Download PDF
Synlett 2004(2): 0251-0254  
DOI: 10.1055/s-2003-44966
LETTER
© Georg Thieme Verlag Stuttgart · New York

Cation Radical [3+2] Cycloaddition of Chalcone Epoxides: A Facile Synthesis of Highly Substituted Tetrahydrofurans

Congde Huo, Xiaodong Jia, Wei Zhang, Li Yang, Jianming Lü, Zhong-Li Liu*
National Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, P. R. China
Fax: +86(931)8625657; e-Mail: liuzl@lzu.edu.cn;
Further Information

Publication History

Received 11 November 2003
Publication Date:
08 December 2003 (online)

    Permissions and Reprints All articles of this category

Abstract

Cycloaddition of electron-rich chalcone epoxides with electron-rich olefins was efficiently catalyzed by tris(4-bromo­phenyl)aminium hexachloroantimonate producing poly-substituted tetrahydrofuran derivatives in high yield.

Key words

cation radical - cycloaddition - epoxides - tetrahydrofurans

10

Representative spectral data for the products: (±)-cic,cis-2-Benzoyl-3-(4-methoxyphenyl)-5-phenyl-5-methyl tetrahydrofuran (3a-A): colorless oil. HR-ESI-MS: m/z calcd for C25H24O3 + Na+: 395.1618). Found: 395.1614. 1H NMR (400 MHz, CDCl3): δ = 1.73 (s, 3 H, Me), 2.62 (dd, J = 12.4, 12.0 Hz, 1 H, H-4a), 2.67 (dd, J = 12.4, 8.4 Hz, 1 H, H-4e), 3.63 (s, 3 H, MeO), 4.15 (m, 1 H, H-3a), 5.91 (d, J = 8.8 Hz, 1 H, H-2e), 6.51 (d, J = 8.8 Hz, 2 H, Ar), 6.86 (d, J = 8.8 Hz, 2 H, Ar), 7.26 (dd, J = 8.0, 7.6 Hz, 2 H, Bz), 7.32 (t, J = 8.0 Hz, 1 H, Ph), 7.40 (t, J = 8.0 Hz, 1 H, Bz), 7.42 (dd, J = 8.0, 8.0 Hz, 2 H, Ph), 7.57 (d, J = 8.0 Hz, 2 H, Bz), 7.68 (d, J = 8.0 Hz, 2 H, Ph). 13C NMR (100.08 MHz, CDCl3): δ = 29.3 (Me), 46.2 (C-4), 48.5 (C-3), 55.1 (MeO), 82.6 (C-2), 85.2 (C-5), 113.4 (Ar), 124.8 (Ph), 126.5 (Ph), 127.9 (Bz), 128.1 (Ph), 128.4 (Bz), 129.3 (Ar), 130.3 (Ar), 132.4 (Bz), 136.8 (Bz), 147.7 (Ph), 158.2 (Ar), 198.5 (C=O).
(±)-trans,cis-2-Benzoyl-3-(4-methoxyphenyl)-5-phenyl-5-methyl tetrahydrofuran (3a-B): colorless oil, HR-ESI-MS: m/z calcd for C25H24O3 + H+: 373.1798. Found: 373.1794. 1H NMR (400 MHz, CDCl3): δ = 1.67 (s, 3 H, Me), 2.61 (dd, J = 12.4, 7.6 Hz, 1 H, H-4a), 2.79 (dd, J = 12.4, 7.6 Hz, 1 H, H-4e), 3.77 (s, 3 H, MeO), 4.12 (m, 1 H, H-3a), 5.25 (d, J = 8.0 Hz, 1 H, H-2a), 6.80 (d, J = 8.8 Hz, 2 H, Ar), 7.15 (d, J = 8.8 Hz, 2 H, Ar), 7.42 (dd, J = 8.0, 8.0 Hz, 2 H, Bz), 7.33 (t, J = 7.6 Hz, 1 H, Ph), 7.55 (t, J = 8.0 Hz, 1 H, Bz), 7.44 (dd, J = 7.6, 7.6 Hz, 2 H, Ph), 7.99 (d, J = 8.0 Hz, 2 H, Bz), 7.57 (d, J = 7.6 Hz, 2 H, Ph). 13C NMR (100.08 MHz, CDCl3): δ = 30.5 (Me), 48.2 (C-4), 46.8 (C-3), 55.2 (MeO), 86.3 (C-2), 86.3 (C-5), 114,0 (Ar), 124.5 (Ph), 126.7 (Ph), 127.8 (Bz), 128.3 (Bz), 128.8 (Ph), 129.2 (Ar), 131.8 (Ar), 133.1 (Bz), 135.9 (Bz), 148.2 (Ph), 158.4 (Ar), 197.4 (C=O).
(±)-cis,trans-2-Benzoyl-3-(4-methoxyphenyl)-5-phenyl-5-methyl tetrahydrofuran (3a-C): colorless oil. HR-ESI-MS: m/z calcd for C25H24O3 + Na+: 395.1618. Found: 395.1608. 1H NMR (400 MHz, CDCl3: δ = 1.90 (s, 3 H, Me), 2.58 (dd, J = 12.0, 11.5 Hz, 1 H, H-4a), 2.81 (dd, J = 12.4, 7.2 Hz, 1 H, H-4e), 3.63 (s, 3 H, MeO), 3.70 (m, 1 H, H-3a), 5.72 (d, J = 9.1 Hz, 1 H, H-2e), 6.53 (d, J = 8.8 Hz, 2 H, Ar), 6.91 (d, J = 8.8 Hz, 2 H, Ar), 7.20 (dd, J = 8.0, 7.6 Hz, 2 H, Bz), 7.32 (t, J = 7.5 Hz, 1 H, Ph), 7.35 (t, J = 8.0 Hz, 1 H, Bz), 7.42 (dd, J = 7.5, 7.5 Hz, 2 H, Ph), 7.49 (d, J = 7.6 Hz, 2 H, Bz), 7.56 (d, J = 7.5 Hz, 2 H, Ph). 13C NMR (100.08 MHz, CDCl3): δ = 30.2 (Me), 45.4 (C-4), 48.1 (C-3), 55.0 (MeO), 82.4 (C-2), 85.6 (C-5), 113.3 (Ar), 124.7 (Ph), 126.7 (Ph), 127.3 (Bz), 127.8 (Bz), 128.3 (Ph), 129.2 (Ar), 130.0 (Ar), 132.3 (Bz), 136.5 (Bz), 147.0 (Ph), 158.2 (Ar), 198.9 (C=O).
(±)-trans,trans-2-Benzoyl-3-(4-methoxyphenyl)-5-phenyl-5-methyl tetrahydrofuran (3a-D): colorless oil. HR-ESI-MS: m/z calcd for C25H24O3 + H+: 373.1798. Found: 373.1797. 1H NMR (400 MHz, CDCl3): δ = 1.75 (s, 3 H, Me), 2.53 (dd, J = 12.4, 12.4 Hz, 1 H, H-4a), 2.85 (dd, J = 12.4, 6.0 Hz, 1 H, H-4e), 3.77 (s, 3 H, MeO), 3.80 (m, 1 H, H-3a), 5.25 (d, J = 9.2 Hz, 1 H, H-2a), 6.82 (d, J = 8.8 Hz, 2 H, Ar), 7.23 (d, J = 8.8 Hz, 2 H, Ar), 7.43 (dd, J = 8.0, 8.0 Hz, 2 H, Bz), 7.29 (t, J = 7.6 Hz, 1 H, Ph), 7.37 (d, J = 7.6 Hz, 2 H, Ph), 7.39 (dd, J = 7.6, 7.6 Hz, 2 H, Ph), 7.55 (t, J = 8.0 Hz, 1 H, Bz), 8.01 (d, J = 8.0 Hz, 2 H, Bz). 13C NMR (100.08 MHz, CDCl3): δ = 30.9 (Me), 45.2 (C-3), 48.3 (C-4), 55.2 (MeO), 86.0 (C-2), 86.3 (C-5), 114.0 (Ar), 124.8 (Ph), 126.7 (Ph), 128.0 (Bz), 128.3 (Bz), 128.8 (Ph), 129.3 (Ar), 131.6 (Ar), 133.0 (Bz), 136.2 (Bz), 147.1 (Ph), 158.4 (Ar), 196.6 (C=O).