Synthesis of selenoxides by oxidation of selenides with superoxide radical anions and 2-nitrobenzenesulfonyl chloride

Article abstract of DOI:10.1016/j.tetlet.2005.05.122

Alkyl phenyl selenoxides were produced in excellent yields by oxidation of the corresponding selenides with 2-nitrobenzenesulfonyl chloride and potassium superoxide in dry acetonitrile at -15°C.

Full text of DOI:10.1016/j.tetlet.2005.05.122

Tetrahedron
Letters
Tetrahedron Letters 46 (2005) 5165–5168
Synthesis of selenoxides by oxidation of selenides
with superoxide radical anions and 2-nitrobenzenesulfonyl chloride
*
Marcello Tiecco, Lorenzo Testaferri, Andrea Temperini, Raffaella Terlizzi,
Luana Bagnoli, Francesca Marini and Claudio Santi
Dipartimento di Chimica e Tecnologia del Farmaco, Sezione di Chimica Organica, Universit a` di Perugia, I-06123 Perugia, Italy
Received 4 May 2005; accepted 27 May 2005
Available online 15 June 2005
Abstract—Alkyl phenyl selenoxides were produced in excellent yields by oxidation of the corresponding selenides with 2-nitro-
benzenesulfonyl chloride and potassium superoxide in dry acetonitrile at À15 °C.
Ó 2005 Elsevier Ltd. All rights reserved.
Organoselenium reagents are routinely employed in
many synthetic transformations. Among the various
types of organoselenium compounds, selenoxides are
Selenoxides are generally prepared from the correspond-
ing selenides using common oxidants such as hydro-
8
9
10
gen peroxide, ozone, tert-butyl hydroperoxide,
11
1
12
13
frequently employed as versatile intermediates. The
most commonly used reaction of these compounds is
oxaziridines,
(dichloroiodo)benzene,
sodium metaperiodate,
1
m-PBA,
14
2
N-chlorosuccinimide,
tert-
2
14
15
the spontaneous syn-elimination which provides a facile
butyl hypochlorite or nitrogen oxides. Due to the
several synthetic utilities of the selenoxides, their prepa-
ration is an area of current interest.
route to olefins and to a,b-unsaturated carbonyl com-
pounds. Allylic selenoxides, on the other hand, undergo
a facile [2,3] sigmatropic rearrangement to afford allylic
3
,1
alcohols. Selenoxides are also known as mild reagents
4
We now report that various alkyl phenyl selenides 1 can
be oxidized to the corresponding selenoxides 3, in excel-
lent yields and under mild reaction conditions, by the 2-
nitrobenzenesulfonyl peroxy intermediates generated in
situ from the reaction of 2-nitrobenzenesulfonyl chloride
2 with potassium superoxide at À15 °C in dry acetoni-
trile (Scheme 1). This method was previously employed
for oxidation of various organic compounds such as
olefins, thiols, sulfides, phosphines, hydrazides, amines,
alcohols and catechols. It has also been recently demon-
5
strated that selenoxides can be used as catalysts in the
activation of hydrogen peroxide for the oxidation of
bromide anions.
1
6
for the oxidation of sulfides to sulfoxides and of sulf-
1
oxides to sulfones. The reactions of superoxide radical
7
Only sporadic reports on the preparation and isolation
of stable selenoxides from aryl-, benzyl- or methyl-
1
6
17
18
anions with sulfinyl, sulfonyl and silyl chlorides
generate the corresponding peroxy radical intermediates
which were found to be more efficient oxidizing agents
than the superoxide itself.
6
substituted selenides are present in the literature. Selen-
oxides can be isolated whenever the syn-elimination
reaction is impossible because of the absence of hydro-
gen atoms in the b-carbon or because the oxygen atom
of the selenoxide gives an hydrogen bond with a close
acidic hydrogen atom. Also isolable are those b-alkoxy
selenoxides in which the elimination can only proceed
by abstraction of an hydrogen atom linked to a carbon
The oxidation reactions were carried out according to
the following general procedure. To a stirred solution
7
holding an oxygen function.
SO3-
NO2
SO Cl
O
2
KO2
R
SePh
+
R
SePh
+
MeCN, -15 °C
NO2
Keywords: Selenides; Selenoxides; Oxidation; Potassium superoxide.
*
1
2
3
Corresponding author. Tel.: +39 0755855100; fax: +39
755855116; e-mail: tiecco@unipg.it
0
Scheme 1.
0
040-4039/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2005.05.122

5166
M. Tiecco et al. / Tetrahedron Letters 46 (2005) 5165–5168
of 2-nitrobenzenesulfonyl chloride (0.154 g, 0.7 mmol)
and benzyl phenyl selenide 1a (0.124 g, 0.5 mmol) in
dry acetonitrile (10 ml), under argon atmosphere and
at À15 °C, potassium superoxide (0.106 g, 1.5 mmol)
was added. After stirring for 1 h at À15 °C, the reaction
mixture was allowed to slowly reach room temperature.
Stirring was continued until TLC analysis showed that
the starting selenide was completely converted into the
corresponding selenoxide. The reaction mixture was di-
luted with anhydrous dichloromethane and then filtered
through Celite. The filtrate was dried and concentrated
to afford the highly pure selenoxide 3a in excellent yield
and with spectral data in good agreement with those
which the syn-elimination reaction cannot occur (entries
a and g), in the case of b-oxy selenoxides (entries c–e and
1
9,7
h)
and in the cases in which the oxygen atom of the
selenoxide gave an hydrogen bond with a close acidic
hydrogen atom (entries i and j). The primary alkyl phe-
2
0
nyl selenoxides 3b and f were also obtained in moder-
ate to good yields. This result was not surprising since it
is known that the syn-elimination reaction of simple al-
2
1
kyl phenyl selenoxides is retarded in polar solvents.
Moreover, in these cases the elimination would afford
a terminal alkene. The undesired oxidation of selenox-
ides to selenones did not occur with the present method.
This was confirmed by the comparison of the spectral
data of 3c with those of an authentic sample of the cor-
1
5
reported in the literature. The stable selenoxides which
could be isolated are reported in Table 1 (entries a–j).
2
3
responding selenone which was prepared by oxidation
with m-chloroperoxybenzoic acid in tetrahydrofuran in
the presence of potassium hydrogenphosphate, as
It can be observed that excellent yields were obtained in
most cases. Good results were obtained in the cases in
2
2
recently described. Selenoxide 3c showed the charac-
a
Table 1. Oxidation of selenides 1 with 2-nitrobenzenesulfonyl chloride and potassium superoxide in MeCN at À15 °C
b
Yield (%)
Entry
Selenides 1
PhCH –SePh
nC10
Time (h)
Reaction products
PhCH –SeOPh
nC10
a
b
2
2
23
2
3
3
88
c,d
45
H
21–SePh
H21–SeOPh
OMe
OMe
c
c
36
2
3
3
76
SePh
SeOPh
nC H
nC H
6
13
6
13
OCOPh
SePh
OCOPh
SeOPh
e
82
d
nC10H21
nC10H21
SePh
SeOPh
e
5
3
98
O
O
f
NC
SePh
5
7
NC
SeOPh
3
3
90
85
g
SePh
SeOPh
O
Ph
O
O
Ph
O
h
i
22
6
3
3
89
98
SePh
SePh
SeOPh
SeOPh
OH
OH
SePh
SeOPh
c
j
6
72
18
3
4
5
94
NHCO Bn
NHCO Bn
2
2
SePh
OMe
f
k
nC H
OMe
75
5
11
nC6H13
O
O
g
l
67
Ph
Ph
SePh
a
b
c
d
e
f
Molar ratio KO
2
:ArSO Cl:selenide = 3:1.4:1.
2
Isolated yields. All compounds were characterized by IR and NMR spectroscopy.
The pure selenoxide was obtained after column chromatography on a silica gel column (CH
A 28% of the eliminated product was isolated.
2 2
Cl /MeOH, 5%).
Oxidation with 4-nitrobenzenesulfonyl chloride and superoxide anion under the same reaction conditions yielded the selenoxide in 90%.
Mixture of the two geometrical isomers.
A 15% of the starting selenide was recovered.
g

M. Tiecco et al. / Tetrahedron Letters 46 (2005) 5165–5168
5167
À1
teristic IR absorption at 820 cm and the selenone
absorptions at 870–970 and 912–1059 cm were not
10. Sharpless, K. B.; Hiroi, T. J. Org. Chem. 1978, 43, 1689–
697.
À1
1
1
3
1
1
1
1
1. Davis, F. A.; Stringer, O. D.; Billmers, J. M. Tetrahedron
Lett. 1983, 1213–1216.
2. Cinquini, M.; Colonna, S.; Giovini, R. Chem. Ind.
present. Moreover, in the C NMR spectra the carbon
bearing the heteroatom is gradually deshielded on pass-
ing from the selenides to the selenoxides and to the sele-
nones. No absorptions due to the selenone were
observed in the spectrum of 3c.
(
London) 1969, 1737–1740.
3. Reich, H. J.; Renga, J. M.; Reich, I. L. J. Am. Chem. Soc.
975, 97, 3250–3252.
4. Detty, M. R. J. Org. Chem. 1980, 45, 274–279.
1
Also reported in Table 1 are the results of two oxidation
reactions (entries k and l) from which the selenoxides
could not be isolated because of their rapid elimination
reactions. In the first case the selenoxide obtained from
the secondary selenide 1k gave a spontaneous syn-elimi-
nation reaction to afford excellent yield of the internal
alkene 4 as a 4:1 mixture of the two E/Z isomers. As ex-
pected the selenoxide derived from of the a-phenylseleno
ketone 1l gave the elimination reaction to afford the con-
15. Kochi, J. K.; Bosch, E. J. Chem. Soc., Perkin Trans. 1
1996, 2731–2737.
16. Kim, Y. H.; Yoon, D. C. Tetrahedron Lett. 1988, 29,
6
453–6456.
1
1
7. Kim, Y. H.; Lee, H. K. Chem. Lett. 1987, 1499–1502.
8. Chen, Y. J.; Huang, Y. P. Tetrahedron Lett. 2000, 41,
5
9. [(2-Methoxyoctyl)seleninyl]benzene 3c. Mixture of two
233–5236.
1
1
diastereoisomers (2:1). Oil. Major diastereoisomer:
NMR (200 MHz, CDCl ): d 7.89–7.68 (m, 2H), 7.60–7.42
m, 3H), 3.94–3.76 (m, 1H), 3.46 (s, 3H), 3.11–2.87 (m,
H), 1.80–1.42 (m, 2H), 1.40–1.11 (m, 8H), 0.91–0.80 (m,
H
3
2
4
jugated enone 5.
(
2
1
3
In conclusion, the present results demonstrate that the
-nitrobenzenesulfonyl chloride–potassium superoxide
3H); C NMR (50 MHz, CDCl ): d 140.9, 131.0, 129.5
3
2
(2C), 125.7 (2C), 75.0, 60.2, 57.1, 32.7, 31.5, 29.2, 24.2,
2
1
2.4, 13.9. Minor diastereoisomer: H NMR (200 MHz,
system is a good reagent for the oxidation of selenides
to selenoxides. The proposed method represents a sim-
ple protocol which is compatible with a variety of func-
tional groups and should be of general application in
synthesis.
CDCl ): d 7.80–7.68 (m, 2H), 7.60–7.42 (m, 3H), 3.40–3.15
3
(
2
m, 1H), 3.21 (s, 3H), 3.11–2.87 (m, 2H), 1.82–1.43 (m,
1
H), 1.40–1.11 (m, 8H), 0.91–0.80 (m, 3H); C NMR
3
(
7
50 MHz, CDCl
3
): d 140.1, 131.3, 129.5 (2C), 126.3 (2C),
6.2, 58.8, 55.9, 32.7, 31.5, 29, 24.4, 22.4, 13.9. FT-IR
À1
(
Anal. Calcd for C15
diffuse reflectance): 2930, 1441, 1090, 819, 742, 691 cm
O
.
Se: C, 57.14; H, 7.67. Found: C,
H
24
2
5
1
7.08; H, 7.84.
-[(Phenylseleninyl)methyl]undecyl benzoate 3d. Mixture
Acknowledgments
of two diastereoisomers (1.2:1). Oil. Major diastereoiso-
Financial support from MIUR, National Projects
PRIN2003, FIRB2001 and Consorzio CINMPIS is
gratefully acknowledged.
1
mer: H NMR (200 MHz, CDCl
3
): d 8.02–7.91 (m, 2H),
.81–7.71 (m, 1H), 7.27–7.60 (m, 1H), 7.55–7.30 (m, 6H),
.14–4.98 (m, 1H), 3.41 (dd, 1H, J = 12.9 and 8.4 Hz), 3.25
7
5
(
1
dd, 1H, J = 12.9 and 3.1 Hz), 1.70–1.55 (m, 2H), 1.40–
1
.05 (m, 16H), 0.8 (t, 3H, J = 6.2 Hz); C NMR (50 MHz,
3
References and notes
CDCl ): d 166.0, 140.3, 133.3, 131.3, 121.6 (3C), 129.3,
3
1
29.1 (2C), 28.9, 24.9, 22.9, 14.0. Minor diastereoisomer:
H NMR (200 MHz, CDCl ): d 8.03–7.91 (m, 2H), 7.81–
3
28.4 (3C), 126.1 (2C), 70.1, 58.9, 34.5, 31.7, 29.3 (2C),
1
. (a) Paulmier, C. Selenium Reagents and Intermediates in
Organic Synthesis; Pergamon: Oxford, 1986; (b) Liotta, D.
Organoselenium Chemistry; Wiley: New York, 1987; (c)
Organoselenium Chemistry—A Practical Approach; Back,
T. G., Ed.; Oxford: New York, 2000; (d) Organoselenium
Chemistry: Modern Developments in Organic Synthesis.
In Topics in Current Chemistry; Wirth, T., Ed.; Springer:
Berlin, 2000.
1
7.71 (m, 1H), 7.71–7.62 (m, 1H), 7.55–7.30 (m, 6H), 5.56–
5.41 (m, 1H), 3.48 (dd, 1H, J = 12.7 and 9.5 Hz), 3.11 (dd,
1H, J = 12.7 and 2.9 Hz), 1.91–1.55 (m, 2H), 1.40–1.05 (m,
1
3
16H), 0.8 (t, 3H, J = 6.2 Hz); C NMR (50 MHz, CDCl ):
3
d 165.7, 140.8, 133.2, 131.2, 129.6 (3C), 129.3, 128.4 (3C),
125.8 (2C), 70.2, 59.3, 34.8, 31.7, 29.3 (2C), 29.1 (2C), 28.9,
2
3
4
. Sharpless, K. B.; Lauer, L. F.; Teranishi, A. Y. J. Am.
Chem. Soc. 1973, 95, 6137–6139; Reich, H. J.; Renga, J.
M.; Reich, I. L. J. Am. Chem. Soc. 1975, 97, 5813–5815.
. Campbell Bourland, T.; Carter, R. G.; Yokochi, A. F. T.
Org. Biomol. Chem. 2004, 2, 1315–1329, and references
cited therein.
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Wojtowicz, H. Eur. J. Org. Chem. 2003, 4329–4339, and
references cited therein.
24.9, 22.5, 14.0. FT-IR (diffuse reflectance): 2925, 1717,
O
À1
1268, 1111, 828, 742 cm . Anal. Calcd for C25
C, 65.06; H, 7.43. Found: C, 64.93; H, 7.57.
H
34
Se:
3
1
20. (Decylseleninyl)benzene 3b. Oil. H NMR (200 MHz,
CDCl
2.66 (m, 2H), 1.85–1.45 (m, 2H), 1.41–1.13 (m, 14H), 0.81
3
): d 7.70–7.61 (m, 2H), 7.50–7.38 (m, 3H), 2.92–
1
3
3
(t, 3H, J = 6.3 Hz); C NMR (50 MHz, CDCl ): d 140.1,
131.1, 129.5 (2C), 125.8 (2C), 52.7, 31.7, 29.3, 29.2 (2C),
29.1, 28.9, 22.5, 22.4, 14.0. FT-IR (diffuse reflectance):
À1
5
6
. Detty, M. R.; Goodman, M. A. Organometallics 2004, 23,
3
. Uemura, S. In Comprehensive Organic Synthesis; Trost, B.
M., Fleming, I., Eds.; Pergamon: New York, 1992; Vol. 7,
pp 769–774.
2924, 2853, 817, 741, 691 cm
.
Anal. Calcd for
016–3020.
16
C H26OSe: C, 61.33; H, 8.36. Found: C, 61.12; H, 8.66.
1
4-(Phenylseleninyl)butanenitrile 3f. Oil:
(200 MHz, CDCl ): d 7.72–7.60 (m, 2H), 7.60–7.48 (m,
3H), 3.13–2.92 (m, 1H), 2.85–2.68 (m, 1H), 2.55–2.40 (m,
H
NMR
3
1
3
7
8
9
. Tiecco, M.; Testaferri, L.; Tingoli, M.; Marini, F. J. Org.
Chem. 1993, 58, 1349–1354, and references cited therein.
. Sharpless, K. B.; Lauer, L. F. J. Am. Chem. Soc. 1973, 95,
2H), 2.25–2.05 (m, 1H), 2.02–1.78 (m, 1H); C NMR
(50 MHz, CDCl ): d 141.5, 139.5, 129.8 (2C), 125.6 (2C),
118.4, 48.2, 18.1, 17.0. FT-IR (diffuse reflectance): 3053,
2927, 2265, 1441, 871, 818, 743 cm . Anal. Calcd for
H11NOSe: C, 50.01; H, 4.62; N, 5.83. Found: C, 50.14;
H, 4.85; N, 5.77.
3
À1
2
697–2699.
. Jones, D. N.; Mundy, D.; Whitehouse, R. D. J. Chem.
Soc., Chem. Commun. 1970, 86–87.
C
10

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