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Volumn 121, Issue 32, 1999, Pages 7431-7432

Total synthesis of (±)-isostemofoline [14]

Author keywords

[No Author keywords available]

Indexed keywords

ALKALOID; ISOSTEMOFOLINE; PLANT EXTRACT; STEMOFOLINE; UNCLASSIFIED DRUG;

EID: 0033581207     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja991528a     Document Type: Letter
Times cited : (81)

References (36)
  • 9
    • 0344142416 scopus 로고    scopus 로고
    • note
    • 1H NMR spectra.
  • 13
    • 0344142415 scopus 로고    scopus 로고
    • note
    • 4: m/z = 283. Found: mlz = 283.
  • 14
    • 9044253320 scopus 로고    scopus 로고
    • An alternate procedure was developed using the chemistry described by Mann: (a) de Almeida Barbosa, L. C.; Mann, J. Synthesis 1996, 31-33.
    • (1996) Synthesis , pp. 31-33
    • De Almeida Barbosa, L.C.1    Mann, J.2
  • 19
    • 0345435988 scopus 로고    scopus 로고
    • note
    • +).
  • 20
    • 0345435987 scopus 로고    scopus 로고
    • note
    • Alkylation of 12 was attempted with LiHMDS, LDA, and KHMDS with allyl iodide. The only products isolated were axial and equatorial C-allylation products at the methylene distal to the n-butyl group.
  • 27
    • 0344573827 scopus 로고    scopus 로고
    • note
    • The stereochemistry about the methyl center was determined from the X-ray crystal structure of pentacyclic lactone 24. The structure revealed the methyl group to be equatorial as in the natural product. Homonuclear decoupling of the methyl group revealed a coupling constant J = 11.3 Hz between the bridgehead proton and the methine proton, further confirming the assigned stereochemistry.
  • 28
    • 0344142414 scopus 로고    scopus 로고
    • note
    • Molecular modeling suggested that the α,β-unsaturated ketone should be oriented to preferentially allow attack from the bottom face of the alkene. The steric bulk of the TIPS protecting group may also have helped direct the approach of the nucleophile from the bottom face.
  • 29
    • 0344142413 scopus 로고    scopus 로고
    • note
    • +).
  • 35
    • 0345435982 scopus 로고    scopus 로고
    • note
    • 5 or Burgess reagent gave no reaction. Direct addition of the lithium enolate of the butenolide to lactone 24 was unsuccessful; the retro-aldol equilibrium favors the lactone 24.
  • 36
    • 0345004870 scopus 로고    scopus 로고
    • note
    • 2.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.