Unexpected benzylic carbon-carbon bond cleavage by transfer epizirconation: Indications of an SET pathway and implications for alkane metathesis

Organometallics

Volumn 24, Issue 26, 2005, Pages 6291-6294

  Eisch, John J ^a   Dutta, Somnath ^a   Gitua, John N ^a  

^a BINGHAMTON UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALKANE METATHESIS; BENZYLIC HYDROCARBONS; ZIRCONATION;

CARBON; HYDROCARBONS; ORGANIC SOLVENTS; PARAFFINS;

CHEMICAL BONDS;

EID: 30344432088     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om050744r     Document Type: Article

References (19)

1. Organic Chemistry of Subvalent Transition Metal Complexes. 37. Part 36: Eisch, J. J.; Otieno, P. O.; Gitua, J. N.; Adeosun, A. A. Eur. J. Org. Chem. 2005, 4364.
2. Eisch, J. J.; Gitua, J. N. Organometallics 2003, 22, 24.
3. Eisch, J. J.; Gitua, J. N. Organometallics 2003, 22, 4172.
4. Eisch, J. J.; Otieno, P. O. Eur. J. Org. Chem. 2004, 3269.
5. Eisch, J. J.; Gitua, J. N. U.S. Patent 6,743,872, June 1, 2004.
6. Eisch, J. J.; Adeosun, A. A. Eur. J. Org. Chem. 2005, 993.
7. Eisch, J. J.; Adeosun, A. A.; Dutta, S.; Fregene, P. O. Eur. J. Org. Chem. 2005, 2657.
8. Eisch, J. J.; Owuor, F. A.; Shi, X. Polyhedron 2005, 24, 1325 (Symposium-in-Print).
9. Eisch, J. J.; Dutta, S. Organometallics 2004, 23, 4181.
10. 4 with 2 equiv of n-butyllithium must catalyze benzylic C-H zirconation.
11. 9
12. (12) (a) The agostic C- - -H- - -Zr interaction indicated in 16 is as yet only proposed as occurring in the ground state. Low-temperature NMR experiments with the unstable 3 have not been able to corroborate such bonding.
13. (b) Eisch, J. J.; Dutta, S. Organometallics 2005, 24, 3355.
14. 2O may be either the C-Zr bond or the C-Li bond in mutual equilibrium. The deep colors (orange to wine red) would be consistent with the presence of delocalized anions of such organolithium compounds.
15. +. However, with other substrates known to add butyllithium, such as diphenylacetylene and 1,1-diphenylethylene, no such butylation by 3 has been observed by us.
16. For example, allowing solutions of the 2:1 lithium-biphenyl adduct in THF to come to reflux causes consumption of the reagent and cleavage of the THF ring. An equivalent amount of 1-butanol is produced upon hydrolysis. Cf.: Eisch, J. J. J. Org. Chem. 1963, 28, 707.
17. Eisch, J. J.; Gitua, J. N. Organometallics 2003, 22, 24.
18. n substrates by Li, Na, or K in liquid ammonia or in ethers. For a leading reference, cf.: Gilman, H.; Gaj, B. J. J. Org. Chem. 1963, 28, 1725.
19. For the seminal publication on alkane metathesis through the use of zirconium hydrides bonded on silica for the hydrogenolysis of simple alkanes at mild temperatures (150°C), cf.: Corker, J.; Lefebvre, F.; Lecuyer, C.; Dufaud, V.; Quignard, F.; Choplin, A.; Evans, J.; Basset, J.-M. Science 1996, 271, 966.