Mechanism of oxygen transfer in the epoxidation of an olefin by molecular oxygen in the presence of an aldehyde

Organic Letters

Volumn 2, Issue 3, 2000, Pages 357-360

  Jarboe, Stephen G ^a   Beak, Peter ^a  

^a UNIVERSITY OF ILLINOIS AT URBANA CHAMPAIGN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001171923     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol991304x     Document Type: Article

References (23)

1. (a) Catalytic Activation of Dioxygen by Metal Complexes; Simandi, L. I., Ed.; Kluwer Academic Publishers: Dordrect, The Netherlands, 1992; pp 318-331.
2. (b) Yamada, T.; Takai, T.; Rhode, O.; Mukaiyama, T. Bull. Chem. Soc. Jpn. 1991, 64, 2109.
3. (c) Haber, J.; Mlodnicka, T.; Poltowicz, J. J. Mol. Catal. 1989, 54, 451.
4. Kaneda, K.; Haruna, S.; Imanaka, T.; Hamamoto, M.; Nishiyama, Y.; Ishii, Y. Tetrahedron Lett. 1992, 33, 6827.
5. (a) Nam, W.; Kim, H. J.; Kim, S. H.; Ho, R. Y. N.; Valentine, J. S. Inorg. Chem. 1996, 35, 1045.
6. (b) Mizuno, N.; Weiner, H.; Finke, R. G. J. Mol. Catal. A 1996, 114, 15.
7. We believe that the reactions without added initiator are being initiated by adventitious initiators and propagated by a radical chain mechanism (vide infra).
8. For evidence establishing an intramolecular peracid epoxidation cannot occur within a small endocyclic ring, see: Woods, K. W.; Beak, P. J. Am. Chem. Soc. 1991, 113, 6281. For a review of the endocyclic restriction test, see: Beak, P. Acc. Chem. Res. 1992, 25, 215.
9. For evidence establishing an intramolecular peracid epoxidation cannot occur within a small endocyclic ring, see: Woods, K. W.; Beak, P. J. Am. Chem. Soc. 1991, 113, 6281. For a review of the endocyclic restriction test, see: Beak, P. Acc. Chem. Res. 1992, 25, 215.
10. Groenewegen, P.; Kallenberg, H.; van der Gen, A. Tetrahedron Lett. 1978, 5, 491.
11. Control experiments were performed in the absence of either the aldehyde functionality or the oxygen atmosphere to test for direct oxidation by the initiator. No oxidation was detected.
12. Out of concern for the potential hazards of peroxides, this compound was isolated only once in a small quantity.
13. (a) Maslov, S. A.; Blyumberg, E. A. Russ. Chem. Rev. 1976, 45 (2), 155.
14. (b) McNesby, J. R.; Heller, C. A. Chem. Rev. 1954, 54, 325.
15. Filippova, T. V.; Blyumberg, E. A. Rus. Chem. Rev. 1982, 51 (2), 582.
16. Martin, J. C.; Dombchik, S. A. Adv. Chem. Ser. 1968, 75, 269.
17. The formation and decarboxylation of an acyl radical, followed by oxygen trapping and hydroperoxide reduction, has been reported as a synthetic method of converting a carboxylic acid to an alcohol, less a single carbon unit. Barton, D. H. R.; Géro, S. D.; Holliday, P.; Quiclet-Sire, B.; Zard, S. Z. Tetrahedron 1998, 54, 6751.
18. This cyclization is, according to Baldwin's rules for ring closures, a formally disfavored process. However, Hevko and co-workers have reported a similar epoxide-opening reaction under basic conditions, where the product of the 6-endo-cyclization is preferred over that from a 4-exo-process. Baldwin, J. E. J. Chem. Soc., Chem. Commun. 1976, 734. Hevko, J. M.; Dua, S.; Talyor, M. S.; Bowie, J. H. J. Chem. Soc., Perkin Trans. 2 1998, 1629.
19. This cyclization is, according to Baldwin's rules for ring closures, a formally disfavored process. However, Hevko and co-workers have reported a similar epoxide-opening reaction under basic conditions, where the product of the 6-endo-cyclization is preferred over that from a 4-exo-process. Baldwin, J. E. J. Chem. Soc., Chem. Commun. 1976, 734. Hevko, J. M.; Dua, S.; Talyor, M. S.; Bowie, J. H. J. Chem. Soc., Perkin Trans. 2 1998, 1629.
20. 1H NMR), while a single recrystallization provided 12% of 17 suitable for X-ray crystallographic analysis.
21. A control experiment exposing triphenylphosphine to workup conditions afforded only about 3% the phosphine oxide. This control, however, does not include the possible oxidation by residual tert-butyl hydroperoxide, nor does it exclude the formation of a phoshine complex in the presence of the reaction mixture that is more easily oxidized during workup. Thus, at this time, we are unable to provide a definitive source of the excess phosphine oxide.
22. 2. This control experiment resulted in no detectable isomerization, indicating that the formation of 6 from 19 presumably proceeds via 12.
23. 1H NMR, 6 is the major product (> 70% by integration) of the reaction of 19. Although the cis-diastereomer was not identified, we believe that, if present, it would have constituted < 10% of the total reaction mixture.