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Volumn 127, Issue 7, 2005, Pages 2147-2155

Dynamic ligand exchange of the lanthanide complex leading to structural and functional transformation: One-pot sequential catalytic asymmetric epoxidation-regioselective epoxide-opening process

Author keywords

[No Author keywords available]

Indexed keywords

CARBON; CATALYSTS; COMPLEXATION; IN SITU PROCESSING; INFRARED SPECTROSCOPY; OXIDATION;

EID: 13944249839     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja043770+     Document Type: Article
Times cited : (100)

References (73)
  • 33
    • 13944280737 scopus 로고    scopus 로고
    • note
    • 3As= O (1:1:1) complex was used.
  • 42
    • 13944266088 scopus 로고    scopus 로고
    • note
    • The syn isomer was contaminated with the anti isomer (anti:syn = 11:1). The moderate overall yield was due to the partial decomposition of the corresponding α,β-epoxy amide during the epoxidation reaction.
  • 50
    • 13944273489 scopus 로고    scopus 로고
    • note
    • 3 or (S)-Sm complex 1 resulted in similar IR spectra. For details, see the Supporting Information.
  • 51
    • 13944261314 scopus 로고    scopus 로고
    • note
    • BINOL would not be involved in the samarium azide complex because all of the BINOL was silylated in the reaction mixture.
  • 52
    • 13944260590 scopus 로고    scopus 로고
    • note
    • -1 suggested that the samarium azide complex exists as a mixture of several oligomeric species in equilibrium.
  • 53
    • 13944264776 scopus 로고    scopus 로고
    • note
    • α,β-Epoxy chalcone: no reaction. α,β-Epoxy methyl cinnamate: trace.
  • 55
    • 13944263324 scopus 로고    scopus 로고
    • note
    • The catalytic asymmetric epoxidation of α,β-unsaturated N-acylimidazolides or α,β-unsaturated ketones would proceed easily because of their low enough LUMO energy level and thus would not require the Lewis base enhancements.
  • 56
    • 13944267615 scopus 로고    scopus 로고
    • note
    • The initial rate of step A should be increased as the LUMO energy level decreased (6a → 6e) if the effects of Lewis basicity of carbonyl moiety were ignored. As observed in the Hammett plot of Scheme 3, the range of the initial rate of step A was smaller than that of step B, where only the Lewis basicity defines the reactivity.
  • 59
    • 0001699856 scopus 로고
    • Azide groups can act as bridging ligands between metal atoms leading to di- and polynuclear complexes. For selected examples, see: (a) Fehlhammer, W. P.; Dahl, L. F. J. Am. Chem. Soc. 1972, 94, 3377.
    • (1972) J. Am. Chem. Soc. , vol.94 , pp. 3377
    • Fehlhammer, W.P.1    Dahl, L.F.2
  • 62
    • 84955828127 scopus 로고
    • (d) Clegg, W.; Krischner, H.; Saracoglu, A. I.; Sheldrick, G. M. Z. Kristallogr. 1982, 161, 307. On the basis of the large coordination numbers of lanthanide metals, the samarium azide complex might contain an azido-bridging structure to form the oligomer.
    • (1982) Z. Kristallogr. , vol.161 , pp. 307
    • Clegg, W.1    Krischner, H.2    Saracoglu, A.I.3    Sheldrick, G.M.4
  • 63
    • 13944270725 scopus 로고    scopus 로고
    • note
    • 9a was obtained in 75% yield after 48 h.
  • 64
    • 13944277210 scopus 로고    scopus 로고
    • note
    • Tertiary amides gave the epoxide-opened products with low regioselectivity (ca. 1:1) although the reaction proceeded smoothly under the same reaction conditions. For the difference of the regioselectivity between secondary and tertiary amides, see ref 12.
  • 65
    • 13944280374 scopus 로고    scopus 로고
    • note
    • Less than 10% of the oxidized product was formed. When sulfide 9a was subjected to conditions for the catalytic asymmetric epoxidation [(S)-Sm complex 1 (10 mol %), TBHP (1.2 equiv), THF, room temperature], a complex mixture of oxidized products was obtained.
  • 66
    • 0034697199 scopus 로고    scopus 로고
    • For reviews of asymmetric synthesis of vicinal amino alcohols, see: (a) Bergmeire, S. C. Tetrahedron 2000, 56, 2561.
    • (2000) Tetrahedron , vol.56 , pp. 2561
    • Bergmeire, S.C.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.