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Volumn 47, Issue 39, 2008, Pages 7446-7449

Formation of α-hydroxy-β-diketones through hydroxylation of isoxazolium salts: Stereoselective approach to angular cis-diols in polycyclic systems

Author keywords

Alkylation; Asymmetric synthesis; Hydroxylation; Isoxazoles; Polyketides

Indexed keywords

CHEMICAL REACTIONS; KETONES; RAW MATERIALS;

EID: 54749116930     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200801586     Document Type: Article
Times cited : (35)

References (52)
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    • To the best of our knwledge the only oxidative transformation of isoxazoles known is ozonolysis, which gives oxime ester derivatives through C4-C5 double-bond cleavage. See: a J. Meisenheimer, K. Weibezahn, Ber. Dtsch. Chem. Ges. 1921, 54, 3195-3206;
    • To the best of our knwledge the only oxidative transformation of isoxazoles known is ozonolysis, which gives oxime ester derivatives through C4-C5 double-bond cleavage. See: a) J. Meisenheimer, K. Weibezahn, Ber. Dtsch. Chem. Ges. 1921, 54, 3195-3206;
  • 24
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    • 4) failed to react with 3,5-diphenylisoxazole (3e).
    • 4) failed to react with 3,5-diphenylisoxazole (3e).
  • 28
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    • reference [6b] and references therein.
    • d) reference [6b] and references therein.
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    • For the two-step α-hydroxylation of ketones via silyl enol ethers (Rubottom oxidation)and its applications to β-dicarbonyl compounds, see: a) G. M. Rubottom, M. A. Vazquez, D. R. Pelegrina, Tetrahedron Lett. 1974, 15, 4319-4322;
    • For the two-step α-hydroxylation of ketones via silyl enol ethers (Rubottom oxidation)and its applications to β-dicarbonyl compounds, see: a) G. M. Rubottom, M. A. Vazquez, D. R. Pelegrina, Tetrahedron Lett. 1974, 15, 4319-4322;
  • 36
    • 54749114495 scopus 로고    scopus 로고
    • 2]/tBuOOH, dimethyldioxirane) were tested. Although the ROOH/base system led to complete consumption of the substrates, no hydroxylated product 5a was obtained.
    • 2]/tBuOOH, dimethyldioxirane) were tested. Although the ROOH/base system led to complete consumption of the substrates, no hydroxylated product 5a was obtained.
  • 37
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    • For nucleophilic epoxidation by NaOCl, see: a
    • For nucleophilic epoxidation by NaOCl, see: a) S. Marmor, J. Org. Chem. 1963, 28, 250-251;
    • (1963) J. Org. Chem , vol.28 , pp. 250-251
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  • 41
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    • For the oxidation of secondary alcohols with NaOCl, see
    • For the oxidation of secondary alcohols with NaOCl, see: G. A. Mirafzal, A. M. Lozeva, Tetrahedron Lett. 1998, 39, 7263-7266.
    • (1998) Tetrahedron Lett , vol.39 , pp. 7263-7266
    • Mirafzal, G.A.1    Lozeva, A.M.2
  • 42
    • 54749104319 scopus 로고    scopus 로고
    • Direct assessment of the ee value of isoxazolium salt 7a was not possible. Instead, the ee value was assessed after oxidation to form 8a and conversion of this product into the bis(trimethylsilyl) derivative (trimethylsilyl trifluoromethanesulfonate, 2,6-lutidine, N,N-dimethylformamide (DMF), RT, 97%). See the Supporting Information.
    • Direct assessment of the ee value of isoxazolium salt 7a was not possible. Instead, the ee value was assessed after oxidation to form 8a and conversion of this product into the bis(trimethylsilyl) derivative (trimethylsilyl trifluoromethanesulfonate, 2,6-lutidine, N,N-dimethylformamide (DMF), RT, 97%). See the Supporting Information.
  • 43
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    • 4 (for example, 60% ee in THF, 40°C, 12 h). See reference [4e].
    • 4 (for example, 60% ee in THF, 40°C, 12 h). See reference [4e].
  • 44
    • 54749130439 scopus 로고    scopus 로고
    • The following scheme shows a possible mechanism for the formation of phthalimide 9: (Chemical Equation Presented)
    • The following scheme shows a possible mechanism for the formation of phthalimide 9: (Chemical Equation Presented)
  • 45
    • 54749088384 scopus 로고    scopus 로고
    • Upon treatment with 1M NaOH (1 equiv; 0.1M THF, 0°C), diol 8a decomposed to give carboxylic acid 10 in 41% yield.
    • Upon treatment with 1M NaOH (1 equiv; 0.1M THF, 0°C), diol 8a decomposed to give carboxylic acid 10 in 41% yield.
  • 46
    • 8544251150 scopus 로고    scopus 로고
    • While the active species, OCl is abundant at higher pH values, HOCl and Cl2 begin to prevail at pH values below 10. Indeed, no hydroxylated product 8a was obtained at pH 7.0 (data not shown, For the pH-dependent composition of aq NaOCl, see: a) J. C. Morris, J. Phys. Chem. 1966, 70, 3798-3805;
    • 2 begin to prevail at pH values below 10. Indeed, no hydroxylated product 8a was obtained at pH 7.0 (data not shown). For the pH-dependent composition of aq NaOCl, see: a) J. C. Morris, J. Phys. Chem. 1966, 70, 3798-3805;
  • 49
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    • 2O.
    • 2O.
  • 50
    • 54749138108 scopus 로고    scopus 로고
    • Upon acid treatment (0.5M HCl, THF, 0°C), epoxide 11 was smoothly hydrolyzed to give diol 8a.
    • Upon acid treatment (0.5M HCl, THF, 0°C), epoxide 11 was smoothly hydrolyzed to give diol 8a.
  • 51
    • 54749138917 scopus 로고    scopus 로고
    • The position of chlorination was confirmed by X-ray analysis of the chlorinated product. See the Supporting Information
    • The position of chlorination was confirmed by X-ray analysis of the chlorinated product. See the Supporting Information.
  • 52
    • 54749122104 scopus 로고    scopus 로고
    • Other solvents (THF, DMF, acetone)for the hydrolysis gave mixtures of 8e and unidentified byproducts.
    • Other solvents (THF, DMF, acetone)for the hydrolysis gave mixtures of 8e and unidentified byproducts.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.