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Volumn 73, Issue 2, 2008, Pages 435-444

Face-selective Diels-Alder reactions between unsymmetrical cyclohexadienes and symmetric trans-dienophile: An experimental and computational investigation

Author keywords

[No Author keywords available]

Indexed keywords

COMPUTATIONAL METHODS; DENSITY FUNCTIONAL THEORY; GEOMETRY; MOLECULAR ORBITALS; OPTIMIZATION; REACTION KINETICS;

EID: 40949135011     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo701884d     Document Type: Article
Times cited : (10)

References (133)
  • 12
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    • The ORTEP diagram can be seen from Figure 1 in the Supporting Information. The X-ray data for 3nx were collected at 293(2) K on a diffractometer with graphite monochromated Mo Kα radiation (λ, 0.71073 Å, The structure was solved by direct methods (SHELXS-97, Crystals of 3nx are colorless with a size of 0.27 x 0.19 x 0.18 mm 3: prism, space group P21/c, a, 9.005(5) Å, b, 14.836 (8) Å, c, 14.242(8) Å, α, 90.00°, β, 91.149(9)°, γ, 90.00°, V, 1902.2(17) Å3, Z, 4. Crystallographic data (excluding structure factors) for this structure have been deposited with the Cambridge Crystallographic Data Center as supplementary publication number CCDC 607025. Copies of the data can be obtained free of charge, on application to CCDC, 12, Union Road, Cambridge CB2 TEZ, UK [fax: +44(0)-1223-336033; e-mail:deposit@ccdc. cam.ac.uk
    • 3, Z = 4. Crystallographic data (excluding structure factors) for this structure have been deposited with the Cambridge Crystallographic Data Center as supplementary publication number CCDC 607025. Copies of the data can be obtained free of charge, on application to CCDC, 12, Union Road, Cambridge CB2 TEZ, UK [fax: +44(0)-1223-336033; e-mail:deposit@ccdc. cam.ac.uk].
  • 90
    • 41249099478 scopus 로고    scopus 로고
    • See Table S1 in the Supporting Information for activation parameters for diastereomeric transition states as well as the predicted selectivities obtained at the B3LYP/6-311+G**//B3LYP/6-31G* level of theory.
    • See Table S1 in the Supporting Information for activation parameters for diastereomeric transition states as well as the predicted selectivities obtained at the B3LYP/6-311+G**//B3LYP/6-31G* level of theory.
  • 91
    • 41249097878 scopus 로고    scopus 로고
    • ‡ delocalizations was found to be quite negligible, suggesting that this interaction cannot be responsible for the product selectivity in the present case. See Table S2 in the Supporting Information for further details.
    • ‡ delocalizations was found to be quite negligible, suggesting that this interaction cannot be responsible for the product selectivity in the present case. See Table S2 in the Supporting Information for further details.
  • 92
    • 41249098947 scopus 로고    scopus 로고
    • See Table S4 in the Supporting Information for a full list of Coulombic interactions calculated with use of the Mulliken partial charges obtained at the mPW1PW91/6-311+G**//mPW1PW91/6-31G* level of theory.
    • See Table S4 in the Supporting Information for a full list of Coulombic interactions calculated with use of the Mulliken partial charges obtained at the mPW1PW91/6-311+G**//mPW1PW91/6-31G* level of theory.
  • 93
    • 41249093546 scopus 로고    scopus 로고
    • The effect was found to be quite similar even with an alternative orientation of the -OTMS group, see Figure 1.
    • (a) The effect was found to be quite similar even with an alternative orientation of the -OTMS group, see Figure 1.
  • 94
    • 41249083779 scopus 로고    scopus 로고
    • ‡, which could offer additional stabilization. See Table S5 in the Supporting Information.
    • ‡, which could offer additional stabilization. See Table S5 in the Supporting Information.
  • 95
    • 41249101041 scopus 로고    scopus 로고
    • ‡ it was much closer, 3.1 Å. See Table S4 in the Supporting Information.
    • ‡ it was much closer, 3.1 Å. See Table S4 in the Supporting Information.
  • 96
    • 41249102806 scopus 로고    scopus 로고
    • To obtain an approximate measure of Coulombic interactions due to the oxygen of the -OTMS group toward diastereoselectivity, we have carried out additional single-point energy calculations by replacing the oxygen of the -OTMS groups with a dummy atom. The difference in energies (bottom-of-the-well values) between the diastereomeric transition states 4nx ‡ and 4xn‡ were found to be only 0.1 kcal/mol. The corresponding difference is about 0.5 kcal/mol in the real system, implying that the Coulombic interaction indeed contributes to the predicted diastereoselectivity
    • ‡ were found to be only 0.1 kcal/mol. The corresponding difference is about 0.5 kcal/mol in the real system, implying that the Coulombic interaction indeed contributes to the predicted diastereoselectivity.
  • 97
    • 41249098299 scopus 로고    scopus 로고
    • The concerted nature of these transition states was further confirmed by the Intrinsic Reaction Coordinate (IRC) calculations, starting from the transition state, toward the reactant and the product. It was noticed that the transition structures in general show a smooth connection to the products, without the involvement of any intermediates along the IRC trajectory. See Figure S2 in the Supporting Information for the IRC profile generated at the mPW1PW91/6-31G* level of theory
    • The concerted nature of these transition states was further confirmed by the Intrinsic Reaction Coordinate (IRC) calculations, starting from the transition state, toward the reactant and the product. It was noticed that the transition structures in general show a smooth connection to the products, without the involvement of any intermediates along the IRC trajectory. See Figure S2 in the Supporting Information for the IRC profile generated at the mPW1PW91/6-31G* level of theory.
  • 98
    • 41249091047 scopus 로고    scopus 로고
    • It appears that the bond length threshold at the mPW1PW91/6-311+G **//mPW1PW91/6-31G* level of theory is about 2.06 Å, beyond which the delocalizations involving the incipient bonds are absent.
    • (a) It appears that the bond length threshold at the mPW1PW91/6-311+G **//mPW1PW91/6-31G* level of theory is about 2.06 Å, beyond which the delocalizations involving the incipient bonds are absent.
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    • 6 bond.
    • 6 bond.
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    • Frisch, M. J.; et al, Gaussian 98, Revision A.11.4; Gaussian, Inc.: Pittsburgh, PA, 2001.
    • (a) Frisch, M. J.; et al, Gaussian 98, Revision A.11.4; Gaussian, Inc.: Pittsburgh, PA, 2001.
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    • Gaussian, Inc, Wallingford, CT, See the Supporting Information for a full citation
    • (b) Frisch, M. J.; et al. Gaussian 03, Revision C.02; Gaussian, Inc.: Wallingford, CT, 2004. See the Supporting Information for a full citation.
    • (2004) Gaussian 03, Revision , Issue.C.02
    • Frisch, M.J.1
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    • Issues related to the mechanism of the Diels-Alder reaction remained a topic for several leading discussions as it can follow concerted or step-wise pathways depending upon the nature of the reactants.25a-f However, many reports are available wherein only the concerted pathway has been considered to explain selectivity of reactions having sufficiently large size reactants.25g-k In general, the concerted pathways are reported to have lower barriers as compared to the corresponding step-wise route. 25l (a) Storer, J. W, Raimondi, L, Houk, K. N. J. Am. Chem. Soc. 1994, 116, 9675
    • 25l (a) Storer, J. W.; Raimondi, L.; Houk, K. N. J. Am. Chem. Soc. 1994, 116, 9675.
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    • Lutz, R. E. Organic Syntheses; Wiley: New York, 1960; Collect. Vol. III, p 248.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.