W.-G. Shou et al. / Tetrahedron Letters 47 (2006) 1845–1847
1847
): d
À1
1
3
. Krauth a¨ user, S.; Christianson, L. A.; Powell, D. R.;
Gellman, S. H. J. Am. Chem. Soc. 1997, 119, 11719–11720.
. Rosenblum, S. B.; Huynh, T.; Afonso, A.; Davis, H. R.,
Jr.; Yumibe, N.; Clader, J. W.; Burnett, D. A. J. Med.
Chem. 1998, 41, 973–980.
1375, 1250, 1178 cm ; H NMR (500 MHz, CDCl
3
7.38–7.32 (m, 2H), 7.21–7.15 (m, 4H), 6.41 (d, J = 8.8 Hz,
2H), 5.80 (d, J = 9.4 Hz, 1H), 5.50 (dd, J = 4.3, 9.4 Hz,
1H), 4.24–4.02 (m, 5H), 1.20 (t, J = 7.1 Hz, 3H), 1.11 (t,
4
1
3
3
J = 7.1 Hz, 3H) ppm; C NMR (125 MHz, CDCl ): d
5
. (a) Kobayashi, S.; Matsubara, R.; Kitagawa, H. Org. Lett.
168.5, 167.4, 145.4, 13.16, 133.1, 132.2, 132.1, 130.1, 129.4,
2
002, 4, 143–145; (b) Davis, F. A.; Zhang, Y.; Anilkumar,
128.8, 127.4, 115.3, 115.2, 109.9, 62.3, 61.8, 54.6, 54.3,
14.2, 14.1 ppm; MS (ESI) m/z 478 ([M+Na] ).
C H21BrClNO (454.74) Calcd: C, 52.82; H, 4.65; N,
20 4
+
G. J. Org. Chem. 2003, 68, 8061–8064; (c) Evans, G. B.;
Furneaux, R. H.; Tyler, P. C.; Schramm, V. L. Org. Lett.
2
2
003, 5, 3639–3640; (d) Martin, S. F. Acc. Chem. Res.
002, 35, 895–904; (e) Fujita, T.; Nagasawa, H.; Uto, Y.;
3.08. Found: C, 52.78; H, 4.67; N, 2.84.
9. The single crystal of 3a was successfully grown as a
racemic mixture from hexane. CCDC 288449 contains the
supplementary crystallographic data for compound 3a.
data_request@ccdc.cam.ac.uk, or by contacting The Cam-
bridge Crystallographic Data Centre, 12, Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
10. (a) Cui, S. L.; Lin, X. F.; Wang, Y. G. J. Org. Chem. 2005,
70, 2866; (b) Wang, Y. G.; Lin, X. F.; Cui, S. L. Synlett
2004, 1175; (c) Xia, M.; Wang, Y. G. Tetrahedron Lett.
2002, 43, 7703.
Hashimoto, T.; Asakawa, Y.; Hori, H. Org. Lett. 2004, 6,
27–830; (f) Joshi, N. S.; Whitaker, L. R.; Francis, M. B.
8
J. Am. Chem. Soc. 2004, 126, 15942–15943; (g) Wenzel, A.
G.; Jacobern, E. N. J. Am. Chem. Soc. 2002, 124, 12964–
1
2
2965; (h) Ueno, M.; Ishitani, H.; Kobayashi, S. Org. Lett.
002, 4, 3395–3397; (i) Ishimaru, K.; Kojima, T. Tetra-
hedron Lett. 2003, 44, 5441–5444; (j) Badorrey, R.;
Cativiela, C.; Diaz-de-Villegas, M. D.; G a´ lvez, J. A.
Tetrahedron Lett. 2003, 44, 9189–9192; (k) C o´ rdova, A.
Acc. Chem. Res. 2004, 37, 102–112; (l) Wayne, E. J.;
Cohen, J. B. J. Chem. Soc. 1925, 127, 458.
6
. For excellent reviews, see: (a) Arend, M.; Westerman, B.;
Risch, N. Angew. Chem., Int. Ed. 1998, 37, 1044–1070; (b)
Kabayashi, S.; Ishitani, H. Chem. Rev. 1999, 99, 1069–
11. Typical procedure for the synthesis of 3j: A mixture of
2-chlorophenylamine (4 mmol), 2-nitrobenzaldehyde
(4 mmol), diethyl malonic ester (4 mmol), and Zn(OTf)2
1
094.
2 2
(0.04 mmol) in CH Cl (15 ml) was stirred at room
7
. (a) Periasamy, M.; Suresh, S.; Ganesan, S. S. Tetrahedron
Lett. 2005, 46, 5521–5524; (b) Jacobsen, M. F.; Ionita, L.;
Skrydstrup, T. J. Org. Chem. 2004, 69, 4792–4796; (c)
Komoto, I.; Kobayashi, S. J. Org. Chem. 2004, 69, 680–
temperature for 4 h. After removing the solvent in
vacuum, the residues were purified by a flash column
chromatography on silica gel with ethyl acetate–hexane
(1:10) as eluent to afford pure 3j as a yellow solid. Mp 99–
À1
6
88; (d) Chung, W. J.; Omote, M.; Welch, J. T. J. Org.
100 °C; IR (KBr) 3398, 1721, 1598, 1531, 1352, 1269 cm
;
1
Chem. 2005, 70, 7784–7787; (e) Pandey, G.; Singh, R. P.;
Garg, A.; Singh, V. K. Tetrahedron Lett. 2005, 46, 2137–
H NMR (500 MHz, CDCl ): d 8.26 (s, 1H), 8.13–8.11 (m,
3
1H), 7.73 (t, J = 7.8 Hz, 1H), 7.50 (t, J = 8.0 Hz, 1H),
6.66–6.64 (m, 1H), 6.57–6.56 (m, 1H), 6.47–6.46 (m, 1H),
6.44 (d, J = 6.4 Hz, 1H), 5.56 (d, J = 9.0 Hz, 1H), 5.28
(dd, J = 5.4, 9.0 Hz, 1H), 4.19–4.08 (m, 4H), 3.91 (d,
J = 5.4 Hz, 1H), 1.19 (t, J = 7.1 Hz, 3H), 1.11 (t,
2
140.
8
. Typical procedure for the synthesis of 3a: To a mixture of
imine 1a (4 mmol) and diethyl malonic ester (4 mmol) in
2 2 2
CH Cl (15 ml) was added Zn(OTf) (0.04 mmol). The
1
3
mixture was stirred at room temperature for 2 h. After
completion of the reaction, the solvent was evaporated in
vacuum. The resulting residue was purified by a flash
column chromatography on silica gel with ethyl acetate–
hexane (1:10) as eluent to give pure 3a as a colorless solid.
Mp 106–107 °C; IR (KBr) 3394, 2981, 1745, 1569, 1499,
3
J = 7.1 Hz, 3H) ppm; C NMR (125 MHz, CDCl ): d
167.8, 166.8, 148.8, 147.3, 142.1, 135.3, 133.3, 130.5, 130.0,
123.2, 122.1, 118.7, 113.7, 122.1, 62.5, 62.2, 57.7, 56.5,
+
14.1, 14.0 ppm; MS (ESI) m/z 444 ([M+Na] ).
C
20
H21ClN
2 6
O (420.84) Calcd: C, 57.08; H, 5.03; N,
6.66. Found: C, 57.08; H, 4.90; N 6.58.