Synthesis of a new class of C2-symmetrical biheteroaryls by ammonium cerium(IV) nitrate mediated dimerization of 2-(furan-3-yl)pyrroles

European Journal of Organic Chemistry

Volumn , Issue 5, 2010, Pages 823-826

  Alcaide, Benito ^a   Almendros, Pedro ^b   Carrascosa, Rocío ^a   Rosario Torres, M ^a  

^a UNIVERSIDAD COMPLUTENSE DE MADRID   (Spain)

^b INSTITUTO DE QUÍMICA ORGÁNICA GENERAL   (Spain)

Author keywords

Alienes; Cerium; Chemoselectivity; Dimerization; Heterocycles

Indexed keywords

EID: 76149131330     PISSN: 1434193X     EISSN: 10990690     Source Type: Journal    
DOI: 10.1002/ejoc.200901314     Document Type: Article

References (23)

1. The most extensively used cerium(IV) reagent in organic chemistry is ammonium cerium(lV) nitrate (CAN). For reviews on the use of CAN as a versatile single-electron oxidant, see: a) V. Nair, A. Deepthi, Tetrahedron 2009, 65, 10745;
2. b) V. Nair, A. Deepthi, Chem. Rev. 2007, 107, 1862: for selected examples on CAN-promoled oxidative dimerization and oxidative arylation.
3. see: c) C. Xi. Y. Jiang, X. Yang, Tetrahedron Lett. 2005. 46. 3909:
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6. b) B. Alcaide, P. Almendros, M. C. Redondo. Chem. Commun. 2006, 2616.
7. For a report available in the literature on the DDQ-mediated oxidative cleavage of 3-alkoxy-2.5-dihydrofurans to afford α,βunsaturated γ-oxo aldehydes, see: a) M. Brasholz. H.-U. Reissig. Angew. Chem. Int. Ed. 2007, 46, 1634;
8. Angew. Chem. 2007, 119, 1659;for a report available in the literature on the CAN- mediated oxidative cleavage of a 3-ethoxycarbonyl-2-methylfuran to afford an oct-2-enoate,
9. see: b)A.J.Moreno-Vargas,I.Robina,J.Fernández-Bolaños, J. Fuentes. Tetrahedron Lett. 1998, 39, 9271.
10. Furans and pyrroles constitute an important structural component in pharmaceuticals and natural products, being some of the best-selling drug heterocycles of these types. For atorvastatin (a pyrrole used Io control high cholesterol), see: a) M. E. M. Noble. J. A. Endicolt. L. N. Johnson, Science 2004, 303,1800;
11. b) J. C. Reed. M. Pellecchia. Blood2WS, 106, 408;
12. c) A. R Lea. D. Mctavish, Drugs 1997, 53, 828; for ranitidine (a furan used to treat stomach ulcers),
13. see; d) J. A. Joule, K. Mills. Heterocyclic Chemistry. 4th ed. Blackwell Science Ltd. Maiden, MA. 2000: in particular, bipyrroles are natural products belonging to the prodigiosins, and they are also capable of inducing apoptosis in human cancer cells,
14. see; e) H. Rapoport, K. G. Holden. J. Am. Chem. Soc. 1962, 84, 635;
15. f) B. Montaner. R. Pérez-Tomás, Life Sci. 2001, 68, 2025; on the other hand, bifurans are key motifs in natural products, such as licorice, present in foods and beverages,
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17. Biaryls, important constituents of natural products and of pharmaceutical agents, have been recently recognized as a core functional group in organic molecular materials, and have received attention due to the use of axially chiral biaryls as Iigands in asymmetric reactions: for selected reviews, see: a) J.-P. Corbet. G. Mignani, Chem. Rev. 2006. 106, 2651;
18. b) J. Hagen. Industrial Catalysis, Wiley-VCH, Weinheim, 2nd ed., 2006. pp. 59-80;
19. c) A. O. King, N.Yasuda.inOrganometallic s in Process Chemistry (Ed.: R. D. Larsen), Springer-Verlag, Berlin, Heidelberg. 2004, pp. 205-245;
20. d) R. Noyori, Chem. Soc. Rev. 1989. 18, 187:
21. e) K. Narasaka, Synthesis 1991, 1.
22. 2 (SHELXL97). All non-hydrogen atoms were refined anisotropically. All hydrogen atoms were included in calculated positions and refined riding on the respective carbon atoms. Final R(Rw) values were R\ = 0.0394 and wR2 = 0.0941. CCDC-675795 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-/cif.
23. A referee suggested an analogous mechanistic pathway involving the oxidation of the pyrrole segment first. Thus, an oxidation of the pyrrole nucleus and a derealization of the charge into the furan moiety could be envisaged and would explain the selectivity observed and the difference of behavior between 2-furan (2a) and 3-furan (2b e) compounds under such conditions. However, we think that both the presence of the ester group as well as the relatively low ionization potentials of the furan ring will undergo electron transfer particularly easily into the oxygenated heterocycle.