Fluorine-directed Nazarov cyclizations 2: Regioselective synthesis of 5-trifluoromethyl-2-Cyclopentenones

Synlett

Volumn , Issue 8, 1998, Pages 927-929

  Ichikawa, Junji ^a   Fujiwara, Masaki ^a   Okauchi, Tatsuo ^a   Minami, Toni ^a  

^a KYUSHU INSTITUTE OF TECHNOLOGY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001555854     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1998-1817     Document Type: Article

References (31)

1. Reviews of the Nazarov cyclization: Habermas, K. L.; Denmark, S. E.; Jones, T. K. In Organic Reactions; Paquette, L. A. Ed.; John Wiley & Sons: New York, 1994; Vol. 45, p 1.
2. Denmark, S. E. In Comprehensive Organic Synthesis; Trost, B. M.; Fleming, I. Eds.; Pergamon Press: Oxford, 1991; Vol. 5, p 751.
3. (a) Silicon-directed Nazarov cyclizations: Denmark, S. E.; Jones, T. K. J. Am. Chem. Soc. 1982, 104, 2642.
4. Denmark, S. E.; Wallace, M. A.; Walker, Jr., C. B. J. Org. Chem. 1990, 55, 5543.
5. Kang, K. -T.; Kim, S. S.; Lee, J. C.; U, J. S. Tetrahedron Lett. 1992, 33, 3495.
6. Tin-directed Nazarov cyclizations: Peel, M. R.; Johnson, C. R. Tetrahedron Lett. 1986, 27, 5947.
7. Ichikawa, J.; Yokota, N.; Kobayashi, M.; Minami, T. Synlett, 1993, 186.
8. Ichikawa, J.; Kobayashi, M.; Yokota, N.; Noda, Y.; Minami, T. Tetrahedron, 1994, 50, 11637.
9. Ichikawa, J.; Yokota, N.; Kobayashi, M.; Amano, K.; Minami, T. Synlett, 1996, 243.
10. Ichikawa, J.; Kobayashi, M.; Noda, Y.; Yokota, N.; Amano, K.; Minami, T. J. Org. Chem., 1996, 61, 2763.
11. Ichikawa, J.; Wada, Y.; Okauchi, T.; Minami, T. Chem. Commun., 1997, 1537.
12. Fluorine-directed Nazarov cyclizations 1: Ichikawa, J.; Miyazaki, S.; Fujiwara, M.; Minami, T. J. Org. Chem. 1995, 60, 2320.
13. Smart, B. E. In Organofluorine Chemistry, Principles and Commercial Applications, Banks, R. E.; Smart, B. E.; Tatlow, J. C. Eds.; Plenum Press: New York, 1994; p 57.
14. Only a limited number of methods have been reported for the synthesis of 5-trifluoromethyl-2-cyclopentenones despite the potential utility of trifluoromethyl substitution in modifying the properties and activities of biologically important small molecules. Kawada, K.; Kitagawa, O.; Kobayashi Y. Chem. Pharm. Bull. 1985, 33, 3670.
15. Cruciani, G.; Margaretha, P. Helv. Chim. Acta 1990, 73, 890.
16. Hanzawa, Y.; Ito, H.; Kohara, N.; Sasaki, H.; Fukuda, H.; Morikawa, T.; Taguchi, T. Tetrahedron Lett. 1991, 32, 4143.
17. Xu, Y.; Jin, F.; Huang, W. J. Org. Chem. 1994, 59, 2638.
18. Ye, J.; Bhatt, R. K.; Falck, J. R. J. Am. Chem. Soc. 1994, 116, 1.
19. We have recently observed that fluorine-free Nazarov cyclizations were also highly promoted under these conditions. These results will be reported elsewhere.
20. Schadt, F. L.; Schleyer, P. v. R.; Bentley, T. W. Tetrahedron Lett. 1974, 2335.
21. Allard, B.; Casadevall, A.; Casadevall, E.; Largeau, C. Nouv. J. Chim. 1979, 3, 335.
22. For recent reports on the cationic reactions conducted in HFIP, see: Ref. 4. Leonard, N. J.; Neelima Tetrahedron Lett. 1995, 36, 7833.
23. Ohwada, A.; Li, H.; Sakamoto, T.; Kikugawa, Y. Heterocycles 1997, 46, 225.
24. 13C NMR, IR, MS and combustion analysis (±0.3%) and/or HRMS.
25. 2 also promoted these cyclizations at room temperature in moderate yields.
26. Allen, A. D.; Fujio, M.; Mohammed, N.; Tidwell, T. T.; Tsuji, Y. J. Org. Chem. 1997, 26, 246 and references cited therein.
27. For reports on cationic cyclizations where fluorine acts as an α-cation-stabilizing substituent, see: Johnson, W. S.; Daub, G. W.; Lyle, T. A.; Niwa, M. J. Am. Chem. Soc. 1980, 102, 7800.
28. Johnson, W. S.; Lyle, T. A.; Daub, G. W. J. Org. Chem. 1982, 47, 161.
29. Fish, P. V.; Johnson, W. S.; Jones, G. S.; Tham, F. S.; Kullnig, R. K. J. Org. Chem. 1994, 59, 6150 and references cited therein.
30. Morikawa, T.; Kumadaki, I.; Shiro, M. Chem. Pharm. Bull. 1985, 33, 5144.
31. The differing propensities of these substrates for defluorination are not yet fully understood. Crowley, P. J.; Percy, J. M.; Stansfield, K. Tetrahedron Lett. 1996, 37, 8233.