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Volumn 13, Issue 7, 2011, Pages 1742-1745

Mechanistic investigation of the enantioselective intramolecular stetter reaction: Proton transfer is the first irreversible step

Author keywords

[No Author keywords available]

Indexed keywords

ALDEHYDE; PROTON;

EID: 79953171934     PISSN: 15237060     EISSN: 15237052     Source Type: Journal    
DOI: 10.1021/ol200256a     Document Type: Article
Times cited : (86)

References (45)
  • 35
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    • Lopez-Calahorra and co-workers proposed an alternative mechanism involving thiazolium dimer VI with the reaction occurring through nucleophilic attack of this species on benzaldehyde to yield VII, followed by formation of intermediate type VIII, lacking stabilization of the carbanion. See, for example
    • Lopez-Calahorra and co-workers proposed an alternative mechanism involving thiazolium dimer VI with the reaction occurring through nucleophilic attack of this species on benzaldehyde to yield VII, followed by formation of intermediate type VIII, lacking stabilization of the carbanion. See, for example: Lopez-Calahorra, F.; Rubires, R. Tetrahedron 1995, 51, 9713
    • (1995) Tetrahedron , vol.51 , pp. 9713
    • Lopez-Calahorra, F.1    Rubires, R.2
  • 39
    • 79953222851 scopus 로고    scopus 로고
    • See Supporting Information for the details of the kinetic experiments and the corresponding graphs.
    • See Supporting Information for the details of the kinetic experiments and the corresponding graphs.
  • 40
    • 79953218273 scopus 로고    scopus 로고
    • The same kinetic analysis was conducted on catalyst 3a showing little difference in the corresponding catalytic cycle.
    • The same kinetic analysis was conducted on catalyst 3a showing little difference in the corresponding catalytic cycle.
  • 41
    • 77956896366 scopus 로고    scopus 로고
    • This is consistent with Berkessel's observation that the catalyst resting state in the triazolylidene-catalyzed benzoin in THF is a dioxolane resulting from the tetrahedral alkoxy intermediate analogous to II adding another molecule of aldehyde in a reversible process. Thus, if proton transfer to generate III is slow, the alkoxide would prefer adding to an aldehyde to avoid the charge on oxygen in the absence of solvation. See
    • This is consistent with Berkessel's observation that the catalyst resting state in the triazolylidene-catalyzed benzoin in THF is a dioxolane resulting from the tetrahedral alkoxy intermediate analogous to II adding another molecule of aldehyde in a reversible process. Thus, if proton transfer to generate III is slow, the alkoxide would prefer adding to an aldehyde to avoid the charge on oxygen in the absence of solvation. See: Berkessel, A.; Elfert, S.; Etzenbach-Effers, K.; Teles, J. H. Angew. Chem., Int. Ed. 2010, 49, 7120
    • (2010) Angew. Chem., Int. Ed. , vol.49 , pp. 7120
    • Berkessel, A.1    Elfert, S.2    Etzenbach-Effers, K.3    Teles, J.H.4
  • 42
    • 33947293711 scopus 로고
    • A 1,2-proton shift is a symmetry forbidden transformation (, and references therein) but has been calculated to have an ∼29 kcal/mol barrier (thiazolylidine) and ∼51 kcal/mol barrier (cyanide) in the formation of the acyl anion equivalent from formaldehyde See:; J. Mol. Model. 2006, 12, 591
    • A 1,2-proton shift is a symmetry forbidden transformation (Kemp, D. S. J. Org. Chem. 1971, 36, 202 and references therein) but has been calculated to have an ∼29 kcal/mol barrier (thiazolylidine) and ∼51 kcal/mol barrier (cyanide) in the formation of the acyl anion equivalent from formaldehyde See: Goldfuss, B.; Schumacher, M. J. Mol. Model. 2006, 12, 591
    • (1971) J. Org. Chem. , vol.36 , pp. 202
    • Kemp, D.S.1    Goldfuss, B.2    Schumacher, M.3
  • 44
    • 79953185990 scopus 로고    scopus 로고
    • 4 is completely insoluble under these conditions.
    • 4 is completely insoluble under these conditions.
  • 45
    • 79953206159 scopus 로고    scopus 로고
    • That substrate 12 still undergoes reaction means that there must be another mechanism available for proton transfer, presumably either via Hypothesis II above or involving another molecule of catalyst or intermediate, as argued by Yates (see ref 18).
    • That substrate 12 still undergoes reaction means that there must be another mechanism available for proton transfer, presumably either via Hypothesis II above or involving another molecule of catalyst or intermediate, as argued by Yates (see ref 18).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.