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Volumn 68, Issue 19, 2003, Pages 7448-7454

Convenient asymmetric synthesis of, β-substituted α,α -difluoro-β-amino acids via reformatsky reaction between Davis' N-sulfinylimines and ethyl bromodifluoroacetate

Author keywords

[No Author keywords available]

Indexed keywords

ADDITION REACTIONS; SYNTHESIS (CHEMICAL); THERMAL EFFECTS;

EID: 0141454899     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo030082k     Document Type: Article
Times cited : (94)

References (58)
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    • (a) Fluorine. Containing Amino Acids. Synthesis and properties; Kukhar', V. P., Soloshonok, V. A., Eds.; John Wiley and Sons Ltd.: Chichester, UK, 1994.
    • (1994) Fluorine. Containing Amino Acids. Synthesis and Properties
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    • Ojima, I., McCarthy J.R., Welch J.T., Eds.: ACS Books, American Chemical Society, Washington D.C.
    • (b) Biomedical Frontiers of Fluorine Chemistry; Ojima, I., McCarthy, J. R., Welch, J. T., Eds.; ACS Books, American Chemical Society: Washington, DC, 1996.
    • (1996) Biomedical Frontiers of Fluorine Chemistry
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    • 0042412010 scopus 로고    scopus 로고
    • Biomimetic reducing agent-free reductive amination of fluoro-carbonyl compounds. Practical asymmetric synthesis of enantiopure fluoro-amines and amino acids
    • Ramachandran, P. V., Ed.; ACS Books, American Chemical Society: Washington, DC, Chapter 6
    • Soloshonok, V. A. Biomimetic Reducing Agent-Free Reductive Amination of Fluoro-Carbonyl Compounds. Practical Asymmetric Synthesis of Enantiopure Fluoro-Amines and Amino Acids. In Asymmetric Fluoro-Organic Chemistry: Synthesis, Applications, and Future Directions; Ramachandran, P. V., Ed.; ACS Books, American Chemical Society: Washington, DC, 1999; Chapter 6, pp 74-83.
    • (1999) Asymmetric Fluoro-Organic Chemistry: Synthesis, Applications, and Future Directions , pp. 74-83
    • Soloshonok, V.A.1
  • 29
    • 0141807196 scopus 로고    scopus 로고
    • note
    • We were first to demonstrate that Reformatsky-type additions between chiral N-sulfinylimines and ethyl bromodifluoroacetate affords an efficient approach for preparing the target β-substituted α,α- difluoro-α-amino acids 2; see ref 12 (Received: March 20, 2002). While the work on scope of this method was in progress, Staas et al. published their results on the asymmetric synthesis of amino acids 2, using N-tert-butylsulfinimines; see ref 13 (Received: May 13, 2002).
  • 44
    • 0000071283 scopus 로고
    • Barton and co-workers demonstrated that the α,α -difluoro-Reformatsky reagents generated in ether-type solvents exist in carbon-metal form, see: Barton, D.; Easdon, J. J. Fluorine Chem. 1988, 38, 125.
    • (1988) J. Fluorine Chem. , vol.38 , pp. 125
    • Barton, D.1    Easdon, J.2
  • 48
    • 85087596329 scopus 로고    scopus 로고
    • note
    • 2COOMe could be generated at room temperature by treating a methyl iododifluoroacetate with activated Zn powder; see ref 9a.
  • 49
    • 0141695724 scopus 로고    scopus 로고
    • note
    • Besides the high temperature, as an unfavorable factor for achieving high diastereoselectivity in the addition reactions under study, the use of THF as a solvent was shown to result in reduced stereoselectivity as compared with the stereochemical outcome of the reactions conducted in diethyl ether; see refs 14c and 19.
  • 50
    • 0026514092 scopus 로고
    • The procedures previously developed for determination of enantiomeric composition of various β-amino acids were used: Galushko, S. V.; Shishkina, I. P.; Soloshonok, V. A. J. Chromatogr. 1992, 592, 345. Racemic samples of amino acids 2a-e,g-i were prepared by the method described in this paper protocol, using racemic 4a-e,g-i as starting compounds.
    • (1992) J. Chromatogr. , vol.592 , pp. 345
    • Galushko, S.V.1    Shishkina, I.P.2    Soloshonok, V.A.3
  • 51
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    • For various effects of fluorine and fluorine-containing substituents on the stereochemical outcome of the asymmetric reactions see ref 4c, as well as the following original papers: (a) Soloshonok, V. A.; Avilov, D. V.; Kukhar, V. P. Tetrahedron 1996, 52, 12433-12442.
    • (1996) Tetrahedron , vol.52 , pp. 12433-12442
    • Soloshonok, V.A.1    Avilov, D.V.2    Kukhar, V.P.3
  • 53
    • 84981828672 scopus 로고
    • The (S)-configuration of amino acids 2, a consequence of the Cahn - Ingold - Prelog priority, is stereochemically equivalent to the (R)-configuration in the hydrocarbon series: Cahn, R. S.; Ingold, C.; Prelog, V. Angew. Chem., Int. Ed. Engl. 1966, 5, 385.
    • (1966) Angew. Chem., Int. Ed. Engl. , vol.5 , pp. 385
    • Cahn, R.S.1    Ingold, C.2    Prelog, V.3
  • 58
    • 0141695723 scopus 로고    scopus 로고
    • note
    • As suggested by the referee, the insignificant differences in the diastereoselectivity observed in the aliphatic series can be accounted for by the high-temperature reaction conditions required for these addition reactions.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.