1984
J.-M. Brunel et al. / Tetrahedron: Asymmetry 10 (1999) 1979–1984
4.2. Determination of the enantiomeric excess of cyanohydrins
(1R,2S,5R)-(−)-Menthyl chloroformate (0.025 mL, 0.012 mmol) was added to a solution of cyanohy-
drin (0.057 mmol) in toluene (0.5 mL). Pyridine (0.015 mL, 0.019 mmol) was added and the reaction
1
stirred at room temperature for 12 h. The mixture was concentrated in vacuo and analyzed by H
1
NMR. The diastereomeric excess was determined by H NMR analysis of methine signals near δ 6,
corresponding to the methine proton α to the cyano group of each diastereomer of the cyanohydrin
menthyl carbonate.
References
1. (a) Ziegler, T.; Horsch, B.; Effenberger, F. Synthesis 1990, 575. (b) Jackson, W. R.; Jacobs, H. A.; Jayatilake, G. S.;
Watson, K. G. Aust. J. Chem. 1990, 43, 2045. (c) Effenberger, F.; Stelzer, U. Angew. Chem., Int. Ed. Engl. 1991, 30, 873.
(
d) Zandbergen, P.; Brussee, J.; van der Gen, A. Tetrahedron: Asymmetry 1992, 3, 769. (e) Effenberger, F.; Eichhorn, J.;
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3
. (a) Hayashi, M.; Miyamoto, Y.; Inoue, T.; Oguni, N. J. Org. Chem. 1993, 58, 1515. (b) Hayashi, M.; Inoue, T.; Miyamoto,
Y.; Oguni, N. Tetrahedron 1994, 50, 4385. (c) Yaozhong, J.; Xiangge, Z.; Wenhao, H.; Zhi, L.; Aiqiao, M. Tetrahedron:
Asymmetry 1995, 6, 2915.
4
. For significant publications dealing with asymmetric trimethylsilylcyanation reactions, see: (a) Hwang, C. D.; Hwang, D.
R.; Uang, B. J. J. Org. Chem. 1998, 63, 6762. (b) Tararov, V.; Hibbs, D. E.; Hursthouse, M. B.; Ikonnikov, N.; Malik, K. M.
A.; North, M.; Orizu, C.; Belokon, Y. Chem. Commun. 1998, 387. (c) Jiang, Y.; Gong, L.; Feng, X.; Hu, W.; Pan, W.; Li,
Z.; Mi, A. Tetrahedron 1998, 53, 14327. (d) Mori, M.; Imma, H.; Nakai, T. Tetrahedron Lett. 1997, 38, 6229. (e) Belokon,
Y.; Flego, M.; Ikonnikov, N.; Moscalenko, M.; North, M.; Orizu, C.; Tararov, V.; Tasinazzo, M. J. Chem. Soc., Perkin
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8, 3245. (h) Belokon, Y.; Ikonnikov, N.; Moscalenko, M.; North, M.; Orlova, S.; Tararov, V.; Yashkina, L. Tetrahedron:
Asymmetry 1996, 7, 851. (i) Bolm, C.; Muller, P.; Harms, K. Acta Chem. Scand. 1996, 50, 305. (j) Qian, C.; Zhu, C.;
Huang, T. J. Chem. Soc., Perkin Trans. 1 1998, 2131. (k) Yang, W. B.; Fang, J. M. J. Org. Chem. 1998, 63, 1356. (l) Iovel,
I.; Popelis, Y.; Fleisher, M.; Lukevics, E. Tetrahedron: Asymmetry 1997, 8, 1279. (m) Wada, M.; Takahashi, T.; Domae,
T.; Fukama, T.; Miyoshi, N.; Smith, K. Tetrahedron: Asymmetry 1997, 8, 3939. (n) Hayashi, M.; Inoue, T.; Miyamoto, Y.;
Oguni, N. Tetrahedron 1994, 50, 4385. (o) Abiko, A.; Wang, G. Q. J. Org. Chem. 1996, 61, 2264.
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Buono, G. Eur. J. Org. Chem. 1999, in press.
6
. These compounds may be reviewed as analogues of 1,3-diketone type ligand of various transition metals. They may form
complexes with metal ions and have been used in the preparation of ligands capable of extracting ammonium compounds
from aqueous to organic phases. Alberts, A. H.; Timmer, K.; Noltes, J. G.; Spek, A. L. J. Am. Chem. Soc. 1979, 101, 3375.
. (a) Brunel, J. M.; Constantieux, T.; Legrand, O.; Buono, G. Tetrahedron Lett. 1998, 39, 2961. (b) Legrand, O.; Brunel, J.
M.; Buono, G. Tetrahedron Lett. 1998, 39, 9419.
7
8
9
4
. The use of a stoichiometric amount of titanium complexes generated from Ti(O-iPr) and anti-1a in a 1:4 molar ratio led
to the formation of mandelonitrile in 91% yield and 36% ee.
. Similar results have been previously reported by Oguni et al. using a modified Sharpless catalyst. In this case, it has been
clearly demonstrated that the resulting active species are different depending on the method used for the preparation of
the titanium catalyst. (a) Hayashi, M.; Matsuda, T.; Oguni, N. J. Chem. Soc., Perkin Trans. 1 1992, 3135. (b) Hayashi, M.;
Matsuda, T.; Oguni, N. J. Chem. Soc., Chem. Commun. 1990, 1364.
1
0. About nonlinear effects in asymmetric catalysis, see: (a) Girard, C.; Kagan, H. B. Angew. Chem., Int. Ed. Engl. 1998, 37,
922. (b) Puchot, C.; Samuel, O.; Dunach, E.; Zhao, S.; Agami, C.; Kagan, H. B. J. Am. Chem. Soc. 1986, 108, 2353. (c)
Kitamura, M.; Okada, S.; Suga, S.; Noyori, R. J. Am. Chem. Soc. 1989, 111, 4028.
2