Metal- And solvent-free direct C-H thiolation of aromatic compounds with sulfonyl chlorides

Article abstract of DOI:10.1039/c9gc03384j

A simple, efficient and green method for the direct thiolation of aromatic compounds using commercially available sulfonyl chlorides as the sulfur source was developed under metal- and solvent-free conditions. The C-S bond was constructed via direct C-H functionalization of diverse aromatic compounds under an oxygen atmosphere. In this process, various diaryl sulfides were synthesized in moderate to excellent yields. This protocol shows a broad substrate scope and good functional group tolerance. Moreover, a gram-scale experiment was also conducted to prove the prospect of this method for the scale-up synthesis of diaryl sulfides. Mechanistic studies indicate that this procedure probably undergoes a radical pathway.

Full text of DOI:10.1039/c9gc03384j

Green Chemistry
View Article Online
View Journal
PAPER
Metal- and solvent-free direct C–H thiolation of
aromatic compounds with sulfonyl chlorides†
Cite this: DOI: 10.1039/c9gc03384j
b,c
Feng Zhao,
*
a,b Qi Tan,a Dahan Wangb and Guo-Jun Deng
*
A simple, efficient and green method for the direct thiolation of aromatic compounds using commercially
available sulfonyl chlorides as the sulfur source was developed under metal- and solvent-free conditions.
The C–S bond was constructed via direct C–H functionalization of diverse aromatic compounds under an
oxygen atmosphere. In this process, various diaryl sulfides were synthesized in moderate to excellent yields.
This protocol shows a broad substrate scope and good functional group tolerance. Moreover, a gram-scale
experiment was also conducted to prove the prospect of this method for the scale-up synthesis of diaryl
sulfides. Mechanistic studies indicate that this procedure probably undergoes a radical pathway.
Received 28th September 2019,
Accepted 25th November 2019
DOI: 10.1039/c9gc03384j
rsc.li/greenchem
of them are limited due to the employment of expensive and
toxic metals and/or stoichiometric amounts of oxidants (per-
Introduction
Diaryl sulfides are ubiquitous chemical structures that gener- oxides are commonly used). In the pharmaceutical field, trace
ally exist in natural products, biologically active compounds metal impurities should be avoided because of the low
and functional materials.1 As crucial building blocks, diaryl threshold residual tolerance of metals in drug synthesis.
sulfides are employed to treat HIV and cancer as well as Besides, owing to the increasing attention towards the influ-
Parkinson’s and Alzheimer’s diseases.2 Given such importance ence of organic solvents on the environment as well as on the
of diaryl sulfides, plenty of significant reactions have been human body, organic reactions in the absence of classical
developed for the construction of the C–S bond.3
organic solvents have aroused intensive interest of organic
Recently, highly selective and direct functionalization of the researchers.10 Even though a variety of modern solvents have
C–H bond has attracted great attention in both organic and been extensively explored lately,11,12 not employing a solvent at
pharmaceutical fields. The merits of this strategy include its all is undoubtedly the best choice. As a consequence, develop-
high efficiency, low consumption, and little influence on the ment of solvent-free reactions is important.
environment.4,5 From the perspective of environmentally
As the precursor of sodium sulfinates and sulfonyl hydra-
friendly and green chemistry, selective oxidative coupling via zides, sulfonyl chlorides are inexpensive, commercially avail-
direct functionalization of the C–H bond has proved to be an able and easily accessible to generally serve as sulfonylating
efficient and economical route for C–S bond formation. In agents to construct the C–S bond.13 Nevertheless, sulfonyl
these transformations, various novel and practical sulfenylat- chlorides as sulfenylation sources are relatively less studied.14
ing or thiolating reagents, such as thiols,6 disulfides,7 sodium Recently, our group described a series of methodologies for
sulfinates8 and sulfonyl hydrazides,9 have been used well. direct thiolation of the C–H bond under metal-free con-
These methods have been powerful tools for the synthesis of ditions.15 As our continuing interest in this area, herein, we
diaryl sulfides. Despite the advantages of these reactions, most report a simple and convenient method for the synthesis of
diaryl sulfides by direct C–H thiolation of various aromatic
compounds with sulfonyl chlorides under metal- and solvent-
free conditions (Scheme 1).
aKey Laboratory for Antibody-based Drug and Intelligent Delivery System, Biomedical
Research Center of Hunan Province, Key Laboratory of Dong Medicine of Hunan
Province, School of Pharmaceutical Sciences, Hunan University of Medicine, Huaihua
418000, China. E-mail: zhaofenghnmu@163.com
bKey Laboratory for Green Organic Synthesis and Application of Hunan Province, Key
Results and discussion
Laboratory of Environmentally Friendly Chemistry and Application of Ministry of
Screening and optimization of the reaction conditions
Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China.
E-mail: gjdeng@xtu.edu.cn
We started our investigation by choosing 1-methoxynaphtha-
lene (1a) and p-tolylsulfonyl chloride (2a) as the model sub-
strates and using I2 and diethyl phosphite as the additives.
Initially, several iodine additives were examined when the reac-
cBeijing National Laboratory for Molecular Sciences, Chinese Academy of Sciences
(CAS), Beijing 100190, China
†Electronic supplementary information (ESI) available. See DOI: 10.1039/
c9gc03384j
This journal is © The Royal Society of Chemistry 2019
Green Chem.

View Article Online
Paper
Green Chemistry
entry 14). Lower yields were obtained upon decreasing the
reaction temperature or performing the reaction under air
(Table 1, entries 15 and 16).
Substrate scope and scale-up of the reaction
With the optimized reaction conditions in hand, we next set to
investigate the scope of this method. As summarised in
Table 2, a series of arylsulfonyl chlorides bearing electron-
donating groups or electron-withdrawing groups at the para
position were successfully coupled with 1-methoxynaphthalene
(1a) to afford the corresponding diaryl sulfides in moderate to
excellent yields (Table 2, 3aa–3ai). Functional groups at the
ortho or meta position of sulfonyl chlorides were also well tol-
erated under the optimized conditions (Table 2, 3aj–3ap).
Additionally, the reaction of multi- or naphthyl-substituted sul-
fonyl chlorides, which have large steric hindrance, proceeded
smoothly to give the desired products in moderate to high
yields (Table 2, 3aq–3at). It should be noted that the heteroaro-
matic substrate, 3,5-dimethylisoxazole-4-sulfonyl chloride, was
found to react with 1a and provided aryl–heteroaryl sulfide 3au
in good yield.
Under the optimized reaction conditions, we further exam-
ined other aromatic compounds such as ethers and phenols
(Table 3). The reaction of 2-naphthol with p-tolsulfonyl chlor-
ide (2a) gave the corresponding thiolating product in a high
yield. Interestingly, the same results were obtained upon
employing 1-bromo-2-naphthol and 2-tetralone as the sub-
strates (Table 3, 4aa). 2-Methoxynaphthalene and 2-ethoxy-
naphthalene also successfully coupled with 2a to afford 4ab
Scheme 1 Metal- and solvent-free direct C–H thiolation of aromatic
compounds using sulfonyl chlorides.
tion was performed in acetonitrile at 100 °C under an oxygen
atmosphere for 18 hours. Among them, tetramethyl-
ammonium iodide (TMAI) showed the best efficiency to give
the thiolating product 3aa in 74% yield (Table 1, entries 1–5).
Then, different phosphorus reagents such as di-iso-propyl
phosphite, tri-n-butyl phosphine and triphenylphosphine were
used, which were less efficient (Table 1, entries 6–8). Next, we
probed the effect of the solvent on this transformation. When
the reaction was carried out in 1,2-dichloroethane or chloro-
benzene, lower yields of the desired product were obtained
(Table 1, entries 9 and 10). However, strong polar solvents
such as N,N-dimethylformamide and dimethyl sulfoxide were
totally negative for this kind of transformation, as no desired
product was acquired by TLC and GC-MS methods (Table 1,
entries 11 and 12). When the reaction was conducted without
any organic solvents,
a satisfactory result was achieved
(Table 1, entry 13). Upon increasing the amount of 2a to two
equivalents, 3aa was afforded in an excellent yield (Table 1,
Table 1 Optimization of the reaction conditionsa
Table 2 Reaction of 1-methoxynaphthalene with sulfonyl chloridesa
Entry
Additive 1
Additive 2
Solvent
Yieldb (%)
1
2
3
4
5
6
7
8
I2
KI
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(iPrO)2P(O)H
nBu3P
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
DCE
PhCl
DMF
DMSO
Neat
Neat
30
46
52
63
74
55
16
68
62
65
n.d.
n.d.
76
96
58
80
NH4I
TBAI
TMAI
TMAI
TMAI
TMAI
TMAI
TMAI
TMAI
TMAI
TMAI
TMAI
TMAI
TMAI
Ph3P
9
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
(EtO)2P(O)H
10
11
12
13
14c
15c,d
16c,e
Neat
Neat
a Reaction conditions: 1a (0.2 mmol), 2a (0.3 mmol), additive 1
(0.1 mmol), additive 2 (0.4 mmol), 100 °C, 18 h under O2, unless other-
wise noted. b GC yield based on 1a. c 2a (0.4 mmol). d 80 °C. e Under a Reaction conditions: 1 (0.2 mmol), 2a (0.4 mmol), TMAI (0.1 mmol),
air.
(EtO)2P(O)H (0.4 mmol), 100 °C, O2, 18 h. Isolated yield based on 1.
Green Chem.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Green Chemistry
Paper
Table 3 Substrate scopea
Table 4 Substrate scopea
a Reaction conditions: 1 (0.2 mmol), 2a (0.4 mmol), TMAI (0.1 mmol),
(EtO)2P(O)H (0.4 mmol), 100 °C, O2, 18 h. Isolated yield based on 1. PT
= p-Tol. b 2-Tetralone as the substrate. c 1-Bromo-2-naphthol as the
substrate.
a Reaction conditions: 5 (0.2 mmol), 2a (0.4 mmol), TMAI (0.1 mmol),
(EtO)2P(O)H (0.4 mmol), 100 °C, O2, 18 h. Isolated yield based on 5. PT
= p-Tol; Ts = p-tolsulfonyl.
Encouraged by this convenient and effective approach for
the direct synthesis of aryl sulfides, a gram-scale experiment
was executed to testify the potential of this protocol. As shown
in Scheme 2, we conducted the reaction of 1-methoxynaphtha-
lene (1a, 4 mmol) with p-tolsulfonyl chloride (2a, 8 mmol)
under the optimized conditions to afford the corresponding
diaryl sulfide 3aa in good yield, proving the prospect of this
method for the scale-up synthesis of diaryl sulfides.
and 4ac in 52% and 76% yields, respectively. When 2-naphthol
containing a bromo group at the C-6 or C-7 site was subjected
to this reaction system, sulfenylating products were achieved
in good yields without the cleavage of the C–Br bond (Table 3,
4ad–4ae). Notably, 5,6,7,8-tetrahydro-2-naphthol was also com-
patible with this kind of transformation, even though the yield
of the reaction decreased obviously (Table 3, 4af). It is interest-
ing to note that when dihydroxyl naphthalenes were used in
this reaction, some of them generated dithiolating products
(Table 3, 4ag–4aj). To our delight, when we tested this protocol
with 3,5-dimethylphenol, the reaction proceeded well to afford
the target compound 4ak in a moderate yield.
Apart from the above-mentioned substrates, the reaction of
aromatic amines also proceeded smoothly under optimal con-
ditions, and the results are illustrated in Table 4. Various
1-naphthylamine derivatives were successfully coupled with
p-tolsulfonyl chloride (2a) to afford aryl sulfides in moderate to
good yields (Table 4, 6aa–6ad). The reaction of trimethoxy-sub-
stituted aniline with 2a led to the formation of a disulfenyla-
tion compound along with the formation of N-sulfonylated
products (Table 4, 6ae–6af). When N-phenyl-2-naphthylamine
was subjected to this transformation, 6ag was obtained in a
yield of 50%. Subsequently, indole, a versatile building block
in organic and pharmaceutical chemistry, was also compatible
with this method to provide the dithiolation product 6ah at
the C-2 and C-3 positions.
Mechanistic investigations
In order to obtain more information on the reaction mecha-
nism, several control experiments were carried out. When the
model reaction was performed in the absence of TMAI, no
reaction occurred (Scheme 3a). The same result was obtained
when the reaction was carried out without (EtO)2P(O)H
(Scheme 3b). The reaction of 1,2-di-p-tolyldisulfane with 1a did
not afford the desired product 3aa (Scheme 3c). Furthermore,
under standard conditions, the use of 2,2,4,4-tetramethyl-1-
Scheme 2 Gram-scale experiment.
This journal is © The Royal Society of Chemistry 2019
Green Chem.

View Article Online
Paper
Green Chemistry
reductive reagents. Then, ArSCl is attacked by iodide anions to
yield ArSI. Subsequently, an ArS radical intermediate is pro-
duced by the homolysis of ArSI under heating. Finally, this key
radical is added to an arene to give an arene–SAr radical inter-
mediate, which is coupled with ArSI to afford the desired
diaryl sulfide accompanied by the formation of the ArS radical
and HI.
Conclusions
In summary, we have described a metal- and solvent-free meth-
odology for the direct C–H thiolation of aromatic compounds
using readily available arylsulfonyl chlorides as the thiolating
reagents. The C–S bond was constructed via direct C–H
functionalization of various aromatic compounds under an
oxygen atmosphere. The reaction shows a broad substrate
scope and good functional group tolerance. This method pro-
vides a simple, green and economical route for the synthesis
of versatile diaryl sulfides. Mechanistic investigations indicate
Scheme 3 Control experiments.
that
a
radical pathway might be involved in this
transformation.
piperidinyloxy (TEMPO), a radical scavenger, overtly sup-
pressed the formation of 3aa (Scheme 3d), indicating that this
transformation probably undergoes a radical procedure. When
1a was employed without the addition of 2a under optimal
conditions, the homocoupling product of 1a was not observed
by TLC and GC-MS methods (Scheme 3e).
Experimental
General procedure for the synthesis of 3aa
p-Tolsulfonyl chloride (0.4 mmol, if solid) and TMAI
(0.1 mmol) were added to an oven-dried reaction vessel
equipped with a magnetic stirring bar. Then the vessel was
purged with oxygen three times, and p-tolsulfonyl chloride
(0.4 mmol, if liquid), 1-methoxynaphthalene (0.2 mmol) and
(EtO)2P(O)H (0.4 mmol) were added by using a syringe. The
vessel was sealed and stirred at 100 °C for 18 hours. After the
completion of the reaction, the reaction mixture was diluted
with ethyl acetate and washed with saturated sodium thiosul-
fate solution. The organic layer was concentrated under
reduced pressure to yield the crude product, which was puri-
fied by flash chromatography (silica gel, petroleum ether/ethyl
acetate = 50 : 1) to give the desired product 3aa in 90% yield as
a yellow oil.
Based on the above results and previous reports,8a–c,g,14c
a
plausible reaction mechanism is proposed, as shown in
Scheme 4. Firstly, the reduction of arylsulfonyl chloride gener-
ates ArSCl with the assistance of diethyl phosphite or other
For full experimental data, see the ESI.†
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (21801076), Hunan Provincial Natural
Science Foundation of China (2019JJ50415), the Scientific
Research Program of Huaihua (2018N2204) and Hunan
University of Medicine.
Scheme 4 Proposed mechanism.
Green Chem.
This journal is © The Royal Society of Chemistry 2019

View Article Online
Green Chemistry
Paper
15, 3302; (k) Y. Liao, H. Qi, S. Chen, P. Jiang, W. Zhou and
G.-J. Deng, Org. Lett., 2012, 14, 6004; (l) Y.-P. Zhu, M. Lian,
F.-C. Jia, M.-C. Liu, J.-J. Yuan, Q.-H. Gao and A.-X. Wu,
Chem. Commun., 2012, 48, 9086.
Notes and references
1 (a) T. Nakazawa, J. Xu, T. Nishikawa, T. Oda, A. Fujita,
K. Ukai, R. E. P. Mangindaan, H. Rotinsulu, H. Kobayashi
and M. Namikoshi, J. Nat. Prod., 2007, 70, 439;
(b) G. D. Martino, M. C. Edler, G. L. Regina, A. Coluccia,
M. C. Barbera, D. Barrow, R. I. Nicholson, G. Chiosis,
A. Brancale, E. Hamel, M. Artico and R. Silvestri, J. Med.
Chem., 2006, 49, 947.
2 (a) H. Peng, Y. Cheng, N. Ni, M. Li, G. Choudhary,
H. T. Chou, C.-D. Lu, P. C. Tai and B. Wang,
ChemMedChem, 2009, 4, 1457; (b) A. Gangjee, Y. Zeng,
T. Talreja, J. J. McGuire, R. L. Kisliuk and S. F. Queener,
J. Med. Chem., 2007, 50, 3046; (c) T. Oda, T. Fujiwara,
H. Liu, K. Ukai, R. E. P. Mangindaan, M. Mochizuki and
M. Namikoshi, Mar. Drugs, 2006, 4, 15; (d) G. Liu,
J. R. Huth, E. T. Olejniczak, R. Mendoza, P. De Vries,
S. Leitza, E. B. Reilly, G. F. Okasinski, S. W. Fesik and
T. W. von Geldern, J. Med. Chem., 2001, 44, 1202;
(e) S. F. Nielsen, E. O. Nielsen, G. M. Oslen, T. Liljefors and
D. Peters, J. Med. Chem., 2000, 43, 2217.
7 (a) F. Xiao, D. Wang, S. Yuan, H. Huang and G.-J. Deng,
RSC Adv., 2018, 8, 23319; (b) X. Zhu, X. Xie, P. Li, J. Guo
and L. Wang, Org. Lett., 2016, 18, 1546; (c) J.-W. Zeng,
Y.-C. Liu, P.-A. Hsieh, Y.-T. Huang, C.-L. Yi, S. S. Badsara
and C.-F. Lee, Green Chem., 2014, 16, 2644; (d) L. Yang,
Q. Wen, F. Xiao and G.-J. Deng, Org. Biomol. Chem., 2014,
12, 9519; (e) G. Yan, A. J. Borah and L. Wang, Org. Biomol.
Chem., 2014, 12, 9557; (f) S. Guo, Y. Yuan and J. Xiang, Org.
Lett., 2013, 15, 4654; (g) W. Ge and Y. Wei, Green Chem.,
2012, 14, 2066; (h) L.-H. Zou, J. Reball, J. Mottweiler and
C. Bolm, Chem. Commun., 2012, 48, 11307; (i) R.-Y. Tang,
Y.-X. Xie, Y.-L. Xie, J.-N. Xiang and J.-H. Li, Chem. Commun.,
2011, 47, 12867.
8 (a) F. Zhao, Q. Tan, D. Wang, J. Chen and G.-J. Deng, Adv.
Synth. Catal., 2019, 361, 4075; (b) F. Xiao, S. Chen, J. Tian,
H. Huang, Y. Liu and G.-J. Deng, Green Chem., 2016, 18,
1538; (c) Y. Lin, G. Lu, G. Wang and W. Yi, Adv. Synth.
Catal., 2016, 358, 4100; (d) Y. Lin, G. Lu, C. Cai and W. Yi,
Org. Lett., 2015, 17, 3310; (e) D. Wang, R. Zhang, S. Lin,
Z. Yan and S. Guo, RSC Adv., 2015, 5, 108030; (f) F. Xiao,
H. Xie, S. Liu and G.-J. Deng, Adv. Synth. Catal., 2014, 356,
364; (g) Y. Chen, F. Xiao, H. Chen, S. Liu and G.-J. Deng,
RSC Adv., 2014, 4, 44621; (h) P. Katrun, C. Mueangkaew,
M. Pohmakotr, V. Reutrakul, T. Jaipetch, D. Soorukram and
C. Kuhakarn, J. Org. Chem., 2014, 79, 1778; (i) S. Guo,
W. He, J. Xiang and Y. Yuan, Tetrahedron Lett., 2014, 55,
6407; ( j) H. Rao, P. Wang, J. Wang, Z. Li, X. Sun and S. Cao,
RSC Adv., 2014, 4, 49165.
3 For selected reviews, see: (a) C. Shen, P. Zhang, Q. Sun,
S. Bai, T. S. Andy Hor and X. G. Liu, Chem. Soc. Rev., 2015,
44, 291; (b) L. Pan, X. Bi and Q. Liu, Chem. Soc. Rev., 2013,
42, 1251.
4 (a) G. Dyker, Handbook of C-H Transformations, Wiley-VCH,
Weinheim, 2005; (b) R. G. Bergman, Nature, 2007, 446, 391.
5 For selected reviews on C–H functionalization, see:
(a) J. Xie, C. Pan, A. Abdukader and C. Zhu, Chem. Soc. Rev.,
2014, 43, 5245; (b) D. A. Colby, A. S. Tsai, R. G. Bergman
and J. A. Ellman, Acc. Chem. Res., 2012, 45, 814;
(c) C.-L. Sun, B.-J. Li and Z.-J. Shi, Chem. Rev., 2011, 111,
1293; (d) C. S. Yeung and V. M. Dong, Chem. Rev., 2011,
111, 1215; (e) C. Liu, H. Zhang, W. Shi and A. Lei, Chem.
Rev., 2011, 111, 1780; (f) T. W. Lyons and M. S. Sanford,
Chem. Rev., 2010, 110, 1147; (g) C.-J. Li, Acc. Chem. Res.,
2009, 42, 335; (h) O. Daugulis, H. Q. Do and D. Shabashov,
Acc. Chem. Res., 2009, 42, 1074; (i) X. Chen, K. M. Engle,
D. Wang and J.-Q. Yu, Angew. Chem., Int. Ed., 2009, 48,
5094; ( j) L. Ackermann, R. Vicente and A. Kapdi, Angew.
Chem., Int. Ed., 2009, 48, 9792.
9 (a) L. Chen, P. Liu, J. Wu and B. Dai, Tetrahedron, 2018, 74,
1513; (b) D. S. Raghuvanshi and N. Verma, RSC Adv., 2017,
7, 22860; (c) J. Chen, J. Mao, Y. He, D. Shi, B. Zou and
G. Zhang, Tetrahedron, 2015, 71, 9496; (d) S. Guo, W. He,
J. Xiang and Y. Yuan, Chem. Commun., 2014, 50, 8578;
(e) X. Kang, R. Yan, G. Yu, X. Pang, X. Liu, X. Li, L. Xiang
and G. Huang, J. Org. Chem., 2014, 79, 10605; (f) N. Singh,
R. Singh, D. S. Raghuvanshi and K. N. Singh, Org. Lett.,
2013, 15, 5874; (g) R. Singh, D. S. Raghuvanshi and
K. N. Singh, Org. Lett., 2013, 15, 4202; (h) F.-L. Yang and
S.-K. Tian, Angew. Chem., Int. Ed., 2013, 52, 4929.
6 (a) X. Ji, M. Tan, M. Fu, G.-J. Deng and H. Huang, Org.
Biomol. Chem., 2019, 17, 4979; (b) K. D. Jones, D. J. Power,
D. Bierer, K. M. Gericke and S. G. Stewart, Org. Lett., 2018, 10 (a) M. B. Gawande, V. D. B. Bonifácio, R. Luque,
20, 208; (c) Y. Yuan, Y. Chen, S. Tang, Z. Huang and A. Lei,
Sci. Adv., 2018, 4, eaat5312; (d) F. Xiao, S. Yuan, H. Huang
and G.-J. Deng, Synlett, 2018, 2693; (e) F. Xiao, J. Tian,
Q. Xing, H. Huang, G.-J. Deng and Y. Liu, ChemistrySelect,
2017, 2, 428; (f) P. Wang, S. Tang, P. Huang and A. Lei,
P. S. Branco and R. S. Varma, Chem. Soc. Rev., 2013, 42,
5522; (b) M. S. Singh and S. Chowdhury, RSC Adv., 2012, 2,
4547; (c) N. Isambert, M. del M. S. Duque, J.-C. Plaquevent,
Y. Génisson, J. Rodriguez and T. Constantieux, Chem. Soc.
Rev., 2011, 40, 1347.
Angew. Chem., Int. Ed., 2017, 56, 3009; (g) Z. Huang, 11 (a) P. H. Dixneuf and V. Cadierno, Metal-Catalyzed
D. Zhang, X. Qi, Z. Yan, M. Wang, H. Yan and A. Lei, Org.
Lett., 2016, 18, 2351; (h) S. K. R. Parumala and
R. K. Peddinti, Green Chem., 2015, 17, 4068; (i) D. Yang,
Reactions in Water, Wiley-VCH, Weinheim, 2012; (b) C.-J. Li
and T.-H. Chan, Comprehensive Organic Reactions in
Aqueous Media, Wiley, New York, 2007.
K. Yan, W. Wei, J. Zhao, M. Zhang, X. Sheng, G. Li, S. Lu 12 (a) B. Li and P. H. Dixneuf, Chem. Soc. Rev., 2013, 42, 5744;
and H. Wang, J. Org. Chem., 2015, 80, 6083; ( j) Y. Liao,
P. Jiang, S. Chen, H. Qi and G.-J. Deng, Green Chem., 2013,
(b) M.-O. Simon and C.-J. Li, Chem. Soc. Rev., 2012, 41,
1415; (c) C. I. Herrerías, X. Yao, Z. Li and C.-J. Li, Chem.
This journal is © The Royal Society of Chemistry 2019
Green Chem.

View Article Online
Paper
Green Chemistry
Rev., 2007, 107, 2546; (d) C.-J. Li and L. Chen, Chem. Soc.
Rev., 2006, 35, 68.
13 For selected examples, see: (a) L.-Y. Xie, S. Peng, J.-X. Tan,
M. K. Whittlesey and C. G. Frost, J. Am. Chem. Soc., 2011,
133, 19298; (h) X. Zhao, E. Dimitrijević and V. M. Dong,
J. Am. Chem. Soc., 2009, 131, 3466.
R.-X. Sun, X. Yu, N.-N. Dai, Z.-L. Tang, X. Xu and W.-M. He, 14 For selected recent studies, see: (a) W.-H. Bao, M. He,
ACS Sustainable Chem. Eng., 2018, 6, 16976; (b) L.-Y. Xie,
Y.-J. Li, J. Qu, Y. Duan, J. Hu, K.-J. Liu, Z. Cao and W.-M. He,
Green Chem., 2017, 19, 5642; (c) K. Sun, X.-L. Chen, X. Li,
L.-B. Qu, W.-Z. Bi, X. Chen, H.-L. Ma, S.-T. Zhang,
B.-W. Han, Y.-F. Zhao and C.-J. Li, Chem. Commun., 2015, 51,
12111; (d) X. Liu, X. Chen and J. T. Mohr, Org. Lett., 2015,
17, 3572; (e) H. Qiao, S. Sun, F. Yang, Y. Zhu, W. Zhu,
Y. Dong, Y. Wu, X. Kong, L. Jiang and Y. Wu, Org. Lett.,
J.-T. Wang, X. Peng, M. Sung, Z. Tang, S. Jiang, Z. Cao and
W.-M. He, J. Org. Chem., 2019, 84, 6065; (b) D. Wang,
S. Guo, R. Zhang, S. Lin and Z. Yan, RSC Adv., 2016, 6,
54377; (c) X. Zhao, X. Lu, A. Wei, X. Jia, J. Chen and K. Lu,
Tetrahedron Lett., 2016, 57, 5330; (d) M. Chen, Z.-T. Huang
and Q.-Y. Zheng, Chem. Commun., 2012, 48, 11686;
(e) Y. He, Q. Wu, D. Zhao, X. Qin, J. Lan and J. You, Chem.
Commun., 2011, 47, 9188.
2015, 17, 6086; (f) D. Zhang, X. Cui, Q. Zhang and Y. Wu, 15 In previous literature studies, our group has reported a
J. Org. Chem., 2015, 80, 1517; (g) O. Saidi, J. Marafie,
A. E. W. Ledger, P. M. Liu, M. F. Mahon, G. Kociok-Köhn,
series of methods for direct C–H thiolation employing thiols
or sodium sulfinates. See: ref. 6d, e, j, k, 8a, b, f and g.
Green Chem.
This journal is © The Royal Society of Chemistry 2019