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Volumn 125, Issue 46, 2003, Pages 14133-14139

Chiral Bis-π-allylpalladium Complex Catalyzed Asymmetric Allylation of Imines: Enhancement of the Enantioselectivity and Chemical Yield in the Presence of Water

Author keywords

[No Author keywords available]

Indexed keywords

ALLYLATION;

EID: 0242497940     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja037272x     Document Type: Article
Times cited : (137)

References (41)
  • 5
  • 24
    • 0000276556 scopus 로고
    • Semmelhack, M. F., Ed.; Pergamon Press: Oxford
    • (b) Codleski, S. A. In Comprehensive Organic Synthesis; Semmelhack, M. F., Ed.; Pergamon Press: Oxford, 1991; Vol. 4, p 585.
    • (1991) Comprehensive Organic Synthesis , vol.4 , pp. 585
    • Codleski, S.A.1
  • 31
    • 0025309685 scopus 로고
    • Olefin 7 (E:Z = 1:1) was prepared starting from (1S)-(-)-β-pinene available in Aldrich Chemical Co. in 97% ee. Though (IR)-(+)-nopinone (90% ee) is also available, we preferred to prepare it from (1S)-(-)-β-pinene by ozonolysis of exocyclic double bond. Further Wittig reaction with ethyltriphenylphosphonium bromide and BuOK gave 7 (E:Z = 1:1) [see: Brown, H. C.; Weissman, S. A.; Perumal, P. T.; Dhokte, U. P. J. Org. Chem. 1990, 55, 1217].
    • (1990) J. Org. Chem. , vol.55 , pp. 1217
    • Brown, H.C.1    Weissman, S.A.2    Perumal, P.T.3    Dhokte, U.P.4
  • 32
    • 0242478548 scopus 로고    scopus 로고
    • note
    • The solvents tried were 2-butanone, propionitrile, 2-propanol, and diisopropyl ether. Among all, propionitrile gave best upgradation ratio of 2a: 2b and recovery of catalyst during recrystalization. Though the catalyst is not freely soluble in propionitrile, warming to 90 °C gave clear solution. Higher temperatures or boiling should be avoided to prevent catalyst decomposition.
  • 33
    • 0242646942 scopus 로고    scopus 로고
    • note
    • 1H NMR of 2a:2b = 1.3:1, 100:1, and >400:1.
  • 34
    • 0242478547 scopus 로고    scopus 로고
    • note
    • 1H NMR spectrum available the ratio of the catalyst 2a:2b was 20:1. To the best of our knowledge, this is the first report of preparation of the catalyst 2a and separated from its undesired stereoisomer with a ratio of 2a:2b >400:1.
  • 35
    • 0242562342 scopus 로고    scopus 로고
    • note
    • 3). See the Supporting Information for more details.
  • 36
    • 0242395115 scopus 로고    scopus 로고
    • note
    • 3CN was added for better solubilization of stannane byproducts.
  • 37
    • 0242562343 scopus 로고    scopus 로고
    • note
    • Details for each compound are giving in the Supporting Information.
  • 40
    • 0242562341 scopus 로고    scopus 로고
    • note
    • However, the enhancement of enantioselectivity by water is not clear. Formation of pentacoordinate Si is known, see reference (2), probably similar is the case with stannane.
  • 41
    • 0242646941 scopus 로고    scopus 로고
    • note
    • A similar explanation is given by Hou, see: ref (2c).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.