Reactive geometries in Lewis acid-mediated Diels - Alder reactions: Insights from covalently attached acids

Journal of Organic Chemistry

Volumn 61, Issue 4, 1996, Pages 1443-1446

  Springer, James B ^a   Corcoran, Robert C ^a  

^a UNIVERSITY OF WYOMING   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000588549     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo9518922     Document Type: Article

References (27)

1. Portions of this work were presented at the 210th National Meeting of the American Chemical Society, Chicago, Illinois, August, 1995.
2. Two recent related studies of chiral Lewis acids which also provide leading references to the literature in this field: (a) Haase, C.; Sarko, C. R.; DiMare, M. J. Org. Chem. 1995, 60, 1777. (b) Seebach, D.; Dahinden, R.; Marti, R. E.; Beck, A. K.; Plattner, D. A.; Kuhnle, F. N. M. J. Org. Chem. 1995, 60, 1788.
3. Two recent related studies of chiral Lewis acids which also provide leading references to the literature in this field: (a) Haase, C.; Sarko, C. R.; DiMare, M. J. Org. Chem. 1995, 60, 1777. (b) Seebach, D.; Dahinden, R.; Marti, R. E.; Beck, A. K.; Plattner, D. A.; Kuhnle, F. N. M. J. Org. Chem. 1995, 60, 1788.
4. The extensive literature on this subject has been cogently summarized and discussed by Denmark and Almstead as a part of their work on the spectroscopic characterization of enone-Lewis acid complexes: Denmark, S. E.; Almstead, N. G. J. Am. Chem. Soc. 1993, 115, 3133.
5. Seeman, J. I. Chem. Rev. 1983, 83, 83.
6. The extensive studies of Gladysz and coworkers on the reactions of complexes of carbonyl compounds with chiral rhenium Lewis acids provide a particularly apt example. For leading references to this work, see: (a) Wang, Y.; Gladysz, J. A. J. Org. Chem. 1995, 60, 903. (b) Klein, D. P.; Gladysz, J. A. J. Am. Chem. Soc. 1992, 114, 8710.
7. The extensive studies of Gladysz and coworkers on the reactions of complexes of carbonyl compounds with chiral rhenium Lewis acids provide a particularly apt example. For leading references to this work, see: (a) Wang, Y.; Gladysz, J. A. J. Org. Chem. 1995, 60, 903. (b) Klein, D. P.; Gladysz, J. A. J. Am. Chem. Soc. 1992, 114, 8710.
8. Corcoran, R. C.; Ma, J. J. Am. Chem. Soc. 1991, 113, 8973.
9. Coreoran, R. C.; Ma, J. J. Am. Chem. Soc. 1992, 114, 4536.
10. An example of a problem of this type may be found in ref 7.
11. Singh, D. K.; Springer, J. B.; Goodson, P. A.; Corcoran, R. C. J. Org. Chem. 1996, 61, 1436-1442.
12. Other examples of carbonyl activation by covalently attached Lewis acids: (a) Wuest, J. D.; Bachand, B. Organometallics 1991, 10, 2015. (b) Bachand, B.; Belanger-Gariepy, G.; Wuest, J. D. Organometallics 1990, 9, 2860. (c) Kelly, T. R.; Whiting, A.; Chandrakumar, N. S. J. Am. Chem. Soc. 1986, 108, 3510.
13. Other examples of carbonyl activation by covalently attached Lewis acids: (a) Wuest, J. D.; Bachand, B. Organometallics 1991, 10, 2015. (b) Bachand, B.; Belanger-Gariepy, G.; Wuest, J. D. Organometallics 1990, 9, 2860. (c) Kelly, T. R.; Whiting, A.; Chandrakumar, N. S. J. Am. Chem. Soc. 1986, 108, 3510.
14. Other examples of carbonyl activation by covalently attached Lewis acids: (a) Wuest, J. D.; Bachand, B. Organometallics 1991, 10, 2015. (b) Bachand, B.; Belanger-Gariepy, G.; Wuest, J. D. Organometallics 1990, 9, 2860. (c) Kelly, T. R.; Whiting, A.; Chandrakumar, N. S. J. Am. Chem. Soc. 1986, 108, 3510.
15. Jung, M. E.; Lyster, M. A J. Org. Chem. 1977, 42, 3761.
16. Denmark, S. E.; Almstead, N. G. Tetrahedron 1992, 44, 5565.
17. Springer, J. B.; DeBoard, J.; Corcoran, R. C. Tetrahedron Lett. 1995, 36, 8733.
18. Keck, G. E.; Castellino, S. J. Am. Chem. Soc. 1986, 108, 3847.
19. When 1-3 equiv of THF is added, the chemical shift of this proton is obscured by other resonances. The peak moves from δ 4.72 at 4 equiv of THF to δ 4.88 at 7 equiv.
20. aTHF, the equilibrium constant for the formation of 2a·THF from 2a and THF. We are unable to calculate this equilibrium constant due to gross uncertainties in the chemical shift value of the β-enone proton of 2a which are a consequence of both exchange broadening and overlapping resonances associated with the phenyl protons of benzyl chloride.
21. Macomber, R. S. J. Chem. Ed. 1992, 69, 375.
22. 2 = 0.006), we are nevertheless inclined to view these results with some caution for the reasons outlined in ref 16.
23. 3.
24. 2.
25. Hunt, I. R.; Rogers, C.; Woo, S.; Rauk, A.; Keay, B. A. J. Am. Chem. Soc. 1995, 117, 1049.
26. o) vs time plots: Young, H. D. Statistical Treatment of Experimental Data; McGraw-Hill: New York, 1962; section IV. 14.
27. 3)(t-Bu) is reported in ref 10b. The RO-Ti bond length is 1.725 Å, as compared to 2.121 Å for the Ti-O=C bond length.