ORGANIC
LETTERS
2004
Vol. 6, No. 4
509-512
Hydrolysis of Alkenyl Esters and Ethers
Catalyzed by Metal Complexes
Hiroshi Aoyama, Makoto Tokunaga,* Shin-ichiro Hiraiwa, Yuki Shirogane,
Yasushi Obora, and Yasushi Tsuji*
Catalysis Research Center and DiVision of Chemistry, Graduate School of Science,
Hokkaido UniVersity and Japan Science and Technology Corporation (JST),
Sapporo 001-0021, Japan
Received November 13, 2003
ABSTRACT
Various kinds of transition metals catalyzed the hydrolysis of alkenyl esters and ethers under buffer-free, high concentration conditions
compared to usual biocatalysts. Hydrolytic kinetic resolution of cis-2-tert-butylcyclohexyl vinyl ether was achieved by chiral (salen)Co complexes
with good selectivity (krel ) 10.0).
Utilization of water as a reagent as well as a solvent is an
important topic in synthetic organic chemistry. Because
hydration and hydrolysis of organic molecules are among
the most common and fundamental reactions, transition metal
catalysts have enabled much innovative progress in recent
years. For example, we opened up a door to direct transfor-
mation of 1-alkynes into aldehydes by RuII-catalyzed hydra-
tion.1 It has been long known as a textbook example that
the hydration follows Markovnikov’s rule to give ketones
as a sole product. In addition, Co(salen)-catalyzed hydrolysis
of 1-epoxides2 to chiral epoxides and diols realized a solvent-
and buffer-free process. This reaction is now applied to
industrial processes,3 with several practical advantages over
biocatalysts especially in the product isolation and volumetric
productivity.4
Asymmetric ester hydrolysis is an unexplored area for
transition metal catalysis where biocatalysts play a predomi-
nant role both in laboratory and industry because of their
high enantioselectivity. Furthermore, many kinds of bio-
mimetic artificial catalysts have been developed for enzyme
model studies;5 however, they are not useful for practical
synthesis since activated substrates such as nitrophenyl esters
have been mainly employed5b under diluted conditions in
the presence of buffer salt.
We are interested in vinyl (alkenyl) esters and ethers as
substrates for hydrolysis because of their high availability
and low preparation cost.6 Little attention has been given to
metal-catalyzed hydrolysis of them, and no systematic studies
have been made, whereas acid-catalyzed hydrolysis has been
(1) (a) Tokunaga, M.; Wakatsuki, Y. Angew. Chem. 1998, 110, 3024-
3027; Angew. Chem., Int. Ed. 1998, 37, 2867-2869. (b) Suzuki, T.;
Tokunaga, M.; Wakatsuki, Y. Org. Lett. 2001, 3, 735-737. (c) Tokunaga,
M.; Suzuki, T.; Koga, N.; Fukushima, T.; Horiuchi, A.; Wakatsuki, Y. J.
Am. Chem. Soc. 2001, 123, 11917-11924. (d) Wakatsuki, Y.; Hou, Z.;
Tokunaga, M. Chem. Rec. 2003, 3, 144-157.
(4) (a) Finney, N. S. Chem. Biol. 1998, 5, R73- R79. (b) Keith, J. M.;
Larrow, J. F.; Jacobsen, E. N. AdV. Synth. Catal. 2001, 343, 5-26. (c)
Blaser H.-U. Chem. Commun. 2003, 293-296.
(2) (a) Tokunaga, M.; Larrow, J. F.; Kakiuchi, F.; Jacobsen, E. N. Science
1997, 277, 936-938. (b) Konsler, R. G.; Karl, J.; Jacobsen, E. N. J. Am.
Chem. Soc. 1998, 120, 10780-10781. (c) Schaus, S. E.; Brandes, B. D.;
Larrow, J. F.; Tokunaga, M.; Hansen, K. B.; Gould, A. E.; Furrow, M. E.;
Jacobsen, E. N. J. Am. Chem. Soc. 2002, 124, 1307-1315. (d) Ready, J.
M.; Jacobsen, E. N. Angew. Chem., Int. Ed. 2002, 41, 1374-1377. (e) Yoon,
T. P.; Jacobsen, E. N. Science 2003, 299, 1691-1693.
(5) (a) D’Souza, V. T.; Bender, M. L. Acc. Chem. Res. 1987, 20, 146-
152. (b) Chin, J. Acc. Chem. Res. 1991, 24, 145-152. (c) Zhang, B.;
Breslow, R. J. Am. Chem. Soc. 1997, 119, 1676-1681. (d) Breslow, R.;
Dong, S. D. Chem. ReV. 1998, 98, 1997-2011.
(6) Okimoto, Y.; Sakaguchi, S.; Ishii, Y. J. Am. Chem. Soc. 2002, 124,
1590-1591 and references therein.
(3) Stinson, S. C. Chem. Eng. News 2000, 78, 55-78.
10.1021/ol036228j CCC: $27.50 © 2004 American Chemical Society
Published on Web 01/24/2004