Angewandte
Chemie
[12] a) A. C. Spivey, T. Fekner, S. E. Spey, J. Org. Chem. 2000, 65,
Experimental Section
3154; b) A. C. Spivey, A. Maddaford, T. Fekner, A. J. Redgrave,
C. S. Frampton, J. Chem. Soc. Perkin Trans. 1 2000, 3460; c) A. C.
Spivey, F. Zhu, M. B. Mitchell, S. G. Davey, R. L. Jarvest, J. Org.
Chem. 2003, 68, 7379.
1: Freshly distilled acetyl chloride (1.88 mL, 2.64 mmol) was added
dropwise by syringe to a stirred solution of 1,2-bis(trifluoromethane-
sulfonamido)cyclohexane (Aldrich; 1.00 g, 2.64 mmol), and triethyl-
amine (5.50 mL, 3.96 mmol) in diethyl ether (20 mL) at À208C. The
mixture was stirred for 3 h at 08C, after which time the solvent was
removed under reduced pressure. The resulting residue was purified
by flash chromatography on silica gel (ethyl acetate/n-hexane 1/9) to
afford the desired product as a white solid in 85% yield. m.p. 1118C;
[a]2D0 = + 17.468 (c = 1.5; CHCl3); 1H NMR (300 MHz, CDCl3): d =
1.10–1.60 (m, 3H), 1.70–2.00 (m, 3H), 2.05–2.35 (m, 1H), 2.35–2.60
(m, 1H), 2.52 (s, 3H), 3.60–4.05 (m, 1H), 4.10–4.60 (m, 1H), 5.04 ppm
(d, J = 10 Hz, 1H); 13C NMR (75 MHz, CDCl3): d = 24.4, 25.5, 26.8,
29.1, 35.4, 54.5, 66.9, 119.4, 119.5, 170.0 ppm; FT-IR (CsI): n˜ = 3296,
3221, 2947, 2868, 1737, 1716, 1456, 1385, 1233, 1200, 1131, 1071, 1016,
971, 942, 918, 896, 737, 611, 532 cmÀ1; MS (IC/NH3): m/z 438
[M+NH4]+.
[13] Besides displaying various biological activities, enantiopure
amines are widely used as reagents in asymmetric synthesis, for
example, see: E. Juaristi, J. L. Leon-Romo, A. Reyes, J.
Escalante, Tetrahedron: Asymmetry 1999, 10, 2441.
[14] K. Kondo, T. Kurosaki, Y. Murakami, Synlett 1998, 725.
[15] The kinetic resolution of (Æ )-1-naphthylethylamine was
obtained with up to 48% ee using 0.25 equivalents of chiral
reagent at room temperature. This ee value corresponds to a
selectivity factor (s) of 3 at 25% conversion.
[16] A. G. Al-Sehemi, R. S. Atkinson, J. Fawcett, D. R. Russell,
Tetrahedron Lett. 2000, 41, 2239.
[17] Y. Ie, G. C. Fu, Chem. Commun. 2000, 119.
[18] Under these reaction conditions, Fu and co-workers achieved
the kinetic resolution of (Æ )-1 phenylethylamine with 87% ee.
[19] S. Arai, S. Bellemin-Laponnaz, G. C. Fu, Angew. Chem. 2001,
113, 667; Angew. Chem. Int. Ed. 2001, 40, 234.
[20] This ee value corresponds to a selectivity factor (s) of 13 at 35%
conversion.
[21] For a review on chiral 1,2-diamines, see: D. Lucet, T. Le Gall, C.
Mioskowski, Angew. Chem. 1998, 110, 2724; Angew. Chem. Int.
Ed. 1998, 37, 2580.
[22] For a review on solvents and solvent effects, see: C. Reichardt,
Solvents and Solvent Effects in Organic Chemistry, 3rd ed.,
Wiley–VCH, Weinheim, Germany, 2002.
General procedure for enantioselective acetylation of secondary
alkyl amines: The racemic amine (0.36 mmol) was added dropwise by
syringe to a stirred solution of chiral acetylating agent (0.12 mmol) in
the chosen solvent/temperature system. The mixture was stirred at the
same temperature and the reaction was followed by thin layer
chromatography analysis (ethyl acetate/n-hexane 2/8). Once com-
plete conversion of the reagent was observed, the solvent was
removed by distillation under reduced pressure. The resulting residue
was then purified by flash chromatography on silica gel (ethyl acetate/
n-hexane 1/1) and analyzed by high-performance liquid chromatog-
raphy (HPLC) on a chiral stationary phase.
Received: February 6, 2004 [Z53956]
Keywords: acylation · enantioselectivity · kinetic resolution ·
.
solvent effects
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Angew. Chem. Int. Ed. 2004, 43, 3314 –3317
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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