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Volumn 692, Issue 11, 2007, Pages 2120-2124

Synthesis of new C1-symmetric bis(oxazoline) ligands with a chelating sidearm for stereoselective Mukaiyama aldol condensations

Author keywords

Chelation; Chiral bis oxazolines; Copper complexes; Enantioselective catalysis; Mukaiyama aldol condensation

Indexed keywords

ALDEHYDES; CATALYSIS; CHELATION; CONDENSATION; ENANTIOSELECTIVITY; SYNTHESIS (CHEMICAL);

EID: 34047107171     PISSN: 0022328X     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.jorganchem.2007.02.009     Document Type: Article
Times cited : (11)

References (33)
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    • For a recent report about the use of secondary binding sites for the asymmetric cyclopropanation of furans see
    • For a recent report about the use of secondary binding sites for the asymmetric cyclopropanation of furans see. Schinnerl M., Bohm C., Seitz M., and Reiser O. Tetrahedron: Asymmetry 14 (2003) 765-771
    • (2003) Tetrahedron: Asymmetry , vol.14 , pp. 765-771
    • Schinnerl, M.1    Bohm, C.2    Seitz, M.3    Reiser, O.4
  • 17
    • 34047187328 scopus 로고    scopus 로고
    • note
    • All the new products were fully characterized and show spectral data in agreement with the proposed structure.
  • 18
    • 34047151128 scopus 로고    scopus 로고
    • note
    • Other combinations such as tosyl chloride/triethylamine or the use of Burgess reagent gave the product in lower yields or did not work at all.
  • 24
    • 10244222363 scopus 로고    scopus 로고
    • For a PEG-supported bis(oxazoline)-copper(II) promoted reaction in water see
    • For a PEG-supported bis(oxazoline)-copper(II) promoted reaction in water see. Benaglia M., Cinquini M., Cozzi F., and Celentano G. Org. Biomol. Chem. 2 (2004) 3401-3407
    • (2004) Org. Biomol. Chem. , vol.2 , pp. 3401-3407
    • Benaglia, M.1    Cinquini, M.2    Cozzi, F.3    Celentano, G.4
  • 25
    • 0033575446 scopus 로고    scopus 로고
    • For the same reaction promoted by bis(oxazoline)-copper (II) complexes in aqueous solvents see
    • For the same reaction promoted by bis(oxazoline)-copper (II) complexes in aqueous solvents see. Kobayashi S., Nagayama S., and Busujiama T. Tetrahedron 55 (1999) 8739-8746
    • (1999) Tetrahedron , vol.55 , pp. 8739-8746
    • Kobayashi, S.1    Nagayama, S.2    Busujiama, T.3
  • 26
    • 34047142511 scopus 로고    scopus 로고
    • note
    • 2 complex catalysed the reaction in 41% yield basically without stereoselection.
  • 28
    • 34047136957 scopus 로고    scopus 로고
    • note
    • 6)/ligand 1 complex at RT promoted the reaction with 7% ee. The result seems to suggest that the addition of a sidearm in the ligand has some beneficial effect on the enantioselectivity of the process. In this sense the figure of Scheme 2 represents a very preliminary working model that accounts for the formation of the product (S)-15.
  • 29
    • 34047156422 scopus 로고    scopus 로고
    • note
    • At the present based on these preliminary results it would be premature to invoke the presence of π-π interactions.
  • 30
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    • note
    • For a discussion on the stereochemical models for bis(oxazolines) copper(II) complexes see Refs. [8,2c].
  • 31
    • 34047118446 scopus 로고    scopus 로고
    • note
    • 1-symmetric bis(oxazoline) might bring about the formation of two different complexes; our working hypothesis is that for steric reasons one should be favoured over the other; of course also the control of the approach of the aldehyde is another point that deserves further studies. Preliminary attempted NMR studies showed the presence of more than one species in solution.
  • 32
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    • For other catalysts prepared following the same design principles see:
    • For other catalysts prepared following the same design principles see:. Le J.C.-D., and Pagenkopf B.L. Org. Lett. 6 (2004) 4097
    • (2004) Org. Lett. , vol.6 , pp. 4097
    • Le, J.C.-D.1    Pagenkopf, B.L.2


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.