Metal- and Reagent-Free Electrochemical Synthesis of Alkyl Arylsulfonates in a Multi-Component Reaction

Article abstract of DOI:10.1002/chem.202001180

This work presents the first electrochemical preparation of alkyl arylsulfonates by direct anodic oxidation of electron-rich arenes. The reaction mechanism features a multi-component reaction consisting of electron-rich arenes, an alcohol of choice and excess SO₂ in an acetonitrile-HFIP reaction mixture. In-situ formed monoalkyl sulfites are considered as key intermediates with bifunctional purpose. Firstly, this species functions as nucleophile and secondly, excellent conductivity is provided. Several primary and secondary alcohols and electron-rich arenes are implemented in this reaction to form the alkyl arylsulfonates in yields up to 73 % with exquisite selectivity. Boron-doped diamond electrodes (BDD) are employed in divided cells, separated by a simple commercially available glass frit.

Full text of DOI:10.1002/chem.202001180

Accepted Article
Accepted Article
Title: Metal- and Reagent-free Electrochemical Synthesis of Alkyl
Arylsulfonates in a Multi-Component Reaction
Authors: Siegfried R Waldvogel, Stephan Blum, Dieter Schollmeyer,
and Maris Turks
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.202001180
Link to VoR: https://doi.org/10.1002/chem.202001180
01/2020

10.1002/chem.202001180
Chemistry - A European Journal
COMMUNICATION
Metal- and Reagent-free Electrochemical Synthesis of Alkyl
Arylsulfonates in a Multi-Component Reaction
Stephan P. Blum,[a] Dieter Schollmeyer,[a] Maris Turks*[b] and Siegfried R. Waldvogel*[a]
Abstract: Herein, we present the first electrochemical preparation of
alkyl arylsulfonates by direct anodic oxidation of electron-rich arenes.
The reaction mechanism features
a multi-component reaction
consisting of electron-rich arenes, an alcohol of choice and excess
SO2 in an acetonitrile-HFIP reaction mixture. In-situ formed monoalkyl
sulfites are considered as key intermediate with bifunctional purpose.
Firstly, this species functions as nucleophile and secondly, excellent
conductivity is provided. Several primary and secondary alcohols and
electron-rich arenes are implemented in this reaction to form the alkyl
arylsulfonates in yields up to 73% with exquisite selectivity. Boron-
doped diamond electrodes (BDD) are employed in divided cells,
separated by a simple commercially available glass frit.
Sulfonate esters are omnipresent in synthetic chemistry,[1] dyes,[2]
materials,[3] drugs and various other bioactive compounds.[4] One
example is the secnidazole sulfonate (1), which proved to exhibit
unique antibacterial and antifungal properties.[5] The drug Busulfan
(2) and Treosulfan (3), are bifunctional DNA alkylating agents and
therefore used in chemotherapy.[6] Additionally, the versatile
reagents methyl triflate (4) and methyl tosylate (5) are employed
as methylation agents.[7] Para-substituted 2,2,2-trifluoro-1-phenyl-
ethyl esters, such as AcOFMB-Dan (6), have been developed for
cytoplasmic delivery of dansyl acid and other dyes into living cells
with subsequent unmasking of the chemically stable sulfonate
ester protecting group by an enzymatic pathway.[2,8] Furthermore,
neopentyl and isopropyl sulfonates in particular have been
successfully applied in multistep synthesis as protection groups for
sulfonic acids and can be cleaved under acidic conditions. Thus,
sulfonate esters can be introduced at an early stage without
dealing with solubility issues in organic solvents, implicated by the
sulfonic acid group.[9] In addition, neopentyl sulfonates are capable
as leaving groups for Ni-catalyzed cross-coupling reactions.[10]
Scheme 2. Comparison and evaluation of different strategies to synthesize alkyl
arylsulfonates. DIPEA = N,N-Diisopropylethylamine.
Traditional strategies in the synthesis of alkyl arylsulfonates
feature the treatment of an arene with chlorosulfonic acid to obtain
the corresponding sulfonyl chloride with subsequent esterification
(scheme 2).[11] However, this two-step synthesis requires harsh
reaction conditions and sulfonyl chlorides are considered sensitive
towards moisture.[12] Furthermore, the regioselectivity is
determined by the inherent reactivity of the substrate, which often
results in mixtures of regioisomers.[11,13] Lei and co-workers
obtained alkyl arylsulfonates directly from the corresponding thiols
by photochemical oxidation. Nevertheless, this approach
comprises several limitations, such as the required
prefunctionalization, the application of an oxygen atmosphere and
the need of a photocatalyst.[14] Another recent approach was
reported by Han and co-workers comprising a Cu-catalyzed
radical reaction of aryl diazonium salts with 1,4-
diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO) as
SO2 source and the desired alcohol in a multi-component
reaction.[15] However, diazonium salts are difficult to handle due to
their sensitivity and explosive nature in their solid state.[16]
Our work implements the metal- and reagent-free electrochemical
synthesis of alkyl arylsulfonates from unfunctionalized electron-
rich arenes with excellent selectivity. Key feature in this one-pot
synthesis is the use of a stock solution of SO2 in acetonitrile with
known concentration, so that no expensive DABSO is required.[17]
Inexpensive electricity is used as oxidant. Electrochemical
reactions comprise the principles of modern green chemistry and
are inherently safe.[18] The benefits of electrosynthesis are further
highlighted in numerous of our research works.[19] The fluorinated
solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)[20] and boron-
doped diamond (BDD) electrodes[21] play a key role in the
Scheme 1. Relevant examples of alkyl sulfonates.
[a]
[b]
S. P. Blum, Dr. D. Schollmeyer, Prof. Dr. S. R. Waldvogel
Department of Chemistry
Johannes Gutenberg-University Mainz
Duesbergweg 10–14, 55128 Mainz (Germany)
E-mail: waldvogel@uni-mainz.de
Prof. Dr. M. Turks
Institute of Technology of Organic Chemistry
Faculty of Materials Science and Applied Chemistry
Riga Technical University
P. Valdena 3, Riga, LV-1048, Latvia
E-mail: maris.turks@rtu.lv
Supporting information for this article is given via a link at the end of the
document.
1
This article is protected by copyright. All rights reserved.

10.1002/chem.202001180
Chemistry - A European Journal
COMMUNICATION
implementation of new electrochemical reactivity. Recently, a
general protocol for the sulfonylation of arenes, phenols and
aniline derivatives was published.[22]
(see supporting information). Neopentyl alcohol was selected due
to the enhanced stability of sulfonate neopentyl esters.[9c,32]
Due to the simple experimental set-up, reaction optimization was
first conducted in undivided cells (table 1). Conductivity of the
electrochemical reaction was improved in an HFIP/MeCN solvent
mixture. Four equivalents of DIPEA and neopentyl alcohol turned
out to be best (entry 1). BDD electrodes proved to be superior in
comparison to other electrode materials (entry 4–7). Interestingly,
the product yield did not improve significantly (entry 8–10) by
application of higher amount of charge.
Sulfur dioxide is utilized as feedstock in chemical industry and
food industry.[23] Synthetic chemistry with SO2 has experienced a
significant boost since the discovery of the reagent DABSO, which
is an easy-to-handle SO2 surrogate.[23a,24] Nevertheless, it is quite
costly and lowers the total atom economy.[25] The usage of a SO2
stock solution is a superior alternative. In fact, SO2 solutions in
aprotic solvents have been applied in electrochemical
transformations featuring the cathodic reduction of SO2.[26] To the
best of our knowledge, anodic reactions involving nonaqueous
SO2 as substrate[27] have not been reported, yet.
Table 2. Optimization of the reaction in divided cells.
Entry
11
Deviation from the standard conditions[a]
None
Yield [%][b]
73
56
64
66
55
70
66
0
12
j = 4.00 mA/cm², 2.50 F
j = 7.00 mA/cm², 2.50 F
j = 11.25 mA/cm², 2.50 F
j = 14.00 mA/cm², 2.50 F
3.25 F
13
14
15
Scheme 3. General reaction scheme for the electrochemical multi-component
synthesis of alkyl arylsulfonates. On the right side: molecular structure of 7a
(determined by X-ray analysis of a suitable single crystal).
16
17
4.00 F
18
No base, 0.2 M [NBu4]+[BF4]−
No electric current
Table 1. Optimization of the reaction in undivided cells.
19
0
Entry
Deviation from the standard conditions[a]
None
Yield [%][b]
20
Only MeCN (no HFIP)
0
1
2
39
32
24
30
40
23
18
45
53
46
[a] Standard conditions: 0.1 M 1,2,3-trimethoxybenzene,
4
eq. neopentyl
2.0 eq. DIPEA and neopentyl alcohol
5.0 eq. DIPEA and neopentyl alcohol
Pt electrodes
alcohol, 4 eq. DIPEA, 15 eq. SO2, HFIP:MeCN = 1:1, r.t., divided cell (frit), BDD
electrodes, constant current, j = 11.25 mA/cm², Q = 3.50 F. [b] Yield determined
by internal NMR standard (1,3,5-trimethoxy-benzene).
3
Higher product yields were obtained by application of a divided
cell (table 2) with a simple commercially available glass frit. The
optimum current density was at 11.25 mA/cm2 (entry 12–15). 3.5
F as amount of charge also gave best results (entry 11, 16, 17).
Omitting of an organic base, HFIP, or no application of electric
current (entry 18–20) resulted in no product formation.
4
5
Pt cathode, BDD anode
Glassy carbon electrodes
Graphite electrodes
3.00 F
6
7
Thereupon, the substrate scope was extended with different
alcohols according to the general reaction shown in scheme 4.
Highest yields were obtained with neopentyl alcohol and 2-
methylpropanol giving substrate 7a with 73% yield and 7b with
69% yield. The molecular structure of 7a was confirmed (scheme
3) for final structural isomer determination. Usage of the simplest
primary alcohols, ethanol and methanol, gave slightly lower yields
(7c, 65% and 7d, 48%). Potential decomposition of the products
could occur during the work-up process due to their minor
stability.[9c] The secondary alcohol isopropanol as reactant
resulted in lower yields (7e, 41%), which can be explained by the
higher steric demand of the isopropyl group. Next, we investigated
the substrate scope of different arenes. The reactivity of 1,4-
dimethoxybenzene was in similar fashion with neopentyl alcohol
and ethanol giving 8a with 58% and 8b with 66% yield. Thus,
further arenes were examined with ethanol as reactant. Substrate
9, 10, and 11 provided comparable yields ranging from 40% to
49%. It is noteworthy to mention, that 10 has a bromo substituent,
which is of high synthetic interest due to potential follow-up
reactions for further functionalization.[33] In general, arenes
bearing methyl groups suffered from lower conversion.
Nevertheless, 12 was isolated with 17% yield. Arenes with higher
oxidation potential resulted in no or very low product formation.
8
9
6.00 F
10
8.00 F
[a] Standard conditions: 0.1 M 1,2,3-trimethoxybenzene,
4
eq. neopentyl
alcohol, 4 eq. DIPEA, 15 eq. SO2, HFIP:MeCN = 1:1, r.t., undivided cell, BDD
electrodes, constant current, j = 12 mA/cm², 2.50 F. [b] Yield determined by
internal NMR standard (1,3,5-trimethoxy-benzene).
The electrochemical synthesis of alkyl arylsulfonates according to
scheme 3 was initially discovered with 1,2,3-trimethoxybenzene
and neopentyl alcohol as substrates in presence of a base and
SO2. At first, the nature of the base was screened.[28] Tertiary
amines, such as TEA or DIPEA turned out to give improved yields
in comparison to heterocyclic bases like DBU. Experimental
details can be retrieved from the supporting information. It is
noteworthy that Olah et al. reported the formation of a tertiary
amine-SO2 complex and the subsequent reaction with oximes,[29]
nitro compounds[30] and pyridine-N-oxide.[31] As mentioned above,
the SO2 source was a freshly prepared stock solution in
acetonitrile. The concentration was determined iodometrically
2
This article is protected by copyright. All rights reserved.

10.1002/chem.202001180
Chemistry - A European Journal
COMMUNICATION
Scheme 6. Proposed mechanism for the generation of monoalkyl sulfites by
addition of an organic base.
According to cyclic voltammetry results (supporting information),
the arene is considered to undergo electrochemical oxidation to
form the radical cation transition state. The monoalkyl sulfite then
undergoes nucleophilic addition as illustrated in scheme 7 to form
the corresponding intermediate adduct. A second oxidation step
then finally provides the alkyl arylsulfonates. SO2 is considered to
be reduced to the SO2 anion radical at the cathode, which was
confirmed via cyclovoltammetry studies (supporting information).
This species is reported to dimerize to dithionite or to undergo the
formation of complex ions with SO2 molecules.[26] Therefore,
divided cells compose the better alternative towards undivided
cells in order to prevent anodic oxidation of these species, which
could explain the low current efficiencies obtained in undivided
cells (table 1, entry 8–10).
Scheme 4. General reaction scheme for the synthesis of alkyl arylsulfonates.
Conditions: HFIP:MeCN = 1:1, r.t., divided cell (frit), BDD electrodes, constant
current, j = 11.25 mA/cm², Q = 3.50 F. The scope of the reaction including
isolated yield are displayed.
Interestingly,
a
competition reaction between 2,2,2-
trifluoroethanol and HFIP was observed (scheme 5). A product
mixture of 13a (12%) and 13b (33%) was isolated. Therefore, we
assume that the nucleophilicity of 2,2,2-trifluoroethanol was not
sufficient so that HFIP was competing to some extent in the
reaction.
Scheme 7. Proposed mechanism for the electrochemical synthesis of alkyl
arylsulfonates. Cathodic and anodic reactions are separated by a dotted line,
which represents the division of the cell by a frit.
Scheme 5. Competition experiment between 2,2,2-trifluroethanol and HFIP.
Conditions: HFIP:MeCN = 1:1, r.t., divided cell (frit), BDD electrodes, constant
current, j = 11.25 mA/cm², Q = 3.50 F.
In summary, we established a new concise electrochemical
methodology to synthesize alkyl arylsulfonates starting from
arenes by a multi-component reaction. A highlight is the in-situ
formation of the monoalkyl sulfite intermediate, which takes the
role as nucleophile and supporting electrolyte. Direct anodic
oxidation of the arene initiates a dehydrogenative reaction
mechanism. More than 11 examples up to 73% yield with a variety
of arenes and different alcohols were implemented.
Due to these results, we conclude that the reaction mechanism
proceeds by an in-situ formed monoalkyl sulfite (scheme 6).
Excess SO2 in presence of an alcohol forms the sulfurous acid
intermediate. Addition of an organic base shifts the equilibrium
towards the monoalkyl sulfite side. Therefore, the presence of a
base is essential for the reaction. However, no additional
supporting electrolyte for the reaction is needed, as the
conductivity given is already sufficient. In fact, a few publications Experimental Section
about monoalkyl sulfites have already been reported,[34] but up to
our knowledge it is the first time that this species is employed as
reactant in organic synthesis.
The anode compartment was charged with the arene substrate
(0.60 mmol). Acetonitrile, SO2 in acetonitrile (30.0 eq.) and the
alcohol (4.80 mmol, 8.0 eq.) were combined in a pear-shaped
flask. The mixture was cooled to 0 °C and N-ethyl-N-
isopropylpropan-2-amine (4.80 mmol, 8.0 eq.) was added
3
This article is protected by copyright. All rights reserved.

10.1002/chem.202001180
Chemistry - A European Journal
COMMUNICATION
[13] a) A. L. Borror, E. Chinoporos, M. P. Filosa, S. R. Herchen, C. P. Petersen,
C. A. Stern, K. D. Onan, J. Org. Chem. 1988, 53, 2047–2052; b) P. R.
Carlier, M. P. Lockshin, M. P. Filosa, J. Org. Chem. 1994, 59, 3232–3236.
[14] A. K. Singh, H. Yi, G. Zhang, C. Bian, P. Pei, A. Lei, Synlett 2017, 28,
1558–1563.
[15] Y. Wang, L. Deng, Y. Deng, J. Han, J. Org. Chem. 2018, 83, 4674–4680.
[16] M. Sheng, D. Frurip, D. Gorman, J. Loss Prevent. Proc. 2015, 38, 114–
118.
[17] a) S. van Mileghem, W. M. de Borggraeve, Org. Process Res. Dev. 2017,
21, 785–787; b) H. Woolven, C. González-Rodríguez, I. Marco, A. L.
Thompson, M. C. Willis, Org. Lett. 2011, 13, 4876–4878.
[18] a) S. R. Waldvogel, S. Lips, M. Selt, B. Riehl, C. J. Kampf, Chem. Rev.
2018, 118, 6706–6765; b) S. Möhle, M. Zirbes, E. Rodrigo, T. Gieshoff, A.
Wiebe, S. R. Waldvogel, Angew. Chem. Int. Ed. 2018, 57, 6018–6041; c)
A. Wiebe, T. Gieshoff, S. Möhle, E. Rodrigo, M. Zirbes, S. R. Waldvogel,
Angew. Chem. Int. Ed. 2018, 57, 5594–5619.
dropwise through a septum. The reaction mixture was stirred for
5 min and HFIP was added slowly at 0 °C under stirring, so that a
total volume of 12.0 mL and a solvent ratio of HFIP:MeCN = 1:1
was obtained. 6 mL of the reaction mixture was transferred into
the cathode compartment and the other half of the electrolyte was
then immediately transferred to the anode compartment of the
divided cell. The electrolysis was conducted at r.t. at galvanostatic
conditions. The reaction mixture was stirred for 14 h in total. The
anolyte and catholyte were combined and the solvents were
distilled at reduced pressure for reutilization. Cold distilled water
(30.0 mL) was added to the remaining reaction mixture, which
was then extracted in ethyl acetate (3 x 30.0 mL). The combined
organic fractions were dried over Na2SO4. The organic solvent
was removed at reduced pressure and the crude product was
[19] a) S. B. Beil, T. Müller, S. B. Sillart, P. Franzmann, A. Bomm, M. Holtkamp,
U. Karst, W. Schade, S. R. Waldvogel, Angew. Chem. Int. Ed. 2018, 57,
2450–2454; b) M. Dörr, S. Lips, C. A. Martínez-Huitle, D. Schollmeyer, R.
Franke, S. R. Waldvogel, Chem. Eur. J. 2019, 25, 7835–7838; c) B. Elsler,
D. Schollmeyer, K. M. Dyballa, R. Franke, S. R. Waldvogel, Angew. Chem.
Int. Ed. 2014, 53, 5210–5213; d) T. Gieshoff, A. Kehl, D. Schollmeyer, K.
D. Moeller, S. R. Waldvogel, J. Am. Chem. Soc. 2017, 139, 12317–12324;
e) T. Gieshoff, D. Schollmeyer, S. R. Waldvogel, Angew. Chem. Int. Ed.
2016, 55, 9437–9440; f) J. D. Herszman, M. Berger, S. R. Waldvogel, Org.
Lett. 2019, 21, 7893–7896; g) Y. Imada, J. L. Röckl, A. Wiebe, T. Gieshoff,
D. Schollmeyer, K. Chiba, R. Franke, S. R. Waldvogel, Angew. Chem. Int.
Ed. 2018, 57, 12136–12140; h) S. Lips, D. Schollmeyer, R. Franke, S. R.
Waldvogel, Angew. Chem. Int. Ed. 2018, 57, 13325–13329; i) S. Lips, A.
Wiebe, B. Elsler, D. Schollmeyer, K. M. Dyballa, R. Franke, S. R.
Waldvogel, Angew. Chem. Int. Ed. 2016, 55, 10872–10876; j) J. L. Röckl,
D. Schollmeyer, R. Franke, S. R. Waldvogel, Angew. Chem. Int. Ed. 2020,
59, 315–319; k) E. Rodrigo, S. R. Waldvogel, Chem. Sci. 2019, 10, 2044–
2047; l) L. Schulz, M. Enders, B. Elsler, D. Schollmeyer, K. M. Dyballa, R.
Franke, S. R. Waldvogel, Angew. Chem. Int. Ed. 2017, 56, 4877–4881; m)
S. R. Waldvogel, S. Möhle, Angew. Chem. Int. Ed. 2015, 54, 6398–6399;
n) A. Wiebe, S. Lips, D. Schollmeyer, R. Franke, S. R. Waldvogel, Angew.
Chem. Int. Ed. 2017, 56, 14727–14731; o) A. Wiebe, D. Schollmeyer, K.
M. Dyballa, R. Franke, S. R. Waldvogel, Angew. Chem. Int. Ed. 2016, 55,
11801–11805.
purified via column chromatography on silica with
cyclohexane/ethyl acetate solvent gradient.
a
Acknowledgements
The Carl Zeiss Stiftung is gratefully acknowledged for the
electrosynthesis network ELYSION. M. Turks thanks Latvian
Council of Science Grant LZP-2018/1-0315.
Conflict of Interest
The authors declare no conflict of interest.
Keywords: C-H activation • electrochemistry • green chemistry •
oxidation • radical ions
[20] a) B. Elsler, A. Wiebe, D. Schollmeyer, K. M. Dyballa, R. Franke, S. R.
Waldvogel, Chem. Eur. J. 2015, 21, 12321–12325; b) L. Schulz, S. R.
Waldvogel, Synlett 2019, 30, 275–286.
[21] a) S. Lips, S. R. Waldvogel, Chem. Electro. Chem. 2019, 6, 1649–1660;
b) B. Gleede, T. Yamamoto, K. Nakahara, A. Botz, T. Graßl, R. Neuber, T.
Matthée, Y. Einaga, W. Schuhmann, S. R. Waldvogel, Chem. Electro.
Chem. 2019, 6, 2771–2776.
[22] a) J. Nikl, D. Ravelli, D. Schollmeyer, S. R. Waldvogel, Chem. Electro.
Chem. 2019, 6, 4450–4455; b) J. Nikl, S. Lips, D. Schollmeyer, R. Franke,
S. R. Waldvogel, Chem. Eur. J. 2019, 25, 6891–6895;
[23] a) E. J. Emmett, M. C. Willis, Asian J. Org. Chem. 2015, 4, 602–611; b) P.
Vogel, M. Turks, L. Bouchez, D. Marković, A. Varela-Álvarez, J. Á. Sordo,
Acc. Chem. Res. 2007, 40, 931–942.
[24] a) K. Suta, M. Turks, Chem. Heterocycl. Compd. 2018, 54, 584–586; b)
N.-W. Liu, Z. Chen, A. Herbert, H. Ren, G. Manolikakes, Eur. J. Org. Chem.
2018, 2018, 5725–5734.
[1] Y. Joyard, C. Papamicaël, P. Bohn, L. Bischoff, Org. Lett. 2013, 15, 2294–
2297.
[2] a) S. M. Pauff, S. C. Miller, Org. Lett. 2011, 13, 6196–6199; b) S. M. Pauff,
S. C. Miller, J. Org. Chem. 2013, 78, 711–716.
[3] a) H. Mori, E. Kudo, Y. Saito, A. Onuma, M. Morishima, Macromolecules
2010, 43, 7021–7032; b) M. Zhang, J. D. Moore, D. L. Flynn, P. R. Hanson,
Org. Lett. 2004, 6, 2657–2660.
[4] a) K. Hanaya, S. Yoshioka, S. Ariyasu, S. Aoki, M. Shoji, T. Sugai, Bioorg.
Med. Chem. Lett. 2016, 26, 545–550; b) K. B. Daniel, J. L. Major Jourden,
K. E. Negoescu, S. M. Cohen, J. Biol. Inorg. Chem. 2011, 16, 313–323; c)
J. Peiró Cadahía, V. Previtali, N. S. Troelsen, M. H. Clausen, Med. Chem.
Commun. 2019, 10, 1531–1549; d) C. Shen, M. Yang, J. Xu, C. Chen, K.
Zheng, J. Shen, P. Zhang, RSC Adv. 2017, 7, 49436–49439; e) A. Choi,
S. C. Miller, Org. Biomol. Chem. 2017, 15, 1346–1349.
[25] Z. Chen, N.-W. Liu, M. Bolte, H. Ren, G. Manolikakes, Green Chem. 2018,
20, 3059–3070.
[5] S. Wahid, M. Hanif, S. Jahangir, M. Shafique, H. A. Shahid, H. Muhammad,
S. A. A. Shah, M. A. Versiani, K. M. Khan, I. A. Tahiri, J. Mol. Struct. 2019,
1184, 569–575.
[6] a) S. O. Ciurea, B. S. Andersson, Biol. Blood Marrow Transplant. 2009, 15,
523–536; b) J. A. Hartley, C. C. O'Hare, J. Baumgart, Br. J. Cancer 1999,
79, 264–266.
[7] a) M. Glassner, D. R. D’hooge, J. Y. Park, P. H. M. Van Steenberge, B. D.
Monnery, M.-F. Reyniers, R. Hoogenboom, Eur. Polym. J. 2015, 65, 298–
304; b) S. Motokucho, A. Sudo, T. Endo, J. Polym. Sci. Pol. Chem. 2007,
45, 4459–4464; c) M. Salmanpour, A. Tamaddon, G. Yousefi, S.
Mohammadi-Samani, BioImpacts 2017, 7, 155–166; d) J. Wang, J. Zhao,
H. Gong, Chem. Commun. 2017, 53, 10180–10183; e) Z. Liang, W. Xue,
K. Lin, H. Gong, Org. Lett. 2014, 16, 5620–5623.
[8] L. Rusha, S. C. Miller, Chem. Commun. 2011, 47, 2038–2040.
[9] a) J. Wrobel, J. Rogers, D. Green, W. Kao, Synth. Commun. 2002, 32,
2695–2704; b) J. C. Roberts, H. Gao, A. Gopalsamy, A. Kongsjahju, R. J.
Patch, Tetrahedron Lett. 1997, 38, 355–358; c) S. C. Miller, J. Org. Chem.
2010, 75, 4632–4635.
[26] a) B.-S. Kim, S.-M. Park, J. Electrochem. Soc. 1995, 142, 26–33; b) D.
Knittel, Monatsh. Chem. 1982, 113, 37–41; c) D. Knittel, Monatsh. Chem.
1986, 117, 359–367; d) B. K. D. Knittel, J. Appl. Electrochem. 1973, 3,
291–296; e) E. Potteau, E. Levillain, J.-P. Lelieur, J. Electroanal. Chem.
1999, 476, 15–25; f) H. J. Wille, B. Kastening, D. Knittel, J. Electroanal.
Chem. 1986, 214, 221–235; g) H. J. Wille, D. Knittel, B. Kastening, J.
Mergel, J. Appl. Electrochem. 1980, 10, 489–494; h) P. Bruno, M. Caselli,
A. Traini, J. Electroanal. Chem. Interf. Electrochem. 1980, 113, 99–111; i)
R. P. Martin, D. T. Sawyer, Inorg. Chem. 1972, 11, 2645–2647; j) E.
Jacobsen, D. T. Sawyer, J. Electroanal. Chem. Interf. Electrochem. 1967,
15, 181–192; k) D. Knittel, J. Electroanal. Chem. 1985, 195, 345–356.
[27] G. Liu, C. Fan, J. Wu, Org. Biomol. Chem. 2015, 13, 1592–1599.
[28] C. Gütz, B. Klöckner, S. R. Waldvogel, Org. Process Res. Dev. 2016, 20,
26–32.
[29] G. A. Olah, Y. D. Vankar, Synthesis 1978, 1978, 702–703.
[30] G. A. Olah, Y. D. Vankar, M. Arvanaghi, Synthesis 1979, 1979, 984–985.
[31] a) G. A. Olah, M. Arvanaghi, Y. D. Vankar, Synthesis 1980, 1980, 660–
661; b) G. A. Olah, Y. D. Vankar, B. G. Balaram Gupta, Synthesis 1979,
1979, 36–37.
[10] a) C.-H. Cho, H.-S. Yun, K. Park, J. Org. Chem. 2003, 68, 3017–3025; b)
C.-B. Kim, H. Jo, B.-K. Ahn, C. K. Kim, K. Park, J. Org. Chem. 2009, 74,
9566–9569.
[32]
J. C. Roberts, H. Gao, A. Gopalsamy, A. Kongsjahju, R. J. Patch,
Tetrahedron Lett. 1997, 38, 355–358.
[11] L. Malet-Sanz, J. Madrzak, S. V. Ley, I. R. Baxendale, Org. Biomol. Chem.
2010, 8, 5324–5332.
[33] A. Biffis, P. Centomo, A. Del Zotto, M. Zecca, Chem. Rev. 2018, 118,
2249–2295.
[12] a) Y. Fu, W. Zhu, X. Zhao, H. Hügel, Z. Wu, Y. Su, Z. Du, D. Huang, Y.
Hu, Org. Biomol. Chem. 2014, 12, 4295–4299; b) G. Liu, C. Fan, J. Wu,
Org. Biomol. Chem. 2015, 13, 1592–1599.
[34] a) I. Anugwom, P. Mäki-Arvela, P. Virtanen, P. Damlin, R. Sjöholm, J.-P.
Mikkola, RSC Adv. 2011, 1, 452–457; b) V.-C. Arunasalam, I. Baxter, M.
B. Hursthouse, K. M. A. Malik, D. M. P. Mingos, J. C. Plakatouras, J. Chem.
Soc, Chem. Commun. 1994, 2695–2696; c) I. Anugwom, V. Eta, P.
Virtanen, P. Mäki-Arvela, M. Hedenström, M. Hummel, H. Sixta, J.-P.
4
This article is protected by copyright. All rights reserved.

10.1002/chem.202001180
Chemistry - A European Journal
COMMUNICATION
Mikkola, Chem. Sus. Chem. 2014, 7, 1170–1176; d) J. C. Verhoef, E.
Barendrecht, J. Electroanal. Chem. 1977, 75, 705–717; e) F. Mayer, Ber.
Dtsch. Chem. Ges. 1890, 23, 908–912; f) P. Rogne, T. Sparrman, I.
Anugwom, J.-P. Mikkola, M. Wolf-Watz, Chem. Sus. Chem 2015, 8, 3764–
3768; g) A. Rosenheim, O. Liebknecht, Ber. Dtsch. Chem. Ges. 1898, 31,
405–414; h) A. Simon, R. Paetzold, Z. anorg. allg. Chem. 1960, 303, 53–
71; i) E. Szarvasy, Ber. Dtsch. Chem. Ges. 1897, 30, 1836–1838; j) D.
Posevins, K. Suta, M. Turks, Eur. J. Org. Chem. 2016, 1414–1419.
5
This article is protected by copyright. All rights reserved.

10.1002/chem.202001180
Chemistry - A European Journal
COMMUNICATION
Entry for the Table of Contents
Organic electrosynthesis enables the
synthesis of alkyl arylsulfonates
starting from arenes with exquisite
S. P. Blum, D. Schollmeyer, M. Turks*,
S. R. Waldvogel*
selectivity
at
constant
current
Page No. – Page No.
conditions. No prefunctionalization of
the arene is required. A stock solution
in acetonitrile serves as SO2 source
and the in-situ formation of monoalkyl
sulfites omits the necessity of
supporting electrolytes.
Metal- and Reagent-free Electrochemical
Synthesis of Arylsulfonates in a Multi-
Component Reaction
Keywords: C-H activation /
electrochemistry / green chemistry /
oxidation / radical ions
6
This article is protected by copyright. All rights reserved.