Graphitic carbon nitride polymer as a recyclable photoredox catalyst for fluoroalkylation of arenes

Article abstract of DOI:10.1002/chem.201405505

Heterogeneous catalysis for trifluoromethylations and perfluoroalkylations has been performed. Through the usage of cheap, metal-free and recyclable mesoporous graphitic carbon nitride (mpg-CN) it was possible to fluoroalkylate various arenes by the reductive activation of sulfonyl chlorides with visible light. Thus, we were able to demonstrate the robustness and versatility of mpg-CN as a photoredox catalyst beyond water splitting and the activation of oxygen.

Full text of DOI:10.1002/chem.201405505

DOI: 10.1002/chem.201405505
Communication
&
Fluoroalkylation
Graphitic Carbon Nitride Polymer as a Recyclable Photoredox
Catalyst for Fluoroalkylation of Arenes
Moritz Baar and Siegfried Blechert*[a]
the redox potential and the robustness of the employed cata-
Abstract: Heterogeneous catalysis for trifluoromethyla-
lyst hold a crucial role.
tions and perfluoroalkylations has been performed.
Unlike TiO2, mpg-CN absorbs light in the visible area (band
Through the usage of cheap, metal-free and recyclable
gap of 2.7 eV) and is not dependent on a surface complexation
mesoporous graphitic carbon nitride (mpg-CN) it was pos-
with electron-rich substrates for visible light catalysis. With an
sible to fluoroalkylate various arenes by the reductive acti-
oxidation potential of the conduction band at ꢁ1.3 V and a re-
vation of sulfonyl chlorides with visible light. Thus, we
duction level of the valence band at 1.4 V (vs. NHE, pH 7),[8b]
were able to demonstrate the robustness and versatility of
mpg-CN also features an appropriate electrochemical behavior
mpg-CN as a photoredox catalyst beyond water splitting
for the photocatalytic activation of a variety of reagents. In this
and the activation of oxygen.
regard reactive alkyl radicals are of particular interest as they
allow direct CꢁH functionalization of arenes and olefins
(Scheme 1). In particular, fluorinated alkyl radicals play an im-
Using visible light for photoredox catalysis in organic synthesis
portant role in the design of new pharmaceutical agents, be-
cause fluorinated compounds often show improved cellular
membrane permeability and metabolic stability.
has aroused great interest in the last couple of years.[1] In par-
2+ [2]
ticular, light sensitizers like Ru(bpy)3
,
IrIII complexes,[3] or
Eosin Y[4] are often employed to initiate organic reactions.
However, the homogeneous nature of these dyes makes
their separation from the product as well as their recycling dif-
ficult. This is where heterogeneous catalysts show major ad-
vantages. In this context, mesoporous graphitic carbon nitride
(mpg-CN), a metal-free solid-state organocatalyst that is easily
accessible by thermal polymerisation of cheap precursors like
dicyandiamide and cyanamide, holds great potential. Higher
activity was achieved through the introduction of a high meso-
pore surface area (ꢀ200 m2gꢁ1) with silica nanoparticles as
templates.[5] Initially established for photocatalytic water split-
ting,[6] a large variety of morphologies and applications have
been developed.[7] Recently its potential in organic catalysis
was demonstrated, especially for aerobic oxidations.[8]
Scheme 1. Photocatalytic generation of alkyl radicals for CꢁH functionaliza-
tion of arenes.
Within this research we were able to generate a highly reac-
ꢁ
tive superoxide radical anion (·O2 ) photocatalytically through
Recently, different kinds of precursors have been used for
the photocatalytic fluoroalkylation of arenes and olefins. Exam-
ples of these precursors are CF3I, as well as Umemoto’s and
Togni’s reagents, which are activated with homogeneous pho-
toredox catalysts.[10] To the best of our knowledge there is no
application of heterogeneous catalysts for fluoroalkylation re-
actions so far. Hence, we took this as a starting point for our
research.
a one-electron reduction of oxygen. This enabled a variety of
photoredox oxidations or oxidative couplings of alcohols and
amines. Very recently, several of those transformations have
also been performed by using heterogeneous metal catalysts
such as TiO2 or CdS.[9]
Motivated by the possibilities provided by the reductive acti-
vation of oxygen, we intended to expand the application of
mpg-CN towards additional reducible precursors. In this aspect
After less successful attempts with gaseous CF3I we decided
to have a closer look at the oxidation potential of feasible re-
agents. As it turned out, trifluoromethanesulfonyl chloride
1 (TfCl) presents a more convenient oxidation potential of
ꢁ0.18 V (vs. SCE)[11] and an enhanced driving force due to
evolving SO2 after reduction (CF3SO2Cl+eꢁ!·CF3 +SO2 +Clꢁ).
First presented by the MacMillan group[11] as a cheap and easy-
to-handle alternative to CF3I, several reports demonstrated the
versatility of reagent 1 in various applications.[12] Together with
[a] M. Baar, Prof. Dr. S. Blechert
Institut fꢀr Chemie
Technische Universitꢁt Berlin
Straße des 17. Juni 135
10623 Berlin (Germany)
E-mail: blechert@chem.tu-berlin.de
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201405505.
Chem. Eur. J. 2014, 20, 1 – 6
1
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Communication
the advantages of a heterogeneous catalyst, we were delight-
ed to see that it was possible to perform fluoroalkylations of
various arenes with mpg-CN as a photoredox catalyst. Addi-
tionally, the reusability could be demonstrated with recycle ex-
periments (see Figure S-1 in the Supporting Information).
We started our investigation with the trifluoromethylation of
benzene in acetonitrile (8m) using trifluoromethanesulfonyl
chloride (1, 2 eq), mpg-CN (25 mg/0.25 mmol substrate) and
K2HPO4 (3 eq) under visible light irradiation with a 60 W energy
saving bulb, based on the conditions which proved optimal for
homogeneous catalysts. After 48 h reaction time, a conversion
of 50% to the desired product was obtained (Table 1).
ent bases and solvents did not lead to higher yields (Table 1,
entries 5–7). A prolongation of the reaction time, however, in-
creased the yield. A conversion of 65% to the desired product
was obtained without detectable side-products after 60 h
(Table 1, entry 8); subsequent irradiation caused only slow con-
version and unselective double trifluoromethylation.
To examine whether other heterogeneous photocatalysts
can compete with this result, we took three examples to test
their reactivity in this reaction. CdS and TiO2 have been used
under comparable conditions with visible light in previous ap-
plications,[13] whereas BiVO4 is often used as a visible light pho-
tocatalyst for water oxidation,[14] but not for photoredox cataly-
sis in organic synthesis. No conversion was observed for BiVO4,
probably due to its low activity in photoreduction. In this re-
spect CdS and TiO2 have a higher reduction potential[9a] but
show only low conversions for trifluoromethylation (Table 1,
entries 9–11).
Table 1. Screening and control experiments for the trifluoromethylation
of benzene.
During the screening of the reaction conditions, we ob-
served that the conversion was nearly the same when the
amount of TfCl 1 was doubled (Table S-1 in the Supporting In-
formation). However, altering the stoichiometry of the base de-
creased the yield, which is why we suspected the oxidation
process to be the rate-limiting step. Compared to benzene,
this oxidation step should be enhanced for heteroaromatic
substrates.
Entry
t [h] GC yield [%]
1
2
3
4
5
6
7
8
conditions[a]
without mpg-CN
no light
48
48
48
20
50
<0.1
<0.1
trace
31/28/25
21
O2 atm.
K2CO3/DBU[b]/Disodiummalonate as base 60
To prove this theory we decided to use N-methylpyrrole (3)
as a substrate, and indeed much higher reaction rates could
be achieved. Figure 1 demonstrates that we faced two prob-
lems when using N-methylpyrrole (3) as substrate: beside over-
reaction causing double trifluoromethylation, chlorinated side
products 6 and 7 occurred during the reaction.
In contrast to benzene, unselective conversion even takes
place without the catalyst. However, the presence of mpg-CN
increases reactivity and selectivity significantly. The appearance
DCM as solvent
DMF, DMSO or THF as solvent
conditions[a]
CdS (1.5 equiv) instead of mpg-CN
TiO2 (1.5 equiv) instead of mpg-CN
BiVO4 (1.5 equiv) instead of mpg-CN
64
64
60
64
64
64
trace
65
1
9
10
11
9
<0.1
[a] Benzene (0.25 mmol), TfCl 1 (0.5 mmol), mpg-CN (25 mg), K2HPO4
(0.75 mmol), MeCN (2 mL). [b] DBU=1,8-diazabicyclo[5.4.0]undec-7-ene.
To verify the role of mpg-CN,
further control experiments in
the absence of light or catalyst
were conducted. No conversion
was observed under these con-
ditions (Table 1, entries 2 and 3).
This unambiguously proves the
catalytic activity of mpg-CN.
Oxygen can easily be reduced
photocatalytically by mpg-CN[8]
and thus compete with the re-
duction of TfCl 1. To analyse its
influence, the reaction was car-
ried out under an oxygen atmos-
phere. Almost no substrate con-
version was observed (Table 1,
entry 4); hence the reaction is
quenched by oxygen and should
be carried out under inert gas.
In order to optimise the reac-
tion conditions, further parame-
Figure 1. Kinetic studies of the trifluoromethylation of N-methylpyrrole (3). Reaction conditions: substrate 3
ter variations were tested. Differ- (0.25 mmol), TfCl 1 (0.5 mmol), mpg-CN (15 mg), K2HPO4 (0.75 mmol), MeCN (2 mL).
&
&
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
2
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Communication
Table 2. Screening and control experiments for the trifluoromethylation
of N-methylpyrrole (3).[a]
Table 3. Reaction scope for the fluoroalkylation through photoredox cat-
alysis with mpg-CN.[a]
Entry
mpg-CN
[mg]
TfCl
[equiv]
t
[h]
conv.[c]
[%]
select.[c] [%]
4
5
6
7
1
15
15
15
–
2
2
2
2
2
1
1.5
2
1.2
2.5
2.5
17
17
17
4.5
4.5
2
88
57
100
94
90
89
98
100
100
73
–
21
29
4
87
74
77
81
1
–
47
1
–
2
5
12
8
20
91
1
29
51
6
9
2
3
6
2[b]
3
–
31
30
9
4
5[b]
6
–
15
15
45
25
4
7
8
9
11
10
5
1.5
[a] Reaction conditions: substrate 3 (0.25 mmol), TfCl 1 (0.25–0.5 mmol),
mpg-CN (0-45 mg), MeCN (2 mL). [b] Absence of light. [c] Determined by
GC-FID.
of chlorinated side products, especially in the absence of light
(Table 2, entries 2 and 5), suggests an ionic side reaction pro-
cess which correlates to early reports[15] that presented TfCl
1 as a mild, electrophilic chlorination agent: a fact that has not
been discussed for photoredox reactions with TfCl 1 so far.
More electron-rich arenes required higher amounts of cata-
lyst to suppress ionic chlorination. Together with a lower
amount of TfCl 1 to prevent overreaction it was possible to
achieve a good selectivity towards the desired product 4
(Table 2, entry 9).
With these optimised conditions the substrate scope of the
reaction was studied. It was possible to trifluoromethylate vari-
ous heteroaromatic compounds like pyrroles, oxazoles, furanes,
thiophenes, indoles, and pyrazines in moderate to excellent
yields. In the course of these investigations, we were delighted
to observe that different kinds of functional groups were toler-
ated, namely aldehydes, esters, halides, and amides (Table 3).
Depending on the substrate, the reaction time varied between
90 min and 3 days, as well as the optimal amount of TfCl
1 (1.2–2.5 equiv), and catalyst loading (15–25 mg/0.25 mmol
substrate). Only in the case of caffeine the tribasic potassium
phosphate turned out to be the best base instead of the di-
basic one.
[a] Reaction conditions: substrate (0.25 or 0.5 mmol), TfCl
1 (1.2–
2.0 equiv), mpg-CN (15–25 mg/0.25 mmol substrate), K2HPO4 (3 equiv),
MeCN (2 mL/0.25 mmol substrate), 60 W energy saving bulb, 90 min–3 d.
[b] Isolated yield. [c] Determined by GC-FID. Other substrates: determined
1
by H NMR or 19F NMR. [d] K3PO4 (3 equiv) as base. [e] Perfluoro-1-butane-
sulfonyl chloride 22 (1.3 equiv) was used as reagent.
For higher fluorinated reagents, the sulfonyl fluorides are
often much cheaper than the corresponding chloride. In partic-
ular, nonafluoro-1-butanesulfonyl fluoride (23, NfF) is a cheap
and popular perfluorinated reagent in organic synthesis.[16]
Such compounds are therefore very attractive as reagents in
photoredox catalysis. However, sulfonyl fluorides have not
been investigated in photoredox catalysis so far. The experi-
ment with NfF 23 showed only a slow reaction with a low con-
version of 17% to the desired product. This can be explained
by the stronger SꢁF bond of 23 compared to the SꢁCl bond in
22 that inhibits a fast degradation after reduction to generate
the perfluoroalkyl radical. Perfluorinated alkyl iodides, on the
other hand, should have a more challenging reduction poten-
Synthetic procedures for direct couplings with perfluoroalkyl
groups are relatively limited compared to trifluoromethyla-
tions. As a model, we decided to employ the higher fluorinat-
ed sulfonyl chloride 22. With this reagent a fast perfluorobuty-
lation of pyrrole (21) was achieved, demonstrating that the
chain length of sulfonyl chlorides can be varied without losing
reactivity; a higher reactivity was even observed for reagent 22
(Scheme 2). Double fluoroalkylation at positions 2 and 5 of pyr-
role (21) was observed for higher reagent stoichiometries.
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
3
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Communication
rified by column chromatography on silica using either cyclohex-
ane/ethyl acetate or pentane/diethyl ether (volatile products) as
eluent.
Acknowledgements
This work was supported by the Cluster of Excellence UniCat
(financed by the Deutsche Forschungsgemeinschaft and ad-
ministered by the TU Berlin) and the “Light2Hydrogen” Project
of the BMBF (03IS2071D). M.B. thanks the Berlin International
Graduate School of Natural Sciences and Engineering (BIG-
NSE).
Keywords: C3N4
·
carbon nitride
·
fluoroalkylation
·
heterogeneous photoredox catalysis · trifluoromethylation ·
visible light
Scheme 2. Investigations towards the application range for photoredox cat-
alysis with regard to suitable perfluoroalkylation reagents. Reaction condi-
tions: substrate 21 (0.25 mmol), reagent 22/23/24 (0.5 mmol), mpg-CN
(15 mg), MeCN (2 mL).
[1] For reviews about photoredox catalysis see: a) M. Reckenthꢁler, A. G.
Griesbeck, Adv. Synth. Catal. 2013, 355, 2727–2744; b) D. A. Nicewicz,
T. M. Nguyen, ACS Catal. 2014, 4, 355–360; c) C. K. Prier, D. A. Rankic,
D. W. C. MacMillan, Chem. Rev. 2013, 113, 5322–5363; d) L. Shi, W. Xia,
Chem. Soc. Rev. 2012, 41, 7687–7697; e) J. Xie, H. Jin, P. Xu, C. Zhu, Tet-
rahedron Lett. 2014, 55, 36–48; f) J. Xuan, L.-Q. Lu, J.-R. Chen, W.-J. Xiao,
Eur. J. Org. Chem. 2013, 2013, 6755–6770.
tial. There are few reports that use perfluorinated alkyl iodides
in photoredox catalysis for fluoroalkylations of arenes.[17] Using
mpg-CN as a photocatalyst, perfluoroalkylation with iodide 24
was slower than with 22, but a good yield of 68% of the de-
sired product was achieved.
2+
[2] For examples of Ru(bpy)3 catalysed reactions see: a) M. A. Cismesia,
M. A. Ischay, T. P. Yoon, Synthesis 2013, 45, 2699–2705; b) C. Dai, J. M. R.
Narayanam, C. R. J. Stephenson, Nat. Chem. 2011, 3, 140–145; c) D. A.
DiRocco, T. Rovis, J. Am. Chem. Soc. 2012, 134, 8094–8097; d) Y.-X. Liu,
D. Xue, J.-D. Wang, C.-J. Zhao, Q.-Z. Zou, C. Wang, J. Xiao, Synlett 2013,
24, 507–513; e) P. Schroll, D. P. Hari, B. Kçnig, ChemistryOpen 2012, 1,
130–133; f) G. Zhao, C. Yang, L. Guo, H. Sun, C. Chen, W. Xia, Chem.
Commun. 2012, 48, 2337–2339; g) Y.-Q. Zou, J.-R. Chen, X.-P. Liu, L.-Q.
Lu, R. L. Davis, K. A. Jørgensen, W.-J. Xiao, Angew. Chem. Int. Ed. 2012,
51, 784–788; Angew. Chem. 2012, 124, 808–812.
Both reagents 23 and 24 showed a certain degree of reactiv-
ity, illustrating the great potential for broad applicability in fur-
ther investigations.
In summary, we have reported a new photoredox system for
graphitic carbon nitride, in which a photoreductive activation
of sulfonyl chlorides for perfluoroalkylation was achieved. We
were able to demonstrate the high potential and broad applic-
ability in organic synthesis for these kinds of metal-free hetero-
geneous catalysts beyond oxygen activation. With the devel-
oped method it was possible to trifluoromethylate benzene
and a great variety of heteroaromatic compounds. Additionally,
promising prospects for various reagents for perfluoroalkyla-
tion have been pointed out.
[3] For examples of reactions catalysed by IrIII-complexes see: a) Y. Cheng,
X. Gu, P. Li, Org. Lett. 2013, 15, 2664–2667; b) A. G. Condie, J. C. Gon-
zꢂlez-Gꢃmez, C. R. J. Stephenson, J. Am. Chem. Soc. 2010, 132, 1464–
1465; c) H. Jiang, Y. Cheng, R. Wang, M. Zheng, Y. Zhang, S. Yu, Angew.
Chem. Int. Ed. 2013, 52, 13289–13292; Angew. Chem. 2013, 125, 13531–
13534; d) J. D. Nguyen, E. M. D’Amato, J. M. R. Narayanam, C. R. J. Ste-
phenson, Nat. Chem. 2012, 4, 854–859; e) S. Paria, O. Reiser, Adv. Synth.
Catal. 2014, 356, 557–562; f) K. Qvortrup, D. A. Rankic, D. W. C. MacMil-
lan, J. Am. Chem. Soc. 2014, 136, 626–629; g) L. J. Rono, H. G. Yayla,
D. Y. Wang, M. F. Armstrong, R. R. Knowles, J. Am. Chem. Soc. 2013, 135,
17735–17738; h) S. Zhu, A. Das, L. Bui, H. Zhou, D. P. Curran, M. Ruep-
ing, J. Am. Chem. Soc. 2013, 135, 1823–1829.
[4] For examples of reactions catalysed by Eosin Y see: a) D. P. Hari, P.
Schroll, B. Kçnig, J. Am. Chem. Soc. 2012, 134, 2958–2961; b) M. Neu-
mann, S. Fꢄldner, B. Kçnig, K. Zeitler, Angew. Chem. Int. Ed. 2011, 50,
951–954; Angew. Chem. 2011, 123, 981–985; c) V. P. Srivastava, A. K.
Yadav, L. D. S. Yadav, Synlett 2013, 24, 2758; d) D.-T. Yang, Q.-Y. Meng, J.-
J. Zhong, M. Xiang, Q. Liu, L.-Z. Wu, Eur. J. Org. Chem. 2013, 2013,
7528–7532.
[5] a) X. Wang, K. Maeda, X. Chen, K. Takanabe, K. Domen, Y. Hou, X. Fu, M.
Antonietti, J. Am. Chem. Soc. 2009, 131, 1680–1681; b) F. Goettmann, A.
Fischer, M. Antonietti, A. Thomas, Angew. Chem. Int. Ed. 2006, 45, 4467–
4471; Angew. Chem. 2006, 118, 4579–4583.
Experimental Section
General procedure for the trifluoromethylation reaction
Powdered potassium phosphate (3 equiv) and mpg-CN (15–25 mg/
0.25 mmol substrate) were added to
a vacuum-dried 10 mL
Schlenk tube with a septum under nitrogen atmosphere. A solu-
tion of trifluoromethanesulfonyl chloride 1 (1.2–2.0 equiv) in dry
acetonitrile (2 mL/0.25 mmol substrate) was prepared in a glovebox
and added to the Schlenk tube, together with the substrate (0.25
or 0.5 mmol). The resulting suspension was shaken under irradia-
tion with visible light using a Philips cool daylight energy-saving
bulb (60 W). The optimal reaction time was determined by GC-FID.
The reaction mixture was filtered and the filtrate concentrated
under reduced pressure. For volatile products water was added to
the filtrate, extracted with diethyl ether and washed with brine
before concentration to wash out acetonitrile. The residue was pu-
[6] X. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M. Carlsson, K.
Domen, M. Antonietti, Nat. Mater. 2009, 8, 76–80.
[7] a) J. Zhu, P. Xiao, H. Li, S. A. C. Carabineiro, ACS Appl. Mater. Interfaces
2014, 6, 16449–16465; b) K. Kailasam, J. D. Epping, A. Thomas, S. Losse,
H. Junge, Energy Environ. Sci. 2011, 4, 4668–4674; c) N. Cheng, P. Jiang,
Q. Liu, J. Tian, A. M. Asiri, X. Sun, Analyst 2014, 139, 5065–5068; d) J.
Tian, Q. Liu, A. M. Asiri, K. A. Alamry, X. Sun, ChemSusChem 2014, 7,
2125–2130; e) J. Tian, Q. Liu, C. Ge, Z. Xing, A. M. Asiri, A. O. Al-Youbi, X.
Sun, Nanoscale 2013, 5, 8921–8924.
&
&
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
4
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Communication
[8] a) L. Mçhlmann, M. Baar, J. Rieß, M. Antonietti, X. Wang, S. Blechert, Adv.
Synth. Catal. 2012, 354, 1909–1913; b) F. Su, S. C. Mathew, G. Lipner, X.
Fu, M. Antonietti, S. Blechert, X. Wang, J. Am. Chem. Soc. 2010, 132,
16299–16301; c) F. Su, S. C. Mathew, L. Mçhlmann, M. Antonietti, X.
Wang, S. Blechert, Angew. Chem. Int. Ed. 2011, 50, 657–660; Angew.
Chem. 2011, 123, 683–686; d) Y. Wang, X. Wang, M. Antonietti, Angew.
Chem. 2012, 124, 70–92.
[9] a) M. Cherevatskaya, B. Kçnig, Russ. Chem. Rev. 2014, 83, 183; b) X.
Lang, X. Chen, J. Zhao, Chem. Soc. Rev. 2014, 43, 473–486; c) C. Vila, M.
Rueping, Green Chem. 2013, 15, 2056–2059.
[10] For examples of trifluoromethylations by photoredox catalysis see: a) N.
Iqbal, J. Jung, S. Park, E. J. Cho, Angew. Chem. Int. Ed. 2014, 53, 539–
542; b) S. Mizuta, S. Verhoog, K. M. Engle, T. Khotavivattana, M. O’Duill,
K. Wheelhouse, G. Rassias, M. Mꢅdebielle, V. Gouverneur, J. Am. Chem.
Soc. 2013, 135, 2505–2508; c) D. A. Nagib, M. E. Scott, D. W. C. MacMil-
lan, J. Am. Chem. Soc. 2009, 131, 10875–10877; d) D. J. Wilger, N. J. Ges-
mundo, D. A. Nicewicz, Chem. Sci. 2013, 4, 3160–3165; e) Y. Yasu, Y.
Arai, R. Tomita, T. Koike, M. Akita, Org. Lett. 2014, 16, 780–783.
[11] D. A. Nagib, D. W. C. MacMillan, Nature 2011, 480, 224–228.
[12] a) D. Cantillo, O. de Frutos, J. A. Rincꢃn, C. Mateos, C. O. Kappe, Org.
Lett. 2014, 16, 896–899; b) H. Jiang, X. Chen, Y. Zhang, S. Yu, Adv. Synth.
Catal. 2013, 355, 809–813; c) H. Jiang, Y. Cheng, Y. Zhang, S. Yu, Eur. J.
Org. Chem. 2013, 2013, 5485–5492; d) S. H. Oh, Y. R. Malpani, N. Ha, Y.-
S. Jung, S. B. Han, Org. Lett. 2014, 16, 1310–1313.
[13] a) X. Lang, W. Ma, Y. Zhao, C. Chen, H. Ji, J. Zhao, Chem. Eur. J. 2012, 18,
2624–2631; b) T. Mitkina, C. Stanglmair, W. Setzer, M. Gruber, H. Kisch,
B. Konig, Org. Biomol. Chem. 2012, 10, 3556–3561; c) Y. Zhang, N.
Zhang, Z.-R. Tang, Y.-J. Xu, Chem. Sci. 2012, 3, 2812–2822.
[14] N. Aiga, Q. Jia, K. Watanabe, A. Kudo, T. Sugimoto, Y. Matsumoto, J.
Phys. Chem. C 2013, 117, 9881–9886.
[15] G. Hosein Hakimelahi, G. Just, Tetrahedron Lett. 1979, 20, 3643–3644.
[16] R. Zimmer, M. Webel, H.-U. Reißig, Journal Prakt. Chem. 1998, 340, 274–
277.
[17] a) N. Iqbal, S. Choi, E. Ko, E. J. Cho, Tetrahedron Lett. 2012, 53, 2005–
2008; b) Y. Ye, M. S. Sanford, J. Am. Chem. Soc. 2012, 134, 9034–9037.
Received: October 2, 2014
Published online on && &&, 0000
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
5
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Communication
COMMUNICATION
&
Fluoroalkylation
M. Baar, S. Blechert*
&& – &&
Graphitic Carbon Nitride Polymer as
a Recyclable Photoredox Catalyst for
Fluoroalkylation of Arenes
Heterogeneous catalysis for trifluoro-
methylations and perfluoroalkylations
has been performed. Through the
tivation of sulfonyl chlorides with visible
light (see scheme). Thus, the robustness
and versatility of mpg-CN as a photore-
dox catalyst was demonstrated beyond
water splitting and the activation of
oxygen.
usage of cheap, metal-free and recycla-
ble mesoporous graphitic carbon nitride
(mpg-CN), it was possible to fluoroalky-
late various arenes by the reductive ac-
&
&
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
6
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!