Gold(I)-catalyzed oxidative cleavage of a C-C double bond in water

Article abstract of DOI:10.1021/ol052830t

Oxidative cleavage of the C=C bond to afford ketone or aldehyde products with tert-butyl hydrogenperoxide (TBHP) as the oxidant can be catalyzed by AuCl with neocuproine (1) in water.

Full text of DOI:10.1021/ol052830t

ORGANIC
LETTERS
2006
Vol. 8, No. 4
693-696
Gold(I)-Catalyzed Oxidative Cleavage of
a C C Double Bond in Water
−
Dong Xing,† Bingtao Guan,‡ Guixin Cai,‡ Zhao Fang,‡ Liping Yang,† and
Zhangjie Shi*,‡
Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of
Education, College of Chemistry, Peking UniVersity, Beijing 100871, China, State Key
Laboratory of Organometallic Chemistry, Chinese Academy of Sciences,
Shanghai 200032, China, and Department of Chemistry, East China Normal
UniVersity, Shanghai 200062, China
zshi@pku.edu.cn
Received November 23, 2005
ABSTRACT
Oxidative cleavage of the CdC bond to afford ketone or aldehyde products with tert-butyl hydrogenperoxide (TBHP) as the oxidant can be
catalyzed by AuCl with neocuproine (1) in water.
Organic transformations catalyzed by gold complexes have
been a focus of attention in recent years.1 New transforma-
tions, such as direct arene functionalizations2 and carbene
insertions to benzene, O-H, and N-H bonds,3 have been
developed. Both gold(I) and gold(III) species also showed
unique activities in mediating reactions involving alkynes
and alkenes.4 In contrast, gold-catalyzed oxidation chemistry,
in particular oxygen transfer reactions, has been less devel-
oped, which should have potential applications in synthetic
oxidation chemistry. So far, only oxidation of carbon
monoxide and alcohols mediated by heterogeneous gold
nanoparticles were reported.5 The homogeneous oxidation
chemistry catalyzed by gold is still limited.6 Herein, we report
(2) (a) Nevado, C.; Echavarren, A. M. Synthesis 2005, 2, 167-182. (b)
Asao, N.; Takahashi, K.; Lee, S.; Kasahara, T.; Yamamoto, Y. J. Am. Chem.
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126, 13596-13597. (d) Shi, Z.; He, C. J. Org. Chem. 2004, 69, 3669-
3671. (e) Shi, Z.; He, C. J. Am. Chem. Soc. 2004, 126, 5964-5965. (f)
Hashmi, A. S. K.; Schwarz, L.; Choi, J.-H.; Frost, T. M. Angew. Chem.,
Int. Ed. 2000, 39, 2285-2288. (g) Dyker, G.; Muth, E.; Hashmi, A. S. K.;
Ding, L. AdV. Synth. Catal. 2003, 345, 1247-1252. (h) Reetz, M. T.;
Sommer, K. Eur. J. Org. Chem. 2003, 3485-3496. (i) Alfonsi, M.; Arcadi,
A.; Aschi, M.; Bianchi, G.; Marinelli, F. J. Org. Chem. 2005, 70, 2265-
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3164.
(3) Fructos, M. R.; Belderrain, T. R.; de Fre´mont, P.; Scott, N. M.; Nolan,
S. P.; D´ıaz-Requejo, M. M.; Pe´rez, P. J. Angew. Chem., Int. Ed. 2005, 44,
5284-5288.
(4) (a) Shi, X.; Gorin, D. J.; Toste, F. D. J. Am. Chem. Soc. 2005, 127,
5802-5803. (b) Zhang, L.; Kozmin, S. A. J. Am. Chem. Soc. 2005, 127,
6962-6963. (c) Mamane, V.; Gress, T.; Krause, H.; Fu¨rstner, A. J. Am.
Chem. Soc. 2004, 126, 8654-8655. (d) Luzung, M. R.; Markham, J. P.;
Toste, F. D. J. Am. Chem. Soc. 2004, 126, 10858-10859. (e) Yang, C.-G.;
He, C. J. Am. Chem. Soc. 2005, 127, 6966-6967.
† East China Normal University.
‡ Peking University.
(1) (a) Hashmi, A. S. K. Gold Bull. 2004, 37, 51-65. (b) Hoffmann-
Ro¨der, A.; Krause, N. Org. Biomol. Chem. 2005, 3, 387-391. (c) Yao, T.;
Zhang, X.; Larock, R. C. J. Am. Chem. Soc. 2004, 126, 11164-11165. (d)
Sherry, B. D.; Toste, F. D. J. Am. Chem. Soc. 2004, 126, 15978-15979.
(e) Wei, C.; Li, C.-J. J. Am. Chem. Soc. 2003, 125, 9584-9585. (f) Zhang,
L.; Kozmin, S. A. J. Am. Chem. Soc. 2004, 126, 11806-11807. (g) Yao,
X.; Li, C.-J. J. Am. Chem. Soc. 2004, 126, 6884-6885. (h) Nieto-Oberhuber,
C.; Mun˜oz, M. P.; Bun˜uel, E.; Nevado, C.; Ca´rdenas, D. J.; Echavarren, A.
M. Angew. Chem., Int. Ed. 2004, 43, 2402-2406. (i) Teles, J. H.; Brode,
S.; Chabanas, M. Angew. Chem., Int. Ed. 1998, 37, 1415-1418. (j) Arcadi,
A.; Giuseppe, S. D.; Marinelli, F.; Rossi, E. AdV. Synth. Catal. 2001, 343,
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W. Chem.-Eur. J. 2003, 9, 4339-4345. and references therein.
10.1021/ol052830t CCC: $33.50
© 2006 American Chemical Society
Published on Web 01/19/2006

a unique process of oxidizing the CdC bond to afford ketone
or aldehyde products with tertiary butyl hydrogenperoxide
(TBHP) as the oxidant in water.
Table 1. Oxidative Cleavage of Diphenyl Ethylene
Olefins are important building blocks in organic synthesis
and are utilized broadly as starting materials to construct
complex structures with methods such as the Wacker process,
epoxidation, etc.7 The cleavage of the CdC bond to form
two carbonyl products is a synthetically useful method, which
is usually achieved by ozonation followed by reduction or
by dihydroxylation followed by oxidation.8 We chose 1,1-
diphenylethylene (2a) as the starting substrate to explore new
gold-catalyzed oxidation of olefins because conjugation to
the phenyl groups activates the olefin.9 We first tested the
reaction with TBHP as the oxidant and AuCl as the catalyst
in the absence of any ligand in toluene. Only a small amount
of benzophenone was produced (entry 3, Table 1). Then,
we chose to investigate gold complexes supported by various
ligands.3,5,10,11 It has been shown that the linear or four-
coordinated gold(I) complexes can be prepared with support
of different bidentate nitrogen ligands.12 We tested the
reactions with different nitrogen-based ligands such as
pyridine, bipyridine, and phenanthroline. These did not
provide good conversions to the reactions. To our delight,
with the use of neocuprione (1) as the ligand, the oxidation
of 2a ran efficiently to produce benzophenone 3a as the
product in 90% isolated yield in toluene (entry 4, Table 1).
When AgOTf was used to remove the chloride from
AuCl,3b,5g,13 the efficiency of oxidation only increased slightly
time
(h)
yielda
(%)
entry
catalyst
L
solvent
1b
toluene
toluene
toluene
toluene
toluene
toluene
toluene
EtOH
MeCN
THF
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
10
10
10
10
10
10
10
10
10
10
24
24
10
10
10
2
<5
<5
<5
90
2b
1
3b
AuCl
AuCl
AuCl
AuCl3
AuCl
AuCl
AuCl
AuCl
4
1
1
1
1
1
1
1
1
5c
92
6b
<20
<5
<5
<5
<5
<10
<10
41
23
16
93
<10
92
7b
8b
9b
10b
11b
12b
13
14
15
16
17b
18d
AuCl
AuCl
AuCl
AuCl
AuCl
AuCl3
AuCl
py
bipy
phenanthroline
1
1
1
2
6
a Isolated yield. b GC yield with the use of decane as an internal standard.
c 5.0 mol % of AgOTf was used as the cocatalyst. d 1.0 mol % of AuCl
and 1.0 mol % of 1 were used as the catalyst.
(5) (a) Abad, A.; Concepcio´n, P.; Corma, A.; Garc´ıa, H. Angew. Chem.,
Int. Ed. 2005, 44, 4066-4069. (b) Kim, W. B.; Voitl, T.; Rodriguez-Rivera,
G. J.; Dumesic, J. A. Science 2004, 305, 1280-1283. (c) Biella, S.;
Castiglioni, G. L.; Fumagalli, C.; Prati, L.; Rossi, M. Catal. Today 2002,
72, 43-49 and references therein.
(entry 5, Table 1). The oxidation reactions were also studied
in other common organic solvents, such as acetone, THF,
EtOH, and MeCN; however, the conversions and yields were
much lower than those in toluene (entries 7-10, Table 1).
Remarkably, we discovered that this reaction can run
efficiently in water. Product 3a was isolated in 93% yield
with 5 mol % of AuCl plus ligand 1 (entry 16, Table 1).
Similarly, the reactions did not proceed when other ligands,
such as pyridine, bipyridine, and phenanthroline, were
employed in water (entries 13-15, Table 1). Furthermore,
only a small amount of 3a was generated with either AuCl
or 1 as the catalyst under the same conditions (entries 11
and 12, Table 1). The catalyst loading could be decreased
to 1.0 mol %, and the reaction still ran smoothly to afford
3a in high isolated yield when a longer reaction time was
used (entry 18, Table 1). To exclude the gold(III) species as
a potential catalyst under such an oxidizing condition, AuCl3
was employed to replace AuCl. This reaction produced a
mixture with only a small amount of ketone product, which
can be detected by GC, and most of the starting material
was recovered (entries 6 and 17, Table 1).
(6) (a) Boring, E.; Geletti, Y. V.; Hill, C. L. J. Am. Chem. Soc. 2001,
123, 1625. (b) Guan, B.; Xing, D.; Cai, G.; Wan, X.; Yu, N.; Fang, Z.;
Yang, L.; Shi, Z. J. Am. Chem. Soc. 2005, 127, 18004-18005. (c) Cinellu,
M. A.; Minghetti, G.; Cocco, F.; Stoccoro, S.; Zucca, A.; Manassero, M.
Angew. Chem., Int. Ed. 2005, 44, 6892-6895.
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G. J. Org. Chem. 1990, 55, 1323-1328. (b) Baeyer, A.; Villiger, V. Ber.
Dtsch. Chem. Ges. 1899, 32, 3625-3633.
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2004, 104, 2239-2258. (b) Zeni, G.; Larock, R. C. Chem. ReV. 2004, 104,
2285-2310 and references therein.
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8236-8246. (b) Yu, W.; Mei, Y.; Kang, Y.; Hua, Z.; Jin, Z. Org. Lett.
2004, 6, 3217-3219.
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Am. Chem. Soc. 2000, 122, 10289-10297. (b) Adam, W.; Mock-Knoblauch,
C.; Saha-Mo¨eller, C. R.; Herderich, M. J. Am. Chem. Soc. 2000, 122, 9685-
9691. (c) Rodriguez, A. L.; Bunlaksananusorn, T.; Knochel, P. Org. Lett.
2000, 2, 3285-3287. (d) Kawatsura, M.; Hartwig, J. F. J. Am. Chem. Soc.
2000, 122, 9546-9547. (e) Dai, M. J.; Wang, C. H.; Dong, G. B.; Xing, J.;
Luo, T. P.; Liang, B.; Chen, J. H.; Yang, Z. Eur. J. Org. Chem. 2003,
4346-4348.
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E. Angew. Chem., Int. Ed. 2004, 43, 6545-6547. (b) Hashmi, A. S. K.;
Rudolph, M.; Weyrauch, J. P.; Wo¨lfle, M.; Frey, W.; Bats, J. W. Angew.
Chem., Int. Ed. 2005, 44, 2798-2801.
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1994, 13, 418-420. (b) Cinellu, M. A.; Minghetti, G.; Stoccoro, S.; Zucca,
A.; Manassero, M. Chem. Commun. 2004, 1618-1619. (c) Vicente, J.;
Chicote, M.-T.; Guerrero, R.; Jones, P. G.; Ram´ırez de Arellano, M. C.
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A.; Jones, P. G.; Lautner, J. J. Chem. Soc., Dalton Trans.; Inorg. Chem.
1990, 451-456.
A range of substrates were investigated as listed in Table
2. We found, with the use of substituted geminal biaryl
ethylenes as substrates, that the reactions ran quite smoothly,
and corresponding products were produced in moderate to
excellent yields. With either electron-donating or electron-
withdrawing groups at the para position of one of the phenyl
rings, oxidative reactions ran efficiently and finished in 3-6
h (entries 2-3 and 6-7, Table 2). The reaction was slowed
(13) (a) Markham, J. P.; Staben, S. T.; Toste, F. D. J. Am. Chem. Soc.
2005, 127, 9708-9709. (b) Mun˜oz, M. P.; Adrio, J.; Carretero, J. C.;
Echavarren, A. M. Organometallics 2005, 24, 1293-1300.
694
Org. Lett., Vol. 8, No. 4, 2006

reaction (entry 13, Table 2). However, because the efficiency
of the oxidation decreased because of the presence of an
electron-withdrawing group on the phenyl ring with methyl
p-vinylbenzoate as a starting material, the aldehyde was
isolated from this reaction in only 20% yield with 68% of
the starting material recovered (entry 15, Table 2). During
this process, the byproduct formaldehyde was detected by
trapping the reaction mixture with phenyl hydrazine. 2-Me-
thylene-1-phenylhydrazine was isolated as a product in 30%
yield (entry 1, Table 2). This result strongly indicated that
the CdC bond was split into two carbonyl products in the
reaction. It should be noted that the over-oxidation to acid
was not observed under these conditions. Oxidation of
styrenes to give aldehydes and ketones has been studied in
the past.14 The new gold-catalyzed process we report here
is efficient, simple, and can tolerate various functional
groups.
Mechanistically, this reaction may proceed in two steps
involving the first step of epoxidation15 and a subsequent
oxidation to produce carbonyl products.16 To test this
mechanism, the reactions were carried out with two epoxides,
2-methyl-2-phenyloxirane and styrene oxide, which were
prepared from R-methyl styrene and styrene, respectively.17
However, no carbonyl products were observed in either
reaction (eq 1). Thus, the mechanism involving epoxides as
Table 2. Oxidative Cleavage of Substituted Styrenes to
Ketones and Aldehydesa,b
time
(h)
3
(%)
entry
R1
R2
R3
1c,d C6H5
C6H5
4-CH3C6H4
4-CH3OC6H4
2-CH3C6H4
1-C10H7
4-FC6H4
4-BrC6H4
2-CH3O-5-ClC6H3
2-thiophenyl
CH3
H
H
H
H
3
3
3
18
24
3
6
3
24
36
3a (93)
3b (84)
3c (70)
3d (89)
3e (56)
3f (62)
3g (86)
3h (44)
3i (53)
3j (39)
3k (66)
3k (56)
3l (62)
2
3
4
5
6
7
8
9
10
11
12
13
14
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
H
H
H
H
H
H
H
H
H
CH3 36
H
H
H
H
36
24
4-AcOCH2C6H4
2-C10H7
H
H
24 3m (52)
36 3n (20)
15e 4-CH3O2CC6H4
a Isolated yield. b Small molecules, such as formaldehyde, were not
detected in these reactions. c 1.0 mol % of AuCl and 1.0 mol % of 1 were
used as the catalyst. d Phenyl hydrazine was used to trap formaldehyde,
and 2-methylene-1-phenylhydrazine was isolated as a product in 30% yield.
e 68% of starting material was recovered.
with substrates bearing substituted groups at the ortho positon
of the phenyl groups, such as 2-toluyl and 1-naphthyl (entries
4 and 5, Table 2). These results indicated that the electronic
effect on the phenyl group in these geminal diaryl ethylenes
did not play a significant role in affecting the rate of
oxidation, probably because of the high reactivity of these
substrates. In contrast, steric hindrance seems to be a key
factor in affecting the rate of oxidation of these substrates.
Moreover, various functional groups, such as alkyl, alkoxy,
and halide groups on phenyl rings, were well tolerated under
this condition (entries 2-8, Table 2). With the methyl group
at the benzyl position in the geminal diaryl alkenes, potential
byproducts from the radical oxidation of the methyl group
were not observed (entries 2 and 4, Table 2). A heterocyclic
substrate could be employed, and the corresponding product
was obtained in a moderate yield (entry 9, Table 2).
Oxidation of R-methyl styrene was carried out, and ac-
etophenone was acquired in 39% isolated yield (entry 10,
Table 2). Subsequently, â-styrene can also be oxidized to
afford benzaldehyde in 66% isolated yield (entry 11, Table
2). With these two substrates, the competing radical oxidation
of the allylic methyl groups was observed to give the
aldehydes as byproducts in 31% and 16% isolated yields,
respectively, together with lower yields of the desired
carbonyl products (entries 10 and 11, Table 2).
the intermediates could be excluded. Our study also indicated
that (Neo)AuCl and [(Neo)Au(styrene)]+ could be observerd
by ESI mass spectroscopy in the catalytic cycle. Many
mechanistic possibilities should be considered. It seems to
us that the interaction of olefin to a gold center to give the
complexes such as [(Neo)Au(styrene)]+ may be important.
The bulky groups and the electron-withdrawing substitutions
might affect the rate of oxidation because of their varied
binding affinities to gold(I). We also found that this oxidation
was completely inhibited by TEMPO (eq 2),18 which may
suggest a radical initiation pathway; however, the benzylic
methyl group survived well under this condition.
In summary, we developed a novel method to oxidize
olefins to form ketones or aldehydes with the use of a gold-
Finally, styrene and 2-vinylnaphthylene were studied under
this condition and the corresponding aldehydes were obtained
with 5.0 mol % of AuCl and 1 as the catalyst in moderate
isolated yields (entries 12-14, Table 2). The ester as a
substituted group at the benzylic position could survive this
(14) (a) Clennan, E. L.; Pan, G.-L. Org. Lett. 2003, 5, 4979-4982. (b)
Barton, D. H. R.; Wang, T.-L. Tetrahedron Lett. 1994, 35, 1519-1522. (c)
Adams, J. M.; Davies, S. E.; Graham, S. H.; Thomas, J. M. Chem. Commun.
1978, 930-931. (d) Sarneski, J. E.; Michos, D.; Thorp, H. H.; Didiuk, M.;
Poon, T.; Blewitt, J.; Brudvig, G. W.; Crabtree, R. H. Tetrahedron Lett.
1991, 32, 1153-1156.
Org. Lett., Vol. 8, No. 4, 2006
695

(I) complex as the catalyst and TBHP as the oxidant. The
novel redox activity of gold species was demonstrated. This
oxidation reaction proceeds under mild conditions in water.
A series of functional groups can be tolerated. This report
could stimulate further research efforts on redox reactions,
in particular oxygen transfers, mediated by gold species in
solution. Further studies to probe the mechanism of these
transformations, to unambiguously identify the catalytically
active species, and to broaden the scope of these reactions
are currently ongoing and will be reported in due course.
Acknowledgment. Support of this work by a starter grant
from Peking University and National Science Foundation of
China (No. 20542001) is gratefully acknowledged. We are
also indebted to Prof. Xi and Prof. Yang at Peking University
for laboratory space and some chemicals for this research.
(15) Bhor, S.; Tse, M. K.; Klawonn, M.; Do¨ebler, C.; Ma¨gerlein, W.;
Beller, M. AdV. Synth. Catal. 2004, 346, 263-267.
(16) Kurata, T.; Koshiyama, T.; Kawashima, H. Yukagaku 1987, 36,
206-209.
(17) Lane, B. S.; Burgess, K. J. Am. Chem. Soc. 2001, 123, 2933-2934.
(18) (a) Miller, J. B.; Salvador, J. R. J. Org. Chem. 2002, 67, 435-442.
(b) Hontis, L.; Vrindts, V.; Lutsen, L.; Vanderzande, D.; Gelan, J. Polymer
2001, 42, 5793-5796.
Supporting Information Available: Experimental pro-
cedures including compounds 3 along with spectroscopic and
other data. This material is available free of charge via the
Internet at http://pubs.acs.org.
OL052830T
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Org. Lett., Vol. 8, No. 4, 2006