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M. Mataloni et al.
LETTER
cooling at r.t. the mixture was treated with H2O (4 mL),
(4) (a) Blackburn, L.; Taylor, R. J. K. Org. Lett. 2001, 3, 1637.
(b) Iwasaki, F.; Onomura, O.; Mishima, K.; Kanematsu, T.;
Maki, T.; Matsumura, Y. Tetrahedron Lett. 2001, 42, 2525.
(c) Banik, B. K.; Hackfeld, L.; Becker, F. F. Synth. Commun.
2001, 31, 1581. (d) Blackwell, J. M.; Sonmor, E. R.;
Scoccitti, T.; Piers, W. E. Org. Lett. 2000, 2, 3921.
(e) Hansen, M. C.; Buchwald, S. L. Org. Lett. 2000, 2, 713.
(f) Hiroi, R.; Miyoshi, N.; Wada, M. Chem. Lett. 2002, 274.
(g) Pelletier, J. C.; Khan, A.; Tang, Z. Org. Lett. 2002, 4,
4611.
(5) Radivoy, G.; Alonso, F.; Yus, M. Synthesis 2001, 427; and
references cited therein.
(6) (a) Borzilleri, R. M.; Weinreb, S. M. Synthesis 1995, 347.
(b) Scola, P. M.; Weinreb, S. M. Chem. Rev. 1989, 89, 1525.
(7) (a) Zaugg, H. A. Synthesis 1984, 85. (b) Zaugg, H. A.
Synthesis 1984, 181.
(8) For some recent papers on the utilization of a-amidoalkyl-
phenyl sulfones see: (a) Petrini, M.; Profeta, R.; Righi, P. J.
Org. Chem. 2002, 67, 4530. (b) Mecozzi, T.; Petrini, M.;
Profeta, R. J. Org. Chem. 2001, 66, 8264. (c) Dahmen, S.;
Bräse, S. J. Am. Chem. Soc. 2002, 124, 5940. (d) Enders,
D.; Oberbörsch, S. Synlett 2002, 471. (e) Hermanns, N.;
Dahmen, S.; Bolm, C.; Bräse, S. Angew. Chem. Int. Ed.
2002, 41, 3692. (f) Palomo, C.; Oiarbide, M.; Landa, A.;
González-Rego, M. C.; García, J. M.; González, A.;
Odriozola, J. M.; Martín-Pastor, M.; Linden, A. J. Am.
Chem. Soc. 2002, 124, 8637. (g) Zhang, J.; Wie, C.; Li, C.-
J. Tetrahedron Lett. 2002, 43, 5731. (h) Klepacz, A.;
Zwierzak, A. Tetrahedron Lett. 2002, 43, 1079.
extracted with CHCl3 (4 × 10 mL) and the organic phase was
dried over Na2SO4. After evaporation of the solvent the
crude amine was purified by column chromatography.
Alternatively the crude amine was dissolved in HCl sat. in
MeOH to obtain the corresponding hydrochloride salt.
MeOH was evaporated and the residue was taken up in dry
Et2O to precipitate the salt. After filtration, the salt was
dissolved in 2 N NaOH (10 mL) and the free amine was
extracted with CHCl3 (4 × 10 mL). The organic phase was
dried over Na2SO4 and the pure amine was recovered after
evaporation of the solvent. Spectroscopic data for some
representative compounds follows. Compound 4b: oil. IR
(neat): 3255 cm–1. 1H NMR (300 MHz, CDCl3): d = 0.83 (t,
3 H, J = 6.6 Hz), 1.10–1.57 (m, 12 H), 2.51–2.66 (m, 5 H),
2.85 (dt, 2 H, J = 47.6, 4.7 Hz), 4.90 (dt, 2 H, J = 28.2, 4.7
Hz). Compound 4h: oil. IR (neat): 3255 cm–1. 1H NMR (300
MHz, CDCl3): d = 0.91 (t, 3 H, J = 7.0 Hz), 1.21–1.78 (m,
10 H), 2.54–2.66 (m, 5 H), 3.47 (t, 2 H, J = 6.2 Hz), 4.50 (s,
2 H), 7.18–7.38 (m, 5 H). Compound 4n: mp 52 °C.
IR(nujol): 3300 cm–1. 1H NMR (300 MHz, CDCl3): d = 0.88
(t, 6 H, J = 6.6 Hz), 1.11–1.61 (m, 32 H), 2.58 (t, 8 H, J = 6.6
Hz). Compound 7b: mp 58 °C. IR (nujol): 3300, 1660 cm–1.
1H NMR (300 MHz, CDCl3): d = 0.87 (t, 3 H, J = 6.7 Hz),
1.21–1.52 (m, 10 H), 1.75–1.91 (m, 1 H), 2.22–2.38 (m, 1
H), 4.46 (dd, 1 H, J = 47.3, 14.6 Hz), 4.68 (dd, 1 H, J = 47.2,
14.6 Hz), 5.17 (dt, 1 H, J = 10.7, 3.1 Hz), 6.65 (d, 1 H,
J = 8.5 Hz), 7.73–7.58 (m, 2 H), 7.63–7.69 (m, 1 H), 7.88–
7.91 (m, 2 H). Compound 7n: mp 106 °C. IR (nujol): 3300,
1665 cm–1. 1H NMR (300 MHz, CDCl3): d = 0.85 (t, 6 H,
J = 6.6 Hz), 1.10–1.55 (m, 20 H), 1.60–1.91 (m, 4 H), 1.95–
2.25 (m, 8 H), 5.26 (dt, 1 H, J = 10.6, 3.6 Hz), 4.68 (dd, 1 H,
J = 47.2, 14.6 Hz), 5.17 (dt, 1 H, J = 10.7, 3.1 Hz), 6.50 (dd,
1 H, J = 10.6, 7.7 Hz), 7.50–7.71 (m, 3 H), 7.82–7.93 (m,
2H).
(9) Bernacka, E.; Klepacz, A.; Zwierzak, A. Tetrahedron Lett.
2001, 42, 5093.
(10) Periasamy, M.; Thirumalaikumar, M. J. Organomet. Chem.
2000, 609, 137.
(11) Gribble, G. Chem. Soc. Rev. 1998, 27, 395.
(12) (a) Umino, N.; Iwakuma, T.; Itoh, N. Tetrahedron Lett.
1976, 763. (b) Umino, N.; Iwakuma, T.; Itoh, N.
Tetrahedron Lett. 1976, 2875. (c) Godskensen, M.; Lundt,
I.; Madsen, R.; Winchester, B. Bioorg. Med. Chem. 1996, 4,
1857. (d) Morris, J.; Wishka, D. G. J. Org. Chem. 1991, 56,
3549. (e) Sundaramoorthi, R.; Marazano, C.; Fourrey, J.-L.;
Das, B. C. Tetrahedron Lett. 1984, 25, 3191. (f)Nutaitis,C.
F. Synth. Commun. 1992, 22, 1081.
(13) Typical Reduction Procedure: To a stirred suspension of
NaBH4 (10 mmol) in dry dioxane (10 mL), HOAc (10 mmol)
was added dropwise in 10 min. After stirring for further 15
min, sulfone 7 (2 mmol) dissolved in dioxane (3 mL) was
added and the white suspension was refluxed for 3 h. After
(14) Sulfones 7a–d obtained from fluoroacetamide are reduced
faster (1–1.5 h) than other sulfones. Prolonged refluxing
times (3–4 h) causes partial removal of the fluorine atom. N-
Substituted fluoroacetamides have been previously reduced
using BH3–THF system: Aoki, K.; Tomioka, K.; Noguchi,
H.; Koga, K. Tetrahedron 1997, 53, 13641.
(15) Gautam, V. K.; Singh, J.; Dhillon, R. S. J. Org. Chem. 1988,
53, 187.
(16) (a) Baldwin, J. E.; Otsuka, M.; Wallace, P. M. Tetrahedron
1986, 42, 3097. (b) Padwa, A.; Harring, S. R.; Semones, M.
A. J. Org. Chem. 1998, 63, 44.
Synlett 2003, No. 8, 1129–1132 ISSN 1234-567-89 © Thieme Stuttgart · New York