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Volumn 133, Issue 6, 2011, Pages 1902-1908

Evidence that epoxide-opening cascades promoted by water are stepwise and become faster and more selective after the first cyclization

Author keywords

[No Author keywords available]

Indexed keywords

CASCADE REACTIONS; DETAILED KINETICS; EPOXY ALCOHOLS; EXO-CYCLIZATION; H NMR SPECTROSCOPY; NEUTRAL WATER; TEMPLATED; TETRAHYDROPYRAN;

EID: 79951521008     PISSN: 00027863     EISSN: 15205126     Source Type: Journal    
DOI: 10.1021/ja1088748     Document Type: Article
Times cited : (39)

References (55)
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    • For recent perspectives on polyene cyclization cascades in the biosynthesis of lanosterol and the naming of the Stork-Eschenmoser hypothesis, see: Eschenmoser, A.; Arigoni, D. Helv. Chim. Acta 2005, 88, 3011
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  • 11
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    • For an overview of the biosynthesis of polyketide-derived polyether ionophores and ladder polyethers, see:
    • For an overview of the biosynthesis of polyketide-derived polyether ionophores and ladder polyethers, see: Gallimore, A. R. Nat. Prod. Rep. 2009, 26, 266
    • (2009) Nat. Prod. Rep. , vol.26 , pp. 266
    • Gallimore, A.R.1
  • 12
    • 0022545718 scopus 로고
    • For selected examples of epoxide-opening cascades proposed in the biosynthesis of terpenoid polyethers
    • For selected examples of epoxide-opening cascades proposed in the biosynthesis of terpenoid polyethers, see: Sakemi, S.; Higa, T. Tetrahedron Lett. 1986, 27, 4287
    • (1986) Tetrahedron Lett. , vol.27 , pp. 4287
    • Sakemi, S.1    Higa, T.2
  • 23
    • 77955129507 scopus 로고    scopus 로고
    • references therein
    • Shenvi, R. A.; Corey, E. J. Org. Lett. 2010, 12, 3548 and references therein.
    • (2010) Org. Lett. , vol.12 , pp. 3548
    • Shenvi, R.A.1    Corey, E.J.2
  • 24
    • 0021860657 scopus 로고
    • Nakanishi acknowledges Prof. Robert Thomas as having first suggested this biogenetic hypothesis via a private communication
    • Nakanishi acknowledges Prof. Robert Thomas as having first suggested this biogenetic hypothesis via a private communication; see: Nakanishi, K. Toxicon 1985, 23, 473
    • (1985) Toxicon , vol.23 , pp. 473
    • Nakanishi, K.1
  • 39
    • 79951524985 scopus 로고    scopus 로고
    • Our group has reported endo-selective epoxide-opening cascades directed by a disappearing trimethylsilyl directing group and promoted by basic methanol and CsF. The mechanism of these cascades is most likely stepwise; please see ref 16.
    • Our group has reported endo-selective epoxide-opening cascades directed by a disappearing trimethylsilyl directing group and promoted by basic methanol and CsF. The mechanism of these cascades is most likely stepwise; please see ref 16.
  • 40
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    • For pioneering mechanistic analyses of these cyclization cascades, including determination of reaction rates in ref 19d, see
    • For pioneering mechanistic analyses of these cyclization cascades, including determination of reaction rates in ref 19d, see: Bartlett, P. A.; Brauman, J. I.; Johnson, W. S.; Volkmann, R. A. J. Am. Chem. Soc. 1973, 95, 7502
    • (1973) J. Am. Chem. Soc. , vol.95 , pp. 7502
    • Bartlett, P.A.1    Brauman, J.I.2    Johnson, W.S.3    Volkmann, R.A.4
  • 48
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    • GC analysis of incomplete reaction mixtures led to thermally induced cyclization of remaining epoxide 3 and intermediates 7 and 10 in the GC inlet, thus leading to innaccurate measurements of selectivity.
    • GC analysis of incomplete reaction mixtures led to thermally induced cyclization of remaining epoxide 3 and intermediates 7 and 10 in the GC inlet, thus leading to innaccurate measurements of selectivity.
  • 49
    • 79951539827 scopus 로고    scopus 로고
    • Our previous investigations indicate that epoxy alcohol cyclizations promoted by water are under kinetic control and that endo:exo regioselectivity does not change throughout the reaction; please see ref 21.
    • Our previous investigations indicate that epoxy alcohol cyclizations promoted by water are under kinetic control and that endo:exo regioselectivity does not change throughout the reaction; please see ref 21.
  • 51
    • 79951539373 scopus 로고    scopus 로고
    • For a more detailed discussion of the difficulties associated with calculating rate constants for the reactions of 3, 10, and especially 7 directly from concentration versus time data, please see the Supporting Information.
    • For a more detailed discussion of the difficulties associated with calculating rate constants for the reactions of 3, 10, and especially 7 directly from concentration versus time data, please see the Supporting Information.
  • 53
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    • Other unidentified products were also observed during the cyclization of isolated 7, which account for nearly 30% of the consumption of 7 and explain the difference between k obs 3 and (k hydrolysis 7 + k 5 7). The same unknown compounds were observed in trace amounts in the cascade reaction of 3, where they constitute only about 1% of total concentration after three half-lives. These species were ignored in the kinetic analysis.
    • Other unidentified products were also observed during the cyclization of isolated 7, which account for nearly 30% of the consumption of 7 and explain the difference between k obs3 and (k hydrolysis 7 + k 5 7). The same unknown compounds were observed in trace amounts in the cascade reaction of 3, where they constitute only about 1% of total concentration after three half-lives. These species were ignored in the kinetic analysis.


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