A. Kamal et al. / Tetrahedron Letters 43 (2002) 6947–6951
6951
NBS (15 mol%)
CH Cl , rt
HS
HS
S
S
X
X
SEt
SEt
R
+
HSEt
or
R
or
R
(
)n
(
)n
2
2
R = aryl, allyl, cyclohexyl; X = OMe, OEt, OAc ;XX =O; n = 1,2
Scheme 5.
OEt
SEt
Cl
Cl
Cl
88%
94%
SEt
OEt
HSEt, NBS (15 mol%)
CH Cl , r.t., 20 min
2
2
O
O
Cl
CH3
CH3
Scheme 6.
References
16. (a) Paquette, I. A. Encyclopedia of Reagents for Organic
Synthesis; John Wiley and Sons: New York, 1997; pp.
768–772; (b) Karimi, B.; Seradj, H.; Ebrahimian, G. R.
Synlett 1999, 1456; (c) Karimi, B.; Seradj, H.;
Ebrahimian, G. R. Synlett 2000, 623; (d) Karimi, B.;
Ebrahimian, G. R. Org. Lett. 1999, 1737.
1
2
. (a) Greene, T. W.; Wuts, P. G. M. Protective Groups in
Organic Synthesis, 2nd ed.; Wiley: New York, 1991; pp.
88–191; (b) Kocienski, P. J. Protecting Groups; Thieme:
Stuttgart, 1994; pp. 156–170.
1
. (a) Eliel, E. L.; Morris-Natsche, S. S. J. Am. Chem. Soc.
1
1
7. Kamal, A.; Chouhan, G. Synlett 2002, 474.
1
984, 106, 2937; (b) Lynch, J. E.; Eliel, E. L.; Morris-
8. Typical experimental procedure: To a stirred solution of
NBS (30 mol%) and the appropriate aldehyde (1 mmol)
in dichloromethane (10 ml) at room temperature was
added 2-mercaptoethanol (1.5 mmol). The mixture was
stirred at room temperature for the appropriate time (see
Table 1). After completion of the reaction as indicated by
TLC, the organic solution was washed with aqueous 2N
NaOH, extracted with dichloromethane, dried (Na SO )
Natsche, S. S. J. Am. Chem. Soc. 1984, 106, 2943; (c)
Utimoto, K.; Nakamura, A.; Motsubara, S. J. Am.
Chem. Soc. 1990, 112, 8189.
3
4
5
6
. Ralls, J. W.; Dodson, R. M.; Riegel, B. J. Am. Chem.
Soc. 1949, 71, 3320.
. Djerassi, C.; Gorman, M. J. Am. Chem. Soc. 1953, 75,
3
704.
. Yadav, V. K.; Fallis, A. G. Tetrahedron Lett. 1988, 29,
97–900.
. Wilson, G. E., Jr.; Huang, M. G.; Schloman, W. W., Jr.
J. Org. Chem. 1968, 33, 2133.
. Burczyk, B.; Kortylewicz, Z. Synthesis 1982, 831.
. Karimi, B.; Seradj, H. Synlett 2000, 805.
. Ballini, R.; Bosica, G.; Maggi, R.; Mazzacani, A.; Righi,
P.; Sartori, G. Synthesis 2001, 1826.
0. (a) Kumar, V.; Dev, S. Tetrahedron Lett. 1983, 24, 1289;
b) Firouzabadi, H.; Iranpoor, N.; Karimi, B. Synlett
998, 739; (c) Saraswathy, V. G.; Geetha, V.; Sankarara-
2
4
and concentrated in vacuum and the crude product was
purified by silica gel column chromatography to furnish
the corresponding 1,3-oxathiolanes. Spectroscopic data
8
1
for oxathioacetals; Compound d: H NMR (200 MHz;
7
8
9
CDCl ): l=3.16 (m, 2H), 3.90 (m, 1H), 4.50 (m, 1H),
3
5
.95 (s, 2H), 6.10 (s, 1H), 6.95 (s, 1H), 7.05 (s, 1H).
Compound e: l=3.20 (m, 2H), 3.90 (m, 1H), 4.45 (m,
H), 6.00 (s, 1H), 7.22 (d, 2H, J=8.2 Hz), 7.35 (d, 2H,
J=8.2 Hz). Compound h: l=3.05–3.12 (m, 2H), 4.00 (m,
1
1
(
1
1
6
H), 4.20 (m, 1H), 6.02 (s, 1H), 6.25 (dd, 1H, J=3.6 Hz),
.40 (d, 1H, J=3.6 Hz), 7.40 (d, 1H, J=1.7 Hz). Com-
man, S. J. Org. Chem. 1994, 52, 4665.
pound J: l=1.05–1.50 (m, 4H), 1.52–1.90 (m, 6H), 2.85
t, 2H, J=6.6 Hz), 4.00 (t, 2H, J=6.6 Hz). Spectroscopic
1
1. (a) Park, J. H.; Kim, S. Chem. Lett. 1989, 629; (b) Tani,
H.; Masumoto, K.; Inamasu, T.; Suzuki, H. Tetrahedron
Lett. 1991, 32, 2039; (c) Jnaneshwara, G. K.; Barhate, N.
B.; Sudalai, A.; Deshpande, V. H.; Wakhearar, R. D.;
Gajare, A. S.; Shingggare, M. S.; Sukumar, R. J. Chem.
Soc., Perkin Trans. 1 1998, 965.
(
1
data for thioacetals and dithioacetals; Compound a: H
NMR (200 MHz; CDCl ): l=1.20–1.40 (m, 6H), 2.45–
3
2
.80 (m, 4H), 5.65 (s, 1H), 7.25 (dd, 1H, J=7.4 Hz), 7.40
dd, 1H, J=7.4 Hz), 7.80 (d, 1H, J=7.4 Hz), 7.95 (d, 1H,
J=7.4 Hz). Compound d: l=1.85–2.00 (m, 1H), 2.10–
(
1
1
1
1
2. Ravindranathan, T.; Chavan, S. P.; Danatal, W. Tetra-
2
1
.20 (m, 1H), 2.80–3.10 (m, 4H), 3.70 (s, 3H), 5.10 (s,
H), 6.80 (d, 2H, J=7.3 Hz), 7.30 (d, 2H, J=7.3 Hz).
hedron Lett. 1995, 36, 2285.
3. Streinz, L.; Koutek, B.; Saman, D. Collect. Czech. Chem.
Commun. 1997, 62, 665.
4. Firouzabadi, H.; Iranpoor, N.; Hazarkhani, H. J. Org.
Chem. 2001, 66, 7527.
5. Ranu, B. C.; Das, A.; Samanta, S. Synlett 2002, 727.
Compound i: l=1.40 (m, 2H), 1.60 (m, 4H), 2.00 (m,
4
2
H), 3.25 (s, 4H). Compound k: l=1.20–1.30 (t, 6H),
.45–2.70 (m, 4H), 4.90 (s, 1H), 7.30 (d, 2H, J=8.1 Hz),
7.40 (d, 2H, J=8.1 Hz).