A. Podgorsˇek et al. / Tetrahedron Letters 47 (2006) 7245–7247
7247
8. Anastas, P. T.; Warner, J. C. Green Chemistry; Oxford
University Press: New York, 1998.
9. Amijs, C. H. M.; van Klink, G. P. M.; van Koten, G.
Green Chem. 2003, 5, 470–474.
10. Togo, H.; Hirai, T. Synlett 2003, 702–704.
11. Podgorsˇek, A.; Stavber, S.; Zupan, M.; Iskra, J. Tetra-
hedron Lett. 2006, 47, 1097–1099.
12. Rahman, A. N. M. M.; Bishop, R.; Tan, R.; Shan, N.
Green Chem. 2005, 7, 207–209.
ous H2O2 and HBr on water is an efficient and selective
method for bromination at the benzylic position. The
method also has a lower impact on the environment
since bromine is generated in situ from H2O2 and HBr
and the use of H2O2 as an oxidant gives water as the
only by-product. The method obviates the use of a metal
catalyst for HBr oxidation.
13. Shaw, H.; Perlmutter, H. D.; Gu, C.; Arco, S. D.;
Quibuyen, T. O. J. Org. Chem. 1997, 62, 236–237.
14. Kikuchi, D.; Sakaguchi, S.; Ishii, Y. J. Org. Chem. 1998,
63, 6023–6026.
15. Amati, A.; Dosualdo, G.; Zhao, L. H.; Bravo, A.;
Fontana, F.; Minisci, F.; Bjorsvik, H. R. Org. Proc. Res.
Dev. 1998, 2, 261–269.
16. Mestres, R.; Palenzuela, J. Green Chem. 2002, 4, 314–316.
17. Rothenberg, G.; Clark, J. H. Green Chem. 2000, 2, 248–
251.
Acknowledgements
This research was supported by the Ministry of Higher
Education, Science and Technology of the Republic of
Slovenia and the Young Researcher Program (A.P.).
We are grateful to the staff of the National NMR Centre
at the National Institute of Chemistry in Ljubljana and
the Mass Spectroscopy Centre at the JSI.
18. Sels, B.; De Vos, D.; Buntinx, M.; Pierard, F.; Kirsch-De
Mesmaeker, A.; Jacobs, P. Nature 1999, 400, 855–857.
19. Conte, V.; DiFuria, F.; Moro, S. Tetrahedron Lett. 1996,
37, 8609–8612.
References and notes
20. Typical experiment on 1 mmol scale: Methyl benzene
(1 mmol) was added to 0.8 mL aqueous solution of
2 mmol of H2O2 and 1.1 mmol of HBr. The reaction
mixture was stirred at 500 rpm at room temperature under
irradiation with a 40 W incandescent light bulb for 24 h.
Then the reaction mixture was transferred into a separat-
ing funnel, into which 10 mL of water and 2 mL of 0.01 M
NaHSO3 were added. The crude product was extracted
using 3 · 5 mL CH2Cl2 and the combined organic phase
was dried over Na2SO4 and the solvent was evaporated
under reduced pressure. The crude reaction product was
analyzed by 1H NMR spectroscopy, isolated by column
chromatography (SiO2, appropriate mixture of hexane/
ethyl acetate) and identified on the basis of comparison
with the literature data.
1. van Pee, K. H.; Unversucht, S. Chemosphere 2003, 52,
299–312.
2. Lindstrom, U. M. Chem. Rev. 2002, 102, 2751–2771.
3. Narayan, S.; Muldoon, J.; Finn, M. G.; Fokin, V. V.;
Kolb, H. C.; Sharpless, K. B. Angew. Chem., Int. Ed. 2005,
44, 3275–3279.
4. Biscoe, M. R.; Breslow, R. J. Am. Chem. Soc. 2003, 125,
12718–12719.
5. Lindstrom, U. M.; Andersson, F. Angew. Chem., Int. Ed.
2006, 45, 548–551.
6. Yorimitsu, H.; Shinokubo, H.; Oshima, K. Synlett 2002,
674–686.
7. Smith, M. B.; March, J. Free-Radical Substitution. In
March‘s Advanced Organic Chemistry, 5th ed.; John Wiley
and Sons: New York, 2001; pp 911–914.