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Volumn 125, Issue 46, 2003, Pages 14149-14152

Nucleophilic Additions to Fused Bicyclic Five-Membered Ring Oxocarbenium Ions: Evidence for Preferential Attack on the Inside Face

Author keywords

[No Author keywords available]

Indexed keywords

NUCLEOPHILIC ADDITIONS;

EID: 0242414726     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0375176     Document Type: Article
Times cited : (107)

References (38)
  • 1
    • 0027200955 scopus 로고
    • For a review that includes nucleophilic substitution on five-membered ring acetals, see: Harmange, J.-C.; Figadère, B. Tetrahedron: Asymmetry 1993, 4, 1711-1754.
    • (1993) Tetrahedron: Asymmetry , vol.4 , pp. 1711-1754
    • Harmange, J.-C.1    Figadère, B.2
  • 5
    • 0034597491 scopus 로고    scopus 로고
    • Five-membered ring iminium ions are believed to undergo nucteophilic attack by transition structures similar to those for oxocarbenium ions: Eur. S. K.; Martin, S. F. Org. Lett. 2000, 2, 3445-3447.
    • (2000) Org. Lett. , vol.2 , pp. 3445-3447
    • Bur, S.K.1    Martin, S.F.2
  • 15
    • 0242478525 scopus 로고    scopus 로고
    • note
    • Similarly, the minor product could arise from either outside attack on the diequatorial oxocarbenium ion 7 or inside attack on the diaxial cation 8.
  • 18
    • 0033612214 scopus 로고    scopus 로고
    • For a recent example that compares the stereoselectivity of constrained versus unconstrained five-membered ring oxocarbenium ions, see: Crich, D.; Hao, X. J. Org. Chem. 1999, 64, 4016-4024.
    • (1999) J. Org. Chem. , vol.64 , pp. 4016-4024
    • Crich, D.1    Hao, X.2
  • 28
    • 0000693134 scopus 로고
    • Other reactions of acetals do not appear to involve free cations: (c) Denmark, S. E.; Almstead, N. G. J. Am. Chem. Soc. 1991, 113, 8089-8110.
    • (1991) J. Am. Chem. Soc. , vol.113 , pp. 8089-8110
    • Denmark, S.E.1    Almstead, N.G.2
  • 29
    • 0242646925 scopus 로고    scopus 로고
    • (a) ref 4
    • In our experiments with both tetrahydrofuran and tetrahydropyran acetals, the stereochemistry of nucleophilic substitution was independent of the anomer ratios of the starting acetates: (a) ref 4.
  • 34
    • 0242395100 scopus 로고    scopus 로고
    • note
    • With each Lewis acid, the counterion for the oxocarbenium ion is different, but the selectivity is independent of this counterion. In addition, because the selectivities are insensitive to the solvent, ion pairing is not evidently important.
  • 35
    • 0242395101 scopus 로고    scopus 로고
    • note
    • The diastereoselectivity of this nucleophilic substitution is independent of the ratio of anomeric acetates, consistent with the intermediacy of oxocarbenium ions (details of these experiments are provided as Supporting Information).
  • 36
    • 0242562321 scopus 로고    scopus 로고
    • note
    • Additional details are provided as Supporting Information.
  • 37
    • 0242562320 scopus 로고    scopus 로고
    • While other conformations of the eight-membered ring may be relatively close in energy, it is the conformation of the five-membered ring that is important in controlling stereoselectivity. Oxocarbenium ion 21 and the product 22 are shown with the eight-membered ring in a boat-chair conformation, because the eight-membered rings of trans-fused eight-five ring systems adopt boat-chair forms: Umehara, M.; Hosomi, H.; Ohba, S. Acta Crystallogr., Sect. C 1999, 55, 1721-1725.
    • (1999) Acta Crystallogr., Sect. C , vol.55 , pp. 1721-1725
    • Umehara, M.1    Hosomi, H.2    Ohba, S.3
  • 38
    • 0002538534 scopus 로고
    • The dihedral angle between C3 and C4 within the five-membered ring of structure 25 is about 25° smaller than that for the chair conformation of cyclohexane. Consequently, the six-membered ring of 25 should be distorted from a chair conformation by a comparable angle. For a review of five-membered ring conformational analysis, see: Fuchs, B. Top. Stereochem 1978, 10, 1-94.
    • (1978) Top. Stereochem. , vol.10 , pp. 1-94
    • Fuchs, B.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.