356
MARAVAL, ANCEL, AND MEUNIER
substituents on the selectivity of the catalytic oxidation re-
action (epoxide formation versus allylic oxidation).
• Regio- and stereoselective epoxidation is observed in
the case of the 5-vinyl-2-norbornene (nonconjugated di-
ene). The intracyclic double bond is the only one to be
epoxidized.
• An original oxidative dehydrogenation reaction takes
place in the case of the α-terpinene (conjugated diene).
Such hydrocarbon desaturation is an unusual oxidation
pathway when using metalloporphyrin catalysts.
FIG. 7. Catalytic oxidation reaction of the 1,2-dihydronaphthalene 14.
analyses of the reaction mixtures. In fact, compound 11 is
unstable under the oxidative reaction conditions and prob-
ably gives the corresponding quinone and polymers. The in-
termediate alkoxy radical 10 also produced the correspond-
ing alcohol 12 which was observed in GC/MS at m/z 150.
The mass spectra of this compound exhibited a fragmenta-
tion peak at m/z 91 corresponding to the elimination of the
2-propylalcohol fragment. A further oxidation of this prod-
uct 12 produced traces of the diol 13 which was observed at
m/z 166 in GC/MS.
Thisfreeradicalchainoxidationexplainsthelimitedyield
in p-cymene observed in these biomimetic reactions and
also the formation of the different hydroxylated products
arising from its further oxidation. A blank experiment has
been performed using p-cymene 8 as substrate leading to
the formation of the same oxidation products 12 and 13.
In order to complete this study, a catalytic experiment was
performed with the 1,2-dihydronaphthalene 14 as substrate
(Fig. 7).
ACKNOWLEDGMENTS
The financial support of CNRS and Aventis is gratefully acknowledged.
V.M. is indebted to Aventis-Nutrition Animale for a post-doctoral fellow-
ship.
REFERENCES
1. (a) Meunier, B., “Biomimetic Oxidations Catalyzed by Transition
Metal Complexes,” Imperial College Press, 2000; (b) Meunier, B.,
Robert, A., Pratviel, G., and Bernadou, J., in “The Porphyrin Hand-
book,” Vol. 4, p. 119. Academic Press, San Diego, 1999.
2. Groves, J. T., Nemo, T. E., and Myers, R. S., J. Am. Chem. Soc. 101,
1032 (1979).
3. Guilmet, E., and Meunier, B., Tetrahedron Lett. 4449 (1980).
4. Meunier, B., New J. Chem. 16, 203 (1992).
5. Battioni, P., Renaud, J. P., Bartoli, J. F., and Mansuy, D., J. Chem. Soc.,
Chem. Commun. 888 (1985).
6. Yuan, L. C., and Bruice, T. C., J. Am. Chem. Soc. 108, 1643
(1986).
In this case, the oxidative dehydrogenation reaction com-
petes with the epoxidation reaction. Substrate 14 reacts in
the same way as styrene, which gives the epoxidation prod-
uct on the vinyl group in high yield (22). In contrast with
α-terpinene 7, substrate 14 already possesses an aromatic
ring, thus the epoxidation of the nonaromatic double bond
becomes the major reaction (65% of 16). The naphthalene
15 arising from the dehydrogenation reaction was obtained
in 30% yield; 15 was stable in the oxidative conditions, in
contrast with p-cymene 8. This difference of stability can
be explained by the fact that 15 has no substituents that can
undergo hydrogen abstraction in opposition to p-cymene
which possesses hydrogen atoms in two different allylic
positions.
7. Hoffmann, P., Robert, A., and Meunier, B., Bull. Soc. Chim. Fr. 129,
85 (1992).
8. Adler, A. D., Longo, F. R., Kampas, F., and Kim, J., J. Inorg. Nucl.
Chem. 32, 2443 (1970).
9. Robert, A., Momenteau, M., Loock, B., and Meunier, B., Inorg. Chem.
30, 706 (1991).
10. Lajunen, M. K., and Koskinen, A. M. P., Tetrahedron Lett. 35, 4461
(1994).
11. Games, M. F. T., and Antures, O. A. C., Catal. Lett. 42, 213 (1996).
12. Villa de P., A. L., De Vos, D. E., Montes de C., C., and Jacobs, P. A.,
Tetrahedron Lett. 39, 8521 (1998).
13. Villa de P., A. L., Sels, B. F., De Vos, D. E., and Jacobs, P. A., J. Org.
Chem. 64, 7267 (1999).
14. McMorn, P., Roberts, G., and Hutchings, G. J., Catal. Lett. 67, 203
(2000).
15. Arnold, U., Sepa da Cruz, R., Mandelli, D., and Schuchardt, U., J. Mol.
Catal. A 165, 149 (2001).
16. De Carvalho, M. E., and Meunier, B., Tetrahedron Lett. 24, 3621
(1983).
CONCLUSION
17. De Carvalho, M. E., and Meunier, B., New J. Chem. 10, 223 (1986).
18. Meunier, B., Chem. Rev. 92, 1411 (1992).
19. Meunier, B., Guilmet, E., De Carvalho, M. E., and Poilblanc, R.,
J. Am. Chem. Soc. 106, 6668 (1984).
20. Lajunen, M. K., Maunula, T., and Koskinen, A. M. P., Tetrahedron 56,
8167 (2000).
21. Lajunen, M. K., J. Mol. Catal. A 169, 33 (2001).
22. Robert, A., and Meunier, B., New J. Chem. 12, 885 (1988).
23. Heumann, A., Chauvet, F., and Waegell, B., Tetrahedron Lett. 23, 2767
(1982).
24. Chauvet, F., Heumann, A., and Waegell, B., J. Org. Chem. 52, 1916
(1987).
Manganese(III) porphyrin complexes are efficient oxi-
dation catalysts for the three studied terpene derivatives.
This comparative study allowed us to illustrate the differ-
ent oxidation products that can be generated using three
differently substituted metalloporphyrin catalysts:
• Epoxidation and allylic oxidation reactions were ob-
served with α-pinene (mono-unsaturated substrate). The
experiments reported with this terpene derivative allowed
us to evidence the strong influence of the metalloporphyrin