Direct observation of β-methyl elimination in cationic neopentyl complexes: Ligand effects on the reversible elimination of isobutene

Organometallics

Volumn 15, Issue 12, 1996, Pages 2675-2677

  Horton, Andrew D ^a  

^a SHELL RESEARCH AND TECHNOLOGY CENTRE   (Netherlands)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001521687     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om960089a     Document Type: Article

References (31)

1. (a) Resconi, L.; Piemontesi, F.; Fraciscono, G.; Abis, L.; Fiorani, T. J. Am. Chem. Soc. 1992, 114, 1025.
2. (b) Eshuis, J. J. W.; Tan, Y. Y.; Meetsma, A.; Teuben, J. H.; Renkema, J.; Evens, G. G. Organometallics 1992, 11, 362.
3. Kesti, M. R.; Waymouth, R. M. J. Am. Chem. Soc. 1992, 114, 3565.
4. Yang, X.; Jia, L.; Marks, T. J. J. Am. Chem. Soc. 1993, 115, 3392.
5. (a) Guo, Z.; Swenson, D. C.; Jordan, R. F. Organometallics 1994, 13, 1424.
6. (b) Hajela, S.; Bercaw, J. E. Organometallics 1994, 13, 1147.
7. (c) Watson, P. L.; Roe, D. C. J. Am. Chem. Soc. 1982, 104, 6471.
8. (a) Schrock, R. R. Acc. Chem. Res. 1979, 12, 98.
9. (b) Bruno, J. W.; Smith, G. M.; Marks, T. J.; Fair, C. K.; Schultz, A. J.; Williams, J. M. J. Am. Chem. Soc. 1986, 108, 40.
10. Thermochemical studies predict that β-Me elimination from a group 4 neopentyl complex is weakly exothermic and likely to be entropically driven: Schock, L. E.; Marks, T. J. J. Am. Chem. Soc. 1988, 110, 7701.
11. +, has been obtained from gas-phase studies: Christ, C. S., Jr.; Eyler, J. R.; Richardson, D. E. J. Am. Chem. Soc. 1990, 112, 596.
12. 2 gives cationic neopentyl complexes, which appear not to undergo β-Me elimination: Tjaden, E. B.; Swenson, D. C.; Jordan, R. F. Organometallics 1995, 14, 371.
13. 3 fragment has been obtained: Ankianiec, B. C.; Christou, V.; Hardy, D. T.; Thompson, S. K.; Young, G. B. J. Am. Chem. Soc. 1994, 116, 9963.
14. The first direct observation of reversible β-Me elimination/ migratory insertion (in a 3,3-dimethylruthenacyclobutane) was very recently reported: McNeill, K.; Andersen, R. A.; Bergman, R. J. Am. Chem. Soc. 1995, 117, 3625.
15. 2O, followed by crystallization from hexane/toluene.
16. Horton, A. D.; Orpen, A. G. Organometallics 1991, 10, 3910.
17. 2).
18. Temme, B.; Erker, G. J. Organomet. Chem. 1995, 488, 177.
19. Yang, X.; Stern, C. L.; Marks, T. J. J. Am. Chem. Soc. 1994, 116, 10015.
20. 0 metals (values 3-6 ppm indicate coordination; <3 ppm indicates noncoordination): Horton, A. D. Unpublished results.
21. 4], involving C-H activation of the Lewis base, will be published elsewhere.
22. (a) Gleiter, R.; Hyla-Kryspin, I.; Niu, S.; Erker, G. Organometallics 1993, 12, 3828.
23. (b) Koga, N.; Kawamura-Kuribayashi, H. J. Am. Chem. Soc. 1988, 110, 108.
24. 0 metallocenes see ref 20 and the following: (a) Tjaden, E. B.; Casty, G. L.; Stryker, J. M. J. Am. Chem. Soc. 1993, 115, 9814. (b) Horton, A. D. Organometallics 1992, 11, 3271. (c) Jordan, R. F.; LaPointe, R. E.; Bradley, P. K.; Baenziger, N. Organometallics 1989, 8, 2892.
25. 0 metallocenes see ref 20 and the following: (a) Tjaden, E. B.; Casty, G. L.; Stryker, J. M. J. Am. Chem. Soc. 1993, 115, 9814. (b) Horton, A. D. Organometallics 1992, 11, 3271. (c) Jordan, R. F.; LaPointe, R. E.; Bradley, P. K.; Baenziger, N. Organometallics 1989, 8, 2892.
26. 0 metallocenes see ref 20 and the following: (a) Tjaden, E. B.; Casty, G. L.; Stryker, J. M. J. Am. Chem. Soc. 1993, 115, 9814. (b) Horton, A. D. Organometallics 1992, 11, 3271. (c) Jordan, R. F.; LaPointe, R. E.; Bradley, P. K.; Baenziger, N. Organometallics 1989, 8, 2892.
27. 0 metallocenes see the following: (a) Thompson, M. E.; Baxter, S. M.; Bulls, A. R.; Burger, B. J.; Nolan, M. C.; Santarsiero, B. D.; Schaefer, W. P.; Bercaw, J. E. J. Am. Chem. Soc. 1987, 109, 203. (b) Jeske, G.; Lauke, H.; Mauermann, H.; Schumann, H.; Marks, T. J. J. Am. Chem. Soc. 1985, 107, 8091.
28. 0 metallocenes see the following: (a) Thompson, M. E.; Baxter, S. M.; Bulls, A. R.; Burger, B. J.; Nolan, M. C.; Santarsiero, B. D.; Schaefer, W. P.; Bercaw, J. E. J. Am. Chem. Soc. 1987, 109, 203. (b) Jeske, G.; Lauke, H.; Mauermann, H.; Schumann, H.; Marks, T. J. J. Am. Chem. Soc. 1985, 107, 8091.
29. 3-allyl formation was insignificant.
30. Preparation of 8 and 9: A large excess of isobutene (or 2.5 mmol of methylenecyclopentane) was added to a bromobenzene (4-7 mL) solution of 6 (0.60 mmol) at 25 °C. After 5-15 min, hexane addition afforded a yellow oil, which was washed with hexane; the resulting solid was dried in vacuo (NMR: 8, 85% pure; 9, >90% pure).
31. c = -30 °C).