Copper-catalyzed direct thiolation of pentafluorobenzene with diaryl disulfides or aryl thiols by C-H and C-F bond activation

Article abstract of DOI:10.1002/ejoc.201101676

A Cu-catalyzed cross-coupling reaction of diaryl disulfides or aryl thiols with pentafluorobenzene using CuBr as the catalyst, tBuOLi or tBuOK as the base in DMSO at 60 °C under an O₂ atmosphere was investigated. The corresponding bisarylthiola

Full text of DOI:10.1002/ejoc.201101676

FULL PAPER
DOI: 10.1002/ejoc.201101676
Copper-Catalyzed Direct Thiolation of Pentafluorobenzene with Diaryl
Disulfides or Aryl Thiols by C–H and C–F Bond Activation
Chuanming Yu,*[a] Cuiling Zhang,[a] and Xiangjun Shi[a]
Keywords: Copper / Sulfur / Fluorine / C–H activation / C–F activation / Cross-coupling
A Cu-catalyzed cross-coupling reaction of diaryl disulfides or
tem, monoarylthiolation products, with/without bisarylthiol-
aryl thiols with pentafluorobenzene using CuBr as the cata- ation products, could be isolated in moderate yields. A plaus-
lyst, tBuOLi or tBuOK as the base in DMSO at 60 °C under
an O2 atmosphere was investigated. The corresponding bis-
arylthiolation products were obtained in moderate to good
yields by C–H bond and C–F bond activation. When 1,10-
phenanthroline·H2O and DDQ were added to the above sys-
ible mechanism for these transformations was given. Thus, it
represents a method for the synthesis of polyfluorinated di-
aryl sulfides and polyfluorinated triarylbisulfides through
C–H bond and C–F bond activation.
matic C–F bonds have now also been observed. Several ex-
cellent reviews and articles on the structural and synthetic
aspects of C–F bond activation by metal complexes have
been published.[14] Selective C–F activation of pentafluoro-
benzene derivatives were also reported by Radius,[15a] Sand-
ford,[15b] and Zhu and Xu.[15c]
Introduction
Transition-metal-catalyzed carbon–carbon and carbon–
heteroatom bond formation has become a powerful tool to
construct organic molecules. The construction of carbon–
sulfur bonds and the direct functionalization of a C–H
bond are central themes in organic synthesis.[1] Diaryl sulf-
ides are common functionalities found in numerous phar-
maceutically active compounds and medicinally important
natural products.[2] Organic molecules containing a poly-
fluorinated aromatic structure have found applications in
medicinal chemistry and material science.[3] Pentafluoro-
benzene (C6F5H) is a representative example of such fluor-
organic molecule, and thus, the development of efficient
methods for its introduction has been an important strategy
for synthetic chemists. The key C–H bond functionalization
step occurs through a concerted arene metalation and car-
bon–hydrogen bond cleaving process, the accessibility of
which depends directly on the acidity of the C–H bond be-
ing cleaved.[4] Recently, the direct arylation, alkenylation,
alkylation, decarboxylation, and olefination of perfluoroar-
enes through C–H activation were reported by Fagnou,[4]
Daugulis,[5] Nakao and Hiyama,[6] Miura,[7] Zhao,[8] Su,[9]
Shi,[10] Zhang,[11] and Liu.[12] Pu and Wu have reported a
copper(I)-catalyzed tandem reaction of 2-(2,2-dibromo-
vinyl)phenol with polyfluoroarene recently.[13]
A rhodium-catalyzed substitution reaction of aryl fluor-
ides with disulfides containing a notable mode of C–F acti-
vation by a transition-metal catalyst was reported by Yama-
guchi.[16] The direct thiolation of azoles through copper-
catalyzed C–H functionalization with thiols or disulfides
has been reported,[17] but the copper-catalyzed direct thiol-
ation of electron-deficient pentafluorobenzene through C–
H and C–F bond activation with diaryl disulfides or aryl
thiols has not been reported to date; this still poses a great
synthetic challenge because of the difficulties in controlling
the selectivity in the activation of the C–H and C–F bonds.
To the best of our knowledge, this is the first copper-
catalyzed direct thiolation of pentafluorobenzene and pro-
vides a new method for the construction of C–S bonds.
Herein we report the preliminary results of the direct thiol-
ation with pentafluorobenzene.
Results and Discussion
Synthetically useful routes for the generation of fluor-
organics by transition-metal-mediated conversions of aro-
We started with the coupling reaction of pentafluoro-
benzene (1) with 1,2-bis(p-tolyl)disulfane (2a) to assess the
catalyst activity and to determine the optimum reaction
conditions. These results are shown in Table 1. To our sur-
prise, we could obtain bisarylthiolation products 4a in a
high yield (85%) when using CuBr (30 mol-%) and tBuOLi
(2 equiv.) in DMSO at 60 °C under an atmosphere of O2
(1 atm) but desired monoarylthiolation products 3a were
not detected (Table 1, Entry 1). We speculated that the C–
[a] Key Laboratory of Pharmaceutical Engineering of Ministry of
Education, College of Pharmaceutical Sciences, Zhejiang
University of Technology,
Hangzhou 310014, P. R. China
Fax: +86-571-88320752
E-mail: pharmlab@zjut.edu.cn
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201101676.
Eur. J. Org. Chem. 2012, 1953–1959
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1953

C. Yu, C. Zhang, X. Shi
FULL PAPER
F bond, which is in the para position to the C–H bond, can in the absence of DDQ at a specific temperature, and it
easily be activated.[15a,15c] Secondly, when 1,10-phenan- could be transformed into 4a by increasing the temperature.
throline (phen)·H2O (30 mol-%) was added, we were excited Further screening of the solvents revealed that DMSO was
to find that products 3a were obtained in low yield (16%; the optimal solvent (Table 1, Entries 20 and 21). Performing
Table 1, Entry 2). Because DDQ may serve as an electron- the reaction under an atmosphere of oxygen was critical
transfer mediator for activating the C–H bond, we were for the reaction, whereas the reaction performed under an
pleased to find that the introduction of DDQ (30 mol-%) atmosphere of nitrogen (in the absence of oxygen) produced
improved the yield of 3a (68%; Table 1, Entry 3). Sub- 3a a low yield (12%; Table 1, Entry 22). Along with reduc-
sequently, the amounts (20 and 40 mol-%) of DDQ were ing the amount of catalyst to 20 or 10 mol-%, the yields of
also examined (Table 1, Entries 4 and 5), indicating that in- 3a and 4a decreased (Table 1, Entries 23 and 24).
troduction of DDQ (30 mol-%) was very important. Under
Having delineated the optimum reaction conditions for
otherwise identical conditions, the replacement of tBuOLi the thiolation of pentafluorobenzene with disulfides to ob-
(2 equiv.) with weaker bases such as tBuOLi (1 equiv.) and tain the bisarylthiolation products through C–H and C–F
K2CO3 (2 equiv.) led to lower yields of 3a and no formation bond activation (Table 1, Entry 1), we then applied them to
of 4a (Table 1, Entries 6 and 7), indicating that the base a variety of substrates to determine the scope and limita-
additive plays an important role in the cleavage of the C–H tions of the method. As depicted in Table 2, electron-donat-
and C–F bonds. CuBr proved to be more active than other ing groups on the phenyl ring of ArSSAr were beneficial to
Cu sources, furnishing 3a in 68% yield (Table 1, Entries 11– the reaction (78–90% yield; Table 2, Entries 1–6).
16). Monoarylthiolation product 3a was obtained in the
Disulfides with electron-withdrawing functionalities had
highest yield when the reaction was performed at 60 °C. limited reactivity with pentafluorobenzene. A possible
Both 40 and 120 °C gave 3a in slightly lower yields. Product reason is that electron-withdrawing groups decrease the re-
4a was also formed in low yield (50 and 69%, respectively; activities of the corresponding disulfides. For example, sub-
Table 1, Entries 17 and 19). We speculated that monoaryl- strate 2g delivered 50% yield of 4g, 2h delivered 55% yield
thiolation product 3a could be obtained in the highest yield of 4h, and 2i delivered 31% yield of 4i. Unfortunately, the
Table 1. Optimization of the reaction condition.[a]
Entry
[Cu]
(30 mol-%)
phen·H2O
Base
(2 equiv.)
Additive
(30 mol-%)
Solvent
t
[h]
T
[°C]
Yield [%][b]
3a
4a
1
2
3
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
–
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
K2CO3
Cs2CO3
tBuONa
tBuOK
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
tBuOLi
–
–
–
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMF
4
4
4
4
4
8
8
8
8
8
4
4
5
6
4
8
5
5
5
8
8
8
8
8
8
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
40
80
120
60
60
60
60
60
60
–
85
75
31
29
36
–
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
20
10
30
16
68
49
39
20
10
27
45
21
57
12
40
21
48
–
25
40
18
33
21
12
35
21
–
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
4[c]
5[d]
6[e]
7
–
8
9
48
30
22
32
65
19
43
44
trace
50
51
69
40
32
50
45
40
–
10
11
12
13
14
15
16
17
18
19
20
21
22[f]
23[g]
24[h]
25
CuBr
CuI
CuCl
CuCl2·2H2O
Cu(OAc)2·H2O
Cu(OTf)2
CuO
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
CuBr
NMP
DMSO
DMSO
DMSO
DMSO
CuBr
[a] Reaction conditions: 2a (1 mmol), 1 (5 equiv.). [b] Isolated yield. [c] DDQ (20 mol-%). [d] DDQ (40 mol-%). [e] tBuOLi (1 equiv.).
[f] The reaction was carried out under a N2 atmosphere. [g] CuBr (20 mol-%). [h] CuBr (10 mol-%).
1954
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Eur. J. Org. Chem. 2012, 1953–1959

Cu-Catalyzed Direct Thiolation of Pentafluorobenzene with Diaryl Disulfides
Table 2. Scope of the thiolation of pentafluorobenzene with diaryl thiolation product 3c was obtained in a lower yield (42%)
disulfides.[a]
probably due to the decreased electron density at the meta
position of such a substrate.
Unfortunately, as shown in Table 3, no monoarylthiol-
ation products were detected, but bisarylthiolation products
4g, 4h, and 4i were found in a yield of 41, 50, and 29%,
respectively, when using a series of electron-withdrawing
groups on the phenyl ring of the disulfides (Table 3, En-
tries 7–10). One possible reason for this decreased reactivity
is that the electron-withdrawing groups decreased the reac-
tivities of the corresponding disulfides. Bis(p-nitrophenyl)
disulfide, containing the strong NO2 electron-withdrawing
group on the phenyl ring, was utilized as a substrate and it
did not give 3j and 4j (Table 3, Entry 10). Interestingly, un-
der these conditions another monoarylthiolation product,
which results from C–F bond activation, was obtained
(Table 3, Entries 8, 10, 11).
In comparison to diaryl disulfides, aryl thiols are prone
to undergo C–S coupling reactions and would perform bet-
ter as thiolating agents. Thus, we examined the potential for
aryl thiols to undergo this direct thiolation reaction. These
results are summarized in Table 4. The reactions of 6a, 6b,
and 6c with pentafluorobenzene were carried out by using
the same reaction conditions as those used for the diaryl
disulfides and the corresponding thioethers 3a–c were af-
forded in moderate yields (50–60%; Table 4, Entries 1–3).
Aryl thiol 6i containing an electron-withdrawing group on
the phenyl ring was treated with 1, in the absence of DDQ,
to give bisarylthiolation product 4i in 36% yield and
monoarylthiolation product 5i in 33% yield (Table 4, En-
try 5). For p-nitrophenyl thiol (6j), thioether 5j was ob-
tained in moderate yield (49%) with tBuOK (2 equiv.) and
a longer reaction time (Table 4, Entry 7), whereas benzo[d]-
thiazole-2-thiol (6k) gave 5k in low yield (35%; Table 4, En-
try 8).
Entry
Ar
Product
Yield [%][b]
1
2
3
4
5
6
7
8
4-CH3C6H4 (2a)
C6H5 (2b)
3-CH3C6H4 (2c)
2-CH3C6H4 (2d)
2,4-(CH3)2C6H3 (2e)
4-OCH3C6H4 (2f)
4-FC6H4 (2g)
3-FC6H4 (2h)
4-ClC6H4 (2i)
4-NO2C6H4 (2j)
benzothiazol-2-yl (2k)
4a
4b
4c
4d
4e
4f
4g
4h
4i
85
83
78
84
90
86
50
55
31
–
9[c]
10[c]
11[c]
4j
4k
–
[a] Reaction conditions: 2 (1 mmol), 1 (5 equiv.), CuBr (30 mol-%),
tBuOLi (2 equiv.), DMSO (5 mL), 4 h. [b] Isolated yield. [c] tBuOK
(2 equiv.).
expected products were not detected when using bis(p-ni-
trophenyl)disulfide (2j) and benzothiazol-2-yl disulfide (2k)
as substrates (Table 2, Entries 10 and 11).
With the optimal conditions in hand to obtain the
monoarylthiolation product by C–H bond activation
(Table 1, Entry 3), we next examined the substrate scope
with respect to the pentafluorobenzene. As depicted in
Table 3, a series of electron-donating groups on the phenyl
ring of disulfides, such as p-methyl, m-methyl, o-methyl,
and p-methoxy, afforded the corresponding monoarylthiol-
ation products 3b–f in moderate to good yields (Table 3,
Entries 1, 3–6), and for the m-methyl substrate, monoaryl-
Table 3. Scope of the thiolation of pentafluorobenzene with diaryl
disulfides.[a]
Table 4. Scope of the thiolation of pentafluorobenzene with
thiols.[a]
Entry
Ar
Product, yield [%][b]
Entry
Ar
Product, yield [%][b]
1
2
3
4
5
6
7
8
4-CH3C6H4 (2a)
C6H5 (2b)
3-CH3C6H4 (2c)
2-CH3C6H4 (2d)
2,4-(CH3)2C6H3 (2e)
4-OCH3C6H4 (2f)
4-FC6H4 (2g)
3-FC6H4 (2h)
4-ClC6H4 (2i)
4-NO2C6H4 (2j)
benzothiazol-2-yl (2k)
3a, 68
4a, 31
4b, 42
4c, 45
4d, 27
4e, 30
4f, 23
4g, 41
4h, 50
4i, 29
–
–
–
–
–
–
–
–
3b, 56
1
2
3
4-CH3C6H4 (6a)
C6H5 (6b)
3-CH3C6H4 (6c)
4-ClC6H4 (6i)
4-ClC6H4 (6i)
3a, 60
4a, 32
4b, 40
4c, 35
4i, 26
4i, 36
–
–
–
–
3c, 42
3b, 50
3d, 63
3c, 55
3e, 68
4
–
–
–
–
–
5i, 23
5i, 33
5j, 39
5j, 49
5k, 35
3f, 70
5[c]
6
–
–
–
–
–
4-NO2C6H4 (6j)
4-NO2C6H4 (6j)
benzothiazol-2-yl (6k)
–
7[d]
8[d]
–
–
9
10
11
5i, 24
5j, 45
5k, 26
[a] Reaction conditions: 6 (1 mmol), 1 (2.5 equiv.), CuBr (30 mol-
%), phen·H2O (30 mol-%), tBuOLi (2 equiv.), DDQ(30 mol-%),
–
[a] Reaction conditions: 2a (1 mmol), 1 (5 equiv.), CuBr (30 mol- DMSO (5 mL), 60 °C, 1 atm of O2. [b] Isolated yield. [c] Without
%), phen·H2O (30 mol-%), tBuOLi (2 equiv.), DDQ(30 mol-%),
DMSO (5 mL), 4–8 h. [b] Isolated yield.
DDQ. [d] Without DDQ, and tBuOK(2 equiv.) was used instead of
tBuOLi.
Eur. J. Org. Chem. 2012, 1953–1959
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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1955

C. Yu, C. Zhang, X. Shi
FULL PAPER
Scheme 1. Preliminary mechanistic study.
More experiments were carried out to gain preliminary a base and under an atmosphere of O2 to generate interme-
insight into the mechanism of the catalytic reaction. As diate D. Finally, reductive elimination of CuII complex D
shown in Scheme 1, when we carried out the reaction of affords products 4 and CuIA, which is oxidized to CuI by
pentafluorobenzene (1) with 1,2-bis(p-tolyl)disulfane (2a) in oxygen.
the presence of CuBr (30 mol-%), phen·H2O (30 mol-%),
tBuOLi (2 equiv.), and DDQ (1 equiv.) at 60 °C under an
atmosphere of oxygen, no reaction occurred. Furthermore,
in the absence of DDQ, product 4a was isolated in high
yield (95%). In the presence of 30 mol-% of DDQ at 60 °C
for 21 h, 4a was obtained in only 38% yield, and when the
temperature was increased to 120 °C, 4a was obtained in
45% yield. Otherwise, under the same reaction conditions,
CuBr (30 mol-%), phen·H2O (30 mol-%), tBuOLi (2 equiv.)
but without of DDQ, 4i could be obtained in the presence
of 5i and 2i. These results indicated that bisarylthiolation
products could be formed from monoarylthiolation prod-
ucts, DDQ may serve an important role in the reaction,
diaryl disulfides were very stable in the presence of 1 equiv.
of DDQ, and the monoarylthiolation products could be ob-
tained with an appropriate amount of DDQ.[9b]
It is known that pentafluorophenylcopper phenanthrol-
ine complex can be synthesized.[5b] The cooper-catalyzed
Scheme 2. Plausible mechanism.
method may contain a notable mode of C–H and C–F acti-
vation by a transition-metal catalyst.[5a] On the basis of the
experimental results, it is reasonable to assume a plausible
pathway for the thiolation reaction of diaryl disulfides with
pentafluorobenzene, as shown in Scheme 2. In step i, com-
plex A reacts with the diaryl disulfides to provide intermedi-
Conclusions
ate B. In step ii, deprotonation of pentafluoro-
In conclusion, we have demonstrated a novel Cu-cata-
benzene (Ar-H) is promoted by base or DDQ followed by lyzed reaction of pentafluorobenzene with diaryl disulfides
cupration through transmetalation, and activation of the or aryl thiols by C–H bond and C–F bond activation. This
C–F bond at the C-4 position is promoted by base. In this reaction proceeds under mild conditions and tolerates some
step, DDQ may serve an important role, and 3 is formed as functional groups, and substrates are strongly influential on
the main product with DDQ. This substrate has a strong the reaction products. Moreover, this is new methodology
influence on the reaction product and the exclusive forma- for the construction of polyfluorinated diaryl sulfides and
tion of 5 can be obtained only in certain cases. Then, in polyfluorinated triaryl bisulfides. Ongoing work seeks to
step iii, complex C reacts with pentafluorobenzene and develop related C–H and C–F bond-cleavage processes un-
monoarylthiolation product 3 or 5 under the promotion of der oxidative copper–oxygen catalysis.
1956
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Eur. J. Org. Chem. 2012, 1953–1959

Cu-Catalyzed Direct Thiolation of Pentafluorobenzene with Diaryl Disulfides
with ethyl acetate (30 mL). The filtrate was washed with brine. The
Experimental Section
organic phase was dried with Na2SO4, filtered, and concentrated
under reduced pressure. The residue was then purified by column
chromatography on silica gel (petroleum ether) to provide the cor-
responding product.
General Information: All reagents unless otherwise noted were ob-
tained from commercial sources (purity Ͼ99%) and used without
further purification. The reactions were carried out under an oxy-
gen atmosphere, and the products were isolated by column
chromatography on silica gel (200–300 mesh or 300–400 mesh) by
using petroleum ether (60–90 °C) and ethyl acetate as eluents. Melt-
ing points were determined using a Büchi B-540 capillary melting
point apparatus. 1H NMR and 13C NMR spectra were recorded
with Varian (400 MHz) instrument by using CDCl3 as the solvent,
and chemical shifts are expressed in parts per million (ppm) by
using TMS as an internal standard. Mass spectra were measured
with a Finnigan Trace DSQ instrument or a GCT Premier mass
spectrometer. High-resolution mass spectral (HRMS) analyses were
measured with an APEX (Bruker) mass III spectrometer or GC
Premier mass spectrometer by using ESI or EI techniques. Silica gel
for column chromatography was purchased from Qingdao Haiyang
Chemical Co., Lt. All yields described herein are the isolated yields
after column chromatography.
General Procedure for the Reaction of (4-Chlorophenyl)(2,3,5,6-
tetrafluorophenyl)sulfane (5i) and 1,1Ј-Disulfanediyl[bis(4-chloro-
benzene)] (2i): To
a solution of CuBr (30 mol-%), 1,10-
phenanthroline·H2O (30 mol-%), tBuOLi (2 equiv.), and DMSO
(5 mL) was added 2i (1 mmol). The mixture was stirred for 2 h at
room temperature. Then, the reaction flask was evacuated and re-
filled with O2 three times. Subsequently, 5i (1 equiv.) was added
under an oxygen flow. The mixture was stirred under an O2 atmo-
sphere at the indicated temperature for a given time and then co-
oled to room temperature. Upon completion, the reaction mixture
was diluted with ethyl acetate (10 mL), filtered through a pad of
silica gel, followed by washing the silica gel pad with ethyl acetate
(30 mL). The filtrate was washed with brine. The organic phase
was dried with Na2SO4, filtered, and concentrated under reduced
pressure. The residue was then purified by column chromatography
on silica gel (petroleum ether) to provide the corresponding prod-
uct.
General Procedure for the Reaction of Pentafluorobenzene and Di-
aryl Disulfides: To
a solution of CuBr (30 mol-%), 1,10-
phenanthroline·H2O (30 mol-%), DDQ (30 mol-%), tBuOLi
(2 equiv.), and DMSO (5 mL) was added the disulfide (1 mmol).
The mixture was stirred for 2–3 h at room temperature. Then the
reaction flask was evacuated and refilled with O2 three times. Sub-
sequently, pentafluorobenzene (5 equiv.) was added under an oxy-
gen flow. The mixture was stirred at the indicated temperature un-
der an atmosphere of oxygen for a given time and cooled to room
temperature. Upon completion, the reaction mixture was diluted
with ethyl acetate (10 mL), filtered through a pad of silica gel, fol-
lowed by washing the silica gel pad with ethyl acetate (30 mL). The
filtrate was washed with brine. The organic phase was dried with
Na2SO4, filtered, and concentrated under reduced pressure. The
residue was then purified by column chromatography on silica gel
(petroleum ether/ethyl acetate) to provide the corresponding prod-
uct.
(Perfluorophenyl)(p-tolyl)sulfane (3a): Colorless oil. CAS: 16495-78-
6.[18] 1H NMR (400 MHz, CDCl3): δ = 7.28 (d, J = 8.0 Hz, 2 H),
7.08 (d, J = 8.0 Hz, 2 H), 2.31 (s, 3 H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 148.45 (m), 145.99 (m), 142.93 (m), 140.45 (m), 138.81
(m), 138.36, 136.38 (m), 131.32, 130.00, 129.03, 109.72 (m),
21.20 ppm. 19F NMR (376 MHz, CDCl3): δ = –132.16 to –132.28
(m, 2 F), –151.87 (m, 1 F), –160.42 to –160.62 (m, 2 F) ppm. MS
(EI): m/z = 290 [M]+.
(Perfluorophenyl)(phenyl)sulfane (3b): Colorless oil. CAS: 16496-09-
6.[20a] 1H NMR (400 MHz, CDCl3): δ = 7.34 (m, 2 H), 7.27 (m, 3
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 148.58 (m), 146.12 (m),
143.19 (m), 140.61 (m), 138.90 (m), 136.39 (m), 132.78, 130.42,
129.25, 127.83, 108.90 (m) ppm. 19F NMR (376 MHz, CDCl3): δ
= –131.28 (m, 2 F), –151.25 (m, 1 F), –160.26 (m, 2 F) ppm. GC–
MS (EI): m/z = 276 [M]+.
(Perfluorophenyl)(m-tolyl)sulfane (3c): Colorless oil. 1H NMR
(400 MHz, CDCl3): δ = 7.19–7.11 (m, 3 H), 7.06 (d, J = 8.0 Hz, 1
H), 2.31 (s, 3 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 148.59
(m), 146.14 (m), 143.07 (m), 140.49 (m), 138.83 (m), 136.36 (m),
132.45, 130.98, 129.05, 128.72, 127.47, 109.13 (m), 21.36 ppm. 19F
NMR (376 MHz, CDCl3): δ = –131.85 (m, 2 F), –151.41 (m, 1 F),
–160.25 to –160.42 (m, 2 F) ppm. GC–MS (EI): m/z = 290 [M]+.
HRMS (EI): calcd. for C13H7F5S [M]+ 290.0189; found 290.0175.
(Perfluorophenyl)(o-tolyl)sulfane (3d): Colorless oil. 1H NMR
(400 MHz, CDCl3): δ = 7.21–7.12 (m, 3 H), 7.09 (m, 1 H), 2.47 (s,
3 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 148.51 (m), 146.06
(m), 142.87 (m), 140.36 (m), 139.01 (m), 138.76, 136.39 (m), 131.73,
130.89, 130.59, 127.98, 126.74, 108.84 (m), 20.53 ppm. 19F NMR
(376 MHz, CDCl3): δ = –131.98 (m, 2 F), –151.69 (m, 1 F), –160.35
(m, 2 F) ppm. GC–MS (EI): m/z = 290 [M]+. HRMS (EI): calcd.
for C13H7F5S [M]+ 290.0189; found 290.0238.
General Procedure for the Reaction of Pentafluorobenzene and Aryl
Thiols: To
a
solution of CuBr (30 mol-%), 1,10-
phenanthroline·H2O (30 mol-%), DDQ (30 mol-%), tBuOLi
(2 equiv.), and DMSO (5 mL) was added aryl thiol (1 mmol). Sub-
sequently, pentafluorobenzene 1 (5 equiv.) was added under an O2
atmosphere. The mixture was stirred under an O2 atmosphere at
the indicated temperature for a given time and then cooled to room
temperature. Upon completion, the reaction mixture was diluted
with ethyl acetate (10 mL), filtered through a pad of silica gel, fol-
lowed by washing the silica gel pad with ethyl acetate (30 mL). The
filtrate was washed with brine. The organic phase was dried with
Na2SO4, filtered, and concentrated under reduced pressure. The
residue was then purified by column chromatography on silica gel
(petroleum ether/ethyl acetate) to provide the corresponding prod-
uct.
General Procedure for the Reaction of (Perfluorophenyl)(p-tolyl)-
sulfane (3a) with 1,2-Bis(p-tolyl)disulfane (2a): To a solution of
CuBr (30 mol-%), 1,10-phenanthroline·H2O (30 mol-%), tBuOLi
(2 equiv.), and DMSO (5 mL) was added 2a (1 mmol). The mixture
was stirred for 2 h at room temperature. Then, the reaction flask
was evacuated and refilled with O2 three times. Subsequently, 3a
(1 equiv.) was added under an oxygen flow. The mixture was stirred
under an O2 atmosphere at the indicated temperature for a given
time and then cooled to room temperature. Upon completion, the
reaction mixture was diluted with ethyl acetate (10 mL), filtered
through a pad of silica gel, followed by washing the silica gel pad
1
(2,4-Dimethylphenyl)(perfluorophenyl)sulfane (3e): Colorless oil. H
NMR (400 MHz, CDCl3): δ = 7.16 (d, J = 8.0 Hz, 1 H), 7.02 (s, 1
H), 6.93–6.88 (m, 1 H), 2.43 (s, 3 H), 2.28 (s, 3 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 148.37 (m), 145.91 (m), 142.62 (m), 140.08
(m), 139.40, 138.84 (m), 138.58, 136.33 (m), 132.28, 131.44, 127.93,
127.51, 109.72 (m), 21.05, 20.51 ppm. 19F NMR (376 MHz,
CDCl3): δ = –132.37 to –132.49 (m, 2 F), –152.42 (m, 1 F), –160.54
to –160.72 (m, 2 F) ppm. GC–MS (EI): m/z = 304 [M]+. HRMS
(EI): calcd. for C14H9F5S [M]+ 304.0345; found 304.0342.
Eur. J. Org. Chem. 2012, 1953–1959
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1957

C. Yu, C. Zhang, X. Shi
FULL PAPER
(4-Methoxyphenyl)(perfluorophenyl)sulfane (3f): Colorless oil. CAS:
57517-98-3.[19] 1H NMR (400 MHz, CDCl3): δ = 7.42 (d, J =
H), 7.14 (d, J = 8.0 Hz, 2 H), 7.05 (d, J = 8.0 Hz, 2 H), 6.98 (m, 2
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 163.77, 161.29, 148.05
8.0 Hz, 2 H), 6.84–6.78 (m, 2 H), 3.78 (s, 3 H) ppm. 13C NMR (m), 145.58 (m), 134.35 (d, J = 7.0 Hz), 130.53 (d, J = 8.0 Hz),
(100 MHz, CDCl3): δ = 160.02, 148.25 (m), 145.81 (m), 142.73 (m),
125.94 (d, J = 2.0 Hz), 117.30 (d, J = 23.0 Hz), 115.06 (d, J =
140.16 (m), 138.79 (m), 136.25 (m), 134.48, 122.66, 114.80, 110.60
21.0 Hz) ppm. 19F NMR (376 MHz, CDCl3): δ = –111.32 (m, 2 F),
(m), 55.34 ppm. 19F NMR (376 MHz, CDCl3): δ = –132.83 (m, 2 –131.40 (s, 4 F) ppm. GC–MS (EI): m/z = 402 [M]+. HRMS (EI):
F), –152.32 (m, 1 F), –160.55 to –160.73 (m, 2 F) ppm. GC–MS
calcd. for C18H8F6S2 [M]+ 401.9972; found 401.9972.
(EI): m/z = 306 [M]+.
1,4-Bis(4-chlorophenylthio)-2,3,5,6-tetrafluorobenzene (4i): White
solid, m.p. 164–166 °C, CAS: 122127-55-3.[19] 1H NMR (400 MHz,
CDCl3): δ = 7.35–7.30 (m, 4 H), 7.26 (m, 4 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 147.88 (m), 145.40 (m), 134.43, 132.48,
131.47, 129.46, 115.15 (m) ppm. 19F NMR (376 MHz, CDCl3): δ
= –131.96 (s, 4 F) ppm. MS (EI): m/z = 434 [M]+.
1,4-Bis(p-tolylthio)-2,3,5,6-tetrafluorobenzene (4a): White solid,
m.p. 119–120 °C, CAS: 55677-92-4.[20b] 1H NMR (400 MHz,
CDCl3): δ = 7.30 (d, J = 8.0 Hz, 4 H), 7.08 (d, J = 8.0 Hz, 4 H),
2.31 (s, 6 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 147.90 (m),
145.44 (m), 138.40, 131.64, 130.01, 128.74, 115.59 (m), 21.28 ppm.
19F NMR (376 MHz, CDCl3): δ = –132.75 (s, 4 F) ppm. MS(EI):
m/z = 394 [M]+.
(4-Chlorophenyl)(2,3,5,6-tetrafluorophenyl)sulfane (5i): White solid,
1
m.p. 61–63 °C. H NMR (400 MHz, CDCl3): δ = 7.32–7.22 (m, 4
1,4-Bis(phenylthio)-2,3,5,6-tetrafluorobenzene (4b): White solid,
m.p. 104–106 °C, CAS: 2712-34-7.[19] 1H NMR (400 MHz, CDCl3):
δ = 7.40–7.34 (m, 4 H), 7.31–7.24 (m, 6 H) ppm. 13C NMR
(100 MHz, CDCl3): δ = 147.97 (m), 145.51 (m), 132.36, 130.78,
129.20, 127.89, 115.10 (m) ppm. 19F NMR (376 MHz, CDCl3): δ
= –132.17 (s, 4 F) ppm. GC–MS (EI): m/z = 366 [M]+
H), 7.15–7.04 (m, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ =
147.86 (d, J = 13.0 Hz), 147.14 (m), 145.40 (d, J = 13.0 Hz), 144.68
(m), 134.06, 132.82, 131.91, 129.36, 114.44 (m), 107.12 (m) ppm.
19F NMR (376 MHz, CDCl3): δ = –132.85 (m, 2 F), –137.26 to
–137.45 (m, 2 F) ppm. GC–MS (EI): m/z = 292 [M]+. HRMS (EI):
calcd. for C12H5F4SCl [M]+ 291.9737; found 291.9724.
1,4-Bis(m-tolylthio)-2,3,5,6-tetrafluorobenzene (4c): White solid,
m.p. 78–80 °C. H NMR (400 MHz, CDCl3): δ = 7.21–7.13 (m, 6
(4-Nitrophenyl)(2,3,5,6-tetrafluorophenyl)sulfane (5j): Yellow solid,
m.p. 93.7–95.2 °C. 1H NMR (400 MHz, CDCl3): δ = 8.14–8.10 (m,
2 H), 7.29 (m, 2 H), 7.27–7.21 (m, 1 H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 148.01 (d, J = 11.0 Hz), 147.26 (m), 146.19, 145.55
(m), 144.76 (m), 142.45, 127.60, 124.19, 111.15 (m), 108.54
(m) ppm. 19F NMR (376 MHz, CDCl3): δ = –131.50 (m, 2 F),
–136.05 to –136.24 (m, 2 F) ppm. MS (EI): m/z = 303 [M]+. HRMS
(EI): calcd. for C12H5NO2F4S [M]+ 302.9977; found 302.9986.
1
H), 7.06 (m, 2 H), 2.30 (s, 6 H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 148.04 (m), 145.56 (m), 139.15, 132.14, 131.39, 129.01, 128.80,
127.88, 115.26 (m), 21.35 ppm. 19F NMR (376 MHz, CDCl3): δ =
–132.25 (s, 4 F) ppm. GC–MS (EI): m/z = 394 [M]+. HRMS (EI):
calcd. for C20H14F4S2 [M]+ 394.0473; found 394.0472.
1,4-Bis(o-tolylthio)-2,3,5,6-tetrafluorobenzene (4d): White solid,
m.p. 107–109 °C. 1H NMR (400 MHz, CDCl3): δ = 7.23 (d, J =
4.0 Hz, 2 H), 7.18 (m, 4 H), 7.12–7.06 (m, 2 H), 2.46 (s, 6 H) ppm.
13C NMR (100 MHz, CDCl3): δ = 147.90 (m), 145.44 (m), 139.13,
131.55, 131.35, 130.57, 128.15, 126.70, 114.79 (m), 20.65 ppm. 19F
NMR (376 MHz, CDCl3): δ = –132.73 (s, 4 F) ppm. GC–MS (EI):
m/z = 394 [M]+. HRMS (EI): calcd. for C20H14F4S2 [M]+ 394.0473;
found 394.0493.
2-(2,3,5,6-Tetrafluorophenylthio)benzo[d]thiazole (5k): Yellow solid,
m.p. 74.2–75.2 °C. 1H NMR (400 MHz, CDCl3): δ = 7.87 (m, 1
H), 7.74–7.70 (m, 1 H), 7.45–7.39 (m, 1 H), 7.35–7.25 (m, 2
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 162.04, 152.94, 148.13
(m), 147.18 (m), 145.63 (m), 144.68 (m), 135.52, 126.29, 124.94,
122.26, 120.86, 109.96 (m), 109.11 (m) ppm. 19F NMR (376 MHz,
CDCl3): δ = –130.64 (m, 2 F), –136.31 to –136.46 (m, 2 F) ppm.
MS (ESI): m/z = 316 [M]+. HRMS (EI): calcd. for C13H5NF4S2
[M]+ 314.9800; found 314.9794.
1,4-Bis(2,4-dimethylphenylthio)-2,3,5,6-tetrafluorobenzene
(4e):
White solid, m.p. 121–123 °C. 1H NMR (400 MHz, CDCl3): δ =
7.20 (d, J = 8.0 Hz, 2 H), 7.01 (s, 2 H), 6.91 (d, J = 8.0 Hz, 2 H),
2.41 (s, 6 H), 2.28 (s, 6 H) ppm. 13C NMR (100 MHz, CDCl3): δ
= 147.75 (m), 145.29 (m), 139.63, 138.61, 132.70, 131.41, 127.63,
127.47, 115.11 (m), 21.12, 20.63 ppm. 19F NMR (376 MHz,
CDCl3): δ = –133.35 (s, 4 F) ppm. GC–MS (EI): m/z = 422 [M]+.
HRMS (EI): calcd. for C22H18F4S2 [M]+ 422.0786; found 422.0782.
Supporting Information (see footnote on the first page of this arti-
1
cle): Copies of the H NMR, 13C NMR, and 19F NMR spectra.
Acknowledgments
1,4-Bis(4-methoxyphenylthio)-2,3,5,6-tetrafluorobenzene (4f): White
solid, m.p. 109–111 °C, CAS: 1173915-06-4.[20b] 1H NMR
(400 MHz, CDCl3): δ = 7.42 (d, J = 8.0 Hz, 4 H), 6.80 (m, 4 H),
3.77 (s, 6 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 159.96, 147.66
We gratefully acknowledge financial support from the National
Natural Science Foundation of China (20876147) and Zhejiang
Natural Science Foundation (Y4090346).
(m), 145.18 (m), 134.67, 122.34, 116.13 (m), 114.77, 55.41 ppm. 19
F
NMR (376 MHz, CDCl3): δ = –133.52 (s, 4 F) ppm. GC–MS (EI): [1] a) T. Kondo, T. Mitsudo, Chem. Rev. 2000, 100, 3205–3220; b)
m/z = 426 [M]+.
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1,4-Bis(4-fluorophenylthio)-2,3,5,6-tetrafluorobenzene (4g): White
solid, m.p. 115–116 °C. 1H NMR (400 MHz, CDCl3): δ = 7.46–7.41
(m, 4 H), 7.02–6.96 (m, 4 H) ppm. 13C NMR (100 MHz, CDCl3): δ
= 163.89, 161.41, 147.77 (m), 145.30 (m), 134.19 (d, J = 8.0 Hz),
127.11, 116.58, 116.36, 115.66 (m) ppm. 19F NMR (376 MHz,
CDCl3): δ = –112.27 to –112.36 (m, 2 F), –132.63 (s, 4 F) ppm.
GC–MS (EI): m/z = 402 [M]+. HRMS (EI): calcd. for C18H8F6S2
[M]+ 401.9972; found 401.9950.
1,4-Bis(3-fluorophenylthio)-2,3,5,6-tetrafluorobenzene (4h): White
solid, m.p. 74–75 °C. H NMR (400 MHz, CDCl3): δ = 7.28 (m, 2
1
1958
www.eurjoc.org
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2012, 1953–1959

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Received: November 28, 2011
Published Online: February 13, 2012
Eur. J. Org. Chem. 2012, 1953–1959
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1959