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Volumn 44, Issue 37, 2005, Pages 6043-6046

Highly enantio- and regioselective quinone Diels-Alder reactions catalyzed by a tridentate [(Schiff base)CrIII] complex

Author keywords

Asymmetric catalysis; Chromium; Cycloaddition; Quinones; Schiff bases

Indexed keywords

ADDITION REACTIONS; CATALYSIS; CHROMIUM; MONOMERS;

EID: 25144436523     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200502176     Document Type: Article
Times cited : (67)

References (42)
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    • see reference [1b]
    • b) for a discussion, see reference [1b].
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    • (1999) Angew. Chem. Int. Ed. , vol.38 , pp. 2398-2400
  • 9
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    • Angew. Chem. Int. Ed. 2002, 41, 3059-3061;
    • (2002) Angew. Chem. Int. Ed. , vol.41 , pp. 3059-3061
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    • Angew. Chem. Int. Ed. 2003, 42, 4771-4774.
    • (2003) Angew. Chem. Int. Ed. , vol.42 , pp. 4771-4774
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    • in press; DOI: 10.1002/anie.200502178
    • Angew. Chem. Int. Ed. 2005, 44, in press; DOI: 10.1002/anie.200502178.
    • (2005) Angew. Chem. Int. Ed. , vol.44
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    • 0346545910 scopus 로고    scopus 로고
    • Angew. Chem. Int. Ed. 2002, 41, 1669-1698;
    • (2002) Angew. Chem. Int. Ed. , vol.41 , pp. 1669-1698
  • 24
    • 25144473032 scopus 로고    scopus 로고
    • note
    • 1H NMR analyses of the unpurified qDA reaction mixtures suggest that the cycloadditions are clean and that product loss occurs during workup.
  • 25
    • 0037018443 scopus 로고    scopus 로고
    • and references therein
    • III-salen complexes have also been shown to catalyze enantioselective Diels-Alder reactions of 1-amino-1,3-butadienes. See: Y. Huang, T. Iwama, V. H. Rawal, Org. Lett. 2002, 4, 1163-1166, and references therein.
    • (2002) Org. Lett. , vol.4 , pp. 1163-1166
    • Huang, Y.1    Iwama, T.2    Rawal, V.H.3
  • 36
    • 25144513456 scopus 로고    scopus 로고
    • unpublished results
    • Kinetic and mechanistic studies of HDA reactions promoted by 8 indicate a dimeric catalyst structure both in the ground state and in the rate-determining transition state. R. T. Ruck, E. N. Jacobsen, unpublished results.
    • Ruck, R.T.1    Jacobsen, E.N.2
  • 37
    • 25144492076 scopus 로고    scopus 로고
    • see ref. [10]
    • See Supporting Information for details. Cationic oxazaborolidine catalysts afford products with opposite regioselectivity (see ref. [10]).
  • 38
    • 25144471159 scopus 로고    scopus 로고
    • Details of the crystal structure analysis are provided as Supporting Information. CCDC-262884 (9) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
  • 39
    • 25144514452 scopus 로고    scopus 로고
    • see preparation of 6 in Scheme 3 in reference [4]
    • For example, the inverse electron demand hetero-Diels-Alder reaction employed in the first step of the colombiasin synthesis (see preparation of 6 in Scheme 3 in reference [4]) proceeded with 78 % ee with monomeric catalyst 9 and 93 % ee with dimeric catalyst 8.
  • 40
    • 25144432368 scopus 로고    scopus 로고
    • note
    • If a monomeric catalyst structure analogous to that of 9 is assumed in the ee-determining step with one of the water molecules replaced by the quinone substrate, then the intriguing question arises about which of the two stereochemically inequivalent binding sites is engaged. Qualitatively, it would appear that binding to the inner, concave face of the catalyst would be most consistent with the high enantioselectivities observed in the qDA.
  • 41
    • 25144436918 scopus 로고    scopus 로고
    • note
    • Reactions carried out at -40°C generally afforded higher enantioselectivity, albeit with slower rates; these conditions were employed for those substrates that were generated in < 90% ee at 0°C. For example, the reaction of benzoquinone with diene 4 afforded cycloadduct in 79% ee at 0°C, and 86% ee at -40°C (Table 2, entry 4).
  • 42
    • 25144463967 scopus 로고    scopus 로고
    • See Supporting Information for details
    • See Supporting Information for details.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.