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Volumn 46, Issue 4, 2007, Pages 545-548

Enantioselective synthesis of oasomycin A, part III: Fragment assembly and confirmation of structure

Author keywords

Aldol reaction; Kocienski Julia olefination; Macrolactonization; Natural products; Total synthesis

Indexed keywords

ALDOL REACTION; ENANTIOSELECTIVE SYNTHESIS; KOCIENSKI JULIA OLEFINATION; MACROLACTONIZATION; NATURAL PRODUCTS; OASOMYCIN;

EID: 33846491932     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200603652     Document Type: Article
Times cited : (25)

References (32)
  • 2
    • 33846495712 scopus 로고    scopus 로고
    • Angew. Chem. Int. Ed. 2007, 46, 537-540;
    • (2007) Chem. Int. Ed , vol.46 , pp. 537-540
    • Angew1
  • 4
    • 33846509947 scopus 로고    scopus 로고
    • Angew. Chem. Int. Ed. 2007, 46, 541-544.
    • (2007) Chem. Int. Ed , vol.46 , pp. 541-544
    • Angew1
  • 8
    • 33846509387 scopus 로고    scopus 로고
    • Our attempts to further optimize the Kocienski-Julia olefination were unsuccessful. In our model studies, the use of LiHMDS eliminates the side product, but decreases the E/Z ratio of the Δ12-olefin isomers to 2:1. Protection of the C15 alcohol as a triisopropylsilyl ether significantly diminishes the reactivity of the aldehyde because of steric hindrance
    • 12-olefin isomers to 2:1. Protection of the C15 alcohol as a triisopropylsilyl ether significantly diminishes the reactivity of the aldehyde because of steric hindrance.
  • 15
    • 33846536371 scopus 로고    scopus 로고
    • D. A. Evans, P. Nagorny, unpublished results. Also see Ref. [7a] for precedent for this coupling.
    • D. A. Evans, P. Nagorny, unpublished results. Also see Ref. [7a] for precedent for this coupling.
  • 16
    • 33947085552 scopus 로고    scopus 로고
    • The stereochemistry of the C29 stereocenter was proven by the Mosher ester analysis. See: J. A. Dale, H. S. Mosher, J. Am. Chem. Soc. 1973, 95, 512-519.
    • The stereochemistry of the C29 stereocenter was proven by the Mosher ester analysis. See: J. A. Dale, H. S. Mosher, J. Am. Chem. Soc. 1973, 95, 512-519.
  • 18
    • 33846543359 scopus 로고    scopus 로고
    • The inseparable impurity (ca. 9%) that arose from the Wacker oxidation of 3a and that was present in the ketone 8 starting material obscured the precise determination of the reaction diastereoselectivity with the lower limit of detection set at 10:1.
    • The inseparable impurity (ca. 9%) that arose from the Wacker oxidation of 3a and that was present in the ketone 8 starting material obscured the precise determination of the reaction diastereoselectivity with the lower limit of detection set at 10:1.
  • 19
    • 0025058974 scopus 로고    scopus 로고
    • 13C NMR shift of the acetonide moiety. See:a S. D. Rychnovsky, D. J. Skalitzky, Tetrahedron Lett. 1990, 31, 945-948;
    • 13C NMR shift of the acetonide moiety. See:a) S. D. Rychnovsky, D. J. Skalitzky, Tetrahedron Lett. 1990, 31, 945-948;
  • 26
    • 33846546684 scopus 로고    scopus 로고
    • For further details, see the Supporting Information
    • For further details, see the Supporting Information.
  • 27
    • 33846515358 scopus 로고    scopus 로고
    • We found the optimal concentration of HF for the deprotection was 1-2 M, at 7°C as more concentrated solutions of HF or higher temperatures decompose oasomycin A. Minor amounts of mono-TBS-protected oasomycin A (ca. 10-20%) were also recovered after workup and then recycled. The yield reported was calculated after one such recycling.
    • We found the optimal concentration of HF for the deprotection was 1-2 M, at 7°C as more concentrated solutions of HF or higher temperatures decompose oasomycin A. Minor amounts of mono-TBS-protected oasomycin A (ca. 10-20%) were also recovered after workup and then recycled. The yield reported was calculated after one such recycling.
  • 28
    • 33846493733 scopus 로고    scopus 로고
    • We thank Professor Y. Kishi for providing the natural samples of oasomycin A and B
    • We thank Professor Y. Kishi for providing the natural samples of oasomycin A and B.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.