Fluorosulfonylation of arenediazonium tetrafluoroborates with Na2S2O5 and N-fluorobenzenesulfonimide

Article abstract of DOI:10.1016/j.jfluchem.2020.109653

A transition-metal-free Sandmeyer-type fluorosulfonylation reaction has been achieved by the three-component reaction of arenediazonium tetrafluoroborates, Na₂S₂O₅, and N-fluorobenzenesulfonimide (NFSI). The reaction proceeds through a radical tandem process, affording various arenesulfonyl fluorides in moderate to high yields. This protocol not only provides a complement to the previous fluorosulfonylation reactions, but also extends the applications of Sandmeyer reaction.

Full text of DOI:10.1016/j.jfluchem.2020.109653

Journal Pre-proof
Fluorosulfonylation of arenediazonium tetrafluoroborates with Na2S2O5
and N-fluorobenzenesulfonimide
Shuai Liu, Yangen Huang, Xiu-Hua Xu, Feng-Ling Qing
PII:
S0022-1139(20)30351-1
DOI:
https://doi.org/10.1016/j.jfluchem.2020.109653
FLUOR 109653
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24 August 2020
28 September 2020
28 September 2020
Please cite this article as: Liu S, Huang Y, Xu X-Hua, Qing F-Ling, Fluorosulfonylation of
arenediazonium tetrafluoroborates with Na2S2O5 and N-fluorobenzenesulfonimide, Journal of
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Fluorosulfonylation of arenediazonium tetrafluoroborates with Na2S2O5 and N-
fluorobenzenesulfonimide
Shuai Liua, Yangen Huanga, Xiu-Hua Xub, Feng-Ling Qinga,b
aCollege of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North
Renmin Lu, Shanghai 201620, China
bKey Laboratory of Organofluorine Chemistry, Center for Excellence in Molecular Synthesis, Shanghai
Institute of Organic Chemistry, University of Chinese Academy of Science, Chinese Academy of Science,
345 Lingling Lu, Shanghai 200032, China
Tel.: 86-21-54925187; Fax: 86-21-64166128; E-mail: flq@mail.sioc.ac.cn
 Corresponding author. Tel.: +86 21 54925187; fax: +86 21 64166128.
E-mail address: flq@mail.sioc.ac.cn (F.-L. Qing).
Graphical Abstract
Highlights
 ·Transition-metal-free Sandmeyer-type fluorosulfonylation.
 ·An alternative approach to arenesulfonyl fluorides.
 ·Three-component reaction.
 ·Mild reaction conditions and broad functional group compatibility.
1

Abstract
A transition-metal-free Sandmeyer-type fluorosulfonylation reaction has been achieved by the three-
component reaction of arenediazonium tetrafluoroborates, Na2S2O5, and N-fluorobenzenesulfonimide
(NFSI). The reaction proceeds through a radical tandem process, affording various arenesulfonyl fluorides
in moderate to high yields. This protocol not only provides a complement to the previous
fluorosulfonylation reactions, but also extends the applications of Sandmeyer reaction.
Keywords: Fluorosulfonylation; arenediazonium salts; sulfur dioxide insert; fluorination; transition-
metal-free; radical.
1. Introduction
Due to the fortuitous balance between reactivity and stability, arenesulfonyl fluorides have found
remarkable utility as intermediates in organic synthesis [1] and covalent probes in chemical biology [2].
Recently, considerable efforts have focused on new applications of sulfonyl fluorides ranging from
fluorinating reagents [3] to Sulfur(VI) Fluoride Exchange (SuFEx) click chemistry [4]. Up to now,
numerous synthetic approaches to arenesulfonyl fluorides have been reported starting from a myriad of
different starting materials. The traditional method involves the nucleophilic fluorination of arenesulfonyl
chlorides [5] (Scheme 1a). However, arenesulfonyl chlorides require harsh conditions to synthesize, thus
rendering this approach incompatible with many functional groups. To address this issue, alternative
fluorination methods have been developed using arenesulfonic acids [6], arenesulfonates [7],
arenesulfinates [8], arenesulfonamides [9], or arenesulfonyl hydrazides [10] as the substrates (Scheme
1b). Arenesulfonyl fluorides could also be prepared from the corresponding thiols [11a], thioethers [11b],
or disulfides [11c,d] through oxidation and fluorination (Scheme 1c). Very recently, Noël and coworkers
developed an oxidant-free electrochemical process to generate arenesulfonyl fluorides from aryl thiols or
2

disulfides [12] (Scheme 1d). Comparing to the above transformations from sulfur-containing compounds,
the direct fluorosulfonylation of easily available aromatic substrates is more attractive. In this context,
Sammis and Ball reported the electrophilic fluorosulfonylation of aryl Grignard reagents with sulfuryl
fluoride (SO2F2) [13] (Scheme 1e). Kim and Kwon also reported the synthesis amino-substituted
arenesulfonyl fluorides by the three-component reaction of aryne precursors, secondary amines, and
SO2F2 [14] (Scheme 1f). In 2017, the groups of Willis and Bagley [15a] as well as Ball [15b] respectively
developed the one-pot synthesis of arenesulfonyl fluorides from the corresponding aryl halides, through
palladium-catalyzed sulfonylation of aryl halides using DABSO as an SO2 source followed by in situ
treatment of the resultant sulfinate with the electrophilic fluorine source NFSI or selectfluor (Scheme 1g).
Willis disclosed a similar strategy employing copper- or nickel-catalyzed sulfination and electrophilic
fluorination for the conversion of aryl boronic acids to arenesulfonyl fluorides [16] (Scheme 1h). Despite
these elegant achievements, the development of new synthetic methods using easily available substrates
and simple reagents is still highly desirable.
Scheme 1 Synthetic approaches to arenesulfonyl fluorides
3

The Sandmeyer reaction is widely used for the preparation of functionalized arenes from aryl
diazonium salts, which are easily accessible from commercially available anilines. In organofluorine
chemistry, the Sandmeyer-type reactions have proven to be an efficient strategy to introduce F atom [17]
and fluorine-containing groups such as CF3 [18], SCF3 [19], and OCF3 [20] into the aromatic rings. In
2015, our group also reported a copper-promoted tunable trifluoromethanesulfonylation and
trifluoromethylation of arenediazonium tetrafluoroborates with NaSO2CF3 [21]. To the best of our
knowledge, the Sandmeyer-type fluorosulfonylation had not been reported before we started this work.
In 2016, Wu and co-workers discovered that the reaction of the SO2 surrogate of DABCO·(SO2)2
and aryldiazonium tetrafluoroborates would provide an arenesulfonyl radical, which then underwent
further transformations for the synthesis of 3-sulfonated coumarins [22]. Recently, the combination of
4

arenediazonium salts and a SO2 surrogate, DABCO·(SO2)2 [23] or inorganic sulfites [24], have been
widely applied in the synthesis of arenesulfonyl-containing compounds. Inspired these achievements, we
envisioned that arenesulfonyl fluorides might be constructed starting from aryldiazonium salts, SO2
surrogates, and F sources via arenesulfonyl radical intermediates. Herein, we disclose a transition-metal-
free fluorosulfonylation of arenediazonium tetrafluoroborates with Na2S2O5 and NFSI for the preparation
of arenesulfonyl fluorides (Scheme 1i). Notably, during the preparation of this manuscript, the analogous
fluorosulfonylation of arenediazonium salts have been reported using different SO2 and F sources [25].
2. Results and Discussion
To test our hypothesis, 4-methoxybenzenediazonium tetrafluoroborate (1a) was chosen as the model
substrate to optimize fluorosulfonylation reaction conditions (Table 1). To our delight, the reaction of 1a
with Na2S2O5 as the SO2 source and N-fluorobenzenesulfonimide (NFSI) as the F source in MeOH at 40
oC afforded the fluorosulfonylated product 2a in 39% yield (entry 1). The screening of solvents revealed
that MeCN was superior, affording 2a in 54% yield (entries 2 and 3). Slightly higher yields were observed
when small amounts of water were added (entries 4 and 5). However, further increasing the amount of
water resulted in a decreased yield of 2a (entry 6). Subsequently, different SO2 sources including K2S2O5
and DABCOSO2 were examined, but no better result was obtained (entries 7 and 8). Switching the F
source from NFSI to selectfluor led to diminished yield (entry 9), whereas the use of KF as the F source
could not deliver the desired product (entry 10). Finally, the reaction temperature was explored, and 60
oC was found to be optimal, furnishing 2a in 74% yield (entries 11-13). Notably, methoxybenzene was
the main by-product of this reaction.
Table 1. Optimization of reaction conditions.a
5

Entry
SO2 source
F source
Solvent
Temperature Yield (%)b
MeOH
1
Na2S2O5
Na2S2O5
Na2S2O5
Na2S2O5
Na2S2O5
Na2S2O5
K2S2O5
NFSI
NFSI
NFSI
NFSI
NFSI
NFSI
NFSI
NFSI
40 oC
40 oC
40 oC
40 oC
40 oC
40 oC
40 oC
40 oC
40 oC
40 oC
rt
39
trace
54
59
58
47
49
23
28
0
DMF
2
MeCN
3
4
MeCN/H2O = 2/0.1
MeCN/H2O = 2/0.02
MeCN/H2O = 2/0.2
MeCN/H2O = 2/0.1
MeCN/H2O = 2/0.1
5
6
7
DABCOSO2
Na2S2O5
Na2S2O5
Na2S2O5
Na2S2O5
Na2S2O5
8
9
Selectfluor MeCN/H2O = 2/0.1
10
11
12
13
KF
MeCN/H2O = 2/0.1
MeCN/H2O = 2/0.1
MeCN/H2O = 2/0.1
MeCN/H2O = 2/0.1
NFSI
NFSI
NFSI
26
74
70
60 oC
80 oC
aReaction conditions: 1a (0.1 mmol), SO2 Source (0.2 mmol), F Source (0.15 mmol), solvent (2.0 mL), temperature, under N2, 6 h.
bYields were determined by 19F NMR spectroscopy using trifluoromethylbenzene as an internal standard.
With the optimized reaction conditions (Table 1, entry 12) in hand, the substrate scope of transition-
metal-free fluorosulfonylation of arenediazonium salts was investigated. Arenediazonium salts (1a-1j)
bearing either electron-donating or electron-withdrawing substituents reacted smoothly to give the
corresponding arenesulfonyl fluorides in moderate to high yields. Notably, the fluoro- and bromo-
containing substrates (1g and 1h) are suitable substrates for the reaction, enabling further
functionalization. Di- and trisubstituted arenediazonium salts 1k and 1l were also compatible under the
standard reaction conditions. Substrates bearing relatively bulky naphthyl group (1m and 1n) proceeded
efficiently to afford the desired products in good yields. Heteroaryl substrates including quinoline (1o),
benzothiazole (1p and 1q), and carbazole (1r) derivatives were smoothly converted to the desired
products. However, the reaction of pyridyl diazonium salts resulted in the corresponding products in low
yields.
Table 2. Scope of aryldiazonium tetrafluoroborates.a
6

aReaction conditions: 1 (0.2 mmol), Na2S2O5 (0.4 mmol), NFSI (0.3 mmol), MeCN/H2O (4.0/0.2 mL), 60 oC,, under N2, 6 h, isolated
yields.
Remarkably, in
a
representative attempt, 4-methoxyaniline was converted into 4-
methoxybenzenesulfonyl fluoride (2a) in a one-pot procedure (Scheme 2), albeit in somewhat lower yield
than that in the standard protocol (Table 2). Furthermore, when the aliphatic amines were subjected to
this one-pot reaction, none of the desired product could be detected.
Scheme 2 One-pot fluorosulfonylation of 4-methoxyaniline
7

In order to understand the reaction mechanism, a typical radical scavenger, 2,2,6,6-tetramethyl-1-
piperidinyloxy (TEMPO), was added to the standard reaction of 1a (Scheme 3a). None of the desired
product 2a was formed, whereas the TEMPO-trapped product could be detected by GC-MS (see the
supporting information). These results indicated that a radical process was probably involved in this
reaction. On the basis of this result and previous reports [24,25], a plausible reaction mechanism was
proposed in Scheme 3b. Initially, aryldiazonium salts 1 undergoes a single electron transfer (SET)
reduction to generate aryl radical A. Then, aryl radical A reacts with SO2 in Na2S2O5, affording the
arenesulfonyl radical B. Finally, fluorine atom transfer from NFSI to arenesulfonyl radical B furnishes
the desired arenesulfonyl fluorides 2. In accordance with the fluorosulfonylation reaction reported by
Weng [25b], Na2S2O5 probably acts as both of the reductant and SO2 source in this reaction.
Scheme 3 Mechanistic investigation
3. Conclusion
8

In conclusion, we have developed an alternative approach to arenesulfonyl fluorides through the three-
component reaction of readily available arenediazonium tetrafluoroborates, Na2S2O5, and NFSI. Unlike
the classic Sandmeyer reaction, this reaction proceeds under copper-free conditions. The mild conditions
allow the tolerance of a variety of functional groups and heterocycles. Further extension of the
applications of Sandmeyer reaction in the synthesis of other valuable fluorine-containing compounds are
currently in progress.
4. Experimental Section
4.1. General information
1H NMR (TMS as the internal standard), 13C NMR, and 19F NMR spectra (CFCl3 as the outside standard
and low field is positive) were recorded on a 400 or 600 MHz spectrometer. Chemical shifts (δ) are
reported in ppm, and coupling constants (J) are in Hertz (Hz). The following abbreviations were used to
explain the multiplicities: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet. HRMS data using
EI were obtained on a GC/MS TOF high resolution mass spectrometer equipped with a liquid
chromatography system. All reagents were used as received from commercial sources without further
purification or prepared as described in references. Substrates were prepared in accordance with methods
described in the reference [26].
4.2. Typical procedure of the preparation for arenediazonium tetrafluoroborates
Method A: In a 100 mL round-bottom flask, the aniline (20 mmol) was dissolved in a mixture of H2O (10
mL) and HBF4 (48% aq, 6 mL). After stirring for 15 minutes, the solution of NaNO2 (1.5 g, 1.1 equiv., in
4.0 mL H2O) was added dropwise at 0 oC. The mixture was stirred for another 30 minutes at 0 oC. Then,
the arenediazonium tetrafluoroborate was removed by filtration and washed successively twice with Et2O.
The crude product was dried in vacuo for 20 minutes and was then directly used without further
purification.
9

Method B: In a 100 mL round-bottom flask, the aniline (20 mmol) was dissolved in a mixture of ethanol
(8.0 mL) and HBF4 (48% aq, 6.0 mL). Subsequently, tert-butyl nitrite (4.7 mL, 2.0 equiv.) was added
dropwise to the solution at 0 °C. The reaction mixture was stirred for 30 minutes at 0 °C, and anhydrous
Et2O was added to precipitate the corresponding arenediazonium tetrafluoroborate. The solid was filtered
off and washed twice with Et2O. The obtained arenediazonium tetrafluoroborate was dried in vacuo for
20 minutes and was then directly used without further purification.
Substrates 1a, 1b, 1c, 1d, 1f, 1h, 1i, 1j, 1l, 1m, 1n, and 1q were prepared according to method A.
Substrates 1e, 1g, 1k, 1o, 1p, and 1r were prepared according to method B.
4.3. General procedures for fluorosulfonylation of aryldiazonium tetrafluoroborates
To a mixture of arenediazonium tetrafluoroborate (0.2 mmol, 1.0 equiv.) and NFSI (94.5 mg, 0.3 mmol,
1.5 equiv.) in MeCN/H2O (4.0/0.2 mL) was added Na2S2O5 (76.0 mg, 0.4 mmol, 2.0 equiv.). The reaction
o
mixture was stirred at 60 C under nitrogen atmosphere for 6 h. After the reaction was complete, brine
was added. The resulting mixture was extracted with EtOAc for three times. The combined organic layer
was washed with brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The
resulting residue was purified by silica gel flash column chromatography to give the product.
4.3.1. 4-Methoxybenzenesulfonyl fluoride (2a). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 10:1), compound 2a was obtained as a yellow oil (26.2 mg, 69%). 1H NMR (400
19
MHz, CDCl3) δ 7.87 (d, J = 8.6 Hz, 2H), 6.99 (d, J = 8.6 Hz, 2H), 3.85 (s, 3H). F NMR (565 MHz,
CDCl3) δ 67.29 (s, 1F). 13C NMR (151 MHz, CDCl3) δ 165.2, 130.9, 124.1 (d, J = 24.7 Hz), 114.9, 55.9.
The spectroscopic data were consistent with those previously published [15a].
4.3.2. 4-Methylbenzenesulfonyl fluoride (2b). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 99:1), compound 2b was obtained as a white solid (24.4 mg, 70%). Mp 41-42 oC.
1H NMR (400 MHz, CDCl3) δ 7.82 (d, J = 8.0 Hz, 2H), 7.35 (d, J = 8.0 Hz, 2H), 2.42 (s, 3H). 19F NMR
(565 MHz, CDCl3) δ 66.29 (s, 1F). 13C NMR (151 MHz, CDCl3) δ 147.1, 130.3, 130.1 (d, J = 24.2 Hz),
10

128.5, 21.9. The spectroscopic data were consistent with those previously published [15a].
4.3.3. 4-(Tert-butyl)benzenesulfonyl fluoride (2c). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 99:1), compound 2c was obtained as a white solid (26.4 mg, 61%). Mp 64-66 oC.
1H NMR (400 MHz, CDCl3) δ 7.86 (d, J = 8.6 Hz, 2H), 7.56 (d, J = 8.3 Hz, 2H), 1.30 (s, 9H). 19F NMR
(565 MHz, CDCl3) δ 66.21 (s, 1F). 13C NMR (151 MHz, CDCl3) δ 159.9, 130.0 (d, J = 24.2 Hz), 128.4,
126.7, 35.6, 31.0. The spectroscopic data were consistent with those previously published [12].
4.3.4. [1,1'-Biphenyl]-4-sulfonyl fluoride (2d). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 10:1), compound 2d was obtained as a white solid (20.3 mg, 43%). Mp 78-79 oC.
1H NMR (600 MHz, CDCl3) δ 8.11 (d, J = 8.4 Hz, 2H), 7.85 (d, J = 8.3 Hz, 2H), 7.65 (d, J = 7.3 Hz, 2H),
7.55 (t, J = 7.4 Hz, 2H), 7.50 (t, J = 7.2 Hz, 1H). 19F NMR (565 MHz, CDCl3) δ 66.53 (s, 1F). 13C NMR
(151 MHz, CDCl3) δ 148.7, 138.5, 131.4 (d, J = 24.5 Hz), 129.3, 129.2, 129.0, 128.2, 127.5. The
spectroscopic data were consistent with those previously published [15a].
4.3.5. Ethyl 4-(fluorosulfonyl)benzoate (2e). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 10:1), compound 2e was obtained as a white solid (27.1 mg, 58%). Mp 36-38 oC.
1H NMR (600 MHz, CDCl3) δ 8.31 (d, J = 8.3 Hz, 2H), 8.11 (d, J = 8.5 Hz, 2H), 4.47 (q, J = 7.1 Hz, 2H),
19
13
1.45 (t, J = 7.1 Hz, 3H). F NMR (565 MHz, CDCl3) δ 65.82 (s, 1F). C NMR (151 MHz, CDCl3) δ
164.4, 136.9, 136.6 (d, J = 25.3 Hz), 130.7, 128.5, 62.2, 14.2. The spectroscopic data were consistent with
those previously published [15a].
4.3.6. 3-Cyanobenzenesulfonyl fluoride (2f). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 10:1), compound 2f was obtained as an orange solid (26.4 mg, 72%). Mp 48-50
oC. 1H NMR (400 MHz, CDCl3) δ 8.35-8.12 (m, 2H), 8.01 (d, J = 7.7 Hz, 1H), 7.77 (t, J = 7.9 Hz, 1H).
13
19F NMR (565 MHz, CDCl3) δ 66.33 (s, 1F). C NMR (101 MHz, CDCl3) δ 137.6, 133.7 (d, J = 27.2
Hz), 131.2, 131.0, 129.9, 115.2, 113.7. MS (EI): m/z 185 M+. HRMS (ESI-TOF): m/z Calculated for
C7H4FNO2S M+:184.9947; Found: 184.9941.
11

4.3.7. 4-Fluorobenzenesulfonyl fluoride (2g). After purification by silica gel column chromatography
1
(cyclohexane/EtOAc = 99:1), compound 2g was obtained as a colourless oil (25.6 mg, 72%). H NMR
(600 MHz, CDCl3) δ 8.09-8.07 (m, 2H), 7.35 (t, J = 8.4 Hz, 2H). 19F NMR (565 MHz, CDCl3) δ 66.79 (s,
1F), -99.28 to -99.32 (m, 1F). 13C NMR (151 MHz, CDCl3) δ 166.9 (d, J = 259.9 Hz), 131.6 (d, J = 10.3
Hz), 129.0 (dd, J = 25.7, 3.4 Hz), 117.3 (d, J = 23.2 Hz). The spectroscopic data were consistent with
those previously published [15a].
4.3.8. 3-Bromobenzenesulfonyl fluoride (2h). After purification by silica gel column chromatography
1
(cyclohexane/EtOAc = 10:1), compound 2h was obtained as a colorless oil (33.9 mg, 71%). H NMR
(600 MHz, CDCl3) δ 8.18 (t, J = 1.9 Hz, 1H), 7.99 (d, J = 9.0 Hz, 1H), 7.94 (d, J = 7.3 Hz, 1H), 7.55 (t,
J = 8.0 Hz, 1H). 19F NMR (565 MHz, CDCl3) δ 66.26 (s, 1F). 13C NMR (151 MHz, CDCl3) δ 138.7, 134.7
(d, J = 25.5 Hz), 131.3, 131.1, 127.0, 123.6. The spectroscopic data were consistent with those previously
published [25b].
4.3.9. 4-(Trifluoromethyl)benzenesulfonyl fluoride (2i). After purification by silica gel column
chromatography (cyclohexane/EtOAc = 99:1), compound 2i was obtained as a white solid (30.0 mg,
68%). Mp 44-46 oC. 1H NMR (400 MHz, CDCl3) δ 8.09 (d, J = 8.3 Hz, 2H), 7.84 (d, J = 8.2 Hz, 2H). 19F
NMR (565 MHz, CDCl3) δ 65.75 (s, 1F), -63.62 (s, 3F). 13C NMR (151 MHz, CDCl3) δ 137.2 (q, J = 33.6
Hz), 136.5 (d, J = 25.9 Hz), 129.1, 126.9 (q, J = 3.7 Hz), 122.7 (q, J = 273.5 Hz). The spectroscopic data
were consistent with those previously published [12].
4.3.10. 4-(Trifluoromethoxy)benzenesulfonyl fluoride (2j). After purification by silica gel column
chromatography (cyclohexane/EtOAc = 20:1), compound 2j was obtained as a brown oil (26.8 mg, 55%).
1H NMR (400 MHz, CDCl3) δ 8.09 (d, J = 8.9 Hz, 2H), 7.46 (d, J = 8.5 Hz, 2H). 19F NMR (565 MHz,
CDCl3) δ 66.57 (s, 1F), -57.71 (s, 3F). 13C NMR (151 MHz, CDCl3) δ 154.3, 131.1, 130.9, 128.6, 125.4
(t, J = 6.2 Hz), 121.2, 120.1 (q, J = 260.8 Hz). The spectroscopic data were consistent with those
previously published [10].
12

4.3.11. Benzo[d][1,3]dioxole-5-sulfonyl fluoride (2k). After purification by silica gel column
chromatography (cyclohexane/EtOAc = 8:1), compound 2k was obtained as a white solid (29.8 mg, 73%).
Mp 71-72 oC. 1H NMR (600 MHz, CDCl3) δ 7.63 (dd, J = 8.3, 1.5 Hz, 1H), 7.39 (d, J = 1.8 Hz, 1H), 6.99
(d, J = 8.1 Hz, 1H), 6.18 (s, 2H).19F NMR (565 MHz, CDCl3) δ 66.84 (s, 1F).13C NMR (151 MHz, CDCl3)
δ 153.9, 148.7, 125.6 (d, J = 25.0 Hz), 125.2, 108.8, 108.2, 103.0. The spectroscopic data were consistent
with those previously published [15a].
4.3.12. 3,4,5-Trimethoxybenzenesulfonyl fluoride (2l). After purification by silica gel column
chromatography (cyclohexane/EtOAc = 50:1), compound 2l was obtained as a white solid (26.0 mg,
52%). Mp 76-78 oC. 1H NMR (600 MHz, CDCl3) δ 7.23 (s, 2H), 3.97 (s, 3H), 3.96 (s, 6H). 19F NMR (565
MHz, CDCl3) δ 66.65 (s, 1F). 13C NMR (151 MHz, CDCl3) δ 153.6, 144.1, 126.9 (d, J = 24.7 Hz), 105.8,
61.1, 56.6. The spectroscopic data were consistent with those previously published [25b].
4.3.13. Naphthalene-1-sulfonyl fluoride (2m). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 50:1), compound 2m was obtained as a colourless oil (33.6 mg, 80%). 1H NMR
(600 MHz, CDCl3) δ 8.58 (dd, J = 8.6, 2.4 Hz, 1H), 8.40 (d, J = 7.4 Hz, 1H), 8.26 (d, J = 8.2 Hz, 1H),
8.03 (d, J = 8.2 Hz, 1H), 7.84-7.76 (m, 1H), 7.75-7.68 (m, 1H), 7.68-7.59 (m, 1H). 19F NMR (565 MHz,
CDCl3) δ 62.58 (s, 1F). 13C NMR (151 MHz, CDCl3) δ 136.9, 134.1, 131.10, 131.09, 129.5, 129.1, 128.3,
127.8, 124.2, 124.1. The spectroscopic data were consistent with those previously published [15a].
4.3.14. 5-Bromonaphthalene-1-sulfonyl fluoride (2n). After purification by silica gel column
chromatography (cyclohexane/EtOAc = 8:1), compound 2n was obtained as a yellow solid (43.9 mg,
o
1
76%). Mp 58-62 C. H NMR (400 MHz, CDCl3) δ 8.71 (d, J = 8.4 Hz, 1H), 8.53 (d, J = 8.6 Hz, 1H),
8.43 (d, J = 7.4 Hz, 1H), 7.97 (d, J = 7.5 Hz, 1H), 7.72 (t, J = 8.0 Hz, 1H), 7.60 (t, J = 8.1 Hz, 1H). 19F
13
NMR (565 MHz, CDCl3) δ 63.18 (s, 1F). C NMR (151 MHz, CDCl3) δ 136.0, 132.6, 132.0, 131.87,
131.86, 129.7, 129.6, 129.54, 125.4, 124.0, 123.9. MS (EI): m/z 288 M+; HRMS (ESI-TOF): m/z
Calculated for C10H6BrFO2S M+: 287.9256; Found: 287.9250.
13

4.3.15. Quinoline-6-sulfonyl fluoride (2o). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 50:1), compound 2o was obtained as a white solid (21.1 mg, 50%). Mp 80-82 oC.
1H NMR (600 MHz, CDCl3) δ 9.18 (dd, J = 4.3, 1.7 Hz, 1H), 8.65 (d, J = 2.1 Hz, 1H), 8.43-8.32 (m, 2H),
8.21 (dd, J = 8.9, 2.2 Hz, 1H), 7.66 (dd, J = 8.3, 4.2 Hz, 1H). 19F NMR (565 MHz, CDCl3) δ 66.41 (s, 1F).
13C NMR (101 MHz, CDCl3) δ 154.5, 150.3, 137.6, 132.0, 131.1, 130.7 (d, J = 25.5 Hz), 127.2, 126.0,
123.3. The spectroscopic data were consistent with those previously published [25b].
4.3.16. Benzo[d]thiazole-5-sulfonyl fluoride (2p). After purification by silica gel column chromatography
(cyclohexane/EtOAc = 10:1), compound 2p was obtained as a white solid (22.9 mg, 53%). Mp 102-104
oC. 1H NMR (400 MHz, CDCl3) δ 9.26 (s, 1H), 8.83 (s, 1H), 8.26 (d, J = 8.4 Hz, 2H), 8.07 (d, J = 8.4 Hz,
19
2H). F NMR (377 MHz, CDCl3) δ 67.38 (s, 1F). 13C NMR (101 MHz, CDCl3) δ 157.5, 152.9, 141.4,
131.1 (d, J = 25.3 Hz), 124.7, 123.9, 123.6. The spectroscopic data were consistent with those previously
published [25b].
4.3.17. 2-Methylbenzo[d]thiazole-5-sulfonyl fluoride (2q). After purification by silica gel column
chromatography (cyclohexane/EtOAc = 10:1), compound 2q was obtained as a white solid (37.4 mg,
o
1
81%). Mp 62-64 C. H NMR (600 MHz, CDCl3) δ 8.61 (d, J = 1.8 Hz, 1H), 8.10 (d, J = 8.4 Hz, 1H),
7.97 (dd, J = 8.5, 1.8 Hz, 1H), 2.94 (s, 3H). 19F NMR (565 MHz, CDCl3) δ 67.33 (s, 1F). 13C NMR (101
MHz, CDCl3) δ 170.9, 153.0, 143.5, 130.6 (d, J = 24.9 Hz), 123.2, 123.1, 122.9, 20.5. MS (EI): m/z 231
M+; HRMS (ESI-TOF): m/z Calculated for C8H6FNO2S2 M+: 230.9824; Found: 230.9818.
4.3.18. 9-Ethyl-9H-carbazole-3-sulfonyl fluoride (2r). After purification by silica gel column
chromatography (cyclohexane/EtOAc = 20:1), compound 2r was obtained as a brown solid (33.2 mg,
60%). Mp 98-100 oC. 1H NMR (400 MHz, CDCl3) δ 8.77 (s, 1H), 8.17 (d, J = 7.6 Hz, 1H), 8.08 (d, J =
8.7 Hz, 1H), 7.63 (t, J = 7.3 Hz, 1H), 7.58-7.52 (m, 2H), 7.40 (t, J = 7.1 Hz, 1H), 4.44 (q, J = 6.5 Hz 2H),
13
1.50 (t, J = 6.6 Hz, 3H). 19F NMR (377 MHz, CDCl3) δ 69.22 (s, 1F). C NMR (101 MHz, CDCl3) δ
143.2, 140.9, 127.7, 125.4, 123.1, 122.3, 122.2, 121.7 (d, J = 23.5 Hz), 121.1, 121.0, 109.5, 109.0, 38.1,
14

13.8. MS (EI): m/z 277 M+; HRMS (EI-TOF): m/z Calculated for C14H12FNO2S [M+H]+: 277.0573; Found:
277.0567.
4.4. One-pot fluorosulfonylation of 4-methoxyaniline
In a 25 mL round-bottom flask, 4-methoxyaniline (61.6 mg, 0.5 mmol) was dissolved in a mixture of
ethanol (2.0 mL) and HBF4 (132 μL, aq. 48%, 1.0 mmol). Subsequently, tert-butyl nitrite (135 μL, 1.0
mmol) was added dropwise to the solution at 0 °C. The reaction mixture was stirred for 30 minutes at
room temperature, then Na2S2O5 (190.1 mg, 1.0 mmol) and NFSI (236.5 mg, 0.75 mmol) were added
o
successively. The reaction mixture was stirred at 60 C under nitrogen atmosphere for 6 h. After the
reaction was complete, brine was added. The resulting mixture was extracted with EtOAc for three times.
The combined organic layer was washed with brine, dried over anhydrous Na2SO4, and concentrated
under reduced pressure. The resulting residue was purified by silica gel flash column chromatography
(cyclohexane/EtOAc = 10:1) to give 2a as a yellow oil (57.3 mg, 60%).
Declaration of interests
The authors declare that they have no known competing financial interests or personal relationships that
could have appeared to influence the work reported in this paper.
Acknowledgement
We thank National Natural Science Foundation of China (21421002, 21991211) and the Strategic Priority
Research Program of the Chinese Academy of Sciences (XDB20000000) for funding this work.
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in the online version, at
http://dx.doi.org/10.1016/j. jfluchem.xxxx.xx.xxx.
References:
15

[1] (a) X.-H. Xu, K. Matsuzaki, N. Shibata, Chem. Rev. 115 (2015) 731-764;
(b) A. S. Barrow, J. E. Moses, Synlett 27 (2016) 1840-1843;
(c) X. Chen, G.-F. Zha, G. A. L. Bare, J. Leng, S.-M. Wang, H.-L. Qin, Adv. Synth. Catal. 359 (2017)
3254-3260;
(d) P. K. Chinthakindi, P. I. Arvidsson, Eur. J. Org. Chem. (2018) 3648-3666;
(e) P. Mukherjee, C. P. Woroch, L. Cleary, M. Rusznak, R. W. Franzese, M. R. Reese, J. W. Tucker,
J. M. Humphrey, S. M. Etuk, S. C. Kwan, C. W. Ende, N. D. Ball, Org. Lett. 20 (2018) 3943-3947;
(f) T. S.-B. Lou, S. W. Bagley, M. C. Willis, Angew. Chem. Int. Ed. 58 (2019) 18859-18863.
[2] (a) A. Narayanan, L. H. Jones, Chem. Sci. 6 (2015) 2650-2659;
(b) P. Martín-Gago, C. A. Olsen, Angew. Chem. Int. Ed. 58 (2019) 957-966;
(c) M. Gehringer, S. A. Laufer, J. Med. Chem. 62 (2019) 5673-5724;
(d) X. Wan, T. Yang, A. Cuesta, X. Pang, T. E. Balius, J. J. Irwin, B. K. Shoichet, J. Taunton, J. Am.
Chem. Soc. 142 (2020) 4960-4964.
[3] (a) M. K. Nielsen, C. R. Ugaz, W. Li, A. G. Doyle, J. Am. Chem. Soc. 137 (2015) 9571-9574;
(b) C. J. Smedley, A. S. Barrow, C. Spiteri, M.-C. Giel, P. Sharma, J. E. Moses, Chem. Eur. J. 23
(2017) 9990-9995;
(c) M. K. Nielsen, D. T. Ahneman, O. Riera, A. G. Doyle, J. Am. Chem. Soc. 140 (2018) 5004-5008.
[4] (a) J. Dong, L. Krasnova, M. G. Finn, K. B. Sharpless, Angew. Chem. Int. Ed. 53 (2014) 9430-9448;
(b) T. A. Fattah, A. Saeed, F. Albericio, J. Fluorine Chem. 213 (2018) 87-112;
(c) A. S. Barrow, C. J. Smedley, Q. Zheng, S. Li, J. Dong, J. E. Moses, Chem. Soc. Rev. 48 (2019)
4731-4758.
[5] (a) T. A. Bianchi, L. A. Cate, J. Org. Chem. 42 (1977) 2031-2032;
(b) H. Zhao, F. P. Gabbaï, Org. Lett. 13 (2011) 1444-1446;
(c) J. A. H. Inkster, K. Liu, S. Ait-Mohand, P. Schaffer, B. Guérin, T. J. Ruth, T. Storr, Chem. Eur.
J. 18 (2012) 11079-11087;
16

(d) L. Matesic, N. A. Wyatt, B. H. Fraser, M. P. Roberts, T. Q. Pham, I. Greguric, J. Org. Chem. 78
(2013) 11262-11270.
[6] (a) V. A. Petrov, S. Swearingen, W. Hong, W. C. Petersen, J. Fluorine Chem. 109 (2001) 25-31;
(b) J.-G. Kim, D. O. Jang, Synlett (2010) 3049-3052.
[7] (a) V. Vedovato, E. P. A. Talbot, M. C. Willis, Org. Lett. 20 (2018) 5493-5496;
(b) Y. Jiang, N. S. Alharbi, B. Sun, H.-L. Qin, RSC Adv. 9 (2019) 13863-13867.
[8] (a) R. E. Banks, M. K. Besheesh, S. N. Mohialdin-Khaffaf, I. Sharif, J. Chem. Soc., Perkin Trans. 1
(1996) 2069-2076;
(b) F. Toulgoat, B. R. Langlois, M. Médebielle, J.-Y. Sanchez, J. Org. Chem. 72 (2007) 9046-9052.
[9] (a) B. I. Halperin, M. Krska, E. Levy, C. A. VanderWerf, J. Am. Chem. Soc. 73 (1951) 1857-1858;
(b) M. Pérez-Palau, J. Cornella, Eur. J. Org. Chem. (2020) 2497-2500.
[10] L. Tang, Y. Yang, L. Wen, X. Yang, Z. Wang, Green Chem. 18 (2016) 1224-1228.
[11] (a) S. W. Wright, K. N. Hallstrom, J. Org. Chem. 71 (2006) 1080-1084;
(b) J. W. Tucker, L. Chenard, J. M. Young, ACS Comb. Sci. 17 (2015) 653-657;
(c) M. Kirihara, S. Naito, Y. Ishizuka, H. Hanai, T. Noguchi, Tetrahedron Lett. 52 (2011) 3086-3089;
(d) M. Kirihara, S. Naito, Y. Nishimura, Y. Ishizuka, T. Iwai, H. Takeuchi, T. Ogata, H. Hanai, Y.
Kinoshita, M. Kishida, K. Yamazaki, T. Noguchi, S. Yamashoji, Tetrahedron 70 (2014) 2464-2471.
[12] G. Laudadio, A. de A. Bartolomeu, L. M. H. M. Verwijlen, Y. Cao, K. T. de Oliveira, T. Noël, J.
Am. Chem. Soc. 141 (2019) 11832-11836.
[13] C. Lee, N. D. Ball, G. M. Sammis, Chem. Commun. 55 (2019) 14753-14756.
[14] J. Kwon, B. M. Kim, Org. Lett. 21 (2019) 428-433.
[15] (a) A. T. Davies, J. M. Curto, S. W. Bagley, M. C. Willis, Chem. Sci. 8 (2017) 1233-1237;
(b) A. L. Tribby, I. Rodríguez, S. Shariffudin, N. D. Ball, J. Org. Chem. 82 (2017) 2294-2299.
[16] (a) Y. Chen, M. C. Willis, Chem. Sci. 8 (2017) 3249-3253;
(b) P. K. T. Lo, Y. Chen, M. C. Willis, ACS Catal. 9 (2019) 10668-10673.
[17] (a) G. Balz, G. Schiemann, Ber. Dtsch. Chem. Ges. B 60 (1927) 1186-1190;
17

(b) M. Döbele, S. Vanderheiden, N. Jung, S. Bräse, Angew. Chem. Int. Ed. 49 (2010) 5986-5988;
(c) N. H. Park, T. J. Senter, S. L. Buchwald, Angew. Chem. Int. Ed. 55 (2016) 11907-11911;
(d) B. Xing, C. Ni, J. Hu, Angew. Chem. Int. Ed. 57 (2018) 9896-9900.
[18] (a) G. Danoun, B. Bayarmagnai, M. F. Grünberg, L. J. Gooβen, Angew. Chem. Int. Ed. 52 (2013)
7972-7975;
(b) J. J. Dai, C. Fang, B. Xiao, J. Yi, J. Xu, Z. J. Liu, X. Lu, L. Liu, Y. Fu, J. Am. Chem. Soc. 135
(2013) 8436-8439;
(c) X. Wang, Y. Xu, F. Mo, G. Ji, D. Qiu, J. Feng, Y. Ye, S. Zhang, Y. Zhang, J. Wang, J. Am. Chem.
Soc. 135 (2013) 10330-10333;
(d) A. Lishchynskyi, G. Berthon, V. V. Grushin, Chem. Commun. 50 (2014) 10237-10240.
[19] (a) D. J. Adams, A. Goddard, J. H. Clark, D. J. Macquarrie, Chem. Commun. (2000) 987-988;
(b) G. Danoun, B. Bayarmagnai, M. F. Gruenberg, L. J. Goossen, Chem. Sci. 5 (2014) 1312-1316;
(c) D. Koziakov, M. Majek, A. J. von Wangelin, Eur. J. Org. Chem. (2017) 6722-6725;
(d) X. Zhao, X. Zheng, M. Tian, Y. Tong, B. Yang, X. Wei, D. Qiu, K. Lu. Org. Chem. Front. 5
(2018) 2636-2640.
[20] (a) S. Yang, M. Chen, P. Tang, Angew. Chem. Int. Ed. 58 (2019) 7840-7844;
(b) Y.-M. Yang, J.-F. Yao, W. Yan, Z. Luo, Z.-Y. Tang, Org. Lett. 21 (2019) 8003-8007.
[21] K. Zhang, X.-H. Xu, F.-L. Qing, J. Org. Chem. 80 (2015) 7658-7665.
[22] D. Zheng, J. Yu, J. Wu, Angew. Chem. Int. Ed. 55 (2016) 11925-11929.
[23] For selected examples, see: (a) K. Zhou, J. Zhang, L. Lai, J. Cheng, J. Sun, J. Wu, Chem. Commun.
54 (2018) 7459-7462;
(b) Y. Wang, L. Deng, Y. Deng, J. Han, J. Org. Chem. 83 (2018) 4674-4680;
(c) H. Xia, Y. An, X. Zeng, J. Wu, Org. Chem. Front. 5 (2018) 366-370;
(d) K. Zhou, M. Chen, L. Yao, J. Wu, Org. Chem. Front. 5 (2018) 371-375;
(e) F. Zhang, D. Zheng, L. Lai, J. Cheng, J. Sun, J. Wu, Org. Lett. 20 (2018) 1167-1170;
(f) G. Li, Z. Gan, K. Kong, X. Dou, D. Yang, Adv. Synth. Catal. 361 (2019) 1808-1814;
18

(g) T.-H. Zhu, X.-C. Zhang, X.-L. Cui, Z.-Y. Zhang, H. Jiang, S.-S. Sun, L.-L. Zhao, K. Zhao, T.-P.
Loh, Adv. Synth. Catal. 361 (2019) 3593-3598;
(h) T.-H. Zhu, X.-C. Zhang, K. Zhao, T.-P. Loh, Org. Chem. Front. 6 (2019) 94-98;
(i) A. M. Nair, S. Kumar, I. Halder, C. M. R. Volla, Org. Biomol. Chem. 17 (2019) 5897-5901;
(j) M. Kumar, R. Ahmed, M. Singh, S. Sharma, T. Thatikonda, P. P. Singh, J. Org. Chem. 85 (2020)
716-725;
(k) B. Ni, B. Zhang, J. Han, B. Peng, Y. Shan, T. Niu, Org. Lett. 22 (2020) 670-674.
[24] For selected examples, see: (a) M. Wang, B.-C. Tang, J.-G. Wang, J.-C. Xiang, A.-Y. Guan, P.-P.
Huang, W.-Y. Guo, Y.-D. Wu, A.-X. Wu, Chem. Commun. 54 (2018) 7641-7644;
(b) X. Gong, J. Chen, L. Lai, J. Cheng, J. Sun, J. Wu, Chem. Commun. 54 (2018) 11172-11175;
(c) M. Wang, Q. Fan, X. Jiang, Green Chem. 20 (2018) 5469-5473;
(d) G. You, D. Xi, J. Sun, L. Hao, C. Xia, Org. Biomol. Chem. 17 (2019) 9479-9488;
(e) X. Gong, X. Li, W. Xie, J. Wu, S. Ye, Org. Chem. Front. 6 (2019) 1863-1867;
(f) K. Zhou, J. Zhang, G. Qiu, J. Wu, Org. Lett. 21 (2019) 275-278.
[25] (a) Y. Liu, D. Yu, Y. Guo, J.-C. Xiao, Q.-Y. Chen, C. Liu, Org. Lett. 22 (2020) 2281-2286;
(b) T. Zhong, M.-K. Pang, Z.-D. Chen, B. Zhang, J. Weng, G. Lu, Org. Lett. 22 (2020) 3072-3078;
(c) Q. Lin, Z. Ma, C. Zheng, X.-J. Hu, Y. Guo, Q.-Y. Chen, C. Liu, Chin. J. Chem. 38 (2020) 1107-
1110.
[26] C. Lian, G. Yue, J. Mao, D. Liu, Y. Ding, Z. Liu, D. Qiu, X. Zhao, K. Lu, M. Fagnoni, S. Protti,
Org. Lett. 21 (2019) 5187-5191.
19