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