2648
P. Srihari et al.
SHORT PAPER
3a–g (1.0 equiv). The reaction was stirred until the starting material
was completely consumed (monitored by TLC), then quenched with
H2O (3 mL), and extracted with CH2Cl2 (2 × 5 mL). The organic ex-
tracts were dried over anhyd Na2SO4, concentrated under vacuum,
and the crude product was purified by column chromatography.
and Natural Products; Padwa, A.; Pearson, W. H., Eds.;
Wiley & Sons: New York, 2002, 169–252. (d) Kraus, G.
A.; Nagy, J. O. Tetrahedron 1985, 41, 3537. (e) Wang, C.-
L.; Ripka, W. C.; Congalone, P. N. Tetrahedron Lett. 1984,
25, 4613. (f) Garner, P.; Ho, W. B.; Shin, H. J. Am. Chem.
Soc. 1992, 114, 2767.
Ethyl 1-Benzylpyrrolidine-3-carboxylate (4a)
(3) (a) Najera, C.; Sansano, J. M. Curr. Org. Chem. 2003, 7,
1105. (b) Dogan, O.; Oner, I.; Ulku, D.; Arici, C.
Tetrahedron: Asymmetry 2002, 13, 2099. (c) Kanemasa, S.
Synlett 2002, 1371.
IR (KBr): 1735, 1617, 1352, 1176, 912 cm–1.
1H NMR (CDCl3, 300 MHz): d = 7.30–7.12 (m, 5 H), 4.12 (q,
J = 7.5 Hz, 2 H), 3.60 (s, 2 H), 3.10–2.86 (m, 2 H), 2.70–2.43 (m, 3
H), 2.12–1.90 (m, 2 H), 1.15 (t, J = 7.5 Hz, 3 H).
13C NMR (CDCl3, 75 MHz): d = 175.0, 138.8, 129.0, 128.0, 127.0,
60.5, 60.0, 56.7, 53.6, 42.2, 27.6, 14.0
(4) (a) Grigg, R.; Kemp, J. J. Chem. Soc., Chem. Commun.
1978, 109. (b) Joucla, M.; Hamelin, J. Tetrahedron Lett.
1978, 19, 2885. (c) Tsuge, O.; Ueno, K.; Oe, K. Chem. Lett.
1979, 1407. (d) Grigg, R. Bull. Soc. Chim. Belg. 1984, 93,
593. (e) Tsuge, O.; Ueno, K. Heterocycles 1982, 19, 1411.
(f) Tsuge, O.; Kanemasa, S.; Yorozu, K.; Ueno, K. Chem.
Lett. 1985, 1601. (g) Tsuge, O.; Ueno, K.; Kanemasa, S.;
Yorozu, K. Bull. Chem. Soc. Jpn. 1986, 59, 1809.
(5) (a) Komatsu, M.; Okada, H.; Yokoi, S.; Minakata, S. S.
Tetrahedron Lett. 2003, 44, 1603. (b) Wee, A. G. H. J.
Chem. Soc., Perkin Trans. 1 1989, 1363. (c) Vedejs, E.;
West, F. G. Chem. Rev. 1986, 86, 941. (d) Padwa, A.;
Fryxell, G. E.; Gasdaska, J. R.; Venkatramanan, M. K.;
Wong, G. S. K. J. Org. Chem. 1989, 54, 644. (e) Grigg, R.;
Kemp, J. J. Chem. Soc., Chem. Commun. 1978, 109.
(f) Tsuge, O.; Kanemasa, S.; Ohe, M.; Takenaka, S. Chem.
Lett. 1986, 973. (g) Tsuge, O.; Kanemasa, M.; Hatada, A.;
Matsuda, K. Bull. Chem. Soc. Jpn. 1986, 59, 2537.
(6) (a) Huisgen, R.; Scheer, W.; Huber, H. Tetrahedron Lett.
1966, 7, 397. (b) Huisgen, R.; Scheer, W.; Huber, H. J. Am.
Chem. Soc. 1967, 89, 1753. (c) Garner, P.; Dogan, O. J.
Org. Chem. 1994, 59, 4. (d) Deshong, P.; Kell, D. A.
Tetrahedron Lett. 1986, 27, 3979.
LC-MS: m/z = 234 (M+), 222, 206, 188, 142, 134, 91.
1-Benzylpyrrolidine-3-carbonitrile (4c)
IR (KBr): 2923, 2160, 1617, 1355, 913 cm–1.
1H NMR (CDCl3, 200 MHz): d = 7.41–7.23 (m, 5 H), 3.62 (s, 2 H),
3.04–2.84 (m, 2 H), 2.78–2.52 (m, 3 H), 2.35–2.02 (m, 2 H).
13C NMR (CDCl3, 75 MHz): d = 137.9, 128.6, 128.4, 127.3, 59.2,
57.1,52.7, 29.7,29.2.
LC-MS: m/z = 187 (M+), 179, 151, 134, 122, 91.
Diethyl 1-Benzylpyrrolidine-3,4-dicarboxylate (4d)
IR (KBr): 1735, 1617, 1352, 1176, 912 cm–1.
1H NMR (CDCl3, 200 MHz): d = 7.32–7.18 (m, 5 H), 4.6 (q, J = 6.8
Hz, 4 H), 3.63 (s, 2 H), 3.23–3.05 (m, 4 H), 2.66 (t, J = 8.4 Hz, 2 H),
1.22 (t, J = 6.7 Hz, 6 H).
13C NMR (CDCl3, 75 MHz): d = 172.7, 138.5, 128.7, 128.3, 127.2,
60.6,59.9, 56.1,45.3, 14.0.
(7) (a) Grigg, R.; Thornton-Pett, M.; Xu, J.; Xu, L.-H.
Tetrahedron 1999, 55, 13841. (b) Alcaide, B.; Almendros,
P.; Alonso, J. M.; Aly, M. F. J. Org. Chem. 2001, 66, 1351.
(c) Garner, P.; Kaniskan, H. U. Tetrahedron Lett. 2005, 46,
5181. (d) Najera, C.; Sansano, J. M. Angew. Chem. Int. Ed.
2005, 44, 6272.
(8) (a) Dogan, O.; Koyuncu, H.; Kaniskan, U. Turk. J. Chem.
2001, 25, 365. (b) Suga, H.; Inoue, K.; Inoue, S.; Kakehi, A.
J. Am. Chem. Soc. 2002, 124, 14836. (c) Husinec, S.; Savic,
V. Tetrahedron: Asymmetry 2005, 16, 2047. (d) Bowman,
R. K.; Johnson, S. J. J. Org. Chem. 2004, 69, 8537.
(9) Chandrasekhar, S.; Raji Reddy, Ch.; Nagendra Babu, B. J.
Org. Chem. 2002, 67, 9080.
LC-MS: m/z = 306 (M+).
Ethyl 1-Benzyl-4-(2,2-dimethyl-1,3-dioxolan-4-yl)pyrrolidine-
3-carboxylate (4f)
1H NMR (CDCl3, 300 MHz): d = 7.32–7.14 (m, 5 H), 4.26–3.93 (m,
4 H), 3.74–3.56 (m, 3 H), 2.92–2.55 (m, 5 H), 2.43–2.38 (m, 1 H),
1.43–1.22 (m, 9 H).
13C NMR (CDCl3, 75 MHz): d = 174.0, 138.6, 128.5, 128.0, 127.0,
109.0, 77.5, 67.5, 60.7, 59.5, 57.0, 56.7, 56.2, 55.6, 45.3, 45.0, 44.3,
44.0, 26.5, 25.3, 14.1.
LC-MS: m/z = 334 (M+).
(10) Chandrasekhar, S.; Raji Reddy, Ch.; Nagendra Babu, B.;
Chandrasekhar, G. Tetrahedron Lett. 2002, 43, 3801.
(11) Chandrasekhar, S.; Nagendra Babu, B.; Chandrasekhar, G.;
Vijeender, K.; Reddy, K. V. Tetrahedron Lett. 2004, 45,
5497.
Acknowledgment
Y.S.R. and D.B. thank CSIR, New Delhi for financial assistance.
(12) For our recent publications on this catalyst, see:
(a) Chandrasekhar, S.; Chandrashekar, G.; Srinivasa Reddy,
M.; Srihari, P. Org. Biomol. Chem. 2006, 4, 1650.
(b) Chandrasekhar, S.; Srinivasa Rao, Y.; Ramakrishna
Reddy, N. Synlett 2005, 1471. (c) Chandrasekhar, S.; Babu,
B. N.; Chandrashekar, G. eEROS Electronic Encyclopedia
of Organic Reagents for Organic Synthesis; J. Wiley: New
York, 2005, 120; and references therein.
(13) For compound preparation, see: (a) Hosomi, A.; Sakata, Y.;
Sakurai, H. Chem. Lett. 1984, 1117. (b) Padwa, A.; Dent,
W. J. Org. Chem. 1987, 52, 235.
(14) No attempts were made to study the mechanism in detail..
(15) Wee, A. G. H. J. Chem. Soc., Perkin Trans. 1 1989, 1363.
References
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Synthesis 2006, No. 16, 2646–2648 © Thieme Stuttgart · New York