Methyltrioxorhenium Catalyzed Oxidative Cleavage of α -Hydroxycarbonyl Compounds to Carboxylic Acids with Hydrogen Peroxide

Article abstract of DOI:10.1081/SCC-120026309

Methyltrioxorhenium catalyzed oxidative cleavage of a variety of α-hydroxycarbonyl compounds with hydrogen peroxide selectively yielded corresponding carboxylic acids in excellent yields.

Full text of DOI:10.1081/SCC-120026309

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016
©2003 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
SYNTHETIC COMMUNICATIONSÕ
Vol. 33, No. 22, pp. 3875–3878, 2003
Methyltrioxorhenium Catalyzed Oxidative
Cleavage of a-Hydroxycarbonyl Compounds to
Carboxylic Acids with Hydrogen Peroxide
*
Suman L. Jain, Vishal B. Sharma, and Bir Sain
Chemical and Biosciences Division,
Indian Institute of Petroleum, Dehradun, India
ABSTRACT
Methyltrioxorhenium catalyzed oxidative cleavage of a variety of
a-hydroxycarbonyl compounds with hydrogen peroxide selectively
yielded corresponding carboxylic acids in excellent yields.
Oxidative cleavage of a-hydroxycarbonyl compounds/a-diketones
in a selective manner to the corresponding carboxylic acids or their
derivatives is an important synthetic transformation[1] and apart from
conventional stoichiometric oxidants like periodic acid,[2] calcium
hypochlorite,[3] lead tetracetate[4] which generates undesirable waste,
the use of molecular oxygen with dichloroethoxy-oxy-vanadium hetero-
poly acids as catalysts[5] and hydrogen peroxide with heteropoly acids as
*Correspondence: Bir Sain, Chemical and Biosciences Division, Indian Institute
of Petroleum, Dehradun 248005, India; E-mail: birsain@iip.res.in.
3875
DOI: 10.1081/SCC-120026309
Copyright & 2003 by Marcel Dekker, Inc.
0039-7911 (Print); 1532-2432 (Online)
www.dekker.com

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016
©2003 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
3876
Jain, Sharma, and Sain
catalysts[6] has been reported in the literature for this transformation in
pursuit to the development of eco-friendly synthetic methodologies.
Methyltrioxorhenium (MTO)/hydrogen peroxide oxidation system
first reported by Herrmann and Kuhn[7] in 1997 for epoxidation of olefins
has proved to be an efficient and versatile system for various oxidation
reactions.[8] The important features of MTO as catalyst are its ease of
synthesis, commercial availability, stability in air, and efficiency to act as
homogeneous oxidation catalyst for hydrogen peroxide in both aqueous
and organic solvents. However, to the best of our knowledge there is no
literature report on oxidative cleavage of a-hydroxycarbonyl compounds
to carboxylic acid with MTO/hydrogen peroxide oxidation system. In
continuation to our studies on transition metal catalyzed oxidations,[9]
herein we report for the first time a simple and more convenient
eco-friendly method for the oxidative cleavage of a-hydroxycarbonyl
compounds to carboxylic acids with methyltrioxorhenium/hydrogen
peroxide system (Sch. 1).
The oxidation of a variety of a-hydroxycarbonyl compounds[10] was
carried out with 30% aqueous hydrogen peroxide using catalytic amount
of methyltrioxorhenium in refluxing acetonitrile in the presence of
dehydrating agent (MgSO4).[12] All the substrates studied were smoothly
and selectively converted to their corresponding acids in excellent yields.
These results are presented in Table 1. In general aromatic a-hydroxy-
carbonyl compounds were found to be more reactive and required lesser
reaction time for their oxidation. The oxidative cleavage of a-hydroxy-
carbonyl compounds was found to be highly dependent upon the reaction
temperature and at room temperature these oxidations were found to be
very slow and did not complete even after 20 h. Further the presence of
water trapping agent (MgSO4) was found to be vital in these reactions
from yields point of view. The reaction involves the formation of
a-dicarbonyl compounds followed by their oxidative cleavage to
carboxylic acids. The intermediacy of a-dicarbonyl compounds was
confirmed in case of benzoin and anisoin by quenching the reactions
after 1 h and isolating benzil and anisil respectively from the reaction
mixture. The a-dicarbonyl compounds separately prepared by oxidation
O
O
OH
MTO (1 mol. %), H
O (aq)
2
2
+
R'
OH
OH
R'
R
R
MgSO , CH CN (refluxing)
4
3
O
Scheme 1.

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016
©2003 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
Methyltrioxorhenium Catalyzed Oxidative Cleavage
3877
Table 1. The oxidative cleavage of a-hydroxycarbonyl compounds using
MTO/H2O2 system.
Run
1
Substrate
Reaction time (h)
6.00
Yield (%)
96
C
O
CH
OH
CH
2
3
4
5
3.50
3.00
4.50
1.50
97
97
94
96
C
OCH3
CH3O
O
C
O
OH
CH
OH
CH
3
CH
3
C
O
CH
O
CH
OH
3
CH
OH
C
O
O
O
6
7
5.00
6.00
90
O H
C
O
CH
O
CH
OH
3
85
OCH
C
CH
O
CH
3
3
O
OH
CH (CH ) CH C(CH
2 12
)
CH
CH
3
2 12
3
3
8
8.00
85
OH
O
CH (CH ) CH C(CH
3 2 14
)
2 14
9
10.00
12.00
80
OH
O
10
75[11]
O
OH
of a-hydroxylcarbonyl compounds[9c] could also easily be converted to the
corresponding carboxylic acids under the similar reaction conditions.
In summary we have demonstrated for the first time, that methyl-
trioxorhenium catalyzed oxidative cleavage of a variety of a-hydroxy-
carbonyl compounds with hydrogen peroxide selectively yields
corresponding carboxylic acids in excellent yields under mild conditions.
REFERENCES
1. Shing, T.K.M. Comprehensive Organic Synthesis; Trost, B.M., Ed.;
Pergamon: New York, 1991; Vol. 7, 703 p.
2. (a) Clutterbuck, P.W.; Renter, F. J. Chem. Soc. 1935, 1467;
(b) Shiner V.J., Jr.; Wasmuth, C.S. J. Am. Chem. Soc. 1959, 81, 37.
3. Baer, E. J. Am. Chem. Soc. 1940, 62, 1597.
4. Nwauka, S.O.; Keehn, P.M. Tetrahedron Lett. 1982, 23, 3135.

MARCEL DEKKER, INC. • 270 MADISON AVENUE • NEW YORK, NY 10016
©2003 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
3878
Jain, Sharma, and Sain
5. Ali, B.E.; El-Ghanam, A.M.; Fettouhi, M. J. Mol. Catal. A: Chem.
2001, 165, 283.
6. Shimizu, M.; Orita, H.; Suzuki, K.; Hayakawa, T.; Hamakawa, S.;
Takehira, K. J. Mol. Catal. A: Chem. 1996, 114, 217.
7. Herrmann, W.A.; Kuhn, F.E. Acc. Chem. Res. 1997, 30, 169.
8. For reviews see: (a) Romao, C.C.; Kuhn, F.E.; Herrmann, W.A.
Chem. Rev. 1997, 97, 3197; (b) Espenson, H. Chem. Commoun.
1999, 479; (c) Owens, S.; Arias, J.; Abu-Omar, M.M. Catal.
Today 2000, 55, 317; (d) Herrmann, W.A.; Kuhn, F.E. Acc.
Chem. Res. 1997, 30, 169.
9. (a) Jain, S. L.; Sain, B. Chem. Commun. 2002, 1040; (b) Sharma,
V.B.; Jain, S.L.; Sain, B. Tetrahedron Lett. 2003, 44, 383; (c) Jain,
S.L.; Sain, B. J. Mol. Catal. 2001, 176, 102; (d) Rao, T.V.; Sain, B.;
Kumar, K.; Murthy, P.S.N.; Prasada Rao, T.S.R.; Joshi, G.C. Synth.
Commun. 1998, 28, 319; (e) Sain, B.; Murthy, P.S.N.; Rao, T.V.;
Prasada Rao, T.S.R.; Joshi, G.C. Tetrahedron Lett. 1994, 35, 5083.
10. (a) Adams, R.; Marvell, C.S. Org. Synth. Coll. 1941, 1, 94; (b)
McElvain, S.M. Org. Reactions 1948, 4, 256.
11. Kirihara, M.; Takizawa, S.; Momose, T. J. Chem. Soc. Perkin
Trans. I 1998, 7.
12. Typical experimental procedure: To a stirred solution of benzoin
(212 mg, 1 mmol) in acetonitrile (5 mL) was added 30% aqueous
hydrogen peroxide (1 mL solution) mixed with drying agent fol-
lowed by the addition of methyltrioxorhenium (0.01 mmol,
1.0 mol%) and the reaction mixture was refluxed for the 6 h. At
the end of reaction, the reaction mixture was treated with excess
MnO2 (for destruction of H2O2) followed by filtration and passing
through a short column of silica gel using dichloromethane as elu-
ent, evaporation of the solvent gave benzoic acid (234 mg, 96%).
Other a-hydroxycarbonyl compounds were oxidized using this pro-
cedure and their reaction times and yields are given in Table 1. The
products were identified by comparing their physical and spectral
data with those of authentic samples reported in literature. In case
of asymmetric a-hydroxycarbonyl compounds the identity of the
acids was established through GC by comparing the retention
time of their methyl esters with those of authentic samples.
Similarly a-dicarbonyl compounds (benzil and anisil) were oxidized
to their corresponding acids.

Copyright of Synthetic Communications is the property of Taylor & Francis Ltd and its content may not be
copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written
permission. However, users may print, download, or email articles for individual use.