1594
J . Org. Chem. 1997, 62, 1594-1598
A New Gold Ca ta lyst: F or m a tion of Gold (I) Ca r bon yl, [Au (CO)n ]+
(n ) 1, 2), in Su lfu r ic Acid a n d Its Ap p lica tion to Ca r bon yla tion of
Olefin s
Qiang Xu,* Yuki Imamura, Masahiro Fujiwara, and Yoshie Souma*
Osaka National Research Institute, AIST, MITI, 1-8-31 Midorigaoka, Ikeda, Osaka 563, J apan
Received October 28, 1996X
A new gold catalyst, [Au(CO)n]+ (n ) 1, 2), was synthesized by using a facile method from commercial
gold(III) oxide, Au2O3, in concentrated H2SO4, which exhibits high catalytic activity for carbonylation
of olefins. The gold monocarbonyl [Au(CO)]+ (1) and dicarbonyl [Au(CO)2]+ (2) cations coexist in
H2SO4 solution, the former of which is much more stable than the latter. Both of the carbonyls
show IR spectra of νCO (2194, 2208 cm-1) higher than that of free CO (2143 cm-1), indicating
nonclassical (σ-only) gold-CO bonding. The gold carbonyl complexes coexisting in the concd H2-
SO4 solution exhibit a single resonance in the 13C NMR spectrum at 171 ppm at ambient temperature
and pressure, reflecting rapid CO exchange between 1 (164 ppm) and 2 (175 ppm). The nonclassical
gold(I) carbonyl solution worked as an excellent catalyst, with which olefins reacted with CO to
give tert-carboxylic acids in good yields at room temperature and atmospheric pressure. The gold-
(I) dicarbonyl cation 2 was found to function as an active species for the carbonylation. An olefin-
gold(I)-carbonyl complex was proposed as a possible intermediate in the metal carbonyl-catalyzed
carbonylation in the strongly acidic medium.
In tr od u ction
tention is focused on the catalytic activity for carbony-
lation related to the high reactivity of CO caused by the
diminishing MfC π-back-bonding in the nonclassical
metal carbonyls.
A group of the noble metal carbonyl derivatives, named
as nonclassical metal carbonyls by Strauss1a and Aubke,2a
are subjected to increasing interest. The electron-rich
metal carbonyls exhibit characteristic CO valence fre-
quencies in the vibrational spectra at considerably higher
wavenumbers relative to the absorption of CO gas (2143
cm-1). In contrast to the “classical” metal carbonyls, in
which CO acts as a σ-donor and a π-acceptor, nonclassical
metal carbonyls have no significant amount of π-back
bonding, resulting in weaker M-C bonds, more unstable
compounds, and more reactive CO ligands, expected to
be more catalytically active for carbonylation.1a Willner
There have been a large number of reports dealing with
the carbonylation of olefins, many of which are catalyzed
by metal carbonyls.9 In Roelen10 and Reppe11 reactions,
the classical metal carbonyls, such as Co2(CO)8 and Ni-
(CO)4, were used to catalyze the carbonylation of olefins
to produce aldehydes and carboxylic acids, which needed
high temperature and high pressure.9 Another carbo-
nylation, the Koch reaction, gave tertiary carboxylic acids
in strong acids such as H2SO4, HF, H3PO4, or BF3‚H2O,
in which no metal catalysts were used and high CO
pressure was necessary.12 We previously reported that
the addition of Cu(I) and Ag(I) carbonyl catalysts caused
the Koch-type reaction to proceed under much milder
conditionssat ambient temperature and pressure.13 Nev-
ertheless, the catalytic properties of the carbonyls of gold,
from the same group 11, has not been known for a long
period. Despite the wide utilities of Cu, Ag, and other
noble metal compounds as heterogeneous or homoge-
neous catalysts, gold and its compounds have been
generally regarded as the least useful of the noble metals
as catalysts.14
first succeeded in the synthesis of [Au(CO)2][Sb2F11
]
crystals by stabilizing the unstable carbonyls with the
very weakly coordinating anions [Sb2F11]-.3 Thereafter,
the nonclassical metal carbonyl cations were isolated
successively as [Cu(CO)n][AsF6] (n ) 1, 2, 3),4 [Ag(CO)n]-
[B(OTeF5)4] (n ) 1, 2, 3),1 [Pt(CO)4][Pt(SO3F)6],5 [Pt(CO)4]-
[Sb2F11]2,6 [Pd(CO)4][Sb2F11]2,6 cis-Pd(CO)2(SO3F)2,2a [c-Pd2-
(µ-CO)2](SO3F)2,2b [M(CO)6][Sb2F11
]
(M ) Ru or Os),7
2
[Hg(CO)2][Sb2F11
]
and [Hg2(CO)2][Sb2F11]2.8 Now, at-
2
X Abstract published in Advance ACS Abstracts, February 15, 1997.
(1) (a) Hurlburt, P. K.; Rack, J . J .; Luck, J . S.; Dec, S. F.; Webb, J .
D.; Anderson, O. P.; Strauss, S. H. J . Am. Chem. Soc. 1994, 116, 10003.
(b) Rack, J . J .; Moasser, B.; Gargulak, J . D.; Gladfelter, W. L.;
Hochheimer, H. D.; Strauss, S. H. J . Chem. Soc., Chem. Commun.
1994, 685. (c) Hurlburt, P. K.; Rack, J . J .; Dec, S. F.; Anderson, O. P.;
Strauss, S. H. Inorg. Chem. 1993, 32, 373. (d) Hurlburt, P. K.;
Anderson, O. P.; Strauss, S. H. J . Am. Chem. Soc. 1991, 113, 6277.
(2) (a) Wang, C.; Willner, H.; Bodenbinder, M.; Batchelor, R. J .;
Einstein, F. W. B.; Aubke, F. Inorg. Chem. 1994, 33, 3521. (b) Wang,
C.; Bodenbinder, M.; Willner, H.; Rettig, S.; Trotter, J .; Aubke, F. Inorg.
Chem. 1994, 33, 779.
(3) (a) Willner, H.; Schaebs, J .; Hwang, G.; Mistry, F.; J ones, R.;
Trotter, J .; Aubke, F. J . Am. Chem. Soc. 1992, 114, 8972. (b) Willner,
H.; Aubke, F. Inorg. Chem. 1990, 29, 2195.
(4) Rack, J . J .; Webb, J . D.; Strauss, S. H. Inorg. Chem. 1996, 35,
277.
This paper presents the gold(I) carbonyl in concen-
trated H2SO4 as a new member in the meager family15,16
of gold catalysts, which catalyzes the carbonylation of
(8) (a) Bodenbinder, M.; Balzer-J o¨llenbeck, G.; Willner, H.; Batch-
elor, R. J .; Einstein, F. W. B.; Wang, C.; Aubke, F. Inorg. Chem. 1996,
35, 82. (b) Willner, H.; Bodenbinder, M.; Wang, C.; Aubke, F. J . Chem.
Soc., Chem. Commun. 1994, 1189.
(9) For leading references, see: (a) Colquhoun, H. M.; Thompson,
D. J .; Twigg, M. V. Carbonylation: Direct Synthesis of Carbonyl
Compounds; Plenum Press: New York, 1991. (b) Falbe, J ., Ed. New
Syntheses with Carbon Monoxide; Springer-Verlag: Berlin, 1980.
(10) Roelen, O. (to Ruhrchemie, A. G.), German Patent no. 849,-
548, 1938.
(5) Hwang, G.; Bodenbinder, M.; Willner, H.; Aubke, F. Inorg. Chem.
1993, 32, 4667.
(6) Hwang, G.; Wang, C.; Aubke, F.; Willner, H.; Bodenbinder, M.
Can. J . Chem. 1993, 71, 1532.
(7) Wang, C.; Bley, B.; Balzer-J o¨llenbeck, G.; Lewis, A. R.; Siu, S.
C.; Willner, H.; Aubke, F. J . Chem. Soc., Chem. Commun. 1995, 2071.
(11) Reppe, W. Liebigs ann. Chem. 1953, 582, 1.
(12) Koch, H. Brennst. Chem. 1955, 36, 321.
(13) (a) Souma, Y.; Sano, H. J . Org. Chem. 1973, 38, 3633. (b)
Souma, Y.; Sano, H.; Iyoda, J . J . Org. Chem. 1973, 38, 2016.
(14) Puddephatt, R. J . The Chemistry of Gold; Elsevier: Amsterdam,
The Netherlands, 1978.
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