One-pot synthesis of aryl sulfones from alcohols

Article abstract of DOI:10.1055/s-2002-20958

A one-pot synthesis of aryl sulfones from primary alcohols is described. Alcohols were treated with N-bromosuccinimide and triphenylphosphine, followed by addition of sodium arenesulfinate with a catalytic amount of tetrabutylammonium iodide to afford the aryl sulfones in good to high yields.

Full text of DOI:10.1055/s-2002-20958

PAPER
479
One-Pot Synthesis of Aryl Sulfones from Alcohols
One-pot
Synthe
e
sis of Aryl
i
Sulfone
i
s
from
c
A
lcohols hi Murakami,* Kiyotaka Furusawa
Institute for Materials and Chemical Process, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba
Central 5, Tsukuba, Ibaraki 305-8565, Japan
Fax +81(298)614421; E-mail: t-murakami@aist.go.jp
Received 18 December 2001; revised 30 January 2002
cinimide, triphenylphosphine, and sodium arenesulfinates
Abstract: A one-pot synthesis of aryl sulfones from primary alco-
under mild reaction conditions.
hols is described. Alcohols were treated with N-bromosuccinimide
and triphenylphosphine, followed by addition of sodium arenesulfi-
nate with a catalytic amount of tetrabutylammonium iodide to af-
ford the aryl sulfones in good to high yields.
In the course of our synthetic studies on sphingolipids, we
required 2(E)-dodecenyl phenyl sulfone in sufficient
quantities.11 We prepared the sulfone from 2(E)-dodecen-
1-ol (1a) in two steps: (1) preparation of 2-dodecenyl
chloride by treatment with methanesulfonyl chloride and
triethylamine in dichloromethane followed by addition of
lithium chloride and DMF;12 (2) displacement of the chlo-
ride with benzenesulfinate in DMF at 50 °C for 5 hours.
The overall yield of the sulfone 2a was satisfactory (83%),
but purification of the intermediate, 2-dodecenyl chloride,
was necessary. Then, we tried a one-pot synthesis of the
sulfone by adding sodium benzenesulfinate to a solution
of the intermediate mesylate. After optimization of the re-
action conditions, sulfone 2a was obtained in 70% yield
from 1a using THF as the solvent and tetrabutylammoni-
um iodide as the catalyst.13 However, the yield was lower
than that of the former two-pot process and 2-dodecenyl
benzenesulfinate was always formed (7 12%).
Key words: sulfones, alcohols, sulfinates, one-pot synthesis
Alkyl aryl sulfones have been widely used as useful inter-
mediates in organic synthesis.1 In particular, allylic aryl
sulfones are versatile agents for carbon-carbon bond
forming reactions. They can act as regio-defined allylic
nucleophiles,2 allylic electrophiles,3 non-stabilized nu-
cleophiles,4 and radical species5 under appropriate reac-
tion conditions. Their versatility stems from the ability of
the sulfone group to stabilize an adjacent carbanion, the
leaving group ability of the arylsulfonyl group, and the
presence of -electrons.
Among the many preparative methods available, aryl sul-
fones are commonly prepared either by substitution reac-
tion of alkyl halides with alkali-metal salts of
arenesulfinates6 or by oxidation of alkyl aryl sulfides.7 For
allylic derivatives, palladium-catalyzed substitution of al-
lylic acetates8 (or other derivatives9) with metal arene-
sulfinates has been developed. These substrates (halides,
sulfides, acetates) can be easily prepared from alcohols,
but their isolation is necessary before sulfonylation. From
an economical and ecological point of view, one-pot reac-
tions have attracted considerable attention in recent years.
Since alcohols are readily available, more stable, and less
toxic than the corresponding alkyl halides or sulfides, in
general, a direct one-pot synthesis procedure of sulfones
from alcohols would be convenient. To our knowledge, a
few reports10a–c exist for the direct sulfonylation of alco-
hols. However, substrates of all the methods are limited to
allylic alcohols and the reaction examples are few (only
one10a or two10b). One of the methods requires acidic con-
ditions.10c Therefore, it would be difficult to apply these
sulfonylations to non-activated alcohols and/or acid-labile
alcohols.
Since sulfinate anion is an ambident nucleophile, both S-
alkylation product (sulfone) and O-alkylation product
(sulfinate ester) can be formed. Meek and Fowler
reported14 that reaction of sodium p-toluenesulfinate with
hard alkylating agents such as dimethyl sulfate gave me-
thyl toluenesulfinate mainly (>50%), whereas reaction
with methyl iodide, a soft alkylating agent, gave methyl
tolyl sulfone predominantly (>90%).
These results prompted us to investigate a halide-mediat-
ed approach to sulfones, which involves (a) activation of
alcohols with a halogenating agent and a trivalent phos-
phorous compound,15 followed by (b) displacement of the
reactive intermediates by sodium arenesulfinate. Similar
halide-mediated approaches have been already used for
the one-pot syntheses of azides,16 nitriles,17 amines,18 and
thiols19 from alcohols. We chose N-bromosuccinimide as
the halogen source in view of its reactivity, ease of han-
dling, and the atom economy for halogen. The results are
summarized in Table 1 (Scheme 1). Thus treatment of 2-
dodecenol (1a) with N-bromosuccinimide (1.3 equiv) and
triphenylphosphine (1.4 equiv) in acetonitrile at 0 °C im-
mediately gave the bromide20 (monitored by TLC). With-
out isolation, the bromide was treated with sodium
benzenesulfinate (2.0 equiv) and tetrabutylammonium io-
dide (0.1 equiv) at 0 °C. The mixture was stirred at 50 °C
for 5 hours to yield phenyl sulfone 2a11 in 84% yield (en-
try 1) along with a small amount of dodecenyl benzene-
sulfinate (ca. 3% yield). In the absence of
We wish to report a convenient one-pot synthesis of alkyl
aryl sulfones from primary alcohols using N-bromosuc-
Synthesis 2002, No. 4, 15 03 2002. Article Identifier:
1437-210X,E;2002,0,04,0479,0482,ftx,en;F09101SS.pdf.
© Georg Thieme Verlag Stuttgart · New York
ISSN 0039-7881

480
T. Murakami, K. Furusawa
PAPER
tetrabutylammonium iodide (entry 2), longer reaction
time was necessary. When the reaction was carried out in
toluene instead of acetonitrile, the yield of 2a slightly de-
creased (entry 3) and the sulfinate ester increased (6%
yield). In THF, the reaction was completed in 2 hours at
50 °C (entry 4) to afford 2a in a similar yield to entry 1.
Readily available sodium benzenesulfinate hydrated crys-
tals can replace the anhydrous salt without lowering the
yield (entry 5).
NBS (1.3 eq.)
Ph3P (1.4 eq.)
ArSO2Na (2 eq.)
R-SO2
R'
R-OH
Bu4NI (0.1 eq.)
Conditions
Solvent
-20 to 0 °C
2a-j
2h : R' = Me
1a-j
others : R' = H
Scheme 1
Table 1 Preparation of Allylic and Benzylic Sulfones
Next, other allylic and benzylic alcohols were examined.
Sulfonylation of 2(Z)-hexen-1-ol (1b) in acetonitrile or in
THF gave 2(Z)-hexenyl phenyl sulfone (2b)10c without
isomerization of the double bond. The yield of 2b from
the reaction in THF (entry 7) was higher than that in ace-
tonitrile (entry 6). The following sulfonylations were car-
ried out in THF. 1-Hexen-3-ol (1c), a secondary allylic
alcohol, gave a mixture of the isomeric sulfones in 71%
Entry
R-
Conditions
(Solventa)
Yieldb (%)
1
2
3
50 °C, 5 h
(CH3CN)
2a
2a
2a
84
83
77
1a
1a
50 °C, 10 hc
(CH3CN)
1
yield (entry 8). The H NMR analysis indicated that the
1a
55 °C, 5 h
(toluene)
mixture consisted of three isomers: the rearranged 2(E)-
hexen-1-yl phenyl sulfone, its 2(Z)-isomer 2b, and 1-hex-
en-3-yl phenyl sulfone (2c) in a ratio of 58:30:12. Thus
this procedure would not be effective for secondary allylic
alcohols. Geraniol (1e) was converted into geranyl phenyl
sulfone (2e)7b in 93% yield. In this case, geranyl bromide,
a presumed intermediate,20 was so reactive that the reac-
tion proceeded smoothly at room temperature. A sensitive
allylic alcohol 1f, bearing an acetal group was also trans-
formed to the sulfone 2f21 in high yield. Benzyl- (1g) and
furfuryl- (1i) alcohols were efficiently converted to the
corresponding phenyl sulfones 2g 22 and 2i,23 respectively.
p-Chlorobenzyl alcohol (1h) was similarly activated and
treated with sodium p-toluenesulfinate tetrahydrate to
give p-chlorobenzyl p-tolyl sulfone (2h)22 in 86% yield.
4
5
6
1a
1a
50 °C, 2 h
50 °C, 2 hd
2a
2a
2b
84
82
73
55 °C, 5 h
(CH3CN)
1b
1b
7
8
50 °C, 6 h
2b
90
55 °C, 24 h
(mix)
(71e)
1c
1d
1e
9
10
11
55 °C, 5 h
r.t., 5 h
2d
2e
2f
79
93
92
We then extended the sulfone synthesis to non-activated
alcohols. 1-Dodecanol (1j) was treated as above in THF at
reflux for 16 hours to give dodecyl phenyl sulfone (2j)24
in 45% yield along with dodecyl bromide (53%). When
the reaction was carried out in DMF instead of THF, the
sulfone 2j was obtained in 76% yield (Table 2, entry 1,
Scheme 2) with consumption of dodecyl bromide. Since
sodium benzenesulfinate is soluble in DMF, tetrabutylam-
monium iodide can be replaced by the inexpensive sodi-
um iodide, which would accelerate the reaction by Br I
exchange. The results for non-activated alcohols are sum-
marized in Table 2. Phenethyl alcohol (1k), 2-propyn-1-ol
(1l), and 4-penten-1-ol (1m) were converted to the corre-
sponding aryl sulfones 2k,25 2l,26 and 2m7a in good yields,
respectively. To examine the scope of the procedure, this
sulfonylation was applied to alcohols bearing a functional
group such as ether 1n, ester 1o, and nitrile 1p. These
groups proved to be compatible under the reaction condi-
tions to afford the corresponding sulfones 2n,27 2o,28 and
2p.29 In most cases, the yields of the sulfones from non-
activated alcohols were slightly lower than those of allylic
sulfones.
r.t., 20 h
1f
12
13
14
15
50 °C, 4 hd
50 °C, 2 hf
r.t., 20 h
2g
2h
2i
97
86
80
45g
1g
1h
1i
CH3 (CH2) 11
1j
-
reflux, 16 h
2j
a THF was used as solvent unless otherwise noted.
b Isolated yield.
c Bu4NI not added.
d PhSO2Na 2H2O used.
e See text.
f TsNa 4H2O used.
g Dodecyl bromide obtained in 53% yield.
Synthesis 2002, No. 4, 479–482 ISSN 0039-7881 © Thieme Stuttgart · New York

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One-Pot Synthesis of Aryl Sulfones from Alcohols
481
mass spectrometer. TLC and column chromatography were per-
formed on Merck pre-coated silica gel 60F254 plates and silica gel
(Wako gel C-200 or C-300), respectively. On TLC, the aryl sulfones
could be detected by UV 254 nm absorption; they had slightly high-
er Rf values than the parent alcohols (eluent: hexane EtOAc mix-
ture). The arenesulfinate esters, if formed, showed higher Rf values
and stronger UV absorption than the corresponding aryl sulfones.
NBS (1.6 eq.)
Ph3P (1.6 eq.)
ArSO2Na (2 eq.)
R-SO2
R'
R-OH
NaI (0.1 eq.)
Conditions
DMF
0 °C to r.t.
2j-p
2k : R' = Me
1j-p
others : R' = H
Scheme 2
Aryl Sulfones (2a p); General procedure
To a stirred soln of alcohol (1.0 mmol) and Ph3P (1.4-1.6 mmol) in
THF (5 mL) at –20 °C (or in DMF at 0 °C for non-activated alco-
hols) under Ar was added NBS (1.3–1.6 mmol) in small portions
over 15 min. The mixture was stirred for 30 min from –10 °C to
0 °C (or at r.t. for non-activated alcohols). To this soln was added a
mixture of ArSO2Na (2.0 mmol) and Bu4NI (0.1 mmol) (or NaI, 0.1
mmol) in 3 portions over 10 min. The mixture was stirred under the
conditions shown in the Tables, and then diluted with EtOAc (10
mL) and 3% aq Na2S2O3 (10 mL). The layers were separated and the
aq phase was extracted with EtOAc (2 20 mL). The combined or-
ganic extracts were successively washed with H2O and brine, and
then dried over Na2SO4. After filtration and removal of the solvent
under reduced pressure, the residue was purified by silica gel chro-
matography (hexane EtOAc) to afford the aryl sulfone.
Table 2 Preparation of Alkyl Sulfones
Entry
1
R-
Conditions
70 °C, 4 h
Yielda (%)
CH3 (CH2) 11
-
2j
76b
1j
2
3
1j
70 °C, 1 hc
70 °C, 2 hd
2j
76
77
Ph CH2CH2-
2k
1k
4
5
6
7
8
HC≡C-CH2-
1l
70 °C, 2 h
70 °C, 4 h
80 °C, 5 h
80 °C, 3 h
70 °C, 7 h
2l
76
64
78
63e
68
The residue from organic extracts contained mainly aryl sulfone and
triphenylphosphine oxide (Ph3PO). For sulfones 2a e, 2j, and 2m,
most of Ph3PO could be removed before chromatography. To the
residue was added (hexane EtOAc, 9:1), and insoluble solid
(Ph3PO) was filtered off and washed with the same solvent.
H2C=CH-(CH2)3-
1m
2m
2n
2o
2p
MeO-CH2CH2-
1n
Sulfones 2g, 2h, and 2o are highly crystalline solids. In these cases,
the residue was dissolved in CH2Cl2 and purified by chromatogra-
phy eluting with (hexane EtOAc CH2Cl2, 3:1:1).
PhC(O)OCH2CH2-
1o
N≡C-CH2CH2-
All the sulfones 2a p (except secondary sulfone 2c) are known
compounds, and their physical and spectroscopic data are consistent
with those reported in the references quoted in the main text (e.g.
2a,11 2d6). However, the optical rotation of 2f is inconsistent, with
the reported value and some sulfones (2k, 2l, 2o) have not been fully
characterized in the literature. Their data are shown below.
1p
a Isolated yield.
b 9% of alcohol 1j recovered.
c PhSO2Na 2H2O used.
d TsNa 4H2O used.
e 21% of alcohol 1o recovered.
(4S)-2,2-Dimethyl-4-[(E)-3-phenylsulfonylprop-1-enyl]-1,3-di-
oxolane (2f)
[ ]D24 +33.7 (c 1.30, CHCl3) {Lit.21 [ ]D20 +13.2 (c 1.03, CHCl3)}.
All the sulfones thus prepared are known compounds and
their structures were unambiguously confirmed by the Spectral data were in good agreement with those reported.21
physical and spectroscopic data, which were in good
Phenethyl p-Tolyl Sulfone (2k)
agreement with the reported values. For reactions per-
formed in THF or DMF, formation of the sulfinate esters
Colorless solid, mp 75 76 °C (Lit.25 mp 73.0 73.5 °C).
1H NMR: = 2.36 (s, 3 H), 2.93 (m, 2 H), 3.25 (m, 2 H), 7.01 (m, 2
was negligible (0 4% yields).
H), 7.14 (m, 3 H), 7.27 (d, 2 H, J = 8.1 Hz), 7.72 (d, 2 H, J = 8.1
In conclusion, a convenient one-pot procedure has been
developed to prepare aryl sulfones from primary alcohols
via activation with N-bromosuccinimide and triphen-
ylphosphine. This one-pot arylsulfonylation proved to be
effective for various alcohols. The double-bond geometry
of primary allylic alcohols was retained.
Hz).
13C NMR: = 21.5, 28.7, 57.5, 126.7, 128.0 (2 C), 128.2 (2 C),
128.7 (2 C), 129.9 (2 C), 135.9, 137.4, 144.7.
HRMS (CI): m/z calcd for C15H17O2S (M + H)+: 261.0879; found:
261.0913.
3-Phenylsulfonyl-1-propyne (2l)
Colorless solid. mp 93 94 °C (Lit.26 mp 93 °C).
1H NMR: = 2.36 (t, 1 H, J = 2.7 Hz), 3.96 (d, 2 H, J = 2.7 Hz),
7.59 (m, 2 H), 7.70 (m, 1 H), 7.99 (m, 2 H).
13C NMR: = 48.3, 71.5, 76.2, 128.8 (2 C), 129.1 (2 C), 134.3,
137.6.
Melting points were determined with a Yanaco melting point appa-
ratus MP-500D and are uncorrected. Optical rotations were mea-
sured with a JASCO DIP-1000 polarimeter. 1H and 13C NMR
spectra were recorded at 270 and 67.8 MHz on a JEOL JNM-GSX-
270 spectrometer for solns in CDCl3 unless otherwise noted. IR
spectra were measured with a JASCO FT-IR 620 spectrophotome-
ter. Elemental analyses were performed by the analytical section in
this Institute (AIST). HRMS were obtained on a Hitachi M-80B
Anal. Calcd for C9H8O2S: C, 59.98; H, 4.47, S, 17.79. Found: C,
59.80; H, 4.27; S, 17.63.
Synthesis 2002, No. 4, 479–482 ISSN 0039-7881 © Thieme Stuttgart · New York

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T. Murakami, K. Furusawa
PAPER
2-(Phenylsulfonyl)ethyl Benzoate (2o)
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A.; Wong, H.; Chambers, L.; Ferro, M. P.; Jackson, W. Helv.
Chim. Acta 1976, 59, 387. (b) Chem. Abstr. 1982, 97,
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Colorless solid, mp 127 129 °C (Lit.28 mp 125 °C).
1H NMR: = 3.61 (t, 2 H, J = 6.0 Hz), 4.67 (t, 2 H, J = 6.0 Hz), 7.35
(m, 2 H), 7.51 (m, 3 H), 7.58 (m, 1 H), 7.72 (m, 2 H), 7.94 (m, 2 H).
13C NMR: = 55.2, 58.2, 128.0 (2 C), 128.3 (2 C), 128.9, 129.4 (2
C), 129.6 (2 C), 133.3, 133.8, 139.4, 165.7.
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Anal. Calcd for C15H14O4S: C, 62.05; H, 4.86, S, 11.04. Found: C,
62.04; H, 4.77; S, 11.11.
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Synthesis 2002, No. 4, 479–482 ISSN 0039-7881 © Thieme Stuttgart · New York