Synthetic approaches to sterically hindered N-arylimidazoles through copper-catalyzed coupling reactions

European Journal of Organic Chemistry

Volumn , Issue 8, 2005, Pages 1637-1643

  Alcalde, Ermitas ^a   Dinarès, Immaculada ^a   Rodríguez, Sandra ^a   De Miguel, Cristina Garcia ^a  

^a UNIVERSITY OF BARCELONA   (Spain)

Author keywords

Arylation; Benzimidazole; Imidazole; N Heterocyclic carbenes; Ullman type condensation

Indexed keywords

EID: 18144376361     PISSN: 1434193X     EISSN: None     Source Type: Journal    
DOI: 10.1002/ejoc.200400453     Document Type: Article

References (29)

1. For a review of the state of the art in modern synthetic methods for copper-mediated C-(aryl)-heteroatom bond formation, see: S. V. Ley, A. W. Thomas, Angew. Chem. 2003,
2. Angew. Chem. Int. Ed. 2003, 42, 5400-5449.
3. a) J. C. Antilla, A. Klapars, S. L. Buchwald, J. Am. Chem. Soc. 2002, 124, 11684-11688, and references cited therein.
4. b) A. Klapars, J. C. Antilla, X. Huang, S. L. Buchwald, J. Am. Chem. Soc 2001, 123, 7727-7729;
5. c) J. C. Antilla, J. M. Baskin, T. E. Barder, S. L. Buchwald, J. Org. Chem. 2004, 69, 5578-5587;
6. d) H.-J. Cristau, P. P. Cellier, J.-F. Spindler, M. Taillefer, Eur. J. Org. Chem. 2004, 695-709;
7. e) H.-J. Cristau, P. P. Cellier, J.-F. Spindler, M. Taillefer, Chem. Eur. J. 2004, 10, 5607-5622.
8. J.-B. Lan, L. Chen, X.-Q. Yu, J.-S. You, R.-G. Xie, Chem. Commun. 2004, 188-189 and references cited therein.
9. For recent reviews on NHC, see: a) W. A. Herrmann, Angew. Chem. 2002,
10. Angew. Chem. Int. Ed. 2002, 41, 1290-1309;
11. b) M. C. Perry, K. Burgess, Tetrahedron: Asymmetry 2003, 14, 951-961. For some examples on chiral NHC ligands for the development of new asymmetric catalysts, see:
12. c) M. C. Perry, X. Cui, M. T. Powell, D.-R. Hou, J. H. Reibenspies, K. Burgess, J. Am. Chem. Soc. 2003, 125, 113-123. For calix[4]arene-supported NHC ligands, see:
13. d) F. Markus, G. Mass, J. Schatz, Eur. J. Org. Chem. 2004, 607-613.
14. a) E. Alcalde, N. Mesquida, M. Vilaseca, Rapid Commun. Mass Spectrom. 2000, 14, 1443-1447 and references cited therein.
15. b) E. Alcalde, N. Mesquida, M. Alemany, C. Alvarez-Rúa, S. Garcia-Granda, P. Pacheco, L. Pérez-García, Eur. J. Org. Chem. 2002, 1221-1231 and references cited therein.
16. Concomitant with our work, an Ullmann-type condensation procedure was also applied to prepare bis(imidazole) 1: V. C. Vargas, R. J. Rubio, T. K. Hollis, M. E. Salcido, Org. Lett. 2003, 5, 4847-4849.
17. [4c] have pointed out that 1,10-phenanthroline can be difficult to separate from the N-arylimidazole product.
18. M. G. Gardiner, W. A. Herrmann, C.-P. Reisinger; J. Schwarz, M. Spiegler, J. Organomet. Chem. 1999, 572, 239-247.
19. Concurrent with our work, Zang et al. reported a convenient modified two-step procedure for the classical synthesis of imidazoles and its applicability to the preparation of sterically hindered N-arylimidazoles; for example 1-mesityl-1H-imidazole (2a, 43%) and l-(2,6-diisopropylphenyl)-1H-imidazole (2b, 45%): J. Liu, J. Chen, J. Zhao, Y. Zhao, L. Li, H. Zhang, Synthesis 2003, 2661-2666 and references cited therein.
20. [9] worked very well (43% yield).
21. K. Okano, H. Tokuyama, T. Fukuyama, Org. Lett. 2003, 5, 4987-4990.
22. a) Y. S. Lam, C. G. Clark, S. Saubern, J. Adams, M. P. Winters, D. M. T. Chan, A. Combs, Tetrahedron Lett. 1998, 39, 2941-2944;
23. b) J. P. Collman, M. Zhong, Org. Lett. 2000, 2, 1233-1236.
24. [14] see:
25. T. D. Quach, R. A. Batey, Org. Lett. 2003, 5, 4397-4440 and references cited therein.
26. [13]
27. 1H NMR spectral simplification, 5,6-dimethyl-1H-benzimidazole (5) was used instead of 1H-benzimidazole.
28. [2b,c]
29. B. S. Jensen, L. Teuber, D. Strobaek, P. Christophersen, S. P. Olesen, PCT Int. Appl. 2000, WO 0069823A120001123.