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Volumn 55, Issue 2, 1999, Pages 433-448

Diels-Alder reaction of 4-bromo-6-spiroepoxycyclohexa-2,4-dienone with electron-rich and neutral dienophiles

Author keywords

[No Author keywords available]

Indexed keywords

4 BROMO 6 SPIROEPOXYCYCLOHEXA 2,4 DIENONE; ALKADIENE; STYRENE DERIVATIVE; UNCLASSIFIED DRUG; VINYL ACETATE;

EID: 0033534434     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4020(98)01041-2     Document Type: Article
Times cited : (27)

References (47)
  • 25
    • 85038206453 scopus 로고    scopus 로고
    • 14b In each case, the fully optimized TS's were characterized by one and only one imaginary frequency corresponding to the concerted cycloaddition. No account has been made of zero point energy corrections. Though these corrections are not negligible in barrier height calculations, they probably become negligible in selectivity studies where similar reactions are compared
    • 14b In each case, the fully optimized TS's were characterized by one and only one imaginary frequency corresponding to the concerted cycloaddition. No account has been made of zero point energy corrections. Though these corrections are not negligible in barrier height calculations, they probably become negligible in selectivity studies where similar reactions are compared.
  • 27
    • 85038198210 scopus 로고    scopus 로고
    • The percentage of adducts have been evaluated assuming that the product distribution is under kinetic control and the relative percentages were then calculated in the context of the transition state theory at 300°K
    • The percentage of adducts have been evaluated assuming that the product distribution is under kinetic control and the relative percentages were then calculated in the context of the transition state theory at 300°K.
  • 32
    • 85038205774 scopus 로고    scopus 로고
    • Additional AM1 calculations reveal interesting trends concerning the LUMO of 1. Indeed, the C5 coefficient (0.49) is significantly larger than the C2 coefficient (0.42). Substituting the 4-bromo substituent by a hydrogen leads to similar C5 and C2 coefficients (0.45 and 0.43 respectively). Retaining the bromo substituent and substituting the carbonyl group by a methylene again leads to significantly different C5 and C2 coefficients (0.58 and 0.49 respectively). From these AM1 results, it appears that the 4-bromo substituent generates a larger LUMO CS coefficient and thus, this bromo effect may lead to an enhanced regioselectivity
    • Additional AM1 calculations reveal interesting trends concerning the LUMO of 1. Indeed, the C5 coefficient (0.49) is significantly larger than the C2 coefficient (0.42). Substituting the 4-bromo substituent by a hydrogen leads to similar C5 and C2 coefficients (0.45 and 0.43 respectively). Retaining the bromo substituent and substituting the carbonyl group by a methylene again leads to significantly different C5 and C2 coefficients (0.58 and 0.49 respectively). From these AM1 results, it appears that the 4-bromo substituent generates a larger LUMO CS coefficient and thus, this bromo effect may lead to an enhanced regioselectivity.
  • 38
    • 85038202810 scopus 로고    scopus 로고
    • 24b an hypothetical s-cis,s-trans structure is shown to rearrange to the s-trans,s-trans conformer
    • 24b an hypothetical s-cis,s-trans structure is shown to rearrange to the s-trans,s-trans conformer.
  • 40
    • 0003942864 scopus 로고
    • Wiley: New-York
    • For instance, the s-cis methyl formate is more stable than the s-trans conformer by about 5-6 kcal/mol. For a discussion on this point, including experimental data and ab initio calculations, see Eliel, E.L.; Wilen, S.H. Stereochemistry of Organic Compounds; Wiley: New-York, 1994.
    • (1994) Stereochemistry of Organic Compounds
    • Eliel, E.L.1    Wilen, S.H.2


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.