R. Bruni et al. / Tetrahedron Letters 43 (2002) 3377–3379
3379
incubation, totally hydrolyses the enol acetate produc-
ing the S-2-methylcyclohexanone in 89% yield (ee 45%)
together with a small amount of the trans-alcohol 5
(5%). The reduction goes on and after 24 h the enan-
tiomerically pure 1S,2S-trans-2-methylcyclohexanol 5
(75% yield, ee 100%) is obtained together with cis-alco-
hol (11%), leaving the pure R-ketone (14% yield, ee
100%).
3. Brown, J. T.; Charlwood, B. V. J. Plant Physiol. 1986,
123, 409.
4. Stepan-Sarkissian, G. In Plant Cells and Tissue Culture;
Stafford, A.; Warren, G., Eds.; Open University Press:
Buckingam, UK, 1997; p. 163.
5. Hirata, T.; Hamada, T.; Aoki, T.; Suga, T. Phytochem-
istry 1982, 21, 2209.
6. Lappin, G. J.; Stride, J. D.; Tampion, J. Phytochemistry
1987, 26, 995.
Cherimoya, wild cucumber and giant granadilla, on the
contrary, hydrolyse the enol acetate 3 more slowly (24
h) and with lower enantioselectivity (ee 8–37%), while
after 3/6 days the reduction products 5 and 6 are
detected in good yields and enantiomeric excesses. In
particular, the enantiomerically pure trans-alcohols 5
(ee 100% of the 1S,2S-enantiomer) are obtained in
26–33% yield, while the cis–alcohol 6 (25–46% yield) is
produced with lower ee (50–95% of the 1S,2R-enan-
tiomer). In all cases the enantiomeric excesses of the
unreacted ketone (24–42% yield) increases (35–85% of
the S-enantiomer). Oca, on the other hand, acts simi-
larly in the hydrolysis of 3 giving, in 24 h, the ketone 4
(95%, ee 7% of the R-enantiomer) with traces of cis-
alcohol, while after 3 days the pure alcohol 6 (ee 100%
of the 1S,2R-enantiomer) is obtained in good yield
(56%) leaving the enantiomerically pure S-ketone (44%,
ee 99%).
7. Hamada, H.; Nakamura, N.; Ito, S.; Kawabe, S.;
Funamoto, T. Phytochemistry 1988, 27, 3807.
8. Hamada, H. Bull. Chem. Soc. Jpn. 1988, 61, 869.
9. Gotoh, S.; Akoi, M.; Iwaeda, T.; Izumi, S.; Hirata, T.
Chem. Lett. 1994, 1519.
10. Villa, R.; Molinari, F.; Levati, M.; Aragozzini, F. Bio-
technol. Lett. 1998, 20, 1105.
11. Nakamura, K.; Miyoshi, H.; Sugiyama, T.; Hamada, H.
Phytochemistry 1995, 40, 1419.
12. Kergomard, A.; Renard, M. F.; Veschambre, H.; Cour-
tois, D.; Petiard, V. Phytochemistry 1988, 27, 407.
13. Takemoto, M.; Yamamoto, Y.; Achiwa, K. Chem.
Pharm. Bull. 1998, 46, 419.
14. Naoshima, Y.; Akakabe, Y. J. Org. Chem. 1989, 54,
4237.
15. Naoshima, Y.; Akakabe, Y. Phytochemistry 1991, 30,
3595.
16. Baldassarre, F.; Bertoni, G.; Chiappe, C.; Marioni, F. J.
Mol. Catal. B: Enzym. 2000, 11, 55.
In conclusion the enantioselective reduction and
hydrolysis with not-cultured cell plants can be viewed
as further tool for the organic chemist, if compared
with the use of baker’s yeast, in virtue both of the
easiness of execution and of the limited biochemical
and microbiological skill needed.
17. All the plants are commercially available.
18. The plants are washed with 5% sodium hypochlorite and
then ethanol, peeled with a sterilised cutter and cut under
a sterile hood.
19. For reduction of 1, enantiomer separation is achieved on
Megadex 5 column (25×0.25 mm) containing dimethyl-n-
pentyl b-cyclodextrin in OV 1701; carrier gas: helium 70
kPa; temp. 70–200°C (1.5°C/min), retention time (min): 1,
9.39 R-2, 14.59; S-2, 15.43. For hydrolysis of 3, enan-
tiomer separation was achieved on a Megadex DETTBSb
column (25×0.25 mm) containing diethyl-tert-butylsilyl
b-cyclodextrin in OV 1701; carrier gas: helium 100 kPa,
temp. 70–200°C (1.5°C/min), retention time (min): S-4,
8.27; R-4, 8.53; 1S,2S-5, 9.60; 1R,2R-5, 9.78; 1R,2S-6,
10.77 (as acetyl derivative); 1S,2R-6, 12.01 (as acetyl
derivative).
References
1. Secondary Metabolism in Plant Cell Cultures; Morris, P.;
Scragg, A. H.; Stafford, A.; Fowler M. W., Eds.; Cam-
bridge University Press: London, 1986.
2. Banthorpe, D. V.; Branch, S. A.; Njar, V. C. O.;
Osborne, M. G.; Watson, D. G. Phytochemistry 1986, 25,
629.