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Experimental and theoretical studies of Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene.

Jasiński R, Kwiatkowska M, Sharnin V, Barański A - Monatsh. Chem. (2013)

Bottom Line: The Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene yields a mixture of carbodiene Diels-Alder adducts.B3LYP/6-31G(d) simulations indicate that the conversion of addends into methyl (1R*,2S*,3S*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate occurs via two-stage heterodiene Diels-Alder reaction and (in a second step) skeleton rearrangement of the primary cycloadduct, whereas the reaction leading to methyl (1R*,2R*,3R*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate is a single-step process.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Technology, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland.

ABSTRACT

Abstract: The Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene yields a mixture of carbodiene Diels-Alder adducts. B3LYP/6-31G(d) simulations indicate that the conversion of addends into methyl (1R*,2S*,3S*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate occurs via two-stage heterodiene Diels-Alder reaction and (in a second step) skeleton rearrangement of the primary cycloadduct, whereas the reaction leading to methyl (1R*,2R*,3R*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate is a single-step process.

No MeSH data available.


Geometries of products of Diels–Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene in the gas phase according to B3LYP/6–31G(d) calculations
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Fig5: Geometries of products of Diels–Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene in the gas phase according to B3LYP/6–31G(d) calculations

Mentions: Within cycloadducts 3–6 new σ bonds are already fully formed. The structure of both CDA adducts is typical of norbornenes (see Fig. 5). The distance between H7 and H6 atoms in molecule 3, relevant for determining the stereoisomerism of the compounds, has a value of 2.45 Å (a correlation signal between protons H6 and H7 is found in the NOESY spectrum), whereas the distance in molecule 4 is as large as 3.76 Å (no correlation signal between protons H6 and H7 is found in the NOESY spectrum). The conformations of HDA adducts, in turn, differ with respect to one another significantly. In particular, bicyclic N-oxide 5 backbone has a “C-like” conformation, whereas N-oxide 6 has a “Z-like” conformation (see Fig. 5).Fig. 5


Experimental and theoretical studies of Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene.

Jasiński R, Kwiatkowska M, Sharnin V, Barański A - Monatsh. Chem. (2013)

Geometries of products of Diels–Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene in the gas phase according to B3LYP/6–31G(d) calculations
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4495048&req=5

Fig5: Geometries of products of Diels–Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene in the gas phase according to B3LYP/6–31G(d) calculations
Mentions: Within cycloadducts 3–6 new σ bonds are already fully formed. The structure of both CDA adducts is typical of norbornenes (see Fig. 5). The distance between H7 and H6 atoms in molecule 3, relevant for determining the stereoisomerism of the compounds, has a value of 2.45 Å (a correlation signal between protons H6 and H7 is found in the NOESY spectrum), whereas the distance in molecule 4 is as large as 3.76 Å (no correlation signal between protons H6 and H7 is found in the NOESY spectrum). The conformations of HDA adducts, in turn, differ with respect to one another significantly. In particular, bicyclic N-oxide 5 backbone has a “C-like” conformation, whereas N-oxide 6 has a “Z-like” conformation (see Fig. 5).Fig. 5

Bottom Line: The Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene yields a mixture of carbodiene Diels-Alder adducts.B3LYP/6-31G(d) simulations indicate that the conversion of addends into methyl (1R*,2S*,3S*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate occurs via two-stage heterodiene Diels-Alder reaction and (in a second step) skeleton rearrangement of the primary cycloadduct, whereas the reaction leading to methyl (1R*,2R*,3R*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate is a single-step process.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Technology, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland.

ABSTRACT

Abstract: The Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene yields a mixture of carbodiene Diels-Alder adducts. B3LYP/6-31G(d) simulations indicate that the conversion of addends into methyl (1R*,2S*,3S*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate occurs via two-stage heterodiene Diels-Alder reaction and (in a second step) skeleton rearrangement of the primary cycloadduct, whereas the reaction leading to methyl (1R*,2R*,3R*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate is a single-step process.

No MeSH data available.