Isopropoxyaluminum 1,1′-biphenyl-2-oxy-2′-perfluorooctanesulfonamide as a catalyst for Tishchenko reaction

Article abstract of DOI:10.1016/S0040-4039(03)00472-6

Isopropoxyaluminum 1,1′-biphenyl-2-oxy-2′-perfluorooctanesulfonamide (3) has been evaluated as an aluminum-based catalyst for the Tishchenko reaction. Compound 3 was found to exert high catalytic activity in the reaction with aliphatic aldehydes and also enabled smooth dimerization of enolizable aldehydes. This advantage was highlighted by the quantitative formation of ethyl acetate from acetaldehyde by the present system.

Full text of DOI:10.1016/S0040-4039(03)00472-6

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 44 (2003) 3191–3193
Isopropoxyaluminum
1,1%-biphenyl-2-oxy-2%-perfluorooctanesulfonamide as a catalyst
for Tishchenko reaction
Takashi Ooi, Kohsuke Ohmatsu, Kouji Sasaki, Tomoya Miura and Keiji Maruoka*
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
Received 15 January 2003; revised 10 February 2003; accepted 14 February 2003
Abstract—Isopropoxyaluminum 1,1%-biphenyl-2-oxy-2%-perfluorooctanesulfonamide (3) has been evaluated as an aluminum-based
catalyst for the Tishchenko reaction. Compound 3 was found to exert high catalytic activity in the reaction with aliphatic
aldehydes and also enabled smooth dimerization of enolizable aldehydes. This advantage was highlighted by the quantitative
formation of ethyl acetate from acetaldehyde by the present system. © 2003 Elsevier Science Ltd. All rights reserved.
We recently introduced modified aluminum alkoxide,
isopropoxyaluminum 1,1%-biphenyl-2-oxy-2%-perfluoro-
octanesulfonamide (3), readily prepared from 2-
hydroxy-2%-(perfluorooctanesulfonylamino)biphenyl (1),
Me3Al and 2-propanol, as a highly reactive aluminum-
based catalyst for Meerwein–Ponndorf–Verley reduc-
tion of ketones with 2-propanol as a hydride donor.1a
In addition, the effectiveness of the organoaluminum
pre-catalyst 2 for Oppenauer oxidation of alcohols with
pivalaldehyde or acetone as a hydride acceptor was also
demonstrated.1b This practical reduction–oxidation
method is found to be broadly useful. In our continuing
effort to further expand the synthetic utility of this type
of catalyst, we have been interested in the application
of 3 to the Tishchenko reaction, a dimerization reaction
of aldehydes that involves an oxidation–reduction
sequence through a six-membered transition state A to
give the corresponding carboxylic esters (Scheme 1).2–4
In this letter, we wish to describe the results of this
attempt, featuring the advantage of 3.
Selected examples are listed in Table 1. Isopropoxyalu-
minum
1,1%-biphenyl-2-oxy-2%-perfluorooctanesulfon-
amide (3) can be prepared in situ by the sequential
treatment of 1 with Me3Al and 2-propanol (molar
ratio=1:1:1) in toluene at room temperature for 30
Scheme 1.
Keywords: aldehydes; aluminum alkoxide; carboxylic esters; Tishchenko reaction.
* Corresponding author. Tel./fax: +00 81 75 753 4041; e-mail: maruoka@kuchem.kyoto-u.ac.jp
0040-4039/03/$ - see front matter © 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0040-4039(03)00472-6

3192
T. Ooi et al. / Tetrahedron Letters 44 (2003) 3191–3193
Table 1. Efficient Tishchenko reaction of aldehydes with modified aluminum alkoxide 3 as a catalysta
a
The reaction was carried out in the presence of modified aluminum catalyst 3 in toluene (substrate concentration=7 M) at room temperature
under the given reaction conditions.
b Isolated yield.
c For the experimental procedure, see note 6.
min.1a,5 Subsequent addition of hexanal and continuous
stirring at room temperature for 1 h resulted in clean
formation of the Tishchenko product in 88% yield. The
catalyst loading can be reduced to 0.5 mol% without
decreasing the catalytic activity (entries 1 and 2). Simi-
larly, other aliphatic aldehydes possessing a-substituent
were smoothly dimerized to the corresponding carb-
oxylic esters in excellent chemical yields (entries 3 and
4). The reaction with aromatic aldehydes also appeared
to be feasible, although a certain decrease in the reac-
tivity was observed (entries 5 and 6).
reaction, was efficiently converted to ethyl acetate
quantitatively, implying the possibility of industrial
applications (entry 9).7,8
A typical experimental procedure is as follows (entry 7
in Table 1): 2-Hydroxy-2%-(perfluorooctanesulfonyl-
amino)biphenyl (1, 66.7 mg, 0.1 mmol) was placed in a
dry two-neck flask with a stirring bar under Ar, and
freshly distilled toluene (200 mL) was introduced. To
this suspension was added a 1 M hexane solution of
Me3Al (100 mL, 0.1 mmol) at room temperature and the
resulting mixture was stirred for 15 min (2 was gener-
ated in situ).1a 2-Propanol (7.7 mL, 0.1 mmol) distilled
from CaH2 was added at the same temperature and the
stirring was continued for an additional 30 min (1
equiv. of methane gas toward the Al-Me of 2 was
evolved). Then, freshly distilled 2-phenylpropionalde-
hyde (1.33 mL, 10 mmol) was added dropwise and the
It should be noted that the aluminum alkoxide 3 is
effective for the dimerization of enolizable aldehydes as
demonstrated in the reactions of 2-phenylpropionalde-
hyde
and
tert-butyldimethylsilyloxyacetaldehyde
(entries 7 and 8). Further, simple acetaldehyde, which is
susceptible to undesired side reactions such as self-aldol

T. Ooi et al. / Tetrahedron Letters 44 (2003) 3191–3193
3193
reaction mixture was stirred for 30 min at room tem-
perature. The reaction was quenched by the addition of
1N HCl and the extractive workup was performed with
ether. The ethereal extracts were washed with brine and
dried over Na2SO4. Evaporation of solvents and purifi-
cation of the residual oil by column chromatography
on silica gel (ether/hexane=1:30 as eluent) gave the
corresponding carboxylic ester as a colorless oil (1.19 g,
4.44 mmol; 89%).
for example: Simpura, I.; Nevalainen, V. Tetrahedron
2001, 57, 9867 and references cited therein.
4. For our contribution with bidentate aluminum catalysts,
see: Ooi, T.; Miura, T.; Takaya, K.; Maruoka, K. Tetra-
hedron Lett. 1999, 40, 7695. See also, Ooi, T.; Miura, T.;
Itagaki, Y.; Ichikawa, H.; Maruoka, K. Synthesis 2002,
279.
5. Although the catalyst 3 can be prepared by simple mixing
of Al(OPri)3 [purchased from Aldrich Chemical Co., Ltd.
(99.99% purity)] and 1 at room temperature,1a in this case
the use of CH2Cl2 as solvent was a prerequisite, and led to
a slight decrease of chemical yield. For instance, attempted
dimerization of 3-cyclohexenecarbaldehyde with 0.5 mol%
of 3 thus prepared in CH2Cl2 at room temperature for 30
min gave the corresponding ester in 88% yield (cf. entry 4
in Table 1).
6. Experimental procedure for the reaction of acetaldehyde
(entry 9 in Table 1): To a solution of 3 prepared as
described in the text was added a solution of acetaldehyde
(10 vol% in toluene–heptane; 5 mL, 8.9 mmol) at 0°C and
the flask was then tightly closed. The reaction mixture was
stirred for 2 h at room temperature. The yield of ethyl
acetate was determined to be >99% by GC analysis using
Shimadzu GC-14A with a capillary column of DB-1 (J&W
Scientific 123–1032, 0.32×30,000 mm); tR=1.1 min for
acetaldehyde, 1.5 min for ethyl acetate and 2.3 min for
heptane (internal standard) at the column temperature of
40°C (3 min) to 140°C (1 min) (100°C/9 min).
Acknowledgements
We gratefully appreciate Messrs. Tetsuo Nakajo and
Yasushi Kuroda (SHOWA DENKO K. K. Corporate
R&D Center) for providing valuable information. This
work was partially supported by a Grant-in-Aid for
Scientific Research from the Ministry of Education,
Culture, Sports, Science and Technology, Japan. T.M.
thanks the Research Fellowships of the Japan Society
for the Promotion of Science for Young Scientists.
References
1. (a) Ooi, T.; Ichikawa, H.; Maruoka, K. Angew. Chem., Int.
Ed. 2001, 40, 3610; (b) Ooi, T.; Otsuka, H.; Miura, T.;
Ichikawa, H.; Maruoka, K. Org. Lett. 2002, 4, 2669.
2. (a) Tischtschenko, W. Chem. Zentralbl. 1906, 77, 1309; (b)
Child, W. C.; Adkins, H. J. Am. Chem. Soc. 1923, 47, 789;
(c) Villani, F. J.; Nord, F. F. J. Am. Chem. Soc. 1947, 69,
2605; (d) Lin, L.; Day, A. R. J. Am. Chem. Soc. 1952, 74,
5133; (e) Saegusa, T.; Ueshima, T. J. Org. Chem. 1968, 33,
3310.
7. The dimerization of acetaldehyde with our previously
developed bidentate catalyst, (2,7-dimethyl-1,8-biphenyl-
enedioxy)bis(diisopropoxyaluminum) (0.5 mol%),4 under
otherwise similar conditions was found to be slower, giv-
ing ethyl acetate in 91% yield after 2.5 h.
8. SHOWA DENKO K. K. produces ethyl acetate from
acetaldehyde on a world-wide level (150,000 ton/year)
using aluminum alkoxide type catalyst.
3. For recent studies on the development of new catalysts, see