Angewandte
Chemie
Table 3: Oxidation of various alcohols catalyzed by 3.
Keywords: alcohols · gold ·
heterogeneous catalysis ·
nanostructures · oxidation
.
[
a]
Entry
Substrate
n
1
1
Base
Solvent
t [h]
5
Yield [%]
[
1] a) C. L. Hill, Advances in Oxygen-
ated Processes, Vol. 1, JAI Press,
London, 1988; b) M. Hundlucky,
Oxidations in Organic Chemistry,
1
2
K2CO3
K2CO3
BTF/H O 1:1
>99
2
BTF/H O 1:1
5
>99
2
American
Washington, DC, 1990.
2] For a review, see: T. Mallat, A.
Chemical
Society,
3
4
5
1
1
1
K2CO3
BTF/H O 1:1
5
5
91
>99
95
2
[
K2CO
3
BTF/H O 1:1
2
Baiker, Chem. Rev. 2004, 104,
3037.
K2CO3
BTF/H O 1:1
30
[3] K. Yamaguchi, K. Mori, T. Mizu-
gaki, K. Ebitani, K. Kaneda, J.
Am. Chem. Soc. 2000, 122, 7144.
4] a) K. Mori, K. Yamaguchi, T.
Hara, T. Mizugaki, K. Ebitani, K.
Kaneda, J. Am. Chem. Soc. 2002,
2
6
7
8
9
cyclopentanol
1
1
1
2
KOH
BTF/H O 1:1
30
12
15
5
>99
64
2
K2CO3
BTF/H O 1:1
2
[
Cs CO3
diglyme
79
78
2
K2CO3
BTF/H O 1:1
2
1
24, 11572; b) K. Mori, T. Hara, T.
1
0
1
3
1
K2CO3
BTF/H O 1:1
24
24
>99
2
Mizugaki, K. Ebitani, K. Kaneda,
J. Am. Chem. Soc. 2004, 126,
10657.
1
K2CO3
BTF/H O 1:1
94
2
[
5] K. Yamaguchi, N. Mizuno, Angew.
Chem. 2002, 114, 4720; Angew.
Chem. Int. Ed. 2002, 41, 4538.
6] A. Abad, C. Concepción, A.
Corma, H. García, Angew. Chem.
[a] Determined by GC analysis.
[
2005, 117, 4134; Angew. Chem. Int. Ed. 2005, 44, 4066.
[
7] D. I. Enache, J. K. Edwards, P. Landon, B. Solsona-Espriu, A. F.
Carley, A. A. Herzing, M. Watanabe, C. J. Kiely, D. W. Knight,
G. J. Hutchings, Science 2006, 311, 362.
Scheme 3. Average TOF for the oxidation of (Æ)-1-phenylethanol for
the initial 0.5 h of reaction (ratio of moles of acetophenone per mole
[
8] a) H.-B. Ji, K. Ebitani, T. Mizugaki, K. Kaneda, Catal. Commun.
of Au per hour). Reaction conditions: (Æ)-1-phenylethanol
2002, 3, 511; b) S. Martín, D. F. Suµrez, Tetrahedron Lett. 2002,
À4
(
29.3 mmol), 6.1ꢀ10 mol% (substrate to catalyst ratio). Yield after
43, 4475; c) K. S. Colemane, M. Coppe, C. Thomas, J. A. Osborn,
0
.5 h was 6.1%.
Tetrahedron Lett. 1999, 40, 3723; d) J. Muldoon, S. N. Brown,
Org. Lett. 2002, 4, 1043; e) F. Minisci, C. Punta, F. Recupero, F.
Fontana, G. F. Peduli, Chem. Commun. 2002, 688; f) F. Minisci,
F. Recupero, A. Cecchetto, C. Gambarotti, C. Punta, R. Faletti,
R. Paganelli, G. F. Pedulli, Eur. J. Org. Chem. 2004, 109.
The uptake of oxygen was measured under the reaction
conditions with of (Æ )-1-phenylethanol (15.6 mmol), 2a
(
0.0048 mol%), anisole (1.0 mL), and KOH (10 mol%). It
[
9] M. Haruta, N. Yamada, T. Kobayashi, S. Iijima, J. Catal. 1989,
was found that almost 0.5 moles of oxygen was used
compared to the formation of 1 mole of the oxidation product
1
15, 301.
[10] M. Okumura, Y. Kitagawa, M. Haruta, K. Yamaguchi, Chem.
Phys. Lett. 2001, 346, 163.
[
13]
in the course of the reaction. From these results, it was
concluded that water was formed as a coproduct in the
presence of PI Au, although hydrogen peroxide might have
[
11] a) L. Prati, M. Rossi, J. Catal. 1998, 176, 552; b) C. Bianchi, F.
Porta, L. Prati, M. Rossi, Top. Catal. 2000, 13, 231; c) F. Porta, L.
Prati, M. Rossi, S. Coluccia, G. Marta, Catal. Today 2000, 61, 165;
d) C. Milone, R. Ingoglia, G. Neri, A. Pistone, S. Galvagno, Appl.
Catal. A 2001, 211, 251; e) S. Carrettin, P. McMorn, P. Johnston,
K. Griffin, G. J. Hutchings, Chem. Commun. 2002, 696; f) S.
Biella, L. Prati, M. Rossi, J. Catal. 2002, 206, 242; g) F. Porta, L.
Prati, M. Rossi, G. Scari, J. Catal. 2002, 211, 464; h) S. Biella,
G. L. Castiglioni, C. Fumagalli, L. Prati, M. Rossi, Catal. Today
[
16]
been formed, which then decomposed to water and oxygen.
In summary, we have developed gold nanoclusters that are
stabilized by multiple interactions with the benzene rings of
polystyrene. This is the first successful example of a stabiliza-
tion of gold nanoclusters using such interactions. These
nanoclusters catalyzed the aerobic oxidation of several
alcohols efficiently at room temperature under atmospheric
conditions, in which only oxygen was consumed and water
produced as a sole coproduct. Moreover, the catalyst was
easily recoverable and could be reused several times without
leaching of metals or loss of activity. Further investigations of
the application of this catalyst to other oxidation processes as
well as to clarify the precise mechanism of this oxidation
process are currently in progress.
2
002, 72, 43; i) H. Berndt, I. Pitsch, S. Evert, K. Sturve, M.-M.
Pohl, J. Radnik, A. Martin, Appl. Catal. A 2003, 244, 169; j) C.
Milone, R. Ingoglia, A. Pistone, G. Neri, S. Galvagno, Catal. Lett.
2
003, 87, 201; k) S. Biella, M. Rossi, Chem. Commun. 2003, 378;
l) S. Carrettin, P. McMorn, P. Johnston, K. Griffin, C. J. Kiely,
G. J. Hutchings, Phys. Chem. Chem. Phys. 2003, 5, 1329; m) S.
Biella, L. Prati, M. Rossi, Inorg. Chim. Acta 2003, 349, 253;
n) C. L. Bianchi, S. Biella, A. Gervasini, L. Prati, M. Rossi, Catal.
Lett. 2003, 85, 91; o) F. Porta, L. Prati, J. Catal. 2004, 224, 397;
p) M. Comotti, C. D. Pina, R. Matarrese, M. Rossi, Angew.
Chem. 2004, 116, 5936; Angew. Chem. Int. Ed. 2004, 43, 5812;
q) H. Tsunoyama, H. Sakurai, Y. Negishi, T. Tsukuda, J. Am.
Chem. Soc. 2005, 127, 9374.
Received: January 8, 2007
Published online: March 30, 2007
Angew. Chem. Int. Ed. 2007, 46, 4151 –4154
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4153