Chemistry Letters 2002
Table 2. Preparation of compounds 4
727
Guijarro, Tetrahedron Lett., 42, 3455 (2001).
For a polymer supported versionof this reaction: a) C. Gomez,
´
S. Ruiz, and M. Yus, Tetrahedron Lett., 39, 1397 (1998). b) C.
Producta
8
9
Run
Starting
material
No.
Y
R1
R2
Yield/%b
´
Gomez, S. Ruiz, and M. Yus, Tetrahedron, 55, 7017 (1999). c)
1
2
3
4
3d
3f
3m4m
3n
4d
4f
O
O
S
Ph
Et
Bu1
Ph
H
Et
H
H
78
85
74
97
T. Arnauld, A. G. M. Barrett, and B. T. Hopkins, Tetrahedron
Lett., 43, 1081 (2002).
Last paper on this topic from our laboratory: M. Yus, P.
4n
S
ꢀ
Martꢁnez, and D. Guijarro, Tetrahedron, 57, 10119 (2001).
aAll products 4 were >95% pure (300 MHz 1H NMR and/or
GLC) and were fully characterized by spectroscopic means
(IR, 1H and 13CNMR, and MS). bIsolated yield after column
chromatography (silica gel, hexane/ethyl acetate) based on the
starting material 3.
10 a) C. G. Screttas and M. Micha-Screttas, J. Org. Chem., 43,
1064 (1978). b) C. G. Screttas and M. Micha-Screttas, J. Org.
Chem., 44, 713 (1979). c) I. D. Kustas and C. G. Screttas, J.
Org. Chem., 62, 5575 (1997).
11 See, for instance: F. Foubelo and M. Yus, Tetrahedron Lett.,
41, 5047 (2000), and references cited therein.
12 J. Almena, F. Foubelo, and M. Yus, Tetrahedron, 53, 5563
(1997).
prepare functionalized organolithium compounds in a direct
manner, which react with electrophiles giving functionalized
molecules, susceptible to generate homologated heterocycles by
cyclization under acidic conditions.16
13 a) J. Almena, F. Foubelo, and M. Yus, J. Org. Chem., 61, 1859
(1996). b) T. Cohen, F. Chem, T. Kulinski, S. Florio, and V.
Capriati, Tetrahedron Lett., 36, 4459 (1995). c) S. Florio, V.
Capriati, A. Gallo, T. Cohen, F. Chem, and T. Kulinski, Gazz.
Chim. Ital., 126, 351 (1996). d) S. Florio, V. Capriati, A.
Gallo, and T. Cohen, Tetrahedron Lett., 36, 4463 (1995).
14 M. Yus and F. Foubelo, Tetrahedron Lett., 42, 2469 (2001).
15 Substituted thiepins of type 4 have found use as pharmaceu-
ticals with CNS-stimulating, antidepressive and anti-inflam-
matory actions: T. Eicher and S. Hauptmann, ‘‘The Chemistry
of Heterocycles,’’ G. Thieme Verlag, Stuttgart (1995), p 464.
16 Typical procedure for compounds 3: To a suspension of
lithium powder (100 mg, 14 mmol) and DTBB (40 mg,
0.15 mmol; 7.5 mol%) in THF (4 mL) was added dropwise a
solution of phenoxathiin (0.40 g, 2 mmol) in THF (0.5 mL) at
À78 ꢁC. The resulting mixture was stirred 45 min at the same
temperature, being then quenched with the corresponding
electrophile (2.4 mmol; 0.5 mL in the case of H2O and D2O).
After 15 min stirring at À78 ꢁC, the mixture was hydrolyzed
with water (10 mL) allowing the temperature to rise to rt. The
resulting mixture was extracted with ether (3 ꢂ 25 mL), the
aqueous layer was acidified with 3 M hydrochloric acid and
extracted with ethyl acetate (3 ꢂ 25 mL). The organic layer
was dried over MgSO4, evaporated under vacuum (15 Torr)
and the resulting residue purified by column chromatography
(silica gel, hexane/ethyl acetate) to yield the expected pure
product 3.
Financial support for this study provided (grant no. PB97-
0133) by the DGES from the current Spanish Ministerio de
ꢀ
Ciencia y Tecnologꢁa. J. V. F. thanks the Generalitat Valenciana
for a fellowship.
This paper is dedicated to Professor Teruaki Mukaiyama with
admiration and respect on occasion of his 75th birthday.
References and Notes
1
B. J. Wakefield, ‘‘Organolithium Methods,’’ Academic Press,
London (1988).
´
2
Reviews: a) C. Najera and M. Yus, Trends Org. Chem., 2, 155
´
(1991). b) C. Najera and M. Yus, Recent. Res. Dev. Org.
Chem., 1, 67 (1997). c) C. Najera and M. Yus, Curr. Org.
´
Chem., in press.
3
4
5
6
Review: M. Yus and F. Foubelo, Rev. Heteroat. Chem., 17, 73
(1997).
Last paper on this topic from our laboratory: M. Yus, F.
´
Foubelo, and J. V. Ferrandez, Eur. J. Org. Chem., 2001, 2809.
First account from our laboratory: M. Yus and D. J. Ramon, J.
´
Chem. Soc., Chem. Commun., 1991, 398.
Reviews: a) M. Yus, Chem. Soc. Rev., 25, 155 (1996). b) D. J.
´
Ramon and M. Yus, Eur. J. Org. Chem., 2000, 225. c) M. Yus,
Synlett, 2001, 1197.
7
For a mechanistic study: M. Yus, R. P. Herrera, and A.