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Volumn 55, Issue 46, 2016, Pages 14394-14399

Exploiting the Imidazolium Effect in Base-free Ammonium Enolate Generation: Synthetic and Mechanistic Studies

Author keywords

imidazolium effect; isothiourea catalysis; mechanistic study; Michael addition; N acyl imidazoles

Indexed keywords

ADDITION REACTIONS; CYCLIZATION; MECHANICS; THIOUREAS;

EID: 84992504728     PISSN: 14337851     EISSN: 15213773     Source Type: Journal    
DOI: 10.1002/anie.201608046     Document Type: Article
Times cited : (45)

References (61)
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    • DMAP salts effectively catalyse acylations via N-acyl ammonium intermediate formation under base-free conditions, see
    • DMAP salts effectively catalyse acylations via N-acyl ammonium intermediate formation under base-free conditions, see:
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    • Enders has reported the use of α,β-unsaturated, N, -acyltriazoles as α,β-unsaturated acyl azolium precursors for annulations with 1,3-dicarbonyls under basic conditions, see
    • Enders has reported the use of α,β-unsaturated N-acyltriazoles as α,β-unsaturated acyl azolium precursors for annulations with 1,3-dicarbonyls under basic conditions, see: Q. Ni, J. Xiong, X. Song, G. Raabe, D. Enders, Chem. Commun. 2015, 51, 14628–14631.
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    • For the corresponding reaction under basic conditions starting from arylacetic acids, see
    • For the corresponding reaction under basic conditions starting from arylacetic acids, see: L. C. Morrill, J. Douglas, T. Lebl, A. M. Z. Slawin, D. J. Fox, A. D. Smith, Chem. Sci. 2013, 4, 4146–4155.
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    • A control experiment in the absence of tetramisole⋅HCl 3 led to the formation of (±)-4 in 28 % yield, suggesting a base-promoted background process is responsible for the observed reactivity
    • A control experiment in the absence of tetramisole⋅HCl 3 led to the formation of (±)-4 in 28 % yield, suggesting a base-promoted background process is responsible for the observed reactivity.
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    • The absolute and relative configuration of the product was confirmed by comparison of its specific rotation and spectral data with the literature, Ref. [14].
    • The absolute and relative configuration of the product was confirmed by comparison of its specific rotation and spectral data with the literature, Ref. [14].
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    • For a complete reaction optimization table, see the Supporting Information.
    • For a complete reaction optimization table, see the Supporting Information.
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    • The absolute and relative configuration of the product was confirmed by comparison of its specific rotation and spectral data with the literature
    • The absolute and relative configuration of the product was confirmed by comparison of its specific rotation and spectral data with the literature: P.-P. Yeh, D. S. B. Daniels, C. Fallan, E. Gould, C. Simal, J. E. Taylor, A. M. Z. Slawin, A. D. Smith, Org. Biomol. Chem. 2015, 13, 2177–2191.
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    • The absolute and relative configuration of the product were assigned by analogy to the other series reported.
    • The absolute and relative configuration of the product were assigned by analogy to the other series reported.
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    • The same equilibrium position was obtained starting from a mixture of N-acyl ammonium 32, obtained from the reaction of (+)-BTM 5 with phenacyl chlorideimidazole 33.
    • The same equilibrium position was obtained starting from a mixture of N-acyl ammonium 32, obtained from the reaction of (+)-BTM 5 with phenacyl chloride, and imidazole 33.
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    • See the Supporting Information for more details.
    • See the Supporting Information for more details.
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    • The observed cross-over may occur via an intermediate N,N′-diacyl imidazolium species, although no direct evidence for this could be obtained. Alternatively, the in situ formation of a ketene intermediate is another possible pathway
    • The observed cross-over may occur via an intermediate N,N′-diacyl imidazolium species, although no direct evidence for this could be obtained. Alternatively, the in situ formation of a ketene intermediate is another possible pathway.
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    • this gave product 11 in 70 % NMR yield, 86:14 d.r. and 81:19 e.r
    • Synthetically, this gave product 11 in 70 % NMR yield, 86:14 d.r. and 81:19 e.r.
    • Synthetically
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    • See the Supporting Information for full reaction profiles and analysis.
    • See the Supporting Information for full reaction profiles and analysis.
  • 54
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    • The same order in catalyst could also be obtained by initial rate analysis. See the Supporting Information for more details.
    • The same order in catalyst could also be obtained by initial rate analysis. See the Supporting Information for more details.
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    • The remaining minor discrepancy between the time-adjusted same-excess profile containing imidazole 33 and the original data may be due to either experimental error or minimal catalyst deactivation.
    • The remaining minor discrepancy between the time-adjusted same-excess profile containing imidazole 33 and the original data may be due to either experimental error or minimal catalyst deactivation.
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    • For other examples of complex reaction kinetics due at least in part to no definitive catalyst resting state, see
    • For other examples of complex reaction kinetics due at least in part to no definitive catalyst resting state, see:
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    • The research data underpinning this publication can be found at DOI: http://dx.doi.org/10.17630/346a5fe8-a636-46e8-9933-71db82f0083a.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.