Novel polyaniline-supported molybdenum-catalyzed aerobic oxidation of alcohols to aldehydes and ketones

Article abstract of DOI:10.1021/ol048195t

(Chemical Equation Presented) Oxidation of alcohols to aldehydes and ketones has been studied in high yields using molecular oxygen and a catalytic amount of 1 in toluene under stirring (ca. 100°C). The reactions of primary alcohols are faster compared to secondary alcohols and the catalyst 1 can be recycled without loss of activity.

Full text of DOI:10.1021/ol048195t

ORGANIC
LETTERS
2004
Vol. 6, No. 26
4821-4824
Novel Polyaniline-Supported
Molybdenum-Catalyzed Aerobic
Oxidation of Alcohols to Aldehydes and
Ketones
Subbarayan Velusamy, Muneer Ahamed, and T. Punniyamurthy*
Department of Chemistry, Indian Institute of Technology Guwahati,
Guwahati 781039, India
tpunni@iitg.ernet.in
Received September 7, 2004 (Revised Manuscript Received November 12, 2004)
ABSTRACT
Oxidation of alcohols to aldehydes and ketones has been studied in high yields using molecular oxygen and a catalytic amount of 1 in toluene
under stirring (ca. 100 C). The reactions of primary alcohols are faster compared to secondary alcohols and the catalyst 1 can be recycled
without loss of activity.
°
Oxidation of alcohols to carbonyl compounds is a funda-
mental functional transformation in organic chemistry.1
Numerous oxidizing agents are available to effect this
transformation. However, most of these oxidizing reagents
are often required in stoichiometric quantities and are
sometimes toxic. From an economical and environmental
viewpoint, catalytic oxidation processes are thus valuable,
and those employing molecular oxygen or air are particularly
attractive. Recently, Ru,2 Ru-Co,2c Co,3 Cu,4 and Zr5
complexes have been shown to catalyze the aerobic oxidation
of alcohols in the presence of co-reductants such as alde-
hydes, N-hydroxyphthalimide, diethyl azodicarboxylate, â-
ketoesters, hydroquinone, or nitrosonium ions, while mo-
lecular oxygen as the sole oxidant is sufficient when catalysts
based on V,6 Pt,7 Rh,8 Pd,9 Ru,10 Co,11 Ni,12 Cu,13 Os,14 and
polyoxometalates15 are used.
The use of heterogeneous catalysts in the liquid phase
offers several advantages over homogeneous ones, such as
ease of recovery and recycling, atom utility, and enhanced
stability.9g,10b,h During the course of our investigation on the
oxidation of organic compounds,6d,16 we have found that
polyaniline-supported MoO2(acac)2 1 is recyclable and
catalyzes efficiently the oxidation of alcohols to aldehydes
and ketones with molecular oxygen in high yields (Scheme
1). This is a clean technology process where compounds are
(1) ComprehensiVe Organic Synthesis; Trost, B. M., Fleming, I., Ley,
S. V., Eds.; Pergamon: Oxford, 1991; Vol. 7, pp 251-325.
(2) (a) Backvall, J. E.; Chowdhury, R. L.; Karlsson, U. J. Chem. Soc.,
Chem. Commun. 1991, 473. (b) Murahashi, S.-I.; Naota, T.; Hirai, N. J.
Org. Chem. 1993, 58, 7318. (c) Marko, I. E.; Giles, P. R.; Tsukazaki, M.;
Chelle-Regnaut, I.; Urch, C. J.; Brown, S. M. J. Am. Chem. Soc. 1997,
119, 12661. (d) Dijksman, A.; Arends, I. W. C. E.; Sheldon, R. A. Chem.
Commun. 1999, 1591. (e) Hanyu, A.; Takezawa, E.; Sakaguchi, S.; Ishii,
Y. Tetrahedron Lett. 1998, 39, 5557. (f) Csjernyik, G.; Ell, A. H.; Fadini,
L.; Pugin, B.; Backvall, J. E. J. Org. Chem. 2002, 67, 1657.
(5) Krohn, K.; Vinke, I.; Adam, H. J. Org. Chem. 1996, 61, 1467.
(6) (a) Kirihara, M.; Ochiai, Y.; Takizawa, S.; Takahata, H.; Nemoto,
H. Chem. Commun. 1999, 1387. (b) Maeda, Y.; Kakiuchi, N.; Matsumura,
S.; Nishimura, T.; Uemura, S. Tetrahedron Lett. 2001, 42, 8877. (c) Maeda,
Y.; Kakiuchi, N.; Matsumura, S.; Nishimura, T.; Kawamura, T.; Uemura,
S. J. Org. Chem. 2002, 67, 6718. (d) Velusamy, S.; Punniyamurthy, T.
Org. Lett. 2004, 6, 217.
(7) Jia, C.-G.; Jing, F.-Y.; Hu, W.-D.; Huang, M.-Y.; Jiang, Y.-Y. J.
Mol. Catal. 1994, 91, 139.
(8) Martin, J.; Martin, C.; Faraj, M.; Bregeault, M. NouV. J. Chim. 1984,
8, 141.
(3) Punniyamurthy, T.; Iqbal, J. Tetrahedron Lett. 1994, 35, 4007.
(4) (a) Semmelhack, M. F.; Schmid, C. R.; Cortes, D. A.; Chou, C. S. J.
Am. Chem. Soc. 1984, 106, 3374. (b) Marko, I. E.; Giles, P. R.; Tsukazaki,
M.; Brown, S. M.; Urch, C. J. Science 1996, 274, 2044. (c) Marko, I. E.;
Gautier, A.; Chelle-Regnaut, I.; Giles, P. R.; Tsukazaki, M.; Urch, C. J.;
Brown, S. M. J. Org. Chem. 1998, 63, 7576. (d) Marko, I. E.; Giles, P. R.;
Tsukazaki, M.; Chelle-Regnaut, I.; Gautier, A.; Brown, S. M.; Urch, C. J.
J. Org. Chem. 1999, 64, 2433.
10.1021/ol048195t CCC: $27.50
© 2004 American Chemical Society
Published on Web 11/26/2004

Scheme 1
formed free from any contaminated byproducts. To the best
of our knowledge, no report is available in the literature in
regard to the aerobic oxidation of alcohols with molecular
oxygen using a recyclable molybdenum catalyst. Further-
more, this is the first example for the activation of molecular
oxygen using a polymer-supported molybdenum catalyst.17
Figure 1. Proposed polyaniline-supported MoO2(acac)2 structure.
Catalyst 1 was prepared by stirring a 1:1 mixture of the
affording 4-methoxybenzaldehyde in 96% yield when the
reaction mixture was allowed to stir at 100 °C for 9.5 h. In
contrast, the corresponding homogeneous process using
MoO2(acac)2 was less effective and provided a mixture of
4-methoxybenzaldehyde and 4-methoxybenzoic acid in 58%
and 13% yield, respectively (Scheme 2).
19
commercially available polyaniline18 and MoO2(acac)2 in
acetonitrile for 50 h at ambient temperature, and a tentative
structure is shown in Figure 1. The oxidation of 4-meth-
oxybenzyl alcohol was then examined as a standard substrate
in the presence of a catalytic amount of 1 in toluene under
molecular oxygen. As expected, the oxidation took place
(9) (a) Blackburn, T. F.; Schwartz, J. J. Chem. Soc., Chem. Commun.
1977, 157. (b) Kaneda, K.; Fujii, M.; Morioka, K. J. Org. Chem. 1996, 61,
4502. (c) Nishimura, T.; Onoue, T.; Ohe, K.; Uemura, S. Tetrahedron Lett.
1998, 39, 6011. (d) Nishimura, T.; Onoue, T.; Ohe, K.; Uemura, S. J. Org.
Chem. 1999, 64, 6750. (e) Peterson, K. P.; Larock, R. C. J. Org. Chem.
1998, 63, 3185. (f) ten Brink, G.-J.; Arends, I. W. C. E.; Sheldon, R. A.
Science 2000, 287, 1636. (g) Uozumi, Y.; Nakao, R. Angew. Chem., Int.
Ed. 2003, 42, 194. (h) Schultz, M. J.; Park, C. C.; Sigman, M. S. Chem.
Commun. 2002, 3034. (i) Nishimura, T.; Maeda, Y.; Kakiuchi, N.; Uemura,
S. J. Chem. Soc., Perkin Trans. 1 2000, 4301. (j) Nishimura, T.; Kakiuchi,
N.; Inoue, M.; Uemura, S. Chem. Commun. 2000, 1245.
Scheme 2
(10) (a) Matsumoto, M.; Watanabe, N. J. Org. Chem. 1984, 49, 3435.
(b) Kaneda, K.; Yamashita, T.; Matsushita, T.; Ebitani, K. J. Org. Chem.
1998, 63, 1750. (c) Hinzen, B.; Lenz, R.; Ley, S. V. Synthesis 1998, 977.
(d) Matsushita, T.; Ebitani, K.; Kaneda, K. Chem. Commun. 1999, 265. (e)
Pagliaro, M.; Ciriminna, R. Tetrahedron Lett. 2001, 42, 4511. (f) Masutani,
K.; Uchida, T.; Irie, R.; Katsuki, T. Tetrahedron Lett. 2000, 41, 5119. (g)
Lee, M.; Chang, S. Tetrahedron Lett. 2000, 41, 7507. (h) Yamaguchi, K.;
Mori, K.; Mizugaki, T.; Ebitani, K.; Kaneda, K. J. Am. Chem. Soc. 2000,
122, 7144. (i) Miyata, A.; Murakami, M.; Irie, R.; Katsuki, T. Tetrahedron
Lett. 2001, 42, 7067.
(11) (a) Iwahama, T.; Sakaguchi, S.; Nishiyama, Y.; Ishii, Y. Tetrahedron
Lett. 1995, 36, 6923. (b) Sharma, V. B.; Jain, S. L.; Sain, B. Tetrahedron
Lett. 2003, 44, 383. (c) Yamada, T.; Mukaiyama, T. Chem. Lett. 1989, 519.
(12) Choudary, B. M.; Kantam, M. L.; Rahman, R.; Reddy, C. V.; Rao,
K. K. Angew. Chem., Int. Ed. 2001, 40, 763.
To study the scope of this procedure, the oxidation of other
alcohols was next studied (Table 1, entries 1-16). Benzyl
(13) (a) Saint-Aman, E.; Menage, S.; Pierre, J.-L.; Defrancq, E.; Gellon,
G. New. J. Chem. 1998, 393. (b) Chaudhuri, P.; Hess, M.; Muller, J.;
Hildenbrand, K.; Bill, E.; Weyhermuller, T.; Wieghardt, K. J. Am. Chem.
Soc. 1999, 121, 9599.
(14) (a) Coleman, K. S.; Coppe, M.; Thomas, C.; Osborn, J. A.
Tetrahedron Lett. 1999, 40, 3723. (b) Shapley, P. A.; Zhang, N.; Allen, J.
L.; Pool, D. H.; Liang, H.-C. J. Am. Chem. Soc. 2000, 122, 1079.
(15) Haimov, A.; Neumann, R. Chem. Commun. 2002, 876.
(16) (a) Das, S.; Punniyamurthy, T. Tetrahedron Lett. 2003, 44, 6033.
(b) Velusamy, S.; Punniyamurthy, T. Eur. J. Org. Chem. 2003, 3913. (c)
Velusamy, S.; Punniyamurthy, T. Tetrahedron Lett. 2003, 44, 8955. (d)
Reddy, R. R.; Das, S.; Punniyamurthy, T. Tetrahedron Lett. 2004, 45, 3561.
(17) Wentzel, B. B.; Leinonen, S.-M.; Thomson, S.; Sherrington, D. C.;
Feiters, M. C.; Nolte, R. J. M. J. Chem. Soc., Perkin Trans. 1 2000, 3428.
(18) (a) Das, B. C.; Iqbal, J. Tetrahedron Lett. 1997, 38, 1235. (b)
Punniyamurthy, T.; Iqbal, J. Tetrahedron Lett. 1997, 38, 4463. (c) Kowalski,
G.; Pielichowski, J. Synlett 2002, 2107. (d) Gong, J.; Cui, X.-J.; Xie, Z.-
W.; Wang, S.-G.; Qu, L. Y. Synth. Met. 2002, 129, 187. (e) Nandy, J. P.;
Prabhakaran, E. N.; Kumar, S. K.; Kunwar, A. C.; Iqbal, J. J. Org. Chem.
2003, 68, 1679.
Figure 2. Progress of the oxidation of benzyl alcohol and
phenylethanol.
(19) Fernelius, W. C.; Terada, K.; Brynt, B. E. Inorganic Synthesis;
Rochow. E. G., Ed.; MeCraw-Hill Book Co. Inc.: London, 1960; Vol. 6,
pp 147-148.
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Org. Lett., Vol. 6, No. 26, 2004

Table 1. Aerobic Oxidation of Alcohols to Aldehydes and Ketones Using Catalyst 1a
a Substrate (1 mmol) and catalyst 1 (22 mg, 3 mol equiv of Mo) were stirred at ca. 100 °C under oxygen balloon for the appropriate time. b Isolated yield.
c GC yield. d Accompanied 5-10% of unidentified products. e Catalyst 1 (44 mg, 6 mol equiv of Mo) used. f 1,2-Dichloroethane was employed as solvent.
g Catalyst 1 (66 mg, 9 mol equiv of Mo) used. h Determined by GC (except entry 13).
alcohol was oxidized to benzaldehyde in 92% conversion
and 98% selectivity. A similar reactivity was observed with
the substrates having electron-withdrawing and -donating
groups in the aromatic ring, i.e., 4-chloro-, 3-nitro-, and 3,4,5-
trimethoxybenzyl alcohols. Allylic alcohols, geraniol, and
cinnamyl alcohol were oxidized to the corresponding alde-
hydes in moderate selectivity. An aliphatic alcohol, heptanol,
could be oxidized to heptanal in 86% yield. Secondary
alcohols such as phenylethanol, diphenylmethanol, benzoin,
cyclohexanol, and (()-menthol required a slightly longer
reaction time compared to primary alcohols to afford the
corresponding ketones in 52-90% yields. The oxidation
profile of a 1:1 mixture of benzyl alcohol and phenylethanol
is shown in Figure 2. In the case of cholesterol, the carbon-
carbon double bond migrated to give 4-cholesten-3-one in
72% yield. Heterocyclic alcohols, 2-furfurol, 2-thiophen-
emethanol, and 2-pyridinemethanol, were oxidized to the
corresponding aldehydes in high yields. No oxidation was
Org. Lett., Vol. 6, No. 26, 2004
4823

catalyst 1 was stirred at 100 °C for 10 h and the filtrate was
used for the oxidation of 4-methoxybenzyl alcohol. No
reaction was observed, indicating that leaching of the metal
complex has not occurred.
Table 2. Recycling of the Catalyst 1
In conclusion, the oxidation of alcohols to aldehydes and
ketones has been studied with molecular oxygen in the
presence of recyclable catalyst 1 in high yields. This reaction
provides a new environmentally friendly route to the conver-
sion of alcoholic functions to carbonyl groups. Aldehydes
do not undergo further oxidation to carboxylic acids.
run
product (%, yield)b
recovery (%)
1
2
3
96
95
94
>99
>98
>97
Acknowledgment. This work was supported by the
Department of Science and Technology (Sanction No. SR/
S1/OC-092002), New Delhi, and by the Council of Scientific
and Industrial Research (Sanction No. 01(1804)/02/EMR-
II), New Delhi.
observed with S and N heteroatoms. However, diols, 1,3-
dihyroxybutane and 1,2-dihydroxypropane, were less reactive
and provided a trace (<3%) of mixture of the corresponding
keto and hydroxy aldehydes after 50 h.
The catalyst 1 could be filtered and recycled (Table 2).
For example, the oxidation of 4-methoxybenzyl alcohol was
performed up to three runs with no loss of activity.
Furthermore, to study the leaching of the metal complex,
Supporting Information Available: General experimen-
tal procedure and data. This material is available free of
charge via the Internet at http://pubs.acs.org.
OL048195T
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Org. Lett., Vol. 6, No. 26, 2004