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Synthesis 2015; 47(17): 2545-2548
DOI: 10.1055/s-0034-1381054
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© Georg Thieme Verlag Stuttgart · New York

Synthetic Studies toward Bi-linderone Lead To Unexpected 6π-Electrocyclization Reactions: A Facile Construction of Highly Congested Spiro Compounds

Fenfen Xiao
School of Chemistry & Material Science, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education of China, Northwest University, Xi’an 710127, P. R. of China   Email: wyx27210@nwu.edu.cn   Email: xiangdonghu@nwu.edu.cn
,
Qing Zhang
School of Chemistry & Material Science, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education of China, Northwest University, Xi’an 710127, P. R. of China   Email: wyx27210@nwu.edu.cn   Email: xiangdonghu@nwu.edu.cn
,
Yunxia Wang*
School of Chemistry & Material Science, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education of China, Northwest University, Xi’an 710127, P. R. of China   Email: wyx27210@nwu.edu.cn   Email: xiangdonghu@nwu.edu.cn
,
Xiangdong Hu*
School of Chemistry & Material Science, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education of China, Northwest University, Xi’an 710127, P. R. of China   Email: wyx27210@nwu.edu.cn   Email: xiangdonghu@nwu.edu.cn
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Further Information

Publication History

Received: 29 May 2015

Accepted after revision: 29 June 2015

Publication Date:
11 August 2015 (online)

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Abstract

During synthetic studies toward bi-linderone, unexpected 6π-electrocyclizations of 4,5-dimethoxy-2-[(E)-1,3-dimethoxy-5-phenylpenta-2,4-dienylidene]cyclopent-4-ene-1,3-dione and 2-[(E)-1-hydroxy-3-methoxy-5-phenylpenta-2,4-dienylidene]-4,5-dimethoxycyclopent-4-ene-1,3-dione were observed. The cyclization of 4,5-dimethoxy-2-[(E)-1,3-dimethoxy-5-phenylpenta-2,4-dienylidene]cyclopent-4-ene-1,3-dione gave a rare example of a 6π-electrocyclization reaction that occurs readily at room temperature in the presence of silica gel. Meanwhile, the intramolecular hydrogen bonding existing in 2-[(E)-1-hydroxy-3-methoxy-5-phenylpenta-2,4-dienylidene]-4,5-dimethoxycyclopent-4-ene-1,3-dione afforded a strong contribution to the stability of the flat conformation, and this hampered the 6π-electrocyclization process. These 6π-electrocyclizations afforded a facile approach to highly congested spiro compounds.

Key words

alkene - electrocyclic reactions - natural products - spiro compounds - transition states

Supporting Information

    Supporting information for this article is available online at http://dx.doi.org/10.1055/s-0034-1381054.
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  • References

  • 2 Tan H, Zheng C, Liu Z, Wang DZ. Org. Lett. 2011; 13: 2192
    CrossrefSearch in Google Scholar
  • 3 Wang GQ, Wei K, Zhang L, Feng T, Wang F, Wang QA, Liu JK. Tetrahedron Lett. 2011; 52: 2719
    CrossrefSearch in Google Scholar
  • 4 Xiao FF, Liu W, Wang YX, Zhang Q, Li X, Hu X. Asian J. Org. Chem. 2013; 2: 216
    CrossrefSearch in Google Scholar
  • 5 The Z-configuration of the enol motif of 6 was confirmed through the 1D NOE experiment; please see the Supporting Information for details.
  • 6 Gai S, Zhang Q, Li X, Hu X. J. Org. Chem. 2014; 79: 2111
    CrossrefSearch in Google Scholar
  • 7 CCDC 1049154 (5) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/ data_request/cif.
  • 8 CCDC 1049153 (11) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/ data_request/cif.
  • 9 CCDC 1049157 (12) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/ data_request/cif.
  • 10 Spangler W, Jondahl TP, Spangler B. J. Org. Chem. 1973; 38: 2478
    CrossrefSearch in Google Scholar
  • 11 Magomedov NA, Ruggiero PL, Tang Y. J. Am. Chem. Soc. 2004; 126: 1624
    CrossrefSearch in Google Scholar
  • 12 Brangänge S, Leijonmarck H. Chem. Commun. 2004; 292
  • 13 Marvell EN, Caple G, Delphey C, Platt J, Polston N, Tashiro J. Tetrahedron 1973; 29: 3797
    CrossrefSearch in Google Scholar
  • 14 Yu T.-Q, Fu Y, Liu L, Guo Q.-X. J. Org. Chem. 2006; 71: 6157
    CrossrefSearch in Google Scholar