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Synlett 2002(8): 1281-1282
DOI: 10.1055/s-2002-32981
LETTER
© Georg Thieme Verlag Stuttgart · New York

Novel Synthesis of (E)-α-Fluorochalcones

Zhi-Zhen Huang*, Lei Wang
Department of Chemistry, Zhejiang University, Hangzhou 310028, P. R. China
Fax: +86(571)88807077; e-Mail: huangzhizhen@hotmail.com;
Further Information

Publication History

Received 13 May 2002
Publication Date:
25 July 2002 (online)

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Abstract

α-Fluorochalcones 4 can be synthesized by the Wittig reaction via α-fluoro substituted ylide 3, affoding a general method for the stereoselective synthesis of (E)-α-fluoro-α,β-unsaturated compounds 4.

Key words

α-fluorochalcones - Wittig reaction - synthesis

    References

  • 1 Bowden K. J. Chem. Res., Synop.  1990,  12:  2801 
    Google Scholar
  • 2 Biligin AA. Palaska E. Abbabbasoglu U. FABAD Farm. Bilimler Derg.  1991,  16(2):  81 
    Google Scholar
  • 3 Gasha M. Tsuji A. Sakurai Y. Kurumi M. Endo T. Sato S. Yamaguchi K. Yagugaku Zasshi  1972,  92(6):  719 
    Google Scholar
  • 4 Yamaguchi K. inventors; Japanese Patent  72, 47, 016, 27. 
  • 5 Carbon-Fluorine Compounds Chemistry, Biochemistry and Biological Activities   Giba Foundation . Elsevier; Amsterdam: 1972. 
    Google Scholar
  • 6 Banks RE. J. Fluorine Chem.  1998,  87:  1 
    CrossrefGoogle Scholar
  • 7a Speziale AJ. Ratts W. J. Am. Chem. Soc.  1963,  85:  2790 
    Google Scholar
  • 7b Seyferth D. Worthorn KR. Lin JF. Sepalak DJ. J. Organomet. Chem.  1979,  181:  293 
    Google Scholar
  • 7c Huang ZZ. Huang X. Huang YZ. Tetranedron Lett.  1995,  36(3):  425 
    Google Scholar
  • 8a Speziale AJ. Ross KW. J. Org. Chem.  1963,  28:  465 
    Google Scholar
  • 8b Huang ZZ. Wu LL. Zhu LS. Synth. Commun.  1996,  26(4):  677 
    Google Scholar
  • 8c Huang YZ. Shi LL. Li SW. Huang R. Synth.Commun.  1989,  19:  2639 
    Google Scholar
  • 9 Yamolenko SN. Fialkov YA. Yagupolskii LM. Zh. Org. Khim.  1989,  25(9):  1955 
    Google Scholar
  • 10 Davis FA. Han W. Murphy CK. J. Org. Chem.  1995,  60:  4730 
    CrossrefGoogle Scholar
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General Procedure for the Stereoseletive Synthesis ofα-Fluorochalcones 4 (Method B): To the solution of benzoylmethylene triphenylphosphorane 1 (0.92 g, 2.0 mmol) in THF (20 mL), was added dropwise the solution of N-fluorodiphenylsulfonamide (0.63 g, 2.0 mmol) in THF (20 mL) at -20 °C. The mixture was stirred at r.t. for 3 h and a lot of precipitate was formed. After LDA (2 mmol) was added dropwise and the reaction mixture was stirred for 30 min, aldehyde (2 mmol) was added and the reaction mixture was stirred at r.t. for 27-40 h (see Table [1] ). After filtration, the filtrate was concentrated and subjected to preparative TLC (silica gel, hexane-ethyl acetate as eluent) to give
α-fluorochalcones 4a-e.

12

4a: Mp 100-101 °C. 1H NMR: δ (ppm) = 8.29 (d, 2 H, J = 8 Hz), 8.04 (d, 2 H, J = 8 Hz), 7.83 (d, 1 H, J = 16 Hz), 7.68-7.60 (m, 3 H), 7.58-7.50 (m, 2 H). MS: m/z (%) = 271(1) [M+], 77(100). Compound 4b: mp 89-90 °C. 1H NMR:
δ (ppm) = 8.03 (d, 2 H, J = 8 Hz), 7.83 (d, 1 H, J = 16 Hz), 7.70-7.61 (m, 2 H), 7.51-7.48 (m, 3 H), 7.45-7.40 (m, 2 H). MS: m/z (%) = 244(4) [M+], 57(100). 4c: Mp 79-80 °C (Lit [9] 77 °C). 1H NMR: δ (ppm) = 8.01 (d, 2 H, J = 8 Hz), 7.76 (d, 1 H, J = 16 Hz), 7.60-7.56(m, 2 H), 7.51-7.46 (m, 3 H), 7.40 (d, 2 H, J = 8 Hz). MS m/z (%) = 260(2) [M+], 157(100). 4d: Mp 52-53 °C (Lit [9] 54 °C). 1H NMR: δ (ppm) = 8.01 (d, 2 H, J = 8 Hz), 7.81 (d, 1 H, J = 16 Hz), 7.65-7.61 (m, 2 H), 7.53-7.49 (m, 3 H), 7.44-7.40 (m, 2 H). MS m/z (%) = 226(13) [M+], 57(100). 4e: Mp 69-70 °C (Lit [9] 69 °C). 1H NMR: δ (ppm) = 8.01(d, 2 H, J = 8 Hz), 7.79(d, 1 H, J = 16 Hz), 7.61-7.45 (m, 5 H), 7.23 (d, 1 H, J = 8 Hz), 2.40 (s, 3 H). MS m/z (%) = 240(2) [M+], 207(100).