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Volumn 8, Issue 15, 2006, Pages 3351-3354

Enantioselective nitrone cycloadditions of α,β-unsaturated 2-acyl imidazoles catalyzed by bis(oxazolinyl)pyridine-cerium(IV) triflate complexes

Author keywords

[No Author keywords available]

Indexed keywords

AMINO ACID; CERIUM; IMIDAZOLE DERIVATIVE; NITROGEN OXIDE; NITRONES; ORGANOMETALLIC COMPOUND; OXAZOLE DERIVATIVE; PYRIDINE; PYRIDINE DERIVATIVE;

EID: 33746879548     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol061223i     Document Type: Article
Times cited : (145)

References (33)
  • 11
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    • For indole Friedel-Crafts reactions with α,β-unsaturated 2-acyl imidazoles, see: (a) Evans, D. A.; Fandrick, K. R.; Song, H.-J. J. Am. Chem. Soc. 2005, 127, 8942-8943.
    • (2005) J. Am. Chem. Soc. , vol.127 , pp. 8942-8943
    • Evans, D.A.1    Fandrick, K.R.2    Song, H.-J.3
  • 12
    • 33745683557 scopus 로고    scopus 로고
    • For pyrrole Friedel-Crafts reactions, see: (b) Evans, D. A.; Fandrick, K. R. Org. Lett. 2006, 8, 2249-2252.
    • (2006) Org. Lett. , vol.8 , pp. 2249-2252
    • Evans, D.A.1    Fandrick, K.R.2
  • 15
    • 0043240876 scopus 로고    scopus 로고
    • For a good review of metal-pybox complexes as chiral catalysts, see: Desimoni, G.; Faita, G.; Quadrelli, P. Chem. Rev. 2003, 103, 3119-3154.
    • (2003) Chem. Rev. , vol.103 , pp. 3119-3154
    • Desimoni, G.1    Faita, G.2    Quadrelli, P.3
  • 16
    • 0034740372 scopus 로고    scopus 로고
    • For the reviews of asymmetric catalysis by lanthanide complexes, see: (a) Steel, P. G. J. Chem. Soc., Perkin Trans. 1 2001, 2727-2751.
    • (2001) J. Chem. Soc., Perkin Trans. 1 , pp. 2727-2751
    • Steel, P.G.1
  • 23
    • 33746906532 scopus 로고    scopus 로고
    • note
    • For Sc(III) and Ni(II), excellent endoselectivity (>99:1) with poor enantioselectivity (max 6% ee) was observed. For Cu(II), a high dr (>99: 1) with low ee (23%) and a low dr (3.5:1) with moderate ee (46% and 58%) were observed.
  • 24
    • 84944648082 scopus 로고
    • For the ionic radii of lanthanide cations, see: Shannon, R. D. Acta Crystallogr. 1976, A32, 751-767.
    • (1976) Acta Crystallogr. , vol.A32 , pp. 751-767
    • Shannon, R.D.1
  • 30
    • 0002741189 scopus 로고
    • Ce(IV) triflate was prepared from CAN and dispensed from a glovebox. For the preparation of Ce(IV) triflate, see: Imamoto, T.; Koide, Y.; Hiyama, S. Chem. Lett. 1990, 1445-1446.
    • (1990) Chem. Lett. , pp. 1445-1446
    • Imamoto, T.1    Koide, Y.2    Hiyama, S.3
  • 31
    • 33746862394 scopus 로고    scopus 로고
    • note
    • The addition of 4 Å MS to the reaction mixture of catalyst 1, 2-acyl imidazole, and (Z)-N-benzylidene(phenyl)methanamine oxide in ethyl acetate (Table 2, entry I) raised the endo:exo diastereoselectivity from 22:1 to >99: 1, the enantioselectivity from 71% ee to 98% ee, and the yield from 86% to 97%.
  • 32
    • 33746920183 scopus 로고    scopus 로고
    • note
    • This absolute stereoconfiguration was consolidated via Mosher's ester analysis and optical rotation comparison with a known compound. Details are provided in the Supporting Information. The stereochemistry of all the other isoxazolidines was assigned by analogy.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.