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Tetrahedron
Volumn 50, Issue 17, 1994, Pages 4937-4948
Conformational analysis of 2-halotetrahydrothiopyran S-oxides. Diminution of the anomeric effect in S(O)-C-X compared to S-C-X segments.
Author keywords

[No Author keywords available]
Indexed keywords

SULFOXIDE; TETRAHYDROPYRAN DERIVATIVE;
EID: 0028288903     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4020(01)90406-5     Document Type: Article
Times cited : (15)
References (53)
  • 1
    • 0006205163 scopus 로고
    • Conformational preference of the s=O group.3. Continued evidence for a very strong s-s=o anomeric interaction from the nmr spectroscopic study of 44,5,5-tetramethyl-1,2-dithiane 1-oxide
    • Conformational Preference of the S=O Group. 4. For Part 3, see:
    • (1988) Tetrahedron , vol.44 , pp. 5653
    • Juaristi1    Cruz-Sánchez2    Petsom3    Glass4
  • 8
    • 84914011515 scopus 로고    scopus 로고
    • Juaristi, E.; Cuevas, G. Recent Studies of the Anomeric Effect, Tetrahedron Report No. 315
  • 10
    • 84914011514 scopus 로고    scopus 로고
    • 9
  • 13
    • 84990683927 scopus 로고
    • Theoretical studies on the conformation of saccharides. V. Hydration of the acetal segment in glycosides
    • Solvent effects on the equilibria of 2-polar substituted tetrahydropyrans are reproduced by theoretical investigations:
    • (1983) International Journal of Quantum Chemistry , vol.23 , pp. 765
    • Tvaroska1    Kozár2
  • 16
    • 0004151408 scopus 로고
    • Nevertheless, the twist-boat conformation of tetrahydrothiopyran is ca. 4.0 kcal/mol higher in energy than the chair energy minimum:, American Chemical Society, Washington, ACS Monograph 177
    • (1982) Molecular Mechanics , pp. 236
    • Burkert1    Allinger2
  • 26
    • 84914011512 scopus 로고    scopus 로고
    • 20 and reduces its overlap with the acceptor σ(inC-X) antibonding orbital.
  • 28
  • 30
    • 84914011511 scopus 로고    scopus 로고
    • See, also: Juaristi, E.; Ordo\́~nez, M. Conformational Preference of the Sulfinyl Group in Six-Membered Heterocycles, In Organosulphur Chemistry Page, P.C.B., Ed.; Academic Press: London, In press.
  • 40
    • 84914011510 scopus 로고    scopus 로고
    • This is, of course, only a rough estimate since it does not take into account the structural differences between the reference models (monosubstituted cyclohexane, parent thiane oxide) and the 2-substituted thiane oxides. For example, the C-S bond length (ca. 1.8 Å) is substantially longer than the C-C bond length (ca. 1.5 Å), and so the purely steric repulsion in an axial 2-halothiane oxide should be less than that present in the corresponding axial halocyclohexane. As a consequence, the magnitude of the S-C-X anomeric effect tends to be overestimated in this simple analysis. See, for example pp 5025-5028.
  • 41
    • 84914011509 scopus 로고    scopus 로고
    • Interestingly, molecular mechanics calculations (MM2 program in Hyperchem package, Release 2 for Windows Autodesk, Inc., Sausalito, CA, 1992) suggest that cis-2ax should be 0.9 kcal/mol higher in energy than cis-2eq, in the absence of quantum mechanical effects. According to these calculations, dipole-dipole electrostatic interactions are essentially equal in cis-2ax and cis-2eq, although substantial ring puckering causes the O-S-C-Br torsional angle to be smaller in cis-2ax (39.8°) than in cis-2(70.3°), which is reflected in increased van der Waals steric repulsion in the former: 2.65 vs 2.12 kcal/mol.
  • 42
    • 84914011508 scopus 로고    scopus 로고
    • The calculated error is ±0.03 kcal/mol in these measurements.
  • 47
    • 84914011507 scopus 로고    scopus 로고
    • 27 who determined that polar solvents stabilize trans-3eq, whereas nonpolar solvents favour the diaxial conformer.

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.