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Acta Chimica Sinica >

2013 , Vol. 71 >Issue 04: 541 - 548

DOI: https://doi.org/10.6023/A13020215

Article

Regio-selective Dehydrogenation on the D or E Rings of Oleanolic Acid by Pd-Promoted C—H Activation

  • Ma Yuyong ,
  • Li Wei ,
  • Yu Biao
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  • State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032

Received date: 2013-02-26

  Online published: 2013-03-15

Supported by

Project supported by the National Basic Research Program of China (No. 2010CB529706).

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Abstract

Oleanane-type triterpenes and their glycosides are a structurally and biologically diverse class of metabolites that are widely distributed in terrestrial plants and some marine organisms. Many of these compounds bear functional groups and modifications on the D and/or E rings of the triterpenes. These triterpenes compounds are of growing interest for drug research as they are active constituents of folk medicines and provide valuable pharmacological profiles. For their limited availability and accessibility, chemical synthesis provides a realistic way to determine the availability of homogenous natural products and their derivatives. Here, we report the selective dehydrogenation on the D or E rings of oleanoic acid by palladium promoted C—H activation with 8-aminoquinoline amide (substrate 12) and 2-aminomethylpyridine amide (substrate 16) as the directing groups. Thus, upon treatment with thionyl chloride, the 28-COOH of oleanoic acid was converted into 28-COCl, which coupled with the corresponding amines to provide the substrates readily for dehydrogenation. Notably, treatment of 12 with optimized conditions (1.0 equiv. Pd(OAc)2, 1.5 equiv. Oxone®, 1,2-dichloroethane, 80 ℃, 24 h) led to the dehydrogenated products 13 [double bond at C(15)—C(16)] and 14 [double bond at C(20)—C(21)] in 55% and 2% yields respectively. Treatment of 16 with optimized conditions (1.0 equiv. Pd(OAc)2, 2.0 equiv. Oxone®, 1,2-dichloroethane, microwave 85 ℃, 50 min) provided 17 [double bond at C(20)—C(21)] and 18 [double bond at C(15)—C(16)] in 42% and 20% yields respectively. Moreover, the distribution of the products varied in different solvents. It is worth mentioning that the N,N-bidentate ligands (two nitrogen atoms as the coordination sites in 12 and 16) are crucial for the palladium promoted olefination.

Key words： oleanoic acid; palladium; C—H activation; dehydrogenation; 8-aminoquinoline; 2-aminomethylpyridine; oxime

Cite this article

Ma Yuyong , Li Wei , Yu Biao . Regio-selective Dehydrogenation on the D or E Rings of Oleanolic Acid by Pd-Promoted C—H Activation[J]. Acta Chimica Sinica, 2013 , 71(04) : 541 -548 . DOI: 10.6023/A13020215

References

[1] (a) Tschesche, R.; Wulff, G. Fortschr. Chem. Org. Naturst. 1973, 30, 461; (b) Hostettmann, K.; Marston, A. Saponins, Cambridge University, Cambridge, UK, 1995.

[2] (a) Advances in Experimental Medicine and Biology, Vol. 404, Eds.: Waller, G. R.; Yamasaki, K., Plenum Press, New York, 1996; (b) Sparg, S. G.; Light, M. E.; Staden, J. V. J. Ethnopharmacol. 2004, 94, 219.

[3] Vincken, J. P.; Heng, L.; Groot, A. D.; Gruppen, H. Phytochemistry 2011, 71, 435.

[4] Augustin, J. M.; Kuzina, V.; Andersen, S. B.; Bak, S. Phytochemistry 2007, 68, 275.

[5] Sheng, H. M.; Sun, H. B. Nat. Prod. Rep. 2011, 28, 543

[6] (a) Yu, B.; Sun, J. S. Chem. Asian J. 2009, 4, 642; (b) Yu, B.; Sun, J. S.; Yang, X. Y. Acc. Chem. Res. 2012, 45, 1227; (b) Yu, B.; Zhang, Y. C.; Tang, P. P. Eur. J. Org. Chem. 2007, 5145; (c) Pellissier, H. Tetrehedron 2004, 60, 5123.

[7]Sun, H.; Liu, T.; Shen, Y. J.; Zang, L. M.; Wang, M. Chin. J. Struct. Chem. 2010, 29, 1798.

[8] For a recent review on the glycosylation methods, see: Zhu, X. M.; Schmidt, R. R. Angew. Chem., Int. Ed. 2009, 48, 1900.

[9] (a) Herrmann, P.; Bach, T. Chem. Soc. Rev. 2011, 40, 2022; (b) Lyons, T. W.; Sanford, M. S. Chem. Rev. 2010, 110, 1147; (c) Desai, L. V.; Hull, K. L.; Sanford, M. S. J. Am. Chem. Soc. 2004, 126, 9542; (d) Zaitsev, V. G.; Shabashov, D.; Daugulis, O. J. Am. Chem. Soc. 2005, 127, 13154; (e) Shabashov, D.; Daugulis, O. J. Am. Chem. Soc. 2010, 132, 3965; (f) Neufeldt, S. R.; Sanford, M. S. Acc. Chem. Res. 2012, 45, 936; (g) Giri, R.; Chen X.; Yu, J. Q. Angew. Chem., Int. Ed. 2005, 44, 2112; (h) Neufeldt, S. R.; Sanford, M. S. Org. Lett. 2010, 12, 532; (i) Reddy, B. V. S.; Reddy, L. R.; Corey, E. J. Org. Lett. 2006, 8, 3391.

[10] Shamsuddin, K. M.; Zobairi, M. O.; Musharraf, M. A. Tetrahedron Lett. 1998, 39, 8153.

[11] Le M閚ez, P.; Hamze, A.; Provot, O.; Brion, J. D.; Alami, M. Synlett 2010, 7, 1101.

[12] (a) Nahm, S.; Weinreb, S. M. Tetrahedron Lett. 1981, 22, 3815; (b) Keck, G. E.; Palani, A.; McHardy, S. F. J. Org. Chem. 1994, 59, 3113.

[13] (a) Li, H.; Zou, H.; Gao, L. X.; Liu, T.; Yang, F.; Li, J. Y.; Li, J.; Qiu, W. W.; Tang, J. Heterocycles 2012, 85, 1117; (b) Zhu, C. S.; Tang, P. P.; Yu, B. J. Am. Chem. Soc. 2008, 130, 5872.

[14] CCDC 923435, 923429, 923434, 923436 contain the supplementary crystallographic data for compounds 13, 14, 15, and 17, respectively. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/ data_request/cif.

[15] Gou, F. R.; Wang, X. C.; Huo, P. F.; Bi, H. P.; Guan, Z. H.; Liang, Y. M. Org. Lett. 2009, 11, 5726.

[16] Feng, Y. Q.; Wang, Y. J.; Landgraf, B.; Liu, S.; Chen, G. Org. Lett. 2010, 12, 3414.

[17] Lafrance, M.; Gorelsky, S. I.; Fagnou, K. J. Am. Chem. Soc. 2007, 129, 14570.
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