Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds

Article abstract of DOI:10.1039/d0gc00383b

Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is

Full text of DOI:10.1039/d0gc00383b

View Article Online
View Journal
Green
Chemistry
Cutting-edge research for a greener sustainable future
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: X. Zhu, Y. Liu, C.
Liu, H. Yang and H. Fu, Green Chem., 2020, DOI: 10.1039/D0GC00383B.
Volume 20
This is an Accepted Manuscript, which has been through the
Number
May 2018
Pages 1919-2160
9
7
Royal Society of Chemistry peer review process and has been
accepted for publication.
Green
Chemistry
Cutting-edge research for a greener sustainable future
rsc.li/greenchem
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
shall the Royal Society of Chemistry be held responsible for any errors
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
ISSN 1463-9262
PAPER
Paul T. Anastas et al.
The Green ChemisTREE: 20 years after taking root with the 12
principles
rsc.li/greenchem

View Article Online
DOI: 10.1039/D0GC00383B
Green Chemistry
Page 1 of 6Green Chemistry
Dynamic Article Links ►
Cite this: DOI: 10.1039/c0xx00000x
www.rsc.org/xxxxxx
ARTICLE TYPE
Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated
selective oxidation of C-H bonds†
Xianjin Zhu, Yong Liu, Can Liu, Haijun Yang and Hua Fu*
Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
5
DOI: 10.1039/b000000x
Visible light-induced organic reactions are important chemical transformation in organic chemistry, and their efficiency highly depends
on suitable photocatalysts. However, the commonly used photocatalysts are the precious transition-metal complexes and elaborate
organic dyes, which hamper large-scale production for high cost. Here, we report a novel strategy for the first time: light and oxygen-
enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, and high-value-added chemicals, aromatic ketones
10 and carboxylic acids, were easily prepared in high to excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as
the materials. The mechanism investigations showed that treatment of inexpensive and readily available sodium
trifluoromethanesulfinate with oxygen under irradiation of light could in-situ form a pentacoordinate sulfide intermediate as the efficient
photosensitizer. The methods are a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled
sodium trifluoromethanesulfinate photocatalytic system breakthroughs the previous photochemical concepts.
15
Introduction
Over the past decade, visible light photocatalysis has received
great attention for its simplicity, economy and environmental
friendliness,1 and the efficiency of reactions is highly dependent
20 on photocatalysts.2 The commonly used photocatalysts are the
precious transition-metal complexes3 and elaborate organic dyes4
(Scheme 1A) that are previously prepared, which is not
conducive to large-scale production for relative high cost. In
addition, non-photosensitive donors and receptors form an
25 electron donor and acceptor (EDA) complexes that can absorb
visible light to realize photocatalytic reactions (Scheme 1B).5
However, the EDA complexes are very limited thus far. Here, we
want to explore a new strategy: an in-situ formed photocatalyst
promotes the corresponding organic reactions. Sodium
30 trifluoromethanesulfinate (1) (Langlois reagent)6 is a readily
available, inexpensive and easily stored reagent, and it is usually
used as the trifluoromethyl source.7 We realized that many
transition metals could form metal epoxides by interacting with
oxygen (Scheme 1C).8 The pentacoordinate sulfides were
35 reported although they were seldom developed.9 Atomic valence
state of sulfur is +4 in 1. We hypothesized that the photoinduced
interaction of 1 with oxygen would form a pentacoordinate
sulfide (PS) (2) with +6 valence state of sulfur (Scheme 1D), and
the pentacoordinate sulfide (2) would act as a photosensitizer.
40 Density functional theory (DFT) calculations show that formation
of 2 from treatment of 1 with oxygen only needs 24.12 kcal/mol
activation energy releasing a high energy (105.02 kcal/mol) (see
Scheme 1D and Supporting Information for details).
45 Scheme 1 Previous photosensitizers and our design. (A) Transition-metal
complexes and organic dyes. (B) Electron donor and acceptor (EDA)
complexes as the photosensitizers. (C) Formation of transition-metal
This journal is © The Royal Society of Chemistry [year]
[journal], [year], [vol], 00–00 | 1

View Article Online
DOI: 10.1039/D0GC00383B
Green Chemistry
Page 2 of 6
epoxides. (D) Formation of pentacoordinate sulfide (PS, 2). (E) Proposed
mechanistic pathway of photoredox aerobic oxidation of ethylbenzene (6)
to acetophenone (9).
of 1-ethyl-4-fluorobenzene (10) under different conditions (see
Tables S1-S8 in Supporting Information for details). To our
35 delight, we found that the conditions using 25 mol% sodium
trifluoromethanesulfinate (1) as pre-photosensitizer, acetonitrile
as the solvent with irradiation of a 3 W blue light emitting diode
(LED) bulb (400-405 nm) under oxygen atmosphere (1 atm.),
achieved the desired 1-(4-fluorophenyl)ethanone (11) in almost
40 quantitative yield (Table 1). The same yield was provided when
oxygen was replaced with air (entry 1). However, the reaction did
not work in the absence of oxygen, light or 1 (entries 2-4), which
showed that none was dispensable for oxygen, light and 1 in the
The selective oxidation of saturated C-H bonds of readily
available alkanes to high-value-added chemicals10 using
environmentally benign molecular oxygen11 shows a great
significance in industrial and research fields. In fact, the process
catalyzed by enzymes is commonly seen in nature.12 However,
the selective aerobic oxidation of saturated C-H bonds is a great
5
10 challenge in chemistry. Ketones are versatile intermediates and
important structural motifs in pharmaceuticals, natural products,
and advanced organic materials.13 On the basis of our recent
studies in visible light photocatalysis, we questioned if the
pentacoordinate sulfide (2) could act as a photosensitizer as well
15 as a hydrogen atom grabbing catalyst under oxygen atmosphere
and light irradiation, which might provide a new and useful
strategy for selective oxidation of saturated C-H bonds. From a
design perspective, a detailed description of our proposed
mechanistic cycle for the aerobic oxidation of ethylbenzene (6) to
20 acetophenone (9) is outlined in Scheme 1E. We presumed that
initial light-irradiation of 2 would produce the photoexcited state
2*, and a single-electron transfer (SET) of 2* to oxygen would
generate two radicals 3 and 4. Treatment of 4 with 6 would
deliver 5 and radical 7, and exchange of the proton in 5 with Na+
25 would regenerate 2. Meanwhile, combination of 7 with 3 or
oxygen in the presence of one proton would give 8, and
dehydration of 8 would provide the target product (9).
reaction.
No
reaction
occurred
when
sodium
45 trifluoromethanesulfonate (CF3SO3Na) replaced 1 (entry 5). The
effect of solvents was investigated (entries 6-8), and acetone also
was a suitable solvent (giving 100% yield) (entry 6). We found
that wavelength of light was of great concern for the reaction
(entries 9-11), and wavelengths of 400-405 nm and 380-385 nm
50 were feasible. More conditions were performed in Tables S1-S8
of Supporting Information. Based on the results above, the
aerobic oxidation of alkyl arenes to ketones only needed very
simple conditions: light, oxygen or air, catalytic amount of
sodium trifluoromethanesulfinate (1) and suitable solvents
55 without requirement of previously prepared precious transition-
metal complexes or elaborate organic dyes. Interestingly, sodium
trifluoromethanesulfinate (1) itself is not a photosensitizer, and
the activation of light and oxygen makes it become
a
photosensitizer, pentacoordinate sulfide (2).
Results and discussion
Table 1 Optimization of reaction conditionsa
30
Yield (%)b
100
Entry
Variation of the standard conditions
1
2
3
4
5
6
7
8
air (1atm) instead of oxygen
Ar atmosphere instead of oxygen
without light
nr
nr
without CF3SO2Na
nr
CF3SO3Na instead of 1
acetone instead of CH3CN
DMF instead of CH3CN
DMSO instead of CH3CN
nr
100
20
nr
blue LED (450-455 nm) instead of blue LED 64
(400-405 nm)
9
blue LED (420-425 nm) instead of blue LED 88
(400-405 nm)
10
blue LED (380-385 nm) instead of blue LED 100
(400-405 nm)
11
aReaction conditions: 10 (0.1 mmol), 1 (25 mol%), solvent (1.0 mL),
under O2 atmosphere (1 atm.) and light irradiation at room temperature
(~25 oC) for 12 h. bThe yields were determined by 19F NMR using
benzotrifluoride as the internal standard. nr = no reaction.
Scheme 2 Aerobic oxidation of aryl arenes to ketones. Reaction
conditions: alkyl arene (0.2 mmol), 1 (25 mol%), solvent (1.0 mL),
under O2 atmosphere (1 atm.) and light irradiation at room temperature
(~25 oC) for 12 h. The yields were determined by GC-MS using
dodecane as the internal standard. Using LED (400-405, 380-385 or
420-425 nm) as the light source. Isolated yield.
Investigations on reaction conditions. With this mechanistic
hypothesis in hand, we first tested the proposed aerobic oxidation
2
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

View Article Online
DOI: 10.1039/D0GC00383B
Page 3 of 6
Green Chemistry
molecule (42) in 87% yield (Scheme 3B). Lenperone (44), an
Surveys of the alkyl arene scope on synthesis of ketones.
Having established the optimal conditions for this aerobic 50 effective atypical antipsychotic drug used in the treatment of
oxidation of alkyl arenes, we surveyed the scope of substrates. As
shown in Scheme 2, various ethyl arenes are amenable to this
light and oxygen-enabled sodium trifluoromethanesulfinate-
mediated selective oxidation strategy including neutral (9, 23-25,
schizophrenia,16 was easily prepared in 82% yield through
coupling of 40 with (4-fluorophenyl)(piperidin-4-yl)methanone
(43) (Scheme 3C). Therefore, the results above showed that our
environmentally friendly aerobic oxidative method from alkyl
5
92-100% yields), electron-rich (12, 100 % yield), weak electron- 55 arenes to ketones was very effective, economical and practical.
deficient (11, 13-17, 95-100% yields), strong electron-deficient
dark
light for 2 min
light for 4 min
light for 6 min
ethyl arenes (18-22, 95-99% yields) and O-heterocycle (26, 51%
10 yield). Subsequently, arenes containing different alkyls were
dark
light for 10 min
attempted under the standard conditions, and we found that length
of alkyls and variation of substituents on the alkyls almost did not
affect the reactivity of the substrates (27-31, 95-99% yields).
Next, 1,4-diethylbenzene was used as the substrate under
15 irradiation of 3 W purple light emitting diode (LED) bulb (380-
385 nm), and 1,4-diacetylbenzene (19) was obtained in 97% yield
(see secondary 19 in Scheme 2). We tried the aerobic oxidation of
1,3,5-triethylbenzene and found that different light wavelength
led to different products: irradiation with 420-425 nm blue light
20 gave 32 in 61% yield together with trace amount of 33 appearing,
and irradiation with 380-385 nm purple light afforded 1,3,5-
triacetylbenzene (33) in 96% yield without 32 occurring. Finally,
the aerobic oxidation of hydrocarbons containing two phenyls
were investigated under the standard conditions, and they also
25 exhibited high reactivity (34-37). Diphenylmethane gave
benzophenone (34) in 98% yield, 1,2-diphenylethane provided 2-
phenylacetophenone (35) in 97% yield, and 1,4-diphenylbutane
and 1,5-diphenylpentane afforded diketones 36 and 37 in 89%
and 86% yields, respectively. A gram-scale production of
30 acetophenone (9) was performed using ethylbenzene (6) (10
mmol, 1.06 g) as the material under the standard conditions with
irradiation of 30 W blue LEDs (400 - 405 nm), and 1.07 g of 9
was obtained in 89% isolated yield. The reactions in Scheme 2
could tolerate various functional groups including C-F, C-Cl, C-
35 Br and C-I bonds, ether, CF3, ester, acetyl, cyano and nitro groups.
319 320 321 322 323 324 325 326
Megnetic Field (mT)
319 320 321 322 323 324 325 326
Magnetic Field (mT)
Scheme 4 Investigations on the reaction mechanism.
Mechanistic investigations. To verify the proposed mechanistic
60 pathway of aerobic oxidation of alkyl arenes to ketones in
Scheme 1E, some experiments were carried out as follows: (a) In
order to confirm the active species of oxygen involved in the
present reaction, and the electron paramagnetic resonance (EPR)
experiments were performed. When a solution of 2,2,6,6-
1
65 tetramethylpiperidin-4-one (TMPD) as the trapping agent of O2,
1 and ethylbenzene (6) in acetonitrile was irradiated with full
wavelength light under oxygen atmosphere,
a
stronger
characteristic signal of 1O2 adduct with TMPD was observed
(Scheme 4Aa); When solution of 5,5-dimethyl-1-pyrroline N-
70 oxide (DMPO), 1 and ethylbenzene (6) in acetonitrile was
irradiated with full wavelength light under oxygen atmosphere, a
Scheme 3 Applications of the method.
Applications of the method. To demonstrate synthetic
40 practicability of this aerobic oxidative protocol, three applications
were conducted. As shown in Scheme 3A, O-heterocycle 38 was
easily prepared using synthesized 37 as the intermediate in the
presence of boron trifluoride.14 Melperone (42) is an
antipsychotic drug,15 so it is of important value to develop a
45 convenient and efficient synthetic route. 1-(4-Bromobutyl)-4-
fluorobenzene (39) was used as the starting material, its aerobic
oxidation under our standard conditions provided 40 in 93% yield,
and coupling of 40 with 4-methylpiperidine (41) gave the drug
•-
characteristic signal of O2 adduct with DMPO was found
(Scheme 4Ab). (b) When 18O2 replaced 16O2 as the oxygen source
using propylbenzene as the substrate, propiophenone (27) and
75 18O-labelling propiophenone (27') were obtained in 24% and 76%
yields (GC-MS determination), respectively (Scheme 4B), which
indicated that molecular oxygen (O2) was a sole oxygen source in
the oxidation of alkyl arenes to ketones. (c) Treatment of
ethylbenzene (6) was carried out under argon atmosphere, and no
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 3

View Article Online
DOI: 10.1039/D0GC00383B
Green Chemistry
Page 4 of 6
reaction occurred. Subsequently, the reaction system was
conducted under oxygen atmosphere, product 9 was provided in
almost quantitative yield (Scheme 4C). These results showed that
region, that were assigned to three different binding forms of
oxygen in 2 (Figure 1Ab). (b) Solid 19F NMR spectra of sodium
trifluoromethanesulfinate (1), sodium trifluoromethanesulfonate
O2 is essential for this transformation. (d) Sodium 35 (CF3SO3Na) and 2 were recorded, and they showed the chemical
5
trifluoromethanesulfinate (1) was performed under the standard
conditions (19F NMR showed that 1 was consumed completely),
then ethylbenzene (6) was added to the system, and a nearly
quantitative yield was observed (Scheme 4D). (e) When sodium
shifts at -86.244 ~ -88.701 ppm (m), -78.875 ppm (s) and -77.156
ppm (s), respectively (see Figure S5-S7 in Supporting
Information), which indicated that 2 was different with 1 and
CF3SO3Na. (c) Powder X-ray diffraction (PXRD) patterns of 1,
trifluoromethanesulfonate (CF3SO3Na) instead of 1 was added to 40 CF3SO3Na and 2 were also detected, and they gave different
10 reaction system of 6, no reaction occurred (Scheme 4E). In
addition, the reaction did not work in the presence of other sulfur-
containing compounds with +6 valence state (see Table S13 in
Supporting Information). Therefore, we think that intermediate 2
spectra (Figure 1B). (d) UV-visible absorption spectra of 1,
CF3SO3Na and 2 in MeCN in the range of 200-800 nm were
recorded (Figure S9-S11 in Supporting Information), and 2 gave
the obvious absorption peak in the range of visible light region
could be the real photocatalyst. (f) Ethylbenzene (6) did not react 45 (390 - 420 nm) (Figure 1C), which indicated 2 could act as a
15 in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)
under the standard conditions (Scheme 4F), and the result
exhibited that the aerobic oxidation of 6 to acetophenone (9) was
a radical process.
photosensitizer. (e) Fourier-transform attenuated total reflectance
(FTIR-ATR) spectra of 1, CF3SO3Na and 2 were recorded, and
they showed different peaks (see Figure 1D). According to the
results above, intermediate 2 could be a pentacoordinate sulfide.
50 Therefore, we think that the proposed mechanistic pathway of
photoredox aerobic oxidation of alkyl arenes to ketones in
Scheme 1E is reasonable.
533.02 eV
S 2p
O 1s
169.89 eV
537.49 eV
525.15 eV
174 172 170 168 166 164 162 160 158 156
Binding Energy (eV)
542 540 538 536 534 532 530 528 526 524 522
Binding Energy (eV)
5
4
3
2
1
0
10
20
30
40
50
60
70
80
200
300
400
500
600
700
2θ/degrees
Wavelength (nm)
Scheme 5 Aerobic oxidation of methyl arenes to carboxylic acids.
Reaction conditions: methyl arene (0.2 mmol), 1 (50 mol%), solvent
(1.0 mL), under O2 atmosphere (1 atm.) and light irradiation at room
temperature (~25 oC) for 12 h. Using blue LED (400-405 nm) as the
light source. Isolated yield.
2000
1500
1000
500
-1
Wavenumbers (cm
)
Figure 1 Characterizations for pentacoordinate sulfide (2). (A) XPS
spectra of 2: (a) XPS spectrum of the S 2p energy region; (b) XPS
spectrum of the O 1s energy region. (B) PXRD patterns of 1,
CF3SO3Na and 2. (C) UV-vis spectrum of 2. (D) FTIR-ATR spectra of
1, CF3SO3Na and 2.
Aerobic oxidation of methyl arenes to carboxylic acids.
Carboxylic acids are a kind of important organic compounds, and
55 they are used as the synthetic precursors for various high-value-
added chemicals.17 In the traditional oxidative methods, synthesis
of the kinds of compounds was performed in the presence of
stoichiometric loadings of hazardous oxidants such as
dichromate/permanganate,18 oxone,19 periodate reagent20 with
60 large amounts of wastes containing heavy metals occurring,
which is not environmentally benign. It is an important direction
to develop simple, efficient and environmentally friendly
methods to synthesize the high-value products from simple and
readily available starting materials. To further demonstrate the
Characterizations for pentacoordinate sulfide (2). To further
20 identify the presumed pentacoordinate sulfide (2), sodium
trifluoromethanesulfinate (1) (0.25 mmol) in 2 mL of acetonitrile
was stirred with irradiation of blue LED (400-405 nm) under
oxygen atmosphere (1 atm.) for 12 h, then the sediment was
filtered to get a possible pentacoordinate sulfide (2) (see
25 Supporting information). Subsequently, various characterizations
were performed as follows: (a) Solid 2 was determined by X-ray
photoelectron spectroscopy (XPS), and the binding-energy (BE)
peak at 169.89 eV was observed in the XPS spectrum of the S 2p
energy region (Figure 1Aa), that was assigned to +6 valence state
30 of sulfur. Meanwhile, three strong peaks at 525.15, 533.02 and
537.49 eV were found in the XPS spectrum of the O 1s energy
65 utility
of
this
light
and
oxygen-enabled
sodium
trifluoromethanesulfinate-mediated selective oxidation strategy,
we investigated aerobic oxidation of methyl arenes to carboxylic
acids. As shown in Scheme 5, selective aerobic oxidation of
methyl arenes was carried out in acetonitrile in the presence of 50
4
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

View Article Online
DOI: 10.1039/D0GC00383B
Page 5 of 6
Green Chemistry
mol% of 1 under oxygen atmosphere (1 atm.), and the reactions
were satisfactory for methyl arenes containing different
functional groups including neutral (45 and 61, 93% and 92%
Scheme 6, the excellent results were provided for aromatic
aldehydes containing different functional groups including
neutral (45, 61 and 76, 86-95% yields), electron-rich (46, 64-66,
yields, respectively), electron-rich (46, 87% yield), weak 25 89-94% yields), weak electron-deficient (47-53, 67-72, 92-97%
5
electron-deficient (47-53, 89-97% yields), strong electron-
deficient groups (54-60, 87-95% yields), and O-, S-heterocycles
(62 and 63, 52% and 68% yields, respectively). The present
reactions could tolerate various functional groups including C-F,
yields), and strong electron-deficient groups (54, 57-59, 73-75,
91-96% yields). Four heteroaryl aldehydes also provided the
corresponding carboxylic acids 77-80 in 93-96% yields. Aliphatic
aldehyde, decanal, was attempted to perform this aerobic
C-Cl and C-Br bonds, ether, CF3, acyl, ester, amide and cyano 30 oxidation, and it afforded 81 in 91% yield. Notably, a gram-scale
10 groups, and O-, S-heterocycles. Notably, aerobic oxidation of 4-
production of benzoic acid (45) was conducted under the standard
conditions using benzaldehyde (82) (10 mmol, 1.06 g) as the
example, and 1.15 g of 45 was obtained in 94% yield. The
present reactions could tolerate various functional groups
fluorotoluene was performed with 18O2 as the oxygen source
under the standard conditions, 4-fluorobenzoic acid (47), single
18O-labelling 4-fluorobenzoic acid (47') and double 18O-labelling
4-fluorobenzoic acid (47'') were obtained in 94% total yield with 35 including C-F, C-Cl and C-Br bonds, ether, hydroxyl, CF3, ester,
15 a ratio of 4:32:64 for 47/47'/47''. The result showed that
molecular oxygen (O2) was a sole oxygen source for oxidation of
methyl arenes to carboxylic acids.
amide and cyano groups, and N-, S-heterocycles. Aerobic
oxidation of 4-fluorobenzaldehyde was also performed under the
standard conditions with 18O2 as oxygen source, 4-fluorobenzoic
acid (47) and single 18O-labelling 4-fluorobenzoic acid (47') were
40 obtained in 97% total yield with a ratio of 13:87 for 47/47'.
Conclusions
We have developed a novel light and oxygen-enabled sodium
trifluoromethanesulfinate-mediated selective oxidation of C-H
bonds, and the high-value-added chemicals, aromatic ketones and
45 carboxylic acids, were prepared in high to excellent yields using
readily available alkyl arenes, methyl arenes and aldehydes as the
materials, in which the in situ formed pentacoordinate sulfide
intermediate derived from sodium trifluoromethanesulfinate and
oxygen under irradiation of light acted as the efficient
50 photosensitizer. The present methods show some advantages
including inexpensive and readily available sodium
trifluoromethanesulfinate as the precursor of photosensitizer,
simple and easy operational reaction conditions, use of
environmentally friendly chemicals and high selectivity of the
55 reactions. We believe that the light and oxygen-enabled sodium
trifluoromethanesulfinate
photocatalytic
system
should
breakthrough previous photochemical concepts and will find
wide applications.
Conflict of interest
60 The authors declare no conflict of interest.
Acknowledgements
The authors would like to thank the National Natural Science
Foundation of China (Grant No. 21772108) for financial support.
Notes and references
65 Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical
Biology (Ministry of Education), Department of Chemistry, Tsinghua
University, Beijing 100084, P. R. China. Fax: (+86) 10-62781695; E-
mail: fuhua@mail.tsinghua.edu.cn
† Electronic supplementary information (ESI) available. See DOI:
70 10.1039/xxx.
Scheme 6 Aerobic oxidation of aldehydes to carboxylic acids. Reaction
conditions: aldehyde (0.2 mmol), 1 (50 mol%), solvent (1.0 mL), under
O2 atmosphere (1 atm.) and light irradiation at room temperature (~25
oC) for 12 h. Using blue LED (400-405 nm) as the light source. Isolated
yield.
1
(a) D. A. Nicewicz and D. W. C. MacMillan, Science, 2008, 322, 77–
80; (b) J. Jin and D. W. C. MacMillan, Nature, 2015, 525, 87–90; (c)
E. B. Corcoran, M. T. Pirnot, S. Lin, S. D. Dreher, D. A. DiRocco, I.
W. Davies, S. L. Buchwald and D. W. C. MacMillan, Science, 2016,
353, 279–283; (d) I. Ghosh, T. Ghosh, J. I. Bardagi and B. König,
Science, 2014, 346, 725–728; (e) A. Bauer, F. Westkämper, S.
Grimme and Bach, T. Nature, 2005, 436, 1139–1140; (f) M. Silvi, C.
Verrier, Y. P. Rey, L. Buzzetti and P. Melchiorre, Nat. Chem., 2017,
9, 868–873.
75
80
Aerobic oxidation of aldehydes to carboxylic acids. The
selective photocatalytic aerobic oxidation of aldehydes was
20 surveyed using acetonitrile as the solvent in the presence of 25
mol% of 1 under oxygen atmosphere (1 atm.). As shown in
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 5

View Article Online
DOI: 10.1039/D0GC00383B
Green Chemistry
Page 6 of 6
2
3
(a) J. Twilton, P. Zhang, M. H. Shaw, R. W. Evans and D. W. C.
MacMillan, Nat. Rev. Chem., 2017, 1, 0052; (b) L. Marzo, S. K.
Pagire, O. Reiser and B. König, Angew. Chem., Int. Ed., 2018, 57,
10034–10072; (c) J. M. Narayanam and C. R. J. Stephenson, Chem.
Soc. Rev., 2011, 40, 102–113; (d) K. L. Skubi, T. R. Blum and T. P.
Yoon, Chem. Rev., 2016, 116, 10035–10074.
(a) C. K. Prier, D. A. Rankic and D. W. C. MacMillan, Chem. Rev.,
2013, 113, 5322–5363; (b) J. C. Tellis, D. N. Primer and G. A.
Molander, Science, 2014, 345, 433–436; (c) C. P. Johnston, R. T.
Smith, S. Allmendinger and D. W. C. MacMillan, Nature, 2016, 536,
322–325.
(a) D. Ravelli, M. Fagnoni and A. Albini, Chem. Soc. Rev., 2013, 42,
97–113; (b) N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016,
116, 10075–10166; (c) I. K. Sideri, E. Voutyritsa and C. G. Kokotos,
Org. Biomol. Chem., 2018, 16, 4596–4614.
(a) B. Siegmund, A. Mischok, J. Benduhn, O. Zeika, S. Ullbrich, F.
Nehm, M. Böhm, D. Spoltore, H. Fröb, C. Körner, K. Leo and K.
Vandewal, Nat. Commun., 2017, 8, 15421; (b) J. Davies, S. G. Booth,
S. Essafi, R. A. W. Dryfe and D. Leonori, Angew. Chem., Int. Ed.,
2015, 54, 14017–14021; (c) M. C. Fu, R. Shang, B. Zhao, B. Wang
and Y. Fu, Science, 2019, 363, 1429–1434.
New York, 2007; (b) M. Liu, H. Wang, H. Zeng and C.-J. Li, Sci.
Adv., 2015, 1, e1500020; (c) Q. Yu, Y. Zhang and J.-P. Wan, Green
Chem., 2019, 21, 3436−3441; (d) Y. Yang, G. Zhong, J. Fan and Y.
Liu, Eur. J. Org. Chem., 2019, 27, 4422−4425.
75
5
10
15
20
18. (a) R. L. Shriner and E. C. Kleiderer. Org. Synth., 1930, 10, 82–83;
(b) J. R. Ruhoff, Org. Synth., 1936, 16, 39–40.
19. B. R. Travis, M. Sivakumar, G. O. Hollist and B. Borhan, Org. Lett.,
2003, 5, 1031–1034.
80 20. M. Hunsen, Synthesis, 2005, 15, 2487–2490.
4
5
6
(a) B. R. Langlois, E. Laurent and N. Roidot, Tetrahedron Lett., 1991,
32, 7525–7528; (b) B. R. Langlois, E. Laurent and N. Roidot,
Tetrahedron Lett., 1992, 33, 1291–1294.
25 7
(a) W. Kong, M. Casimiro, N. Fuentes, E. Merino and C. Nevado,
Angew. Chem., Int. Ed., 2013, 52, 13086–13090; (b) Y. Ji, T. Brueckl,
R. D. Baxter, Y. Fujiwara, I. B. Seiple, S. Su, D. G. Blackmond and
P. S. Baran, Proc. Natl. Acad. Sci. U. S. A., 2011, 108, 14411–14415;
(c) A. Deb, S. Manna, A. Modak, T. Patra, S. Maity and D. Maiti,
Angew. Chem., Int. Ed., 2013, 52, 9747–9750.
30
8
(a) D. Wang, A. B. Weinstein, P. B. White and S. S. Stahl, Chem.
Rev., 2018, 118, 2636–2679; (b) J. T. Grant, J. M. Venegas, W. P.
McDermott and I. Hermans, Chem. Rev., 2018, 118, 2769–2815; (c)
Y. Liang, J. Wei, X. Qiu and N. Jiao, Chem. Rev., 2018, 118, 4912–
4945; (d) X. Huang and J. T. Groves, Chem. Rev., 2018, 118, 2491–
2553.
35
9
(a) F. Ohno, T. Kawashima and R. Okazaki, J. Am. Chem. Soc., 1996,
118, 697–698; (b) E. Lork, M. Müller, J. Wessel, R. Mews, T.
Borrmann and W. D. Stohrer, J. Fluorine Chem., 2001, 112, 247–258;
(c) T. Kawashima, Phosphorus Sulfur Silicon, 2011, 186, 1046–1054.
40
10 (a) A. E. Shilov and G. B. Shul'pin, Chem. Rev., 1997, 97, 2879–2932;
(b) J. A. Labinger and J. E. Bercaw, Nature, 2002, 417, 507–514; (c)
M. S. Chen and M. C. White, Science, 2010, 327, 566–571; (d) V.
Kesavan, P. S. Sivanand, S. Chandrasekaran, Y. Koltypin and A.
Gedanken, Angew. Chem., Int. Ed., 1999, 38, 3521–3523; (e) T.
Maschmeyer, R. D. Oldroyd, G. Sankar, J. M. Thomas, I. J. Shannon,
C. R. A. Catlow, J. A. Klepetko, A. F. Masters and J. K. Beattie,
Angew. Chem., Int. Ed., 1997, 36, 1639–1642; (f) N. F. Nikitas, D. I.
Tzaras, I. Triandafillidi and C. G. Kokotos, Green Chem., 2020, 22,
471–477; (g) Y. Zhang, W. Schilling and S. Das, Chem. Sus. Chem.,
2019, 12, 2898–2910; (h) A. K. Sharma, A. Jaiswal and K. N. Singh,
Org. Biomol. Chem., 2019, 17, 9348–9351; (i) L. Deng, B. Huang
and Y. Liu, Org. Biomol. Chem., 2018, 16, 1552–1556;
45
50
55
60
11 (a) M. S. Sigman and D. R. Jensen, Acc. Chem. Res., 2006, 39, 221–
229; (b) S. S. Stahl, Science, 2005, 309, 1824–1826; (c) Z. Shi, C.
Zhang, C. Tang and N. Jiao, Chem. Soc. Rev., 2012, 41, 3381–3430;
(d) A. N Campbell and S. S. Stahl, Acc. Chem. Res., 2012, 45, 851–
863.
12 (a) W. Nam, Acc. Chem. Res., 2007, 40, 465; (b) F. P. Guengerich,
Chem. Res. Toxicol., 2001, 14, 611–650.
13 (a) M. W. Walter, Nat. Prod. Rep., 2002, 19, 278–291; (b) P. V.
Kamat, Chem. Rev., 1993, 93, 267–300.
14 M. Courté, M. Alaaeddine, V. Barth, L. Tortech and D. Fichou, Dyes
Pigments, 2017, 141, 487-492.
65 15. T. Verheyen, L. Turnhout, J. K. Vandavasi, E. S. Isbrandt, W. M. De
Borggraeve and S. G. Newman, J. Am. Chem. Soc., 2019, 141,
6869−6874.
16. J. Liu, K.-F. Hu, J.-P. Qu and Y.-B. Kang. Org. Lett., 2017, 19,
5593−5596.
70 17. (a) Oxidation of Primary Alcohols to Carboxylic Acids: A Guide to
Current Common Practice. G. Tojo and M. Fernandez Eds, Springer:
6
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]