Direct observation of orthogonal orientation of an aromatic ring attached to the carbene carbon in fischer carbene complexes in solution: Diastereotopicity of benzyl protons as a stereochemical probe

Organometallics

Volumn 15, Issue 16, 1996, Pages 3528-3533

  Amin, Sk Rasidul ^a   Jayaprakash, K N ^a   Nandi, Malay ^a,b   Sathe, Kashinath M ^a   Sarkar, Amitabha ^a  

^a NATIONAL CHEMICAL LABORATORY   (India)

^b NATIONAL TSING HUA UNIVERSITY   (Taiwan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0011470735     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om960301a     Document Type: Article

References (32)

1. For recent reviews, see: (a) Wulff, W. D. In Comprehensive Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press: Oxford, U.K., 1995; Vol. 12, Chapter 5.3. Hegedus, L. S. Ibid., Vol. 12, Chapter 5.4. (b) Wulff, W. D. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, U.K., 1991; Vol. 5.
2. For recent reviews, see: (a) Wulff, W. D. In Comprehensive Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press: Oxford, U.K., 1995; Vol. 12, Chapter 5.3. Hegedus, L. S. Ibid., Vol. 12, Chapter 5.4. (b) Wulff, W. D. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, U.K., 1991; Vol. 5.
3. For recent reviews, see: (a) Wulff, W. D. In Comprehensive Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press: Oxford, U.K., 1995; Vol. 12, Chapter 5.3. Hegedus, L. S. Ibid., Vol. 12, Chapter 5.4. (b) Wulff, W. D. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, U.K., 1991; Vol. 5.
4. (a) Schubert, U. Coord. Chem. Rev. 1984, 55, 261.
5. (b) Dötz, K. H.; Fischer, H.; Hofmann, P.; Kreissel, F. R.; Schubert, U.; Weiss, K. Transition Metal Carbene Complexes; Verlag Chemie: Weinheim, Germany, 1983. For the few α,β-unsaturated carbene complexes characterized by crystallography, the π-plane is found to be coplanar: Anderson, B. A.; Wulff, W. D.; Powers, T. S.; Tribbitt, S.; Rheingold, A. L. J. Am. Chem. Soc. 1992, 114, 10784. Huttner, G.; Lange, S. Chem. Ber. 1970, 103, 3149.
6. (b) Dötz, K. H.; Fischer, H.; Hofmann, P.; Kreissel, F. R.; Schubert, U.; Weiss, K. Transition Metal Carbene Complexes; Verlag Chemie: Weinheim, Germany, 1983. For the few α,β-unsaturated carbene complexes characterized by crystallography, the π-plane is found to be coplanar: Anderson, B. A.; Wulff, W. D.; Powers, T. S.; Tribbitt, S.; Rheingold, A. L. J. Am. Chem. Soc. 1992, 114, 10784. Huttner, G.; Lange, S. Chem. Ber. 1970, 103, 3149.
7. (b) Dötz, K. H.; Fischer, H.; Hofmann, P.; Kreissel, F. R.; Schubert, U.; Weiss, K. Transition Metal Carbene Complexes; Verlag Chemie: Weinheim, Germany, 1983. For the few α,β-unsaturated carbene complexes characterized by crystallography, the π-plane is found to be coplanar: Anderson, B. A.; Wulff, W. D.; Powers, T. S.; Tribbitt, S.; Rheingold, A. L. J. Am. Chem. Soc. 1992, 114, 10784. Huttner, G.; Lange, S. Chem. Ber. 1970, 103, 3149.
8. (a) Fischer, E. O.; Kreiter, C. G. Kollmeier, H. J.; Muller, J.; Fischer, R. D. J. Organomet. Chem. 1971, 28, 237.
9. (b) Kreiter, C. G.; Fischer, E. O. Angew. Chem., Int. Ed. Eng. 1969, 8, 761.
10. (c) Moser, E.; Fischer, E. O. J. Organomet. Chem. 1968, 15, 147.
11. The E/Z nomenclature, normally used to define olefin geometries, is adopted throughout this text for convenience of unambiguous stereochemical description.
12. (a) Jennings, W. B. Chem. Rev. 1975, 75, 307.
13. (b) Mislow Raban, M. In Topics in Stereochemistry; Allinger, N. L., Eliel, K. L., Eds.; Wiley: New York, 1967; Vol. 1, p 1.
14. (c) Raban, M.; Lauderback, S. K.; Kost, D. J. Am. Chem. Soc. 1975, 97, 5178.
15. In this paper the term "orthogonal" is used throughout to denote an out-of-plane orientation in which relevant dihedral angles approach 90°.
16. In this model, the alkoxy group is placed anti with respect to the metal fragment (E conformer) for the sake of clarity in the diagram. For the conformation where the alkoxy group is placed syn to the metal fragment (Z conformer), the situation will still hold, but the effect may be differently manifested (vide infra).
17. (a) Fischer, E. O.; Leupold, M. Chem. Ber. 1972, 105, 599.
18. (b) Moser, E.; Fischer, E. O. J. Organomet. Chem. 1969, 16, 275.
19. The rotation barrier of the bond between the ipso carbon of the aromatic ring and the carbonyl carbon in ortho-substituted aromatic ketones or amides are estimated to be 16-20 kcal/mol or more, see: (a) Oki, M. In Topics in Stereochemistry; Allinger, N. L., Eliel, E. L., Wilen, S. H., Eds.; Wiley: New York, 1983; Vol. 14, p 1. (b) Sternhell, S. In Dynamic Nuclear Magnetic Resonance Spectroscopy; Jackman, L. M., Cotton, F. A., Eds.; Academic Press: New York, 1975; p 163. (c) Stewart, W. E.; Siddall, T. H., III. Chem. Rev. 1970, 70, 517. Consequently, the rotation of the bond between ipso carbon of the aromatic ring and carbene carbon is assumed to be slow on the NMR time scale throughout the temperature range used in the present study.
20. The rotation barrier of the bond between the ipso carbon of the aromatic ring and the carbonyl carbon in ortho-substituted aromatic ketones or amides are estimated to be 16-20 kcal/mol or more, see: (a) Oki, M. In Topics in Stereochemistry; Allinger, N. L., Eliel, E. L., Wilen, S. H., Eds.; Wiley: New York, 1983; Vol. 14, p 1. (b) Sternhell, S. In Dynamic Nuclear Magnetic Resonance Spectroscopy; Jackman, L. M., Cotton, F. A., Eds.; Academic Press: New York, 1975; p 163. (c) Stewart, W. E.; Siddall, T. H., III. Chem. Rev. 1970, 70, 517. Consequently, the rotation of the bond between ipso carbon of the aromatic ring and carbene carbon is assumed to be slow on the NMR time scale throughout the temperature range used in the present study.
21. The rotation barrier of the bond between the ipso carbon of the aromatic ring and the carbonyl carbon in ortho-substituted aromatic ketones or amides are estimated to be 16-20 kcal/mol or more, see: (a) Oki, M. In Topics in Stereochemistry; Allinger, N. L., Eliel, E. L., Wilen, S. H., Eds.; Wiley: New York, 1983; Vol. 14, p 1. (b) Sternhell, S. In Dynamic Nuclear Magnetic Resonance Spectroscopy; Jackman, L. M., Cotton, F. A., Eds.; Academic Press: New York, 1975; p 163. (c) Stewart, W. E.; Siddall, T. H., III. Chem. Rev. 1970, 70, 517. Consequently, the rotation of the bond between ipso carbon of the aromatic ring and carbene carbon is assumed to be slow on the NMR time scale throughout the temperature range used in the present study.
22. 3a that such a phenomenon might result from a planar aromatic ring effectively donating electron density toward the carbene carbon and thus reducing the resonance contribution from oxygen lone pair.
23. 1H NMR spectrum reveals eight lines (four doublets) for the four benzylic protons. In this molecule, the aryl ring of the ortho-toluyl group is twisted out of the amide plane.
24. Jennings, W. B.; Tolley, M. S. Tetrahedron Lett. 1976, 17, 695.
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26. (b) Connor, J. A.; Jones, E. M. J. Chem. Soc., Chem. Commun. 1971, 570.
27. Hoye, T. R.; Chen, K.; Vyvyan, J. R. Organometallics 1993, 12, 2806.
28. (a) Klabunde, U.; Fischer, E. O. J. Am. Chem. Soc. 1967, 89, 7141.
29. (b) Connor, J. A.; Fischer, E. O. J. Chem. Soc., Chem. Commun. 1967, 1024.
30. (c) Baikie, P. E.; Fischer, E. O.; Mills, O. S. J. Chem. Soc., Chem. Commun. 1967, 1199.
31. Amin, S. R.; Sarkar, A. Organometallics 1995, 14, 547. See also: Amin, S. R.; Sawant, S. S.; Puranik, V. G.; Sarkar, A. Organometallics 1995, 14, 3617.
32. Amin, S. R.; Sarkar, A. Organometallics 1995, 14, 547. See also: Amin, S. R.; Sawant, S. S.; Puranik, V. G.; Sarkar, A. Organometallics 1995, 14, 3617.