Copper nanopowder catalyzed cross-coupling of diaryl disulfides with aryl iodides in PEG-400

Article abstract of DOI:10.1055/s-0034-1379878

An eco-friendly thiolation via diaryl disulfides and aryl iodides under ligand-free conditions is reported. With copper nanopowder as catalyst and PEG-400 as solvent, a variety of unsymmetrical diaryl sulfides are synthesized in good to excellent yields. The process is free from foul-smelling and unstable thiols and the copper nanopowder-PEG-400 catalytic system can be directly reused for four repetitive cycles.

Full text of DOI:10.1055/s-0034-1379878

SYNLETT
0
9
3
6
-
5
2
1
4
1
4
3
7
-
2
0
9
6
© Georg Thieme Verlag Stuttgart · New York
2015, 26, 537–542
letter
537
X.-m. Wu, G.-b. Yan
Letter
Synlett
Copper Nanopowder Catalyzed Cross-Coupling of Diaryl Disul-
fides with Aryl Iodides in PEG-400
Xiang-mei Wu*
Guo-bing Yan
nano Cu, KOH
PEG-400
S
I
R2
R1
R1
S
S
+
R2
110 °C,12 h
R2
Department of Chemistry, College of Ecology, Lishui University,
Lishui, Zhejiang 323000, P. R. of China
lswxm7162@163.com
Received: 04.10.2014
Accepted after revision: 16.11.2014
Published online: 07.01.2015
of aryl donors was used. It is noteworthy that diaryl disul-
fides can be conveniently prepared from aryl halides with
elemental sulfur11 and are normally nontoxic and air stable
and easy to handle, and sometimes they maybe play as ac-
tual counterpart in the above-mentioned C–S cross-cou-
pling reactions. Hence, to some extent, the employment of
disulfides as sulfanyl precursors is obviously more advanta-
geous than thiols and their derivatives. Indeed, the transi-
tion-metal-catalyzed thiolation with diaryl disulfides as
sulfur source has been involved but contrary to the inten-
sive studies on the coupling reaction with aryl thiols, only a
few protocols have been developed up to now.12 And very
recently, the direct thiolation of arenes and heteroaromatic
compounds, such as benzoxazole, indole, pyrrole ,and so on,
with diaryl disulfides through C–H activation was also ex-
plored, which represents an atom-economical procedure.13
Nevertheless, in general, some or one of the requirements
that expensive metal sources, such as rhodium and indium,
an appropriate ligand, stoichiometric amount of reductant,
and particularly volatile or toxic organic solvent were nec-
essary in the published reports. Therefore, exploration of
efficient and inexpensive protocols for the C–S bond forma-
tion under environmentally benign conditions is still highly
desirable.
On the other hand, over the past decade, the utilization
of metal nanoparticles which have higher surface area, few-
er coordination sites, and reactive morphologies as efficient
catalysts in organic synthesis has attracted considerable in-
terest.10b,f,j,14 In addition, the development of environmen-
tally benign synthetic procedures is one of the expected
targets in organic chemistry and polyethylene glycol (PEG),
which possess negligible vapor pressure, high boiling point,
and biodegradability, are known to be inexpensive, ther-
mally stable, nontoxic, and recoverable reagent and serve as
an alternative medium for environmentally friendly and
safe chemical reactions.15
DOI: 10.1055/s-0034-1379878; Art ID: st-2014-w0838-l
Abstract An eco-friendly thiolation via diaryl disulfides and aryl io-
dides under ligand-free conditions is reported. With copper nanopow-
der as catalyst and PEG-400 as solvent, a variety of unsymmetrical dia-
ryl sulfides are synthesized in good to excellent yields. The process is
free from foul-smelling and unstable thiols and the copper nanopow-
der–PEG-400 catalytic system can be directly reused for four repetitive
cycles.
Key words diaryl sulfide, diaryl disulfide, aryl iodide, cross-coupling
reaction, copper
Aryl sulfides have proven to be fundamental structural
motifs in numerous biologically and pharmaceutically ac-
tive substances. Truly, a large number of drugs which are
employed for Alzheimer’s disease, Parkinson’s disease, asth-
ma, diabetes, as well as immune and inflammatory diseases
bear this core unit in their backbone structures.1 Moreover,
aryl sulfides also act as effective reagents or valuable inter-
mediates in synthetic chemistry. For instance, sulfur func-
tionality in aryl sulfides can be readily converted into other
useful functional groups like sulfoxides or sulfones, which
exhibit important biological properties such as antifungal,
antibacterial, or antitumor activities.2
Considering the limitation of traditional C(aryl)–S bond
synthetic approaches, which usually required harsh reac-
tion conditions,3 in the last decades, transition-metal cata-
lysts such as palladium,4 nickel,5 copper,6 cobalt,7 and indi-
um8 salts have been widely studied for the cross-coupling
reactions of thiols with aryl halides or aryl boronic acids
and aryl triflates4d,9 to provide aryl sulfides with a variety of
functional groups, and some of these studies have led to the
opening of new and efficient protocols under milder condi-
tions, especially in the presence of copper salts and suitable
ligands or additives. Alternatively, several ligand-free, cop-
per-catalyzed procedures have also been described.10 Un-
fortunately, thiols are foul-smelling and hazardous and
prone to undergo oxidative homocoupling to form diaryl di-
sulfides even in air and inevitably often compete with the
expected cross-coupling products even if an excess amount
Owing to our interest for introducing organic reactions
conducted in green media and with the perspective to en-
rich organosulfur chemistry, herein, we wish to describe an
efficient and environmentally friendly methodology for the
preparation of unsymmetrical diaryl sulfides from diaryl
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 537–542

538
X.-m. Wu, G.-b. Yan
Letter
Synlett
disulfides and aryl iodides using the combination of copper
nanopowder as catalyst and PEG-400 as solvent under
ligand-free conditions.
K2CO3 as base, and PEG-200 as reaction medium in air with-
out external ligands. To our delight, 4-methoxyphenyl phe-
nyl sulfide was obtained in 70% yield at 110 °C for 24 hours.
Based on this result, the reaction conditions were opti-
mized further by taking into considering parameters such
as solvent, catalyst, and base, and the results are summa-
rized in Table 1. Firstly, attempts to perform the reaction in
some conventional organic solvents such as DMSO, DMF,
and NMP were also successful; however, the cross-coupling
products were obtained in slightly low yields compared to
PEG-200 (Table 1, entries 2–4). And small amount of the de-
sired product was found when using toluene or dioxane as
solvent (Table 1, entries 5 and 6). Consequently, PEG-200
seemed to be an alternative and ideal medium for the cross-
coupling reaction, which is exactly in agreement with our
perspective for the search of environmentally friendly and
safe chemical procedures. Due to the chain length of PEG
that had a different influence on the efficiency of metal-
catalyzed reactions, the other polyethylene glycols like
PEG-400, PEG-600, and PEG-1000 were further examined
(Table 1, entries 7–9). PEG-400 was observed to mediate the
reaction most efficiently, furnishing 80% yield, whereas
only low yield of desired product was obtained when eth-
ylene glycol and glycerol were used, although the latter was
an excellent renewable solvent in modern chemical pro-
cesses (Table 1, entries 10 and 11).16 Next, comparison of
different copper sources indicated that copper nanopowder
was superior to the other sources including CuI, CuBr, CuCl,
Cu2O, CuCl2·H2O, Cu(OAc)2·H2O and nano CuO (Table 1, en-
tries 12–18). The catalytic activity of bulk copper powder
was also significantly lower as compared to copper nano-
powder (Table 1, entry 19). Control experiments revealed
that the copper catalyst was crucial for this transformation,
and in the absence of catalyst only a trace amount of the C–
S coupling product was observed from GC–MS (Table 1, en-
try 20). Then, several bases were investigated under the
same reaction conditions, and it was observed that KOH
provided target molecule in an impressive yield, up to 95%,
whereas other bases such as KOt-Bu, K3PO4, NaOH, Cs2CO3,
K2CO3, and MeONa gave only moderate yields (Table 1, en-
tries 21–26). Similarly, only trace of the desired product
was formed without the presence of base (Table 1, entry
27). Although the reaction conducted at 80 °C could obtain
satisfactory yield (Table 1, entry 28), the ideal temperature
for the reaction was found to be 110 °C. A catalyst loading of
5 mol% was optimal as decreasing catalyst loading to 3
mol% reduced the yield to 90%, whereas nearly the same
yield was obtained when 10 mol% of copper nanopowder
was used (Table 1, entry 29). Optimization of the reaction
time showed that the reaction was almost completed with-
in 12 hours at 110 °C as comparable yield was obtained
when the reaction were carried out for 24 hours at the
same temperature. On the basis of these results, it was ob-
vious that the optimal conditions for this copper nanopow-
Table 1 Screening Reaction Conditions for Copper Nanopowder Cata-
lyzed Coupling of 4-Methoxyiodobenzene and Diphenyl Disulfidea
catalyst, base,
solvent
S
I
Ph
S
Ph
+
Ph
S
110 °C, 12 h
MeO
MeO
Entry Cu source
Base
Solvent
Yield (%)b
70
60
55
44
10
15
80
74
55
35
18
55
50
48
42
30
35
55
60
<5
1
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
CuI
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
KOt-Bu
KOH
PEG-200
DMSO
2
3
DMF
4
NMP
5
toluene
6
dioxane
PEG-400
PEG-600
PEG-1000
ethylene glycol
glycerol
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28c
29d
CuBr
CuCl
Cu2O
CuCl2·H2O
Cu(OAc)2·H2O
nano CuO
Cu
–
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
nano Cu
54
95
55
85
72
65
<5
K3PO4
NaOH
Cs2CO3
MeONa
–
KOH
88
90
KOH
a Reaction conditions: 4-methoxyiodobenzene (1.0 mmol), diphenyl disul-
fide (0.5 mmol), catalyst (0.05 mmol), base (2.0 mmol), solvent (2.0 mL),
110 °C, 12 h, in air.
b GC yield.
c Temp: 80 °C.
d Catalyst (0.03 mmol).
In a preliminary experiment, we attempted to observe
the cross-coupling of 4-methoxyiodobenzene and diphenyl
disulfide in the presence of copper nanopowder as catalyst,
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 537–542

539
X.-m. Wu, G.-b. Yan
Letter
Synlett
der catalyzed coupling reaction between diphenyl disulfide
and 4-methoxyiodobenzene were using KOH as base and
PEG-400 as solvent at 110 °C for 12 hours in air.
group, like 4-nitro-1-iodobenzene, gave only moderate
yield, which is similar to the previous results reported by
Taniguchi.14b,c As for the ortho-substituted aryl iodides, the
reactivity decreased probably due to steric hindrance (Table
2, entries 5 and 9). A heterocyclic compound, such as 2-io-
dothiophene, could also afford the corresponding product
in 64% yield under the same optimized conditions (Table 2,
entry 15). In the cases where p- or m-bromoiodobenzene
and chloroiodobenzene were employed, the corresponding
diaryl sulfides were obtained while keeping bromide and
chloride functional groups intact. These results implied
that there was good chemoselectivity between iodide and
bromo or chloro groups under the optimal conditions,
which could extend the scope of further functionalization
on the aromatic ring.
To explore the scope of this procedure, we examined the
cross-coupling of diphenyl disulfide with various substitut-
ed aryl iodides. As expected, the system tolerated a wide
range of functional groups, including methyl, methoxy,
methylthio, fluoro, chloro, bromo, and nitro groups and giv-
ing the corresponding diaryl sulfides in 65–92% yields (Ta-
ble 2, entries 2–14). Furthermore, it is obvious that aryl io-
dides containing electron-withdrawing groups (e.g., F, Cl,
and Br) with diphenyl disulfide to produce the correspond-
ing products in good yields, whereas in the presence of
electron-donating groups (Me, OMe, and SCH3) a slight de-
crease in the yields of diaryl sulfides were observed. How-
ever, aryl iodide with a strong electron-withdrawing nitro
Table 2 C–S Coupling of Aryl Iodides with Diaryl Disulfidesa
nano Cu, KOH
PEG-400
S
I
R2
R1
R1
S
S
+
110 °C, 12 h
R2
R2
Entry
1
Aryl halide
Product
Yield (%)b
89
S
I
I
S
S
2
3
4
86
87
84
I
S
I
MeO
OMe
MeO
I
S
5
70
OMe
MeO
MeS
Br
I
I
MeO
MeS
Br
S
S
6
83
82
90
718
S
I
8
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 537–542

540
X.-m. Wu, G.-b. Yan
Letter
Synlett
Table 2 (continued)
Entry
Aryl halide
Product
Yield (%)b
65
Br
I
S
9
Br
I
S
S
10
91
Br
Br
I
11
12
13
92
90
91
Cl
F
Cl
F
S
I
S
S
F
F
I
S
14
15
16
17
18
19
20
68
64
89
86
85
76
78
O2N
S
O2N
I
S
S
S
I
MeO
MeO
MeO
MeO
MeO
MeO
MeO
MeO
Me
Cl
I
I
I
S
S
S
Br
N
I
I
S
S
N
NH2
21
80
a Reaction conditions: aryl iodides (1.0 mmol), diaryl disulfides (0.5 mmol), nano Cu (0.05 mmol), KOH (2.0 mmol), PEG-400 (2.0 mL), 110 °C, 12 h.
b Isolated yield.
Then we investigated the reaction of various substituted
diaryl disulfides with 4-methoxyiodobenzene under identi-
cal conditions as described above (Table 2, entries 16–21).
Electronic effects had no significant influence on the reac-
tion course and the coupling of diaryl disulfides, with elec-
tron-donating or electron-withdrawing groups like methyl,
chloro, bromo, and amino groups attached to the aromatic
ring, afforded the products with a similar level of efficiency.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 537–542

541
X.-m. Wu, G.-b. Yan
Letter
Synlett
Furthermore, the recyclability of the copper nanopow-
der and PEG-400 was also examined (Table 3). After com-
pletion of the reaction of 4-methoxyiodobenzene and di-
phenyl disulfide, the desired products can be carefully ob-
tained by extraction with diethyl ether, and then the
reaction mixture was subjected to the vacuum for one hour
to eliminate the moisture and trace organic solvents. The
copper nanopowder and PEG-400 were used for the next
trial directly and reaction repeated. Only minor decreases
in product yields were observed through four repetitive cy-
cles.
In summary, an efficient and environmentally friendly
methodology for the C–S coupling of aryl iodides and air-
stable diaryl disulfides using copper nanopowder as cata-
lyst and PEG-400 as solvent under ligand-free conditions
was developed. The copper nanopowder–PEG-400 catalytic
system can be directly reused for four repetitive cycles. Fur-
ther efforts to explore the applications of the transforma-
tion in organic synthesis are currently under way in our
laboratories.
Acknowledgment
Table 3 Reuse of Catalytic System of Nano Cu and PEG-400a
We are grateful for financial support from the Natural Science Foun-
dation of Zhejiang Province (NO. LY13B020005).
Entry
Recycle
Yield (%)b
Supporting Information
1
2
3
4
run 1
run 2
run 3
run 4
95
92
88
85
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0034-1379878.
S
u
p
p
ortiInfogrmoaitn
S
u
p
p
o
nrtogI
f
rmoaitn
a Reaction conditions: 4-methoxyiodobenzene (1.0 mmol), diphenyl disul-
fide (0.5 mmol), nano Cu (0.05 mmol), base (2.0 mmol), solvent (2.0 mL),
References and Notes
110 °C, 12 h, in air.
(1) (a) Marcincal-Lefebvre, A.; Gesquiere, J. C.; Lemer, C. J. Med.
Chem. 1981, 24, 889. (b) Kadlor, S. W.; Kalish, V. J.; Davies, J. F.;
Shetty, B. V.; Fritz, J. E.; Appelt, K.; Burgess, J. A.; Campanale, K.
M.; Chirgadze, N. Y.; Clawson, D. K.; Dressman, B. A.; Hatch, S.
D.; Khalil, D. A.; Kosa, M. B.; Lubbehusen, P. P.; Muesing, M. A.;
Patick, A. K.; Reich, S. H.; Su, K. S.; Tatlock, J. H. J. Med. Chem.
1997, 40, 3979. (c) Nielsen, S. F.; Nielsen, E. O.; Olsen, G. M.;
Liljefors, T.; Peters, D. J. Med. Chem. 2000, 43, 2217. (d) Kondo,
T.; Mitsudo, T. Chem. Rev. 2000, 100, 3205. (e) Liu, G.; Huth, J. R.;
Olejniczak, E. T.; Mendoza, R.; DeVries, P.; Leitza, S.; Reilly, E. B.;
Okasinski, G. F.; Stephen, S. W.; Fesik, W.; von Geldern, T. W. J.
Med. Chem. 2001, 44, 1202. (f) Liu, L. P.; Stelmach, J. E.;
Natarajan, S. R.; Chen, M.-H.; Singh, S. B.; Schwartz, C. D.;
Fitzgerald, C. E.; O’Keefe, S. J.; Zaller, D. M.; Schmatz, D. M.;
Doherty, J. B. Bioorg. Med. Chem. Lett. 2003, 13, 3979. (g) De
Martino, G.; Edler, M. C.; La Regina, G.; Cosuccia, A.; Barbera, M.
C.; Barrow, D.; Nicholson, R. I.; Chiosis, G.; Brancale, A.; Hamel,
E.; Artico, M.; Silvestri, R. J. Med. Chem. 2006, 49, 947.
b GC yield.
Based on our experimental results and proposed mech-
anism reported in the literatures,12j,17 a probable and simple
reaction pathway for the copper nanopowder catalyzed li-
gand-free C–S cross-coupling in PEG-400 was proposed in
Scheme 1.
H
O
H
O
OH
OH
(0)
Cu
Cu(0)
O
H
O
H
Ar1SAr2
Ar1I
H
(2) (a) Suirez, A. R.; Rossi, L. I.; Martin, S. E. Tetrahedron Lett. 1995,
36, 1201. (b) Aldea, R.; Alper, H. J. Org. Chem. 1995, 60, 8365.
(c) Reddy, T. I.; Varma, R. S. Chem. Commun. 1997, 471.
(d) Batigalhia, F.; Zaldini-Hernandes, M.; Ferreira, A. G.;
Malvestiti, I.; Cass, Q. B. Tetrahedron 2001, 57, 9669. (e) Mohile,
S. S.; Potdar, M. K.; Salunkhe, M. M. Tetrahedron Lett. 2003, 44,
1255. (f) Xu, L.; Cheng, J.; Trudell, M. L. J. Org. Chem. 2003, 68,
5388. (g) Iranpoor, N.; Firouzabadi, H.; Pourali, A. R. Synlett
2004, 347. (h) Fukuda, N.; Ikemoto, T. J. Org. Chem. 2010, 75,
4629. (i) Bahrami, K.; Khodaei, M. M.; Arabi, M. S. J. Org. Chem.
2010, 75, 6208. (j) Rostami, A.; Akradi, J. Tetrahedron Lett. 2010,
51, 3501. (k) Rahimizadeh, M.; Rajabzadeh, G.; Khatami, S. M.;
Eshghi, H.; Shiri, A. J. Mol. Catal. A: Chem. 2010, 323, 59.
(l) Maggi, R.; Chitsaz, S.; Loebbecke, S.; Piscopo, C. G.; Sartori,
G.; Schwarzer, M. Green Chem. 2011, 13, 1121. (m) Wu, X. F. Tet-
rahedron Lett. 2012, 53, 4328.
Ar1
(II)
I
O
Cu
O
H
KOH
Ar2SSAr2
H
O
Ar1
(II)
Ar2SK
Cu
+
+ KI
SAr2
O
H
OH
PEG-400
OH
Scheme 1 Plausible mechanism for the cross-coupling
(3) (a) Yamamoto, T.; Sekine, Y. Can. J. Chem. 1984, 62, 1544.
(b) Lindley, J. Tetrahedron 1984, 40, 1433. (c) Hickman, R. J. S.;
Christie, B. J.; Guy, R. W.; White, T. J. Aust. J. Chem. 1985, 38, 899.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 537–542

542
X.-m. Wu, G.-b. Yan
Letter
Synlett
(4) (a) Migita, T.; Shimizu, T.; Asami, Y.; Shiobara, J.-I.; Kato, Y.;
Kosugi, M. Bull. Chem. Soc. Jpn. 1980, 53, 1385. (b) Mann, G.;
Baranano, D.; Hartwig, J. F.; Rheingold, A. L.; Guzei, I. A. J. Am.
Chem. Soc. 1998, 120, 9205. (c) Li, G. Y.; Zheng, G.; Noonan, A. F.
J. Org. Chem. 2001, 66, 8677. (d) Itoh, T.; Mase, T. Org. Lett. 2004,
6, 4587. (e) Mispelaere-Canivet, C.; Jean-Francis Spindler, J.-F.;
Perrioa, S.; Beslin, P. Tetrahedron 2005, 61, 5253. (f) Fernández-
Rodríguez, M. A.; Shen, Q.; Hartwig, J. F. J. Am. Chem. Soc. 2006,
128, 2180. (g) Dahl, T.; Tornøe, C. W.; Bang-Andersen, B.;
Nielsen, P.; Jøgensen, M. Angew. Chem. Int. Ed. 2008, 47, 1726.
(h) Lee, C.-F.; Liu, Y.-C.; Badsara, S. S. Chem. Asian J. 2014, 9, 706.
(5) (a) Cristau, H. J.; Chabaud, B.; Chêne, A.; Christol, H. Synthesis
1981, 892. (b) Percec, V.; Bae, J.-Y.; Hill, D. H. J. Org. Chem. 1995,
60, 6895. (c) Millois, C.; Diaz, P. Org. Lett. 2000, 2, 1705.
(d) Zhang, Y.; Ngeow, K. C.; Ying, J. Y. Org. Lett. 2007, 9, 3495.
(6) (a) Kwong, F. Y.; Buchwald, S. L. Org. Lett. 2002, 4, 3517.
(b) Bates, C. G.; Gujadhur, R. K.; Venkataraman, D. Org. Lett.
2002, 4, 2803. (c) Enguehard-Gueiffier, C.; Thery, I.; Gueiffier,
A.; Buchwald, S. L. Tetrahedron 2006, 62, 6042. (d) Carril, M.;
SanMartin, R.; Dominguez, E.; Tellitu, I. Chem. Eur. J. 2007, 13,
5100. (e) Zhang, H.; Cao, W.; Ma, D. Synth. Commun. 2007, 37,
25. (f) Chen, Y.-J.; Chen, H.-H. Org. Lett. 2006, 8, 5609. (g) Verma,
A. K.; Singh, J.; Chaudhary, R. Tetrahedron Lett. 2007, 48, 7199.
(h) Lv, X.; Bao, W. J. Org. Chem. 2007, 72, 3863.
(7) Wong, Y.-C.; Jayanth, T. T.; Cheng, C.-H. Org. Lett. 2006, 8, 5613.
(8) (a) Reddy, V. P.; Swapna, K.; Kumar, A. V.; Rao, K. R. J. Org. Chem.
2009, 74, 3189. (b) Reddy, V. P.; Swapna, K.; Kumar, A. V.;
Swapna, K.; Rao, K. R. Org. Lett. 2009, 11, 1697.
(9) (a) Zheng, N.; McWilliams, J. C.; Fleitz, F. J.; Armstrong, J. D.;
Volante, R. P. J. Org. Chem. 1998, 63, 9606. (b) Herradura, P. S.;
Pendola, K. A.; Guy, R. K. Org. Lett. 2000, 2, 2019. (c) Savarin, C.;
Srogl, J.; Liebeskind, L. S. Org. Lett. 2002, 4, 4309. (d) Mispelaere-
Canivet, C.; Spindler, J.-F.; Perrio, S.; Beslin, P. Tetrahedron 2005,
61, 5253.
(10) (a) Wu, Y.-J.; He, H. Synlett 2003, 1789. (b) Ranu, B. C.; Saha, A.;
Jana, R. Adv. Synth. Catal. 2007, 349, 2690. (c) Rout, L.; Sen, T. K.;
Punniyamurthy, T. Angew. Chem. Int. Ed. 2007, 46, 5583.
(d) Sperotto, E.; van Klink, G. P. M.; deVries, J. G.; van Koten, G. J.
Org. Chem. 2008, 73, 5625. (e) Rout, L.; Saha, P.; Jammi, S.;
Punniyamurthy, T. Eur. J. Org. Chem. 2008, 640. (f) Gonzalez-
Arellano, C.; Luque, R.; Macquarrie, D. J. Chem. Commun. 2009,
45, 1410. (g) Bhadra, S.; Sreedhar, B.; Ranu, B. C. Adv. Synth.
Catal. 2009, 351, 2369. (h) Chen, C.-K.; Chen, Y.-W.; Lin, C.-H.;
Lin, H.-P.; Lee, C.-F. Chem. Commun. 2010, 46, 282. (i) Kovács, S.;
Novák, Z. Org. Biomol. Chem. 2011, 9, 711. (j) Xu, H. J.; Liang, Y.
F.; Zhou, X. F.; Feng, Y. S. Org. Biomol. Chem. 2012, 10, 2562.
(11) Li, Z.; Ke, F.; Deng, H.; Xu, H.; Xiang, H.; Zhou, X. Org. Biomol.
Chem. 2013, 11, 2943.
(12) (a) Chowdhury, S.; Roy, S. Tetrahedron Lett. 1997, 38, 2149.
(b) Taniguchi, N.; Onami, T. J. Org. Chem. 2004, 69, 915.
(c) Taniguchi, N. J. Org. Chem. 2004, 69, 6904. (d) Ranu, B. C.;
Mandal, T. J. Org. Chem. 2004, 69, 5793. (e) Ajiki, K.; Hirano, M.;
Tanaka, K. Org. Lett. 2005, 7, 4193. (f) Kumar, S.; Engman, L. J.
Org. Chem. 2006, 71, 5400. (g) Taniguchi, N. J. Org. Chem. 2007,
72, 1241. (h) Luo, P. S.; Yu, M.; Tang, R. Y.; Zhong, P.; Li, J. H. Tet-
rahedron Lett. 2009, 50, 1066. (i) Yasuike, S.; Nishioka, M.;
Kakusawa, N.; Kurita, J. Tetrahedron Lett. 2011, 52, 6403.
(j) Wang, H.; Jiang, L.; Chen, T.; Li, Y. Eur. J. Org. Chem. 2010,
2324.
(13) (a) Zhang, S. H.; Qian, P. C.; Zhang, M. L.; Hu, M. L.; Cheng, J. J.
Org. Chem. 2010, 75, 6732. (b) Zou, L. H.; Reball, J.; Mottweiler,
J.; Bolm, C. Chem. Commun. 2012, 48, 11307. (c) Huang, D. Y.;
Chen, J. X.; Dan, W. X.; Ding, J. C.; Liu, M. C.; Wu, H. Y. Adv. Synth.
Catal. 2012, 354, 2123. (d) Ge, W. L.; Wei, Y. Y. Chem. Commun.
2012, 48, 2066. (e) Yu, C. M.; Zhang, C. L.; Shi, X. J. Eur. J. Org.
Chem. 2012, 1953. (f) Prasad, C. D.; Balkrishna, S. J.; Kumar, A.;
Bhakuni, B. S.; Shrimali, K.; Biswas, S.; Kumar, S. J. Org. Chem.
2013, 78, 1434.
(14) (a) Thathagar, M. B.; Beckers, J.; Rothenberg, G. J. Am. Chem. Soc.
2002, 124, 11858. (b) Choudary, B. M.; Kantam, M. L.;
Ranganath, K. V. S.; Mahender, K.; Sreedhar, B. J. Am. Chem. Soc.
2004, 126, 3396. (c) Thathagar, M. B.; Beckers, J.; Rothenberg, G.
Green Chem. 2004, 6, 215. (d) Choudary, B. M.; Ranganath, K. V.
S.; Pal, U.; Kantam, M. L.; Sreedhar, B. J. Am. Chem. Soc. 2005,
127, 13167. (e) Karimi, B.; Abedi, S.; Clark, J. H.; Budarin, V.
Angew. Chem. Int. Ed. 2006, 45, 4776. (f) Rout, L.; Jammi, S.;
Punniyamurthy, T. Org. Lett. 2007, 9, 3397. (g) Su, F.-Z.; Liu, Y.-
M.; Wang, L.-C.; Cao, Y.; He, H.-Y.; Fan, K.-N. Angew. Chem. Int.
Ed. 2008, 47, 334. (h) Laurent, S.; Forge, D.; Port, M.; Roch, A.;
Robic, C.; Vander Elst, L.; Muller, R. N. Chem. Rev. 2008, 108,
2064. (i) Jammi, S.; Sakthivel, S.; Rout, L.; Mukherjee, T.;
Mandal, S.; Mitra, R.; Saha, P.; Punniyamurthy, T. J. Org. Chem.
2009, 74, 1971. (j) Sreedhar, B.; Arundhathi, R.; Reddy, P. L.;
Kantam, M. L. J. Org. Chem. 2009, 74, 7951. (k) Stratakis, M.;
Garcia, H. Chem. Rev. 2012, 112, 4469.
(15) (a) Dicherson, T. J.; Reed, N. N.; Janda, K. D. Chem. Rev. 2002,
102, 3325. (b) Chandraskhar, S.; Narsihmulu, C.; Sultana, S. S.;
Reddy, N. R. Org. Lett. 2002, 4, 4399. (c) Luo, C.; Zhang, Y.; Wang,
Y. J. Mol. Catal. A: Chem. 2005, 229, 7. (d) Chen, J.; Spear, S. K.;
Huddleston, J. G.; Rogers, R. D. Green Chem. 2005, 7, 64. (e) Zhao,
H.; Cheng, M.; Zhang, J.; Cai, M. Green Chem. 2014, 16, 2515.
(f) Feu, K. S.; de la Torre, A. F.; Silva, S.; de Moraes, M. A. F. Jr.;
Corrêa, A. G.; Paixão, M. W. Green Chem. 2014, 16, 3169.
(16) Cintas, P.; Tagliapietra, S.; Calcio Gaudino, E.; Palmisano, G.;
Cravotto, G. Green Chem. 2014, 16, 1056.
(17) She, J.; Jiang, Z.; Wang, Y. Tetrahedron Lett. 2009, 50, 593.
(18) General Procedure
Copper nanopowder (0.05 mmol), aryl iodide (1.0 mmol), diaryl
disulfide (0.5 mmol), KOH (2.0 mmol), and PEG-400 (2.0 mL)
were taken in a 25 mL two-neck flask. The reaction mixture was
stirred at 110 °C for 12 h in air. After cooling to r.t., the product
was diluted with H2O (5 mL) and extracted with EtOAc (4 × 10
mL). The extracts were combined and washed by brine (3 × 10
mL), dried over MgSO4, filtered, evaporated, and purified by
chromatography on silica gel to obtain the desired products
with EtOAc–hexane (v/v = 1:5 to 1:100). The products were
characterized by their spectral and analytical data and com-
pared with those of the known compounds (see Supporting
Information).
Typical Data for Representative Compound – 3-Methylthio-
phenyl Phenyl Sulfide (Table 2, Entry 7)
1H NMR (300 MHz, CDCl3): δ = 7.37–7.07 (m, 9 H), 2.40 (s, 3 H).
13C NMR (75 MHz, CDCl3): δ = 139.8, 137.0, 135.1, 131.5, 129.4,
129.3, 128.0, 127.4, 127.2, 125.0, 15.6. GC–MS (EI): m/z = 232
[M]+. Anal Calcd for C13H12S2: C, 67.20; H, 5.21. Found: C, 67.12;
H, 5.15.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2015, 26, 537–542

Copyright of Synlett is the property of Georg Thieme Verlag Stuttgart and its content may not
be copied or emailed to multiple sites or posted to a listserv without the copyright holder's
express written permission. However, users may print, download, or email articles for
individual use.