Seiji Iwasa et al.
COMMUNICATIONS
equivalents of H2O2 to convert methoxybenzenes to qui- References
nones, whereas for hydroxybenzene oxidation, merely
[1] General reviews: a) S. Yamamura, in: The Chemistry of
Phenols, Part 2, (Ed.: Z. Rappoport), chap. 17, Wiley,
Chicester, 2003, pp. 1153–1346; b) J. S. Swenton, in:
The Chemistry of the Quinonoid Compounds, Vol. 2,
(Eds.: S. Patai, Z. Rappoport), chap. 15, Wiley, New
York, 1988, pp. 899–962.
[2] P. Schudel, H. Mayer, O. Isler, in: The Vitamines, Vol. 5,
(Eds.: W. H. Sebroll, R. S. Harris), Academic Press, New
York, 1972, p. 165.
1.1 equivalents of H2O2 are enough. More systemetic in-
vestigation of these oxidation systems is required, which
is now being carried out. Meanwhile, this Ru(II)- or
Ir(I)-catalyzed hydrogen peroxide oxidation system
can be used for the synthesis of very useful biologically
active quinones since these methods are very mild,
easy and simple.
[3] K. S. Feldman, S. Quideau, H. M. Appel, J. Org. Chem.
1996, 61, 6656.
Experimental Section
[4] a) K. Mikami, M. Terada, Y. Motoyama, T. Nakai, Tetra-
hedron: Asymmetry 1991, 2, 643–646; b) K. Mikami, Y.
Motoyama, M. Terada, J. Am. Chem. Soc. 1994, 116,
2812; c) J. D. White, Y. Choi, Org. Lett. 2000, 2, 2373;
d) K. C. Nicolaou, S. A. Snyder, T. Montagnon, G. Vassi-
likogiannakis, Angew. Chem. Int. Ed. 2002, 41, 1668.
[5] T. Land, in: Comprehensive Organic Chemistry, Vol. 1,
(Ed.: J. F. Stoddart), Pergamon Press, Oxford, 1979, p.
1216.
[6] a) H. Teuber, W. Rau, Chem. Ber. 1953, 86, 1036; b) H.
Zimmer, D. C. Lanken, S. W. Morgan, Chem. Rev. 1971,
71, 229; c) O. Cherkaoni, P. Nebois, M. Domard, B. Fe-
net, Tetrahedron 1996, 52, 9499.
General
All reactions were carried out in the normal air atmosphere.
THF and MeOH were purchased as reagent grade and were
used without any purification. Reactions were monitored by
TLC using 250 mm Merck (Art. 5715) precoated silica gel.
Flash column chromatography was performed over Merck
(Art. 7734) silica gel.
Catalysts were synthesized according tothe literature. All start-
ing materials are commercially available and were used as re-
ceived.
[7] D. Liotta, J. Arbiser, J. W. Short, M. Saindane, J. Org.
Chem. 1983, 48, 2932.
[8] a) N. Kato, T. Sugaya, T. Mimura, M. Ikuta, S. Kato, Y.
Kuge, S. Tomioka, M. Kasai, Synthesis 1997, 625; b) H.
Tohma, H. Morioka, Y. Harayama, M. Hashizume, Y.
Kita, Tetrahedron Lett. 2001, 42, 6899.
Ru(II)- or Ir(I)-Catalyzed Oxidation of 1,2- and 1,4-
Dihydroxybenzenes by 31% (Aqueous) H2O2; Typical
Procedure
Table 2, run 7: To a solution of 2-phenylhydroquinone (1b;
1.862 g, 10.0 mmol) in THF (20 mL) was added solid Ru(II)-
(pybox-dh)(pydic) (4.9 mg, 0.01 mmol) at 08C followed by ad-
dition of hydrogen peroxide (aqueous 31%, 1.2 mL,
11.0 mmol). The resulting mixture was stirred for 2.0 h at
room temperature. The organic phase was extracted with di-
chloromethane, and dried over Na2SO4. The solvent was re-
moved under reduced pressure and the residue was purified
by flash column chromatography on silica gel to give quinone
2b; yield: 1.805 g (98% isolated).
[9] M. A. Brimble, L. J. Duncalf, S. J. Phythiom, J. Chem.
Soc. Perkin Trans. 1 1997, 1399.
[10] M. G. Clerici, Studies in Surface Science and Catalysis, in:
Heterogeneous Catalysis and Fine Chemicals III, Vol. 78,
(Eds.: M. Guisnet, J. Barbier, J. Barrault, C. Bouchole, D.
Duprez, G. Perot, C. Montassies), Elsevier, Amsterdam,
1993, p. 21.
[11] D. V. Pratt, F. Ruan, P. B. Hopkins, J. Org. Chem. 1987,
52, 5053.
[12] I. R. Beattie, P. Jones, J. Inorg. Chem. 1979, 18, 2318.
[13] R. Saladino, V. Neri, E. Mincione, P. Filippone, Tetrahe-
dron 2002, 58, 8493.
Ru(II)-Catalyzed Oxidation of Methoxybenzenes by
31% (Aqueous) H2O2; Typical Procedure
[14] F. Minisci, A. Citterio, E. Vismara, F. Fontana, S. De Ber-
nardinis, J .Org. Chem. 1989, 54, 728.
[15] I. Owsik, B. Kolarz, J. Mol. Catal. A: Chemical 2002, 178,
63–71.
[16] O. A. Kholdecva, N. N. Trukhan, M. P. Vanina, V. N. Ro-
mannikov, V. N. Parmon, J. Mrrwiec-Bialon, A. B. Jar-
zebski, Catalysis Today 2002, 75, 204.
[17] a) S. Iwasa, A. Fakhruddin, Y. Tsukamoto, M. Kameya-
ma, H. Nishiyama, Tetrahedron Lett. 2002, 43, 6159;
b) S. Iwasa, K. Tajima, S. Tsushima, H. Nishiyama, Tetra-
hedron Lett. 2001, 42, 5897.
Table 3, run 6: To a solution of 1,3-dimethoxybenzene (5c;
65 mL, 0.5 mmol) in MeOH-H2O (1:1, 1.0 mL) was added solid
Ru(II)(pybox-dh)(pydic) (2.4 mg, 0.005 mmol) at 08C fol-
lowed by addition of hydrogen peroxide (aqueous 31%,
165 mL, 1.5 mmol). The resulting mixture was stirred for 2.0 h
at room temperature. The organic phase was extracted with di-
chloromethane, and dried over Na2SO4. The solvent was re-
moved under reduced pressure and the residue was purified
by flash column chromatography on silica gel to give quinone
6c; yield: 67.3 mg (97% isolated).
[18] T. Higuchi, C. Sataka, M. Hirobe, J. Am. Chem. Soc.
1995, 117, 8879.
Supporting Information
Characterization data for the compounds prepared are con-
tained in the Supporting Information.
520
ꢁ 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2005, 347, 517–520