Electrocatalytic Oxidant-Free Dehydrogenative C?H/S?H Cross-Coupling

Article abstract of DOI:10.1002/anie.201700012

An environmentally friendly electrocatalytic protocol has been developed for dehydrogenative C?H/S?H cross-coupling. This method enabled C?S bond formation under catalyst- and oxidant-free conditions. Under undivided electrolysis conditions, various aryl/heteroaryl thiols and electron-rich arenes afforded the C?S bond-formation products in 24–99 % yield. A preliminary mechanistic study indicated that the generation of aryl radical cation intermediates is key to the success of this transformation.

Full text of DOI:10.1002/anie.201700012

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201700012
German Edition: DOI: 10.1002/ange.201700012
ꢀ
C S Bond Formation
ꢀ
ꢀ
Electrocatalytic Oxidant-Free Dehydrogenative C H/S H
Cross-Coupling
Pan Wang+, Shan Tang+, Pengfei Huang, and Aiwen Lei*
Abstract: An environmentally friendly electrocatalytic proto-
to generate sulfoxides and sulfones.[10] These problems
ꢀ
ꢀ
ꢀ
col has been developed for dehydrogenative C H/S H cross-
hamper the wide application of direct C S cross-coupling.
ꢀ
coupling. This method enabled C S bond formation under
We envision that the use of electrolysis to drive hydrogen
evolution could provide a solution to the above problems,
since it avoids the use of transition-metal catalysts and
oxidants.
catalyst- and oxidant-free conditions. Under undivided elec-
trolysis conditions, various aryl/heteroaryl thiols and electron-
rich arenes afforded the C S bond-formation products in 24–
99% yield. A preliminary mechanistic study indicated that the
generation of aryl radical cation intermediates is key to the
success of this transformation.
ꢀ
During the past decade, the application of electrochemical
anodic oxidation in synthetic organic chemistry has received
increasing attention.[11] However, only limited examples of
ꢀ
oxidant-free dehydrogenative cross-coupling for C C and
ꢀ
ꢀ
C
S bonds are important structural motifs in various
C N bond formation have been developed, since it is difficult
biologically active molecules and functional materials.[1]
Over the past decades, much attention has been paid to the
development of efficient methods for their formation. The
transition-metal-catalyzed cross-coupling of organic halides/
to control the reaction selectivity under electrochemical
conditions.[12] There is no precedent for electrocatalytic
ꢀ
ꢀ
dehydrogenative C H/S H cross-coupling, possible because
of the ready over-oxidation of thiols/thiophenols. Herein, we
communicate our progress on an electrocatalytic oxidant-free
dehydrogenative C H/S H cross-coupling in a simple undi-
vided cell under constant-current conditions (Scheme 1b).
N-Methylindole (1a) and 4-chlorothiophenol (2a) were
chosen as model substrates to test the reaction conditions. By
using a 12 mA constant current in an undivided four-necked
triflates with thiols/thiophenols is one of the most widely
[2]
ꢀ
ꢀ
ꢀ
applied methods for constructing C S bonds. Various
transition metals, including palladium,[3] copper,[4] nickel,[5]
cobalt,[6] and iron,[7] have been identified as catalysts to
promote these transformations. Direct dehydrogenative
ꢀ
ꢀ
C H/S H cross-coupling is a more attractive approach to
ꢀ
ꢀ
C S bond formation than traditional coupling reactions
bottle, we obtained the C S bond-formation product 3aa in
(Scheme 1a).[8] It is well-known that thiols/thiophenols
(RSH) are very good ligands, which can bind with transition
metals tightly and usually poison transition-metal catalysts.[9]
Furthermore, thiols/thiophenols can be easily over-oxidized
85% yield (Table 1, entry 1). Both increasing and decreasing
the constant current led to a decrease in the reaction yield
(Table 1, entries 2 and 3). As for the choice of electrolyte,
ammonium salts showed decreased reaction efficiency as
Table 1: Effects of reaction parameters.[a]
ꢀ
ꢀ
Scheme 1. Dehydrogenative C H/S H cross-coupling.
Entry
Variation from the standard conditions
Yield [%][b]
1
2
3
4
5
6
7
8
9
none
85
16
53
81
71
60
4
67
25
59
79
n.d.
6 mA instead of 12 mA, 6 h
18 mA instead of 12 mA, 2 h
nBu4NBF4 instead of LiClO4
nBu4NClO4 instead of LiClO4
nBu4NPF6 instead of LiClO4
THF instead of MeCN
MeOH instead of MeCN
C (+)jPt (ꢀ) instead of Pt (+)jPt (ꢀ)
Pt (+)jC (ꢀ) instead of Pt (+)jPt (ꢀ)
under air
[*] P. Wang,[+] S. Tang,[+] P. Huang, Prof. Dr. A. Lei
College of Chemistry and Molecular Sciences
Institute for Advanced Studies (IAS), Wuhan University
Wuhan 430072, Hubei (P.R. China)
E-mail: aiwenlei@whu.edu.cn
Homepage: http://aiwenlei.whu.edu.cn/Main_Website/
Prof. Dr. A. Lei
10
11
12
State Key Laboratory for Oxo Synthesis and Selective Oxidation
Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences
Lanzhou 730000 (P.R. China)
no electric current, under air
[+] These authors contributed equally.
[a] Standard conditions: Pt anode, Pt cathode, constant current=12 mA,
1a (0.50 mmol), 2a (1.0 mmol), LiClO4 (2.0 mmol), MeCN (8.0 mL),
room temperature, 3 h. [b] The yield of 3aa was determined by GC
analysis with biphenyl as the internal standard; n.d.=not detected.
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
http://dx.doi.org/10.1002/anie.201700012.
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
These are not the final page numbers!

Angewandte
Communications
Chemie
compared with lithium perchlorate (Table 1, entries 4–6). The
choice of solvent was also important for this dehydrogenative
3ae). Notably, thiophenols bearing halide substituents were
ꢀ
ꢀ
able to furnish the selective dehydrogenative C H/S H cross-
coupling products in high yields (products 3aa–ac). The
ꢀ
ꢀ
C H/S H cross-coupling reaction. Tetrahydrofuran was not
suitable for this transformation, and methanol afforded the
desired product in lower yield (Table 1, entries 7 and 8). The
effect of the electrode material was also explored. Lower
reaction yields were observed when platinum was replaced
with carbon as either the anode or cathode (Table 1, entries 9
and 10). However, a good reaction yield was still observed
under atmospheric conditions (Table 1, entry 11). No desired
product could be obtained without an electric current under
atmospheric conditions (Table 1, entry 12).
reaction of o-methylthiophenol gave 3af in
a slightly
decreased reaction yield, which might be due to the steric
ꢀ
effect of the methyl group. Benzenethiol afforded the C S
bond-formation product 3ag in 82% yield with a lower
operating current, whereas electron-rich p-methoxythiophe-
nol showed decreased reaction efficiency in this transforma-
tion (product 3ah). The strongly electron withdrawing nitro
group was also tolerated in this transformation, and the
desired product 3ai was obtained in good yield. Other aryl
thiols were also applied as substrates in this transformation. 2-
To demonstrate the utility of this method, we applied
ꢀ
different thiols as substrates in this electrocatalytic oxidant-
Naphthalenethiol afforded the desired C S bond formation
ꢀ
ꢀ
free dehydrogenative C H/S H cross-coupling (Table 2).
Thiophenols bearing electron-neutral substituents at the
para position, such as an isopropyl or methyl group, also
showed good reactivity in this transformation (products 3ad,
product 3aj in 79% yield. Heteroaryl thiols were also suitable
substrates: 2-Mercaptobenzothiazole, 2-mercaptobenzoxa-
zole, and 2-mercaptobenzimidazole all furnished the desired
products 3ak–am in good to high yields. Moreover, 2-
mercaptothiophene and 2-mercaptopyrazine were also able
ꢀ
to give the products of C S bond formation 3an and 3ao,
ꢀ
ꢀ
Table 2: Electrocatalytic oxidant-free dehydrogenative C H/S H cross-
coupling with different thiols.[a]
though with decreased reaction yields. Only trace amounts of
products were detected when aliphatic thiols were employed
as substrates, possibly as a result of over-oxidation of these
relatively unstable thiols.
We next studied the tolerance of the reaction towards
functional groups on the indole moiety (Table 3). Unpro-
tected indole showed slightly lower reaction efficiency than
N-protected indoles (products 3ba and 3ca). N-Methyl-
ꢀ
ꢀ
Table 3: Electrocatalytic oxidant-free dehydrogenative C H/S H cross-
coupling with substituted indoles.[a]
[a] Standard conditions: Pt anode, Pt cathode, constant current=12 mA,
1a (0.50 mmol), 2 (1.0 mmol), LiClO4 (2.0 mmol), MeCN (8.0 mL),
room temperature, N2, 3 h. Isolated yields are shown. [b] Constant
current=6 mA, 6 h. [c] The yield was determined by 1H NMR spectros-
copy with CH2Br2 as the internal standard. [d] A mixture of MeCN
(4.0 mL) and CH2Cl2 (4.0 mL) was used as the solvent.
[a] Standard conditions: Pt anode, Pt cathode, constant current=12 mA,
1 (0.50 mmol), 2a (1.0 mmol), LiClO4 (2.0 mmol), MeCN (8.0 mL),
room temperature, N2, 3 h. Isolated yields are shown. [b] The yield was
determined by H NMR spectroscopy with CH2Br2 as the internal
standard.
1
2
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
indoles bearing methyl and phenyl substituents at the C2
3va). A thiophene bearing an electron-donating methoxy
ꢀ
position showed excellent reactivity and afforded the desired
product in quantitative yield (products 3da and 3ea). The
reaction took place efficiently at the C2 position when the C3
position was substituted with a methyl group (product 3 fa).
Moreover, 5- and 6-methyl substituted indoles were also
suitable for this transformation (products 3ga and 3ha).
Notably, an electron-donating methoxy group at the C5
position led to a higher reaction yield (product 3ia). An
electron-withdrawing ester group was also tolerated well in
this transformation (product 3ja). Halide-substituted indoles
were also tested as substrates and selectively furnished the
group at the C2 position could afford the product of C S bond
formation 3wa at a lower operating current.
We evaluated the scalability of this electrocatalytic
ꢀ
ꢀ
dehydrogenative C H/S H cross-coupling by performing
reactions on a 5 mmol scale. The reaction with N-methyl-
indole smoothly furnished the desired product 3aa (0.8 g) in
60% yield (Scheme 2a). Similarly, a gram-scale reaction
between 2a and trimethoxybenzene afforded the desired
product 3oa (1.1 g) in 69% yield (Scheme 2b). These results
show the great potential of this electrocatalytic dehydrogen-
ative cross-coupling in practical synthesis.
ꢀ
ꢀ
dehydrogenative C H/S H cross-coupling products 3ka–na
in good to high yields.
Besides indoles, other electron-rich arenes were also
ꢀ
ꢀ
applied as substrates in this dehydrogenative C H/S H cross-
coupling reaction (Table 4). The very electron rich benzenes
1,3,5-trimethoxybenzene and 1,3,4-trimethoxybenzene gave
the desired products 3oa and 3pa in 74 and 50% yield,
respectively. Furthermore, N,N-dimethylaniline and its deriv-
atives were found to be reactive under the electrocatalytic
conditions and afforded products 3qa–sa of selective mono-
thiolation in moderate yields. Electron-rich 3,5-dimethoxy-
phenol was also suitable for this transformation and afforded
the thiolation product 3ta in 54% yield. Less electron rich
arenes, such as pentamethylbenzene, showed low reactivity in
this transformation (product 3ua). Electron-rich hetero-
arenes were also tested under the electrolysis conditions.
Scheme 2. Gram-scale synthesis.
ꢀ
For example, 2,5-dimethylpyrrole gave the product of C H
thiolation product at the C3 position in 51% yield (product
To gain an understanding of the reaction mechanism, we
conducted experiments to explore the existence of radical
intermediates. When 1 equivalent of (2,2,6,6-tetramethyl-
piperidin-1-yl)oxy (TEMPO) or butylated hydroxytoluene
(BHT) was added in the reaction between 1a and 2a under
ꢀ
ꢀ
Table 4: Electrocatalytic oxidant-free dehydrogenative C H/S H cross-
coupling with other electron-rich arenes.[a]
ꢀ
the standard conditions, no desired C S bond-formation
product was observed (Scheme 3a). Thus, radical intermedi-
ates are possibly involved under the electrocatalytic con-
ditions. We added an excess amount of triethyl phosphite to
the reaction mixture to trap any radical intermediates.
Interestingly, the indole-phosphorylation product 4a was
obtained in 64% yield, thus suggesting the generation of an
indole radical during the reaction (Scheme 3b).[13]
In a control experiment in the absence of arene substrates,
thiophenol 2a underwent dimerization to afford disulfide 5a
in quantitative yield (Scheme 3c). We performed a sampling
experiment of the reaction between 1a and 2a to further
confirm the role of disulfide 5a in this transformation
(Figure 1a). Interestingly, the product 3aa was formed
slowly, whereas 5a was generated fast but the amount
remained nearly constant during the reaction. Since disulfides
were found to be generated under the standard conditions, the
reaction between 1a and disulfide 5a was conducted under
the standard conditions. When a small amount of methanol
was added as a proton source, 3aa was obtained in 56% yield
under the standard conditions (Scheme 3d). In the next step,
we carried out cyclic voltammetry (CV) experiments to study
the redox potential of the substrates (Figure 1b). An oxida-
tion peak of 2a in acetonitrile was observed at 1.27 V. At the
same time, oxidation peaks of 1a could also be observed
[a] Standard conditions: Pt anode, Pt cathode, constant current=12 mA,
1 (0.50 mmol), 2a (1.0 mmol), LiClO4 (2.0 mmol), MeCN (8.0 mL),
room temperature, N2, 3 h. [b] 1 (0.80 mmol), 2a (0.5 mmol), and LiClO4
(3.0 mmol) were used. [c] The yield was determined by 1H NMR
spectroscopy with CH2Br2 as the internal standard. [d] Constant
current=10 mA, LiClO4 (3.0 mmol).
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
3
These are not the final page numbers!

Angewandte
Communications
Chemie
Scheme 4. Proposed mechanism.
ꢀ
In conclusion, an electrocatalytic dehydrogenative C H/
ꢀ
ꢀ
S H cross-coupling has been developed that enables C S
bond formation under catalyst- and oxidant-free conditions.
Various aryl/heteroaryl thiols and electron-rich arenes were
suitable for this transformation. Importantly, the reaction can
be conducted on a gram scale with good reaction efficiency.
Mechanistically, anodic oxidative generation of an aryl cation
radical was found to be the key to this transformation. Further
application of electrocatalytic dehydrogenative cross-cou-
pling in other useful transformations is under way in our
laboratory.
Scheme 3. Mechanistic studies.
Acknowledgements
This research was supported by the National Natural Science
Foundation of China (21390402, 21520102003), the Ministry
of Science and Technology of China (2012YQ120060), the
Fundamental Research Funds for the Central Universities,
and the Program of Introducing Talents of Discipline to
Universities of China (111 Program).
Figure 1. a) Sampling experiment of the reaction between 1a and 2a.
b) Cyclic voltammetry of 1a and 2a in CH3CN with LiClO4 (0.2m)
under nitrogen at a platinum-disk electrode at a scan rate of
v=0.1 Vsꢀ1
.
Conflict of interest
above 1.28 V. Since the operating voltage ranged from 1.8 to
2.2 V, the oxidation of both substrates was possible under the
standard conditions.
The authors declare no conflict of interest.
ꢀ
ꢀ
On the basis of the above experimental results, a plausible
mechanism for the reaction between 1a and 2a is shown in
Scheme 4. Single-electron-transfer (SET) oxidation of the
thiophenol by the anode leads to the formation of a sulfur
radical, which undergoes rapid dimerization to generate
a disulfide. At the same time, N-methylindole can also be
oxidized by the anode to generate a radical-cation intermedi-
ate. The generated indole radical-cation intermediate can
undergo either direct coupling with the sulfur radical or
radical substitution with the generated disulfide 5a to afford
a hydroindole cation intermediate.[8h] Final deprotonation of
Keywords: C H functionalization · C S bond formation ·
dehydrogenation · electrochemistry · radical cations
[1] a) J. Dumas, D. Brittelli, J. Chen, B. Dixon, H. Hatoum-Mokdad,
G. Kçnig, R. Sibley, J. Witowsky, S. Wong, Bioorg. Med. Chem.
Lett. 1999, 9, 2531; b) R. Paramashivappa, P. Phani Kumar, P. V.
Subba Rao, A. Srinivasa Rao, Bioorg. Med. Chem. Lett. 2003, 13,
657; c) L. Zhang, J. Fan, K. Vu, K. Hong, J.-Y. Le Brazidec, J. Shi,
M. Biamonte, D. J. Busch, R. E. Lough, R. Grecko, Y. Ran, J. L.
Sensintaffar, A. Kamal, K. Lundgren, F. J. Burrows, R. Mans-
field, G. A. Timony, E. H. Ulm, S. R. Kasibhatla, M. F. Boehm, J.
Med. Chem. 2006, 49, 5352; d) W. Huang, G.-F. Yang, Bioorg.
Med. Chem. 2006, 14, 8280; e) G. Smith, G. Mikkelsen, J.
ꢀ
the cation intermediate leads to the formation of the C S
bond-formation product. Concomitant cathodic reduction of
thiophenol leads to the formation of hydrogen gas.
4
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
Eskildsen, C. Bundgaard, Bioorg. Med. Chem. Lett. 2006, 16,
[10] a) G. K. S. Prakash, T. Mathew, C. Panja, G. A. Olah, J. Org.
3981; f) G. La Regina, M. C. Edler, A. Brancale, S. Kandil, A.
Coluccia, F. Piscitelli, E. Hamel, G. De Martino, R. Matesanz,
J. F. Dꢀaz, A. I. Scovassi, E. Prosperi, A. Lavecchia, E. Novellino,
M. Artico, R. Silvestri, J. Med. Chem. 2007, 50, 2865; g) M. C.
Bagley, T. Davis, M. C. Dix, V. Fusillo, M. Pigeaux, M. J.
Rokicki, D. Kipling, J. Org. Chem. 2009, 74, 8336.
Chem. 2007, 72, 5847; b) S. Madabhushi, R. Jillella, V. Sriramoju,
R. Singh, Green Chem. 2014, 16, 3125; c) H. Wang, Q. Lu, C.
Qian, C. Liu, W. Liu, K. Chen, A. Lei, Angew. Chem. Int. Ed.
2016, 55, 1094; Angew. Chem. 2016, 128, 1106.
[11] a) J. B. Sperry, D. L. Wright, Chem. Soc. Rev. 2006, 35, 605; b) J.-
i. Yoshida, K. Kataoka, R. Horcajada, A. Nagaki, Chem. Rev.
2008, 108, 2265; c) A. Jutand, Chem. Rev. 2008, 108, 2300; d) R.
Francke, R. D. Little, Chem. Soc. Rev. 2014, 43, 2492; e) E. J.
Horn, B. R. Rosen, P. S. Baran, ACS Cent. Sci. 2016, 2, 302;
f) E. J. Horn, B. R. Rosen, Y. Chen, J. Tang, K. Chen, M. D.
Eastgate, P. S. Baran, Nature 2016, 533, 77; g) A. Badalyan, S. S.
Stahl, Nature 2016, 535, 406.
[2] a) I. P. Beletskaya, V. P. Ananikov, Chem. Rev. 2011, 111, 1596;
b) C.-F. Lee, Y.-C. Liu, S. S. Badsara, Chem. Asian J. 2014, 9, 706.
[3] a) M. A. Fernꢁndez-Rodrꢀguez, Q. Shen, J. F. Hartwig, J. Am.
Chem. Soc. 2006, 128, 2180; b) M. A. Fernꢁndez-Rodrꢀguez, Q.
Shen, J. F. Hartwig, Chem. Eur. J. 2006, 12, 7782; c) X. Moreau,
J. M. Campagne, G. Meyer, A. Jutand, Eur. J. Org. Chem. 2005,
3749.
[12] a) C. Amatore, C. Cammoun, A. Jutand, Adv. Synth. Catal. 2007,
349, 292; b) A. Kirste, G. Schnakenburg, F. Stecker, A. Fischer,
S. R. Waldvogel, Angew. Chem. Int. Ed. 2010, 49, 971; Angew.
Chem. 2010, 122, 983; c) A. Kirste, B. Elsler, G. Schnakenburg,
S. R. Waldvogel, J. Am. Chem. Soc. 2012, 134, 3571; d) T.
Morofuji, A. Shimizu, J.-i. Yoshida, Angew. Chem. Int. Ed. 2012,
51, 7259; Angew. Chem. 2012, 124, 7371; e) B. Elsler, D.
Schollmeyer, K. M. Dyballa, R. Franke, S. R. Waldvogel,
Angew. Chem. Int. Ed. 2014, 53, 5210; Angew. Chem. 2014,
126, 5311; f) W.-J. Gao, W.-C. Li, C.-C. Zeng, H.-Y. Tian, L.-M.
Hu, R. D. Little, J. Org. Chem. 2014, 79, 9613; g) Z.-W. Hou, Z.-
Y. Mao, H.-B. Zhao, Y. Y. Melcamu, X. Lu, J. Song, H.-C. Xu,
Angew. Chem. Int. Ed. 2016, 55, 9168; Angew. Chem. 2016, 128,
9314; h) S. Lips, A. Wiebe, B. Elsler, D. Schollmeyer, K. M.
Dyballa, R. Franke, S. R. Waldvogel, Angew. Chem. Int. Ed.
2016, 55, 10872; Angew. Chem. 2016, 128, 11031; i) H. Gao, Z.
Zha, Z. Zhang, H. Ma, Z. Wang, Chem. Commun. 2014, 50, 5034;
j) Y. Li, H. Gao, Z. Zhang, P. Qian, M. Bi, Z. Zha, Z. Wang,
Chem. Commun. 2016, 52, 8600.
[4] a) Y.-J. Chen, H.-H. Chen, Org. Lett. 2006, 8, 5609; b) L. Rout,
T. K. Sen, T. Punniyamurthy, Angew. Chem. Int. Ed. 2007, 46,
5583; Angew. Chem. 2007, 119, 5679; c) P.-F. Larsson, A. Correa,
M. Carril, P.-O. Norrby, C. Bolm, Angew. Chem. Int. Ed. 2009, 48,
5691; Angew. Chem. 2009, 121, 5801; d) Y. Jiang, Y. Qin, S. Xie,
X. Zhang, J. Dong, D. Ma, Org. Lett. 2009, 11, 5250.
[5] Y. Zhang, K. C. Ngeow, J. Y. Ying, Org. Lett. 2007, 9, 3495.
[6] Y.-C. Wong, T. T. Jayanth, C.-H. Cheng, Org. Lett. 2006, 8, 5613.
[7] A. Correa, M. Carril, C. Bolm, Angew. Chem. Int. Ed. 2008, 47,
2880; Angew. Chem. 2008, 120, 2922.
[8] a) K. M. Schlosser, A. P. Krasutsky, H. W. Hamilton, J. E. Reed,
K. Sexton, Org. Lett. 2004, 6, 819; b) S. Ranjit, R. Lee, D.
Heryadi, C. Shen, J. E. Wu, P. Zhang, K.-W. Huang, X. Liu, J.
Org. Chem. 2011, 76, 8999; c) C. Dai, Z. Xu, F. Huang, Z. Yu, Y.-
F. Gao, J. Org. Chem. 2012, 77, 4414; d) Y. Liao, P. Jiang, S. Chen,
H. Qi, G.-J. Deng, Green Chem. 2013, 15, 3302; e) Y. Liu, Y.
Zhang, C. Hu, J.-P. Wan, C. Wen, RSC Adv. 2014, 4, 35528; f) J.
Yuan, X. Ma, H. Yi, C. Liu, A. Lei, Chem. Commun. 2014, 50,
14386; g) S. K. R. Parumala, R. K. Peddinti, Green Chem. 2015,
17, 4068; h) Z. Huang, D. Zhang, X. Qi, Z. Yan, M. Wang, H.
Yan, A. Lei, Org. Lett. 2016, 18, 2351; i) T. Gensch, F. J. R.
Klauck, F. Glorius, Angew. Chem. Int. Ed. 2016, 55, 11287;
Angew. Chem. 2016, 128, 11457.
[13] X.-Y. Jiao, W. G. Bentrude, J. Am. Chem. Soc. 1999, 121, 6088.
[9] a) L. L. Hegedus, R. W. McCabe, Catalyst Poisoning, M. Dekker,
New York, 1984; b) J. R. Chang, S. L. Chang, T. B. Lin, J. Catal.
1997, 169, 338.
Manuscript received: January 2, 2017
Final Article published: && &&, &&&&
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
ꢀ
C S Bond Formation
P. Wang, S. Tang, P. Huang,
A. Lei*
&&&& — &&&&
Electrocatalytic Oxidant-Free
Evolutionary progress: An environmen-
tally friendly electrocatalytic protocol for
use of electrolysis in this way to drive
hydrogen evolution enabled the direct
cross-coupling of a variety of aryl and
heteroaryl thiols with electron-rich arenes
(see scheme).
ꢀ
ꢀ
Dehydrogenative C H/S H Cross-
Coupling
ꢀ
ꢀ
dehydrogenative C H/S H cross-cou-
ꢀ
pling enabled C S bond formation under
catalyst- and oxidant-free conditions. The
6
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!