Visible light mediated aerobic photocatalytic activation of C–H bond by riboflavin tetraacetate and N-hydroxysuccinimide

Article abstract of DOI:10.1016/j.tetlet.2018.01.011

A green and highly efficient cooperative photocatalytic system which consists of riboflavin tetraacetate (RFT), N-hydroxysuccinimide (NHS) and FeCl₃·6H₂O has been developed for C–H bond oxygenation with visible light under mild reaction conditions. Compared to the previous procedures about C–H bond activation by using flavins as photocatalyst, we use cheap ferric chloride and NHS instead of expensive scandium triflate or biomimetic non-heme iron complex, further expand the substrate scopes. In addition, a possible radical mechanism for the C–H bond oxygenation in this photocatalytic system is proposed.

Full text of DOI:10.1016/j.tetlet.2018.01.011

Accepted Manuscript
Visible Light Mediated Aerobic Photocatalytic Activation of C-H Bond by Ri-
boflavin Tetraacetate and N-Hydroxysuccinimide
Guo Tang, Zhiyu Gong, Wenjun Han, Xiaoling Sun
PII:
S0040-4039(18)30023-6
https://doi.org/10.1016/j.tetlet.2018.01.011
TETL 49598
DOI:
Reference:
To appear in:
Tetrahedron Letters
Received Date:
Revised Date:
Accepted Date:
26 November 2017
2 January 2018
4 January 2018
Please cite this article as: Tang, G., Gong, Z., Han, W., Sun, X., Visible Light Mediated Aerobic Photocatalytic
Activation of C-H Bond by Riboflavin Tetraacetate and N-Hydroxysuccinimide, Tetrahedron Letters (2018), doi:
https://doi.org/10.1016/j.tetlet.2018.01.011
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Visible Light Mediated Aerobic
Photocatalytic Activation of C-H Bond by
Riboflavin Tetraacetate and N-
Hydroxysuccinimide
Leave this area blank for abstract info.
Guo Tang, Zhiyu Gong, Wenjun Han and Xiaoling Sun*

1
Tetrahedron Letters
Visible Light Mediated Aerobic Photocatalytic Activation of C-H Bond by Riboflavin
Tetraacetate and N-Hydroxysuccinimide
a
a
b
a
Guo Tang , Zhiyu Gong , Wenjun Han and Xiaoling Sun
a
School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, China
Huangdao Entry-Exit Inspection and Quarantine Bureau, Qingdao 266555, China
b
ARTICLE INFO
ABSTRACT
Article history:
Received
A green and highly efficient cooperative photocatalytic system which consists of riboflavin
tetraacetate (RFT), N-Hydroxysuccinimide (NHS) and FeCl ·6H O has been developed for C−H
3 2
Received in revised form
Accepted
Available online
bond oxygenation with visible light under mild reaction conditions. Compared to the previous
procedures about C−H bond activation by using flavins as photocatalyst, we use cheap ferric
chloride and NHS instead of expensive scandium triflate or biomimetic non-heme iron complex,
further expand the substrate scopes. In addition, a possible radical mechanism for the C−H bond
oxygenation in this photocatalytic system is proposed.
Keywords:
C−H bond activation
RFT
2
017 Elsevier Ltd. All rights reserved.
NHS
3 2
FeCl ·6H O
Visible light
1
. Introduction
in organic synthesis. The renaissance addresses green chemistry
and renewable energy due to the abundant visible light and clean
The selective C−H bond oxygenation of hydrocarbon to
16-21
energy.
Recent studies on photoredox catalysis focused
produce high value-added products is highly important in organic
synthesis. Synthetic functional molecules by the direct oxidizing
C–H bonds has drawn great interest in both academic and
industrial settings. The oxidation of benzylic and allylic C-H
bonds systems have played a prominent role in C-H bond
activation. Among the oxidation products, Aryl ketones are
recognized as key structural motifs and useful precursors for
synthesis of natural products, active pharmaceutical ingredients,
agrochemicals and other complicated organic molecules. Enones
are versatile intermediates, which are widely used for the
predominantly on the transition metal chromophores as
16-18,22-24
photocatalysts.
Compared with the expensive and toxic
transition metal photocatalysts, photoorganocatalysts are simple
to synthesize, inexpensive, and have good photocatalytic
performance and important applications in photoredox catalysis.
Commonly used photoorganocatalysts are mainly heterocycles
and organic dyes (such as: Eosin Y, Methylene Blue and
1
-4
16,25-28
riboflavin et al.).
Flavins are important photoreceptors and redox cofactors in
29-30
5
-9
nature.
Artificial riboflavin and its derivatives are promising
synsthesis of natural products and unnatural materials. C−H
bond is thermodynamically strong and chemically inert; thus,
their direct activation is difficult. Classical oxidation methods for
C−H bond oxygenation require toxic and expensive reagents as
and versatile catalysts for the aerobic photooxidation of benzyl
3
1-37
38
39-40
alcohols,
benzyl amines, and sulfides
with visible light.
41
Recently, they were applied for cyclobutane ring opening, [2+2]
10-11
42-43
44-45
catalysts or strong oxidants under harsh conditions.
Dioxygen
cycloadditions,
E to Z isomerization of olefins,
However, visible-light-driven aerobic oxidation
of alkylbenzes is difficult to achieve using riboflavin tetraacetate
and other
46-48
is the best oxidant from an atom-economic point of view,
because it is easily accessible and does not produce hazardous
by-products. However, dioxygen is directly an unreactive oxidant
toward the oxidation of the C−H bonds under mild conditions
due to its triplet ground state. Therefore, direct C−H bond
activation with dioxygen as the terminal oxidant remains a
primary challenge.
with dioxygen under visible light irradiation is an atom-economic
and environmentally benign alternative to conventional catalytic
applications.
0
1
2
-
alone because the reduction potential E ( RFT*/ RFT ) =1.67 V
vs. SCE is lower than that of the normal benzylic methylene
oxidation peak potential.
3
1,49-52
In 2015, Wolf et al. investigated
the RFT/Sc(OTf) system for aerobic photocatalytic benzylic
3
1
2-14
Photocatalytic activation of hydrocarbon
C−H bonds, and in 2016, subsequently reported a dual catalyst
system consisted of RFT and biomimetic non-heme iron complex
[Fe(TPA)(MeCN)
C–H bonds, which expanded the scope of the substrate.
two catalytic systems are efficient but expensive, and Wolf did
2 4 2
] (ClO ) for the aerobic oxidation of benzylic
15
53-54
strategies.
These
Over the past decade, visible light photoredox catalysis has
experienced a renaissance due to the revival of radical chemistry

Corresponding author. Tel.: +86-21-60877232; +86-21-60877232; e-mail: xiaolingsun1@msn.com

2
Tetrahedron
f
not study the oxidation of other C−H bonds using the catalytic
The additive was HClO
4
(20 μL).
O are replaced by TBHP (3 equiv.), HCl (37%,
O (20:1, v/v) and irradiated 60 h.
g
The NHS and FeCl
0μL) in 20 mL CH
3
·6H
2
systems.
2
3
CN/H
2
Table 2. Substrate scopes of the photocatalytic benzylic C-H
a
oxidation and related substrates.
Entry Substrate
Product
Time
h)
Yield Ref’
(
(%)
yield
(%)
[
[
[
54]
1
45
20
45
83
85
71
74
59]
54]
2
3
79
72
Scheme 1. Summary of aerobic photocatalytic oxidation of
ethylbenzene with visible light.
c
[53]
4
5
6
60
28
72
76
96
61
71
62
60
Organic nitroxyl radical has been verified as an effective
method for C−H bond oxidation via hydrogen abstraction in the
[53]
5
5-56
past decades.
promising method for generating phthalimide-N-oxyl radical
PINO) from its precursor N-Hydroxyphthalimide (NHPI) using
dioxygen. Li et al. first reported the g-C /NHPI synergistic
catalysis system for aerobic allylic oxidation to enones with
Visible light activation is an effective and
(
c
[54]
3 4
N
57
visible light in 2011. This method is unsuitable for other C−H
bond oxidations due to its poor yield. In this study, we explored
the RFT/NHS catalysis system for the challenging C–H bond
oxidation.
[
[
54]
54]
7
8
9
63
24
72
72
40
81
99
60
50
85
68
68
70
89
77
83
2. Results and discussion
We selected the reaction of ethylbenzene to acetophenone as a
benchmark because the one-electron oxidation potentials of
0
ethylbenzene (E ox = 2.14 νs. SCE) and RFT alone could not
d
e
[5]
3
1
directly oxidize ethylbenzene. We initiated our investigation
a
Table 1. Optimization of reaction conditions.
[60]
1
1
0
1
b
Entry
1
Additive
-
-
Solvent
Yield (%)
[
61]
c
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
3
3
3
3
3
3
3
3
3
3
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
13
33
83
25
24
10
61
28
76
72
79
4
2
3
4
5
FeCl
CoCl
CuCl
FeCl
Fe(NO
Fe(acac)
FeSO
Fe(C
3
·6H
2
O
2
·6H
2
O
2
·2H
2
O
f
[57]
d
12
40
45
21
94
6
3
·6H
2
O
·9H
7
8
9
3
)
3
2
O
3
[
60]
1
3
N.R
4
·7H
2
O
1
1
1
1
1
0
1
2
3
4
5
2
O
4
)·2H
2
O
FeCl
FeCl
3
·6H
·6H
2
2
O
O
EtOAc
EtOH
3
e
f
MnO
2
CH
CH
CH
3
3
3
CN
CN
CN
56
6
74
a
All reactions were performed with substrate (0.4 mmol), RFT (10 mol%),
·6H O (10 mol%) in 15 mL CH CN and irradiated
with blue light (450 nm, 90 W) at room temperature.
HClO
4
g
NHS (20 mol%) and FeCl
3
2
3
1
TBHP
a
Unless otherwise noted, all reactions were performed with ethylbenzene (0.4
b
Yield determined by GC using benzonitrile as an internal standard.
mmol), RFT (10 mol%), NHS (20 mol%) and additive (10 mol%) in 15 mL
c
d
e
f
Isolated yield.
CH CN and irradiated with blue light (450 nm, 90 W) at room temperature
3
2
8% benzaldehyde detected.
6% benzaldehyde detected.
3% styrene oxide detected.
for 45 h.
1
b
Yield determined by GC using benzonitrile as an internal standard.
The NHS was replaced by NHPI (20 mol%).
The NHS was absent.
2
The additive was MnO (60 mol%).
1
c
d
e

3
a
with ethylbenzene 1 in the presence of RFT and NHPI at room
temperature under 90 W blue light-emitting diode (LED)
irradiation. The desired product 2 obtained 13% yield after 45 h
All reactions were performed with substrate (0.4 mmol), RFT (10 mol%),
NHS (20 mol%) and FeCl O (10 mol%) in 15 mL EtOAc and irradiated
3
·6H
2
with blue light (450 nm, 90 W) at room temperature.
b
Yield determined by GC using benzonitrile as an internal standard.
c
(Table 1, entry 1). When we selected NHS alternative to NHPI,
The EtOAc was replaced by CH CN.
3
the product 2 obtained 33% yield. (Table 1, entry 2) Moreover,
the yield of 2 could be increased to 83% when 10 mol%
Moreover, the reactivity of the substrates containing different
substituents was different. For instance, p-bromoacetophenone
was obtained at 71% yield after 45 h, and p-methylacetophenone
was obtained at 85% yield after 20 h. In addition, p-
FeCl
Lewis acids and solvents indicated that FeCl
was the best proposal (Table 1, entry 3-5, 11, 12), and
FeCl ·6H O was the best choice for this reaction among other
3
·6H
2
O was added (Table 1, entry 3). A screening of various
3
·6H O in CH CN
2
3
methylbenzaldehyde was obtained at 96% yield after 28 h,
whereas p-chlorobenzoic acid was obtained at 61% yield after 72
h. Compared with ethylbenzene, the oxidation of 1-phenylethanol
to acetophenone was sluggish (Table 2, entry 7). Furthermore,
tetrahydronaphthalene was oxidized to the corresponding ketone
at 99% yield after 24 h (Table 2, entry 8). When the alkane chain
was extended, reaction selectivity was decreased due to the C−C
bond cleavage (Table 2, entry 9, 10). For instance, propylbenzene
was oxidized to phenyl propanal at 60% yield after 72 h, and the
by-product was benzaldehyde at 28% yield (Table 2, entry 9).
Motivated by the reactions, styrene and 2-phenyl-1-propene were
oxidized to benzaldehyde and acetophenone at 68% and 85%
yields due to the C=C bond cleavage, respectively (Table 2, entry
11, 12). Meanwhile, 3-ethylpyridine did not oxidize to the
corresponding ketone (Table 2, entry 13).
3
2
iron salts (Table 1, entry 3, 7-10). When NHS was absent, the
yield of acetophenone was 10% (Table 1, entry 6). An improved
yield (52%) of 2 was obtained when the additive was MnO
Table 1, entry 13), and this was possibly due to the MnO
decomposed the by-product H
2
(
2
that
2
O
2
, which could degrade RFT
served as an alternative to
O, the 2 obtained only 6% yield (Table 1, entry 14).
We selected TBHP and HCl alternatives to the combination of
NHS and FeCl ·6H O. The desired product 2 obtained 74% yield
49
under irradiation. When HClO
FeCl ·6H
4
3
2
3
2
after 60 h due to TBHP, which served as a valuable catalyst for
the chemoselective oxidation of C−H bond via hydrogen
.
abstraction by generating tert-butoxy radical intermediate (t-BuO )
5-58
(
Table 1, entry 15). Control experiments indicated that the
reaction did not proceed in the absence of RFT, in the dark or
We further expanded the substrate scopes. Cyclohexanol was
oxidized to cyclohexanone at only 32% yield after 72 h (Table 3,
entry 1). Compared with alkyl benzenes, the reaction time of allyl
oxidation reaction was shorter, but its reaction selectivity was
lower. The 2-cyclohexen-1-one was obtained at 61% yield after
10 h, and 3,7,7-trimethylbicyclo [4.1.0] hept-3-en-5-one was
obtained at 40% yield after 5 h (Table 3, entry 2, 3). The visible-
light-driven cooperative photocatalytic system could also be used
for the oxidation of cyclic ethers and cycloalkanes. Compared
with those of alkyl benzenes, its reactions yield was lower. γ-
butyrrolactone was obtained at 36% yield after 24 h (Table 3,
entry 4). Cyclohexanone and cycloheptanone were obtained at
14% and 27% yields after 72 h, respectively (Table 3, entry 5, 6).
under anaerobic conditions (S4, Table 1, ESI†).
Considering this optimized system, we subsequently assessed
the substrate scopes (Table 2). First, a variety of alkyl benzenes
containing different substituted groups on the aromatic ring was
subjected to the cooperative photocatalytic system with
FeCl ·6H O, NHS, and RFT. Results showed that all the tested
3 2
alkyl benzenes could be oxidized into the corresponding ketones,
aldehydes, and acids with excellent yields (Table 2, entry 1-10).
Table 3. Substrate scopes of the photocatalytic other C-H
a
oxidation.
Entry
Substrate
Product
Time
h)
Yield
%)
Ref’
(
(
yield
(%)
c
[58]
1
72
10
5
38
61
40
N.R
[
[
[
57]
2
3
72
20
50
62]
63]
4
5
24
72
36
14
[
57]
6
Scheme 2. Proposed cooperative catalysis mechanism for the
aerobic oxidation of ethylbenzene to acetophenone by RFT, NHS,
[
64]
6
72
27
32
3 2
and FeCl ·6H O with visible light.

4
Tetrahedron
To further elucidate the possible mechanism of this reaction,
an equivalent amount of 2,2,6,6-tetramethyl-1-piperidinyloxy
TEMPO, a well-known radical-capturing species) was added to
17. Kärkäs, M. D.; Porco Jr, J. A.; Stephenson, C. R. J. Chem. Rev.
016, 116, 9683-9747.
8. Corrigan, N.; Shanmugam, S.; Xu, J.; Boyer, C. Chem. Soc. Rev.
016, 45, 6165-6212.
9. Yoon, T. P.; Ischay, M. A.; Du, J. Nat. Chem. 2010, 2, 527-532.
2
1
1
(
2
the aerobic oxidation of 1. The reaction was inhibited completely,
which indicated that a single electron transfer (SET) pathway
might be involved in this transformation. As shown in Scheme 2,
the visible-light-driven catalytic processes probably proceeded as
20. Narayanam, J. M. R.; Stephenson, C. R. J. Chem. Soc. Rev. 2011,
40, 102-113.
2
2
1. Xuan, J.; Xiao, W-J. Angew. Chem. Int. Ed. 2012, 51, 6828-6838.
2. Poplata, S.; Tröster, A.; Zou, Y.-Q.; Bach, T. Chem. Rev. 2016,
follows: (i) O captured the electron from the excited RFT
2
1
16, 9748-9815.
3
•−
(
RFT*) and generated superoxide radical anion (O
2
); and (ii)
•−
2
3. Skubi, K. L.; Blum, T. R.; Yoon, T. P. Chem. Rev. 2016, 116,
after abstracting hydrogen from R=N−OH (NHS), O
2
was
and generated R=N−O . Subsequently,
R=N-O abstracted hydrogen from RH (ethylbenzene) to generate
10035-10074.
.
ultimately reduced to H
2
O
2
24. Perutz, R. N.; Procacci, B. Chem. Rev. 2016, 116, 8506-8544.
25. Ravelli, D.; Fagnoni, M.; Albini, A. Chem. Soc. Rev. 2013, 42, 97-
113.
.
.
.
.
2
R , and the formed R was rapidly trapped by O to obtain ROO ,
2
2
6. Nicewicz, D. A.; Nguyen, T. M. ACS Catal. 2014, 4, 355-360.
7. Arceo, E.; Montroni, E.; Melchiorre, P. Angew. Chem. Int. Ed.
2014, 53, 12064-12068.
which eventually generated R=O. In the catalytic processes, the
by-product 1-phenylethanol was detected by GC-MS (S5, Fig. 2,
ESI†), the phenylethanol could be oxidized to acetophenone
28. Hu, X.; Zhang, G.; Bu, F.; Lei, A. ACS Catal. 2017, 7, 1432-1437.
9. de Gonzalo, G.; Fraaije, M. W. ChemCatChem. 2013, 5, 403-415.
30. Insińska-Rak, M.; Sikorski, M. Chem. Eur. J. 2014, 20, 15280-
5291.
3+
2
(Table 2, entry 7). Fe could have exhibited two functions: (i)
•−
accelerated the formation of O
R=N−O , and (ii) decomposed the by-product H
2
and stabilized the corresponding
to generate
1
.
2
O
2
3
1. Fukuzumi, S.; Yasui, K.; Suenobu, T.; Ohkubo, K.; Fujitsuka, M.;
.
.
OH, which could abstract hydrogen from RH to generate R and
accelerate the catalytic cycle due to H degradation of RFT
Moreover, H was detected by
UV-vis spectroscopy (S6, Fig. 3, ESI†).
Ito, O. J. Phys. Chem. A. 2001, 105, 10501-10510.
2 2
O
32. Cibulka, R.; Vasold, R.; König, B. Chem. Eur. J. 2004, 10, 6223-
231.
3. Svoboda, J.; Schmaderer, H.; König, B. Chem. Eur. J. 2008, 14,
854-1865.
53-54,59-60,65-66
6
under irradiation.
2 2
O
3
3
3
1
4. Schmaderer, H.; Hilgers, P.; Lechner, R.; König, B. Adv. Synth.
Catal. 2009, 351, 163-174.
5. Dadová, J.; Kümmel, S.; Feldmeier, C.; Cibulková, J.; Pažout, R.;
Maixner, J.; Gschwind, R. M.; König, B.; Cibulka, R. Chem. Eur.
J. 2013, 19, 1066-1075.
3. Conclusions
In summary, a cooperative aerobic photocatalytic system
among RFT, NHS, and FeCl ·6H O for C−H bond oxygenation
3
2
with visible light at room temperature was developed. Compared
with the work of Wolf, this cooperative photocatalytic system is
cheaper, and the substrate scopes are further extended. Moreover,
a plausible reaction mechanism through the SET pathway was
proposed. Further studies on both reaction scope and reaction
mechanism are currently underway.
36. Bachl, J.; Hohenleutner, A.; Dhar, B. B.; Cativiela, C.; Maitra, U.;
König, B.; Díaz, D. D. J. Mater. Chem. A. 2013, 1, 4577-4588.
3
3
7. Korvinson, K. A.; Hargenrader, G. N.; Stevanovic, J.; Xie, Y.;
Joseph, J.; Maslak, V.; Hadad, C. M.; Glusac, K. D. J. Phys. Chem.
A. 2016, 120, 7294-7300.
8. Lechner, R.; König, B. Synthsis. 2010, 10, 1712-1718.
39. Daďová, J.; Svobodová, E.; Sikorski, M.; König, B.; Cibulka, R.
ChemCatChem. 2012, 4, 620-623.
Acknowledgments
40. Neveselý, T.; Svobodová, E.; Chudoba, J.; Sikorski, M.; Cibulka,
R. Adv. Synth. Catal. 2016, 358, 1654-1663.
We are grateful to the Shanghai Alliance Program,
Grant/Award Number: LM 201666; the Capacity-building
Projects in Shanghai Local Universities, Grant/Award Number:
41. Hartman, T.; Cibulka, R. Org. Lett. 2016, 18, 3710-3713.
4
2. Mojr, V.; Svobodová, E.; Straková, K.; Neveselý, T.; Chudoba, J.;
Dvořáková, H.; Cibulka, R. Chem. Commun. 2015, 51, 12036-
1
2039.
15120503700.
4
3. Špačková, J.; Svobodová, E.; Hartman, T.; Stibor, I.; Kopecká, J.;
Cibulková, J.; Chudoba, J.; Cibulka, R. ChemCatChem. 2017, 9,
References
1
177-1181.
4. Metternich, J. B.; Gilmour, R. J. Am. Chem. Soc. 2015, 137,
1254-11257.
5. Metternich, J. B.; Gilmour, R. J. Am. Chem. Soc. 2016, 138,
040-1045.
6. Hering, T.; Mühldorf, B.; Wolf, R.; König, B. Angew. Chem. Int.
Ed. 2016, 55, 1-5.
7. März, M.; Chudoba, J.; Kohouta, M.; Cibulka, R. Org. Biomol.
Chem. 2017, 15, 1970-1975.
4
4
4
4
1
2
3
.
.
.
Christophe, C. Chem. Rev. 2010, 110, 656-680.
Labinger, J. A.; Bercaw, J. E. nature. 2002, 417, 507-514.
Newhouse, T.; Baran, P. S. Angew. Chem. Int. Ed. 2011, 50, 3363-
1
1
3
374.
4
5
.
.
Campbell, A. N.; Stahl, S. S. Acc. Chem. Res. 2012, 45, 851-863.
Tan, T. T.; Zheng, T. Y.; Yu, Y. Q.; Xu, K. RSC Adv. 2017, 7,
1
5176-15180.
6
7
.
.
Mizuno, M.; Inagaki, A.; Yamashita, M.; Soma, N.; Maeda, Y.;
Nakatani, H. Tetrahedron. 2006, 62, 4065-4070.
Luque-Ortega, J. R.; Reuther, P.; Rivas, L.; Rivas, C. J. Med.
Chem. 2010, 53, 1788-1798.
4
4
8. Mühldorf, B.; Wolf, R. ChemCatChem. 2017, 9, 920-923.
9. Lechner, R.; Kümmel, S.; König, B. Photochem. Photobiol. Sci.
2
010, 9, 1367-1377.
0. Fukuzumi, S.; Kuroda, S.; Tanaka, T. J. Am. Chem. Soc. 1985,
07, 3020-3027.
5
8
9
.
.
Nakamura, A.; Nakada, M. Synthesis. 2013, 45, 1421-1451.
Horn, E. J.; Rosen, B. R.; Chen, Y.; Tang, J.; Chen, K.; Eastgate,
M. D,; Baran, P. S. nature. 2016, 533, 77-81.
1
5
5
1. Fukuzumi, S.; Kojima, T. J Biol Inorg Chem. 2008, 13, 321-323.
2. Fukuzumi, S.; Jung, J.; Lee, Y. M.; Nam, W. Asian. J. Org. Chem.
1
0. Balcells, D.; Clot, E.; Eisenstein, O. Chem. Rev. 2010, 110, 749-
23.
2
017, 6, 397-409.
8
5
5
5
5
3. Mühldorf, B.; Wolf, R. Chem. Commun. 2015, 51, 8425-8428.
4. Mühldorf, B.; Wolf, R. Angew. Chem. Int. Ed. 2016, 55, 427-430.
5. Recupero, F.; Punta, V. Chem. Rev. 2007, 107, 3800-3842.
6. Horn, E. J.; Rosen, B. R.; Chen, Y.; Tang, J.; Chen, K.; Eastgate,
M. D.; Baran, P. S. nature. 2016, 533, 77-81.
1
1
1. Gunay, A.; Theopold, K. H. Chem. Rev. 2010, 110, 1060-1081.
2. Roduner, E.; Kaim, W.; Sarkar, B.; Urlacher, V. B.; Pleiss, J.;
Gläser, R.; Einicke, W.-D.; Sprenger, G. A.; Beifuß, U.; Klemm,
E.; Liebner, C.; Hieronymus, H.; Hsu, S.-F.; Plietker, B.; Laschat,
S. ChemCatChem. 2013, 5, 82-112.
5
5
5
6
7. Zhang, P.; Wang, Y.; Yao, J.; Wang, C.; Yan, C.; Antonietti, M,;
Li, H. R. Adv. Synth. Catal. 2011, 353, 1447-1451.
8. Devari, S.; Rizvi, M. A.; Shah, B. A. Tetrahedron Lett. 2016, 57,
1
3. Lu, Q.; Zhang, J.; Zhao, G.; Qi, Y.; Wang, H.; Lei, A. J. Am.
Chem. Soc. 2013, 135, 11481-11484.
1
1
4. Zhang, C.; Jiao, N. J. Am. Chem. Soc. 2010, 132, 28-29.
5. Hudlicky, M. Oxidations in Organic Chemistry, American
Chemical Society: Washington, 1990.
3
294-3297.
9. Miao, C. X.; Zhao, H. Q.; Zhao, Q. Y.; Xia, C. G.; Sun, W. Catal.
Sci. Technol. 2016, 6, 1378-1383.
0. Hruszkewycz, D. P.; Miles, K. C.; Thiel, O. R.; Stahl, S. S. Chem.
Sci. 2017, 8, 1282-1287.
1
6. Romero, N. A.; Nicewicz, D. A. Chem. Rev. 2016, 116, 10075-
1
0166.

5
6
6
1. Deng, Y.; Wei, X.; Wang, H.; Sun, Y.; Noël, Wang, X. Angew.
Chem. Int. Ed. 2017, 56, 832-836.
2. Malkov, A. V.; Pernazza, D.; Bell, M.; Massa, A.; Teplý, F.;
Meghani, P.; Kočovský, P. J. Org. Chem. 2003, 68, 4727-4742.
3. Fukuda, O.; Sakaguchi, S.; Ishii, Y. Adv. Synth. Catal. 2001, 343,
6
6
8
09-813.
4. Fernandes, T. A.; Santos, C. I. M.; André, V.; Dias, S. S. P.;
Kirillova, M. V.; Kirillov, A. M. Catal. Sci. Technol. 2016, 6,
4
584-4593.
6
6
5. Xu, F.; Song, X. N.; Sheng, G. P.; Luo, H. W.; Li, W. W.; Yao, R.
S.; Yu, H. Q. ACS Sustainable Chem. Eng. 2015, 3, 1756-1763.
6. Churakova, E.; Kluge, M.; Ullrich, R.; Arends, I.; Hofrichter, M.;
Hollmann, F. Angew. Chem. Int. Ed. 2011, 50, 10716-10719.
Supplementary Material
Supplementary data (experimental procedure, characterization
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data, H and C NMR of relevant compounds) associated with
this article can be found in the online version. That file can then
be transformed into PDF format and submitted along with the
manuscript and graphic files to the appropriate editorial office.

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Tetrahedron
Highlights
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) Developed visible light mediated aerobic
photocatalytic activation of C-H bond
) Used cheap ferric chloride and NHS instead of
expensive scandium triflate
) Proposed a plausible reaction mechanism
through the SET pathway