inactive electron densities of the reacting atoms.

• Journal of the Korean Chemical Society
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• v.16 no.1
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• pp.33-39
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• 1972

The stabilization energies by interconjugations at the transition states in various Diels-Alder reactions were calculated. It has been found that the stabilization energies are inversely proportional to resonance energies of isolated molecules of polyene and heterocyclic system before reactions. It has been noted that the resonance energies of dienes are smaller than those of dienophiles in two different molecules. Therefore, the possibility of charge-transfer from dienes to dienophiles is hinted.