5534
N. Iranpoor et al. / Tetrahedron Letters 47 (2006) 5531–5534
2. (a) Le, Z.-G.; Chen, Z.-C.; Hu, Y.; Zheng, Q.-G. Synthesis
20. Desmaris, L.; Percina, N.; Cottier, L.; Sinou, D. Tetra-
hedron Lett. 2003, 44, 7589–7591.
21. Yoakim, C.; Guse, I.; O’Meara, J. A.; Thavonekham, B.
Synlett 2003, 473–476.
22. Holbrey, J. D.; Turner, M. B.; Reichert, W. M.; Rogers,
R. D. Green Chem. 2003, 5, 731–736.
2004, 2809; (b) Earle, M. J.; Katdare, S. P.; Seddon, K. R.
Org. Lett. 2004, 6, 707.
3. Seddon, K. R. J. Chem. Technol. Biotechnol. 1997, 68, 351.
4. Welton, T. Chem. Rev. 1999, 99, 2071.
5. Wasserscheid, P.; Keim, W. Angew Chem., Int. Ed. 2000,
39, 3772.
6. Blanchard, L. A.; Hancu, D.; Beckman, E. J.; Brennecke,
J. F. Nature 1999, 399, 28.
23. Procedure for the preparation of ionic liquid 2: To a flask
containing the dried ionic liquid 122 (1.15 g, 4 mmol) was
added CH2Cl2 (5 mL), followed by triethylamine
(0.94 mL, 6.03 mmol). The resultant mixture was cooled
to À20 ꢀC, followed by the dropwise addition of a solution
of PPh2Cl (0.73 mL, 4 mmol) in 5 mL of CH2Cl2. The
reaction mixture was left to stir for 1 h and was then
quenched with 5 N NaOH (1.45 mL), followed by water
(2 mL). The aqueous layer was extracted with dichloro-
methane (3 · 5 mL). The combined organic extracts were
dried (Na2SO4) and concentrated in vacuo to afford 89%
7. Prinz, T.; Keim, W.; Driessen-Hollscher, B. Angew.
Chem., Int. Ed. 1996, 35, 1708.
8. (a) Wiley, G. A.; Hershkowitz, R. L.; Rein, B. M.; Chung,
B. C. J. Am. Chem. Soc. 1964, 86, 964–965; (b) Schaefer, J.
P.; Higgins, J. G.; Shenoy, P. K. Org. Synth. 1969, 49, 6–9;
(c) Bose, A. K.; Lal, B. Tetrahedron Lett. 1973, 40, 3937–
3940.
9. (a) Hooz, J.; Gilani, S. S. H. Can. J. Chem. 1968, 46, 86–
87; (b) Trippet, S. J. Chem. Soc. 1962, 2337–2340; (c)
Burns, A. J.; Cadogan, J. I. G. J. Chem. Soc. 1963, 5788–
5796.
10. (a) Iranpoor, N.; Firouzabadi, H.; Akhlaghinia, B.;
Azadia, R. Synthesis 2004, 92–96; (b) Iranpoor, N.;
Firouzabadi, H.; Nowrouzi, N. Tetrahedron 2006, 62,
5498–5501; (c) Loibner, H.; Zbiral, E. Helv. Chim. Acta
1976, 59, 2100.
11. (a) Tamura, Y.; Kawasaki, T.; Adachi, M.; Tanio, M.;
Kita, Y. Tetrahedron Lett. 1977, 4417; (b) Burski, J.;
Kieszkowski, J.; Michaski, J.; Pakulski, M.; Skowroska,
A. Tetrahedron 1983, 39, 4175.
12. (a) Iranpoor, N.; Firouzabadi, H.; Shaterian, H. R.
J. Chem. Res. (S) 1999, 676; (b) Iranpoor, N.; Firouza-
badi, H.; Shaterian, H. R. Synlett 2000, 65; (c) Iranpoor,
N.; Firouzabadi, H.; Shaterian, H. R. Tetrahedron Lett.
2002, 3439.
13. (a) Bernard, M.; Ford, W. T. J. Org. Chem. 1983, 48, 326;
(b) Harrison, C. R.; Hodge, P.; Hunt, B. J.; Khoshdel, E.;
Richardson, G. J. Org. Chem. 1983, 48, 3721–3728.
14. (a) Charette, A. B.; Boezio, A. A.; Janes, M. K. Org. Lett.
2002, 2, 3777; (b) Charette, A. B.; Janes, M. K.; Boezio, A.
A. J. Org. Chem. 2001, 66, 2178.
15. Sieber, F.; Wentworth, P., Jr.; Toker, J. D.; Wentworth,
A. D.; Metz, W. A.; Reed, N. N.; Janda, K. D. J. Org.
Chem. 1999, 64, 5188.
16. Camp, D.; Jenkins, I. D. Aust. J. Chem. 1988, 41, 1835.
17. Itzstein, M. V.; Morino, M. Synth. Commun. 1990, 20, 2049.
18. Pollastri, M. P.; Sagal, J. F.; Chang, G. Tetrahedron Lett.
2001, 42, 2459–2460.
1
of 2 as a white solid (mp 80–81 ꢀC). H NMR 250 MHz
(CDCl3): d (ppm): 1.20 (3H, d, J = 5.4 Hz, –CH3), 3.60
(3H, s, N–CH3), 3.84 (2H, m), 4.12 (1H, m), 6.76 (2H, s
C(4,5)–H), 7.16–7.64 (10H, m), 10.01 (1H, s, C(2)–H); 13
C
NMR 60 MHz (CDCl3): d (ppm): 20.4 (–CH3), 34.5 (N–
CH3), 58.6 (N–CH2), 72.0 (CHOPPH2), 123.1, 123.2 (C4/
5), 129.2, 129.5, 131.1, 137.4, 140.4; 31P NMR 202 MHz
(CDCl3): dp (ppm): 22.15, À144.30.
24. Typical procedure for the conversion of benzyl alcohol to
benzyl bromide: To a flask containing ionic liquid 2
(0.705 g, 1.5 mmol), Br2 (0.075 mL, 1.5 mmol) was added
dropwise. The red color of Br2 immediately disappeared.
Then benzyl alcohol (0.1 mL, 1 mmol) was added at 80 ꢀC.
GC and TLC of the reaction mixture showed immediate
completion of the reaction. The mixture was cooled to
room temperature and benzyl bromide was extracted with
diethyl ether (3 · 5 mL). Evaporation of ether, followed by
chromatography on a short column of silica gel using n-
hexane/ethyl acetate (10/1) as eluent, gave benzyl bromide
as a colorless liquid (0.256 g, 94% yield, bp 196–197 ꢀC,
lit.19 bp 196–198 ꢀC).
25. Typical procedure for the conversion of benzyl alcohol to
benzyl thiocyanate: To a flask containing ionic liquid 2
(0.705 g, 1.5 mmol), Br2 (0.075 mL, 1.5 mmol) was added
dropwise. The red color of Br2 disappeared immediately,
and then KSCN (0.29 g, 3 mmol) and benzyl alcohol
(0.1 mL, 1 mmol) were added at 80 ꢀC. GC and TLC of
the reaction mixture showed the immediate completion of
the reaction after the addition of benzyl alcohol. The
mixture was cooled to rt and benzyl thiocyanate was
extracted with diethyl ether (3 · 5 mL). Evaporation of the
ether and chromatography on a short silica gel column
using n-hexane/ethyl acetate (5/1) as eluent gave benzyl
thiocyanate in 94% yield (mp 39.5–40 ꢀC, lit.12 mp 39–
40 ꢀC).
19. (a) Iranpoor, N.; Firouzabadi, H.; Jamalian, A. Tetra-
hedron 2005, 61, 5699–5704; (b) Iranpoor, N.; Firouza-
badi, H.; Jamalian, A. Synlett 2005, 1447–1449; (c)
Iranpoor, N.; Firouzabadi, H.; Jamalian, A. Tetrahedron
2006, 62, 1823–1827.