Novel Synthesis of (E)-α-Fluorochalcones

Zhi-Zhen  Huang; Lei  Wang

doi:10.1055/s-2002-32981

LETTER

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;

Abstract

All articles of this category

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

Full Text

References

<A NAME="RY01002ST-1">1</A> Bowden K. J. Chem. Res., Synop. 1990, 12: 2801

<A NAME="RY01002ST-2">2</A> Biligin AA. Palaska E. Abbabbasoglu U. FABAD Farm. Bilimler Derg. 1991, 16(2): 81

<A NAME="RY01002ST-3">3</A> Gasha M. Tsuji A. Sakurai Y. Kurumi M. Endo T. Sato S. Yamaguchi K. Yagugaku Zasshi 1972, 92(6): 719

<A NAME="RY01002ST-4">4</A> Yamaguchi K. inventors; Japanese Patent 72, 47, 016, 27.

<A NAME="RY01002ST-5">5</A> Carbon-Fluorine Compounds Chemistry, Biochemistry and Biological Activities Giba Foundation . Elsevier; Amsterdam: 1972.

<A NAME="RY01002ST-6">6</A> Banks RE. J. Fluorine Chem. 1998, 87: 1

<A NAME="RY01002ST-7A">7a</A> Speziale AJ. Ratts W. J. Am. Chem. Soc. 1963, 85: 2790

<A NAME="RY01002ST-7B">7b</A> Seyferth D. Worthorn KR. Lin JF. Sepalak DJ. J. Organomet. Chem. 1979, 181: 293

<A NAME="RY01002ST-7C">7c</A> Huang ZZ. Huang X. Huang YZ. Tetranedron Lett. 1995, 36(3): 425

<A NAME="RY01002ST-8A">8a</A> Speziale AJ. Ross KW. J. Org. Chem. 1963, 28: 465

<A NAME="RY01002ST-8B">8b</A> Huang ZZ. Wu LL. Zhu LS. Synth. Commun. 1996, 26(4): 677

<A NAME="RY01002ST-8C">8c</A> Huang YZ. Shi LL. Li SW. Huang R. Synth.Commun. 1989, 19: 2639

<A NAME="RY01002ST-9">9</A> Yamolenko SN. Fialkov YA. Yagupolskii LM. Zh. Org. Khim. 1989, 25(9): 1955

<A NAME="RY01002ST-10">10</A> Davis FA. Han W. Murphy CK. J. Org. Chem. 1995, 60: 4730

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.

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).