Perfluorinated cyclic and acyclic keto-enol systems: A remarkable contrast

Journal of the American Chemical Society

Volumn 119, Issue 14, 1997, Pages 3259-3266

  Lindner, Patrick E ^a   Lemal, David M ^a  

^a Dartmouth College   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

FLUOROCARBON; ORGANOFLUORINE DERIVATIVE;

ARTICLE; COMPUTER SIMULATION; DRUG STABILITY; DRUG STRUCTURE; MOLECULAR DYNAMICS; QUANTUM MECHANICS; THERMODYNAMICS;

EID: 0030956945     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja963788n     Document Type: Article

References (40)

1. For a concise summary of this work, see: Hart, H.; Rappoport, Z.; Biali, S. E. In ref 3, pp 502-514.
2. The Chemistry of Enols; Rappoport, Z., Ed.; John Wiley and Sons: Chichester, U.K., 1990.
3. Keeffe, J. R.; Kresge, A. J.; Schepp, N. P. J. Am. Chem. Soc. 1990, 112, 4862.
4. Toullec, J. In Advances in Physical Organic Chemistry; Gold, V.; Bethell, Eds.; Academic Press: London, 1982; Vol. 18, pp 1-77. Chiang, Y.; Hojatti, M.; Keeffe, J. R.; Kresge, A. J.; Schepp, N. P.; Wirz, J. J. Am. Chem. Soc. 1987, 109, 4000.
5. Toullec, J. In Advances in Physical Organic Chemistry; Gold, V.; Bethell, Eds.; Academic Press: London, 1982; Vol. 18, pp 1-77. Chiang, Y.; Hojatti, M.; Keeffe, J. R.; Kresge, A. J.; Schepp, N. P.; Wirz, J. J. Am. Chem. Soc. 1987, 109, 4000.
6. Bekker, R. A.; Melikyan, G. G.; Dyatkin, B. L.; Knunyants, I. L. Zh. Org. Khim. 1975, 11, 2370; English translation, p 2415.
7. Bekker, R. A.; Melikyan, G. G.; Dyatkin, B. L.; Knunyants, I. L. Zh. Org. Khim. 1975, 11, 2370; English translation, p 2415.
8. (b) Bekker, R. A.; Melikyan, G. G.; Dyatkin, B. L.; Knunyants, I. L. Zh. Org. Khim. 1975, 11, 1370; English translation, p 1356.
9. (b) Bekker, R. A.; Melikyan, G. G.; Dyatkin, B. L.; Knunyants, I. L. Zh. Org. Khim. 1975, 11, 1370; English translation, p 1356.
10. (a) Correa, R. A.; Lindner, P. E.; Lemal, D. M. J. Am. Chem. Soc. 1994, 116, 10795.
11. (b) Lindner, P. E.; Correa, R. A.; Gino, J.; Lemal, D. M. J. Am. Chem. Soc. 1996, 118, 2556.
12. (c) Lindner, P. E.; Lemal, D. M. J. Org. Chem. 1996, 61, 5109.
13. (a) Bekker, R. A.; Popkova, V. Ya.; Knunyants, I. L. Dokl. Akad. Nauk SSSR 1977, 233, 591; English translation, p 187.
14. (a) Bekker, R. A.; Popkova, V. Ya.; Knunyants, I. L. Dokl. Akad. Nauk SSSR 1977, 233, 591; English translation, p 187.
15. (b) Bekker, R. A.; Popkova, V. Ya. Izv. Akad. Nauk SSSR 1978, 12, 2775; English translation, p 2476.
16. (b) Bekker, R. A.; Popkova, V. Ya. Izv. Akad. Nauk SSSR 1978, 12, 2775; English translation, p 2476.
17. (a) Martini, T.; Schumann, C. J. Fluorine Chem. 1976, 8, 525.
18. (b) Saoutina, L. V.; Zapevalov, A. Ya.; Kodess, M. I.; Kolenko, I. P.; German, L. S. Izv. Akad. Nauk SSSR 1982, 11, 2615.
19. (c) Wiley, D. W.; Simmons, H. E. J. Am. Chem. Soc. 1964, 29, 1876.
20. Gaussian 92. Revision C.3: Frisch, M. J.; Trucks, G. W.; Head-Gordon, M.; Gill, P. M. W.; Wong, M. W.; Foresman, J. B.; Johnson, B. G.; Schelegel, H. B.; Robb, M. A.; Replogle, E. S.; Gomperts, R.; Andres, J. L.; Raghavachari, K.; Binkley, J. S.; Gonzalez, C.; Martin, R. L.; Fox, D. J.; Defrees, D. J.; Baker, J.; Stewart, J. J. P.; Pople, J. A. Gaussian, Inc.; Pittsburgh, PA, 1992.
21. See, for example: Smart, B. E. In Molecular Structure and Energetics: Liebman, J. F.; Greenberg, A., Eds.; VCH Publishers: Deerfield Beach, FL, 1986; Vol. 3, p 141.
22. Postovoi, S. A.; Vol'pin, I. M.; Mysov, E. I.; Zeifman, Yu. V.; German, L. S. Izv. Akad. Nauk SSSR 1989, 5, 1173; English translation, p 1067.
23. Postovoi, S. A.; Vol'pin, I. M.; Mysov, E. I.; Zeifman, Yu. V.; German, L. S. Izv. Akad. Nauk SSSR 1989, 5, 1173; English translation, p 1067.
24. Qian, C. P.; Nakai, T. Tetrahedron Lett. 1988, 29, 4119.
25. Fleming, I. Frontier Orbitals and Organic Chemical Reactions; Wiley: London, 1976; Chap. 3.
26. Qian, C. P.; Nakai, T. Dixon, D. A.; Smart, B. E. J. Am. Chem. Soc. 1990, 112, 4602.
27. We have shown that treating enol 4e with water gives the gemdiol.
28. 4 reduction of Pefluoro-4-heptanone, which was prepared by the method of Tamborski. Chen, L. S.; Chen, G. J.; Tamborski, C. J. J. Fluorine Chem. 1984, 26, 341.
29. 3 with LDA in THF showed a Z:E ratio of 1:3 (ref 15).
30. Fluorinated ketones exist as their hydrates in water. See, for example: Guthrie, J. P. Can. J. Chem. 1975, 53, 898.
31. Gellman, S. H.; Dado, G. P.; Liang, G. B.; Adams, B. R. J. Am. Chem. Soc. 1991, 113, 1164.
32. Deranleau, D. A. J. Am. Chem. Soc. 1969, 91, 4044.
33. (a) Purcell, K. F.; Stikeleather, J. A.; Brunk, S. D. J. Mol. Spectrosc. 1969, 32, 202.
34. (b) Purcell, K. F.; Stikeleather, J. A.; Brunk, S. D. J. Am. Chem. Soc. 1969, 91, 4019.
35. The enthalpy of hydrogen-bond formation between hexafluoroisopropyl alcohol and acetonitrile is 5.9 kcal/mol in methylene chloride (ref 22b). We cannnot assign a corresponding value for the enol because the entropy of hydrogen-bond formation for the two donors may differ considerably. ΔS° for the bulky hexafluoroisopropyl alcohol may be significantly more negative than for the enol (Kivinen, Murto, J.; Liljequist, S.; Vaara, S. Acta Chem. Scand. 1975, A29, 911).
36. The Russian group also prepared the enol of 3H-perfluoro-2-pentanone and reported that it ketonizes in water. As in the case of 3k, however, hydration of the ketone must have driven the equilibrium, so this result does not reveal the relative energies of the keto and enol forms. Bekker, R.A.; Popkova, V. Ya.; Snegirev, V. G.; Knunyants, J. L. Izv. Akad. Nauk SSSR 1983, 3, 620; English translation, p 560.
37. The Russian group also prepared the enol of 3H-perfluoro-2-pentanone and reported that it ketonizes in water. As in the case of 3k, however, hydration of the ketone must have driven the equilibrium, so this result does not reveal the relative energies of the keto and enol forms. Bekker, R.A.; Popkova, V. Ya.; Snegirev, V. G.; Knunyants, J. L. Izv. Akad. Nauk SSSR 1983, 3, 620; English translation, p 560.
38. Hehre, W. J.; Radom, L.; Schleyer, P. v. R.; Pople, J. S. Ab Initio Molecular Orbital Theory; Wiley: New York, 1986.
39. 3 group. Splitting of the vinyl fluorine into a quartet (J = 23 Hz) also reflects this coupling. The E and Z isomers of the enol (5e) were assigned analogously.
40. -1, which is consistent with the literature values. For a discussion of the infrared spectra, see: Kurbakova, A. P.; Leites, L. A.; German, L. S.; Kurykin, M. A. J. Fluorine Chem. 1996, 77, 169.