Transition metal- and oxidant-free sulfonylation of 1-sulfonyl-1H-1,2,3-triazoles to enols for the synthesis of sulfonate derivatives

Article abstract of DOI:10.1080/00397911.2019.1582065

A novel and convenient protocol for the synthesis of sulfonate derivatives via DABCO-catalyzed direct sulfonylation of 1-sulfonyl-1,2,3-triazoles to different enols has been established. This synthetic route could effectively avoid the use of transition m

Full text of DOI:10.1080/00397911.2019.1582065

Synthetic Communications
An International Journal for Rapid Communication of Synthetic Organic
Chemistry
ISSN: 0039-7911 (Print) 1532-2432 (Online) Journal homepage: https://www.tandfonline.com/loi/lsyc20
Transition metal- and oxidant-free sulfonylation
of 1-sulfonyl-1H-1,2,3-triazoles to enols for the
synthesis of sulfonate derivatives
Xinwei He, Yuhao Wu, Youpeng Zuo, Mengqing Xie, Ruxue Li & Yongjia Shang
To cite this article: Xinwei He, Yuhao Wu, Youpeng Zuo, Mengqing Xie, Ruxue Li & Yongjia
Shang (2019): Transition metal- and oxidant-free sulfonylation of 1-sulfonyl-1H-1,2,3-
triazoles to enols for the synthesis of sulfonate derivatives, Synthetic Communications, DOI:
10.1080/00397911.2019.1582065
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SYNTHETIC COMMUNICATIONSV
https://doi.org/10.1080/00397911.2019.1582065
Transition metal- and oxidant-free sulfonylation of
1-sulfonyl-1H-1,2,3-triazoles to enols for the synthesis of
sulfonate derivatives
Xinwei He , Yuhao Wu, Youpeng Zuo, Mengqing Xie, Ruxue Li, and Yongjia
Shang
Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials (State Key Laboratory Cultivation Base), College of Chemistry and Materials Science,
Anhui Normal University, Wuhu, P.R. China
ABSTRACT
ARTICLE HISTORY
Received 4 January 2019
A novel and convenient protocol for the synthesis of sulfonate deriv-
atives via DABCO-catalyzed direct sulfonylation of 1-sulfonyl-1,2,3-tri-
azoles to different enols has been established. This synthetic route
could effectively avoid the use of transition metal catalysts and extra
oxidants, and the target products could be obtained in good to
excellent yields (75–86%) with wide substrate scope under mild con-
ditions at low-catalyst loadings, which would provide a facile and
practical access to enol sulfonates. Furthermore, the use of the
resulting enol sulfonates for the C–C bond formation has been dem-
onstrated via Suzuki-Miyaura, Sonogashira, and Heck cross-coupling
reaction.
KEYWORDS
1,4-Diazabicyclo[2.2.2]
octane; 1-sulfonyl-1,2,3-
triazoles; enols; sulfonates;
sulfonylation
GRAPHIC ABSTRACT
Introduction
Enol esters and their derivatives are valuable synthetic intermediates in organic synthe-
sis.[1] Many natural products containing the enol ester moiety exhibit useful biological
activities.[2] Among them, enol sulfonates play an important role in the fields of organic
reactions,[3] especially in various cross-coupling reactions,[4] such as Suzuki–Miyaura,[5]
CONTACT Xinwei He
xinweihe@mail.ahnu.edu.cn
Anhui Normal University, College of Chemistry and Materials
Science, No. 1 Beijing East Road, Wuhu 241000, China.
Supplemental data for this article is available online at on the publisher’s website.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lsyc.
ß 2019 Taylor & Francis Group, LLC

2
X. HE ET AL.
α
Scheme 1. Chemistry of N-tosyl-1,2,3-triazoles.
Negishi,[6] Stille,[7] Kumada,[8] and Buchwald–Hartwig couplings,[9] serving as effective
equivalents of vinyl halides. The most conventional synthetic route to enol sulfonates is
the sulfonylation of enols and sulfonyl halides. More recently, several sulfonyl precur-
sors including sulfonyl halides,[10] sulfonyl hydrazides,[11] sodium sulfinates,[12] sulfinic
acids,[13] sulfonyl azides,[14] sulfonyl isocyanides,[15] sulfoxides,[16] and DABCOꢀ(SO2)2
(named: DABSO),[17] were employed in the sulfonylation reaction to access organosul-
fone compounds. Therefore, the development of general methods for the synthesis of
enol sulfonates by utilizing new sulfonyl precursors is consequently an important goal
in organic chemistry.
In recent years, the chemistry of 1-tosyl-4-aryl/alkyl-1,2,3-triazoles has attracted much
attention from synthetic chemists since its initial discovery by the groups of Fokin and
Gevorgyan. These compounds are highly useful building blocks and have been abundantly
used as precursors of ketenimine and a-imino rhodium carbenes.[18] N-tosyl a-diazo
imine could be converted into 1-tosyl ketenimine via denitrogenation and rearrangement
and subsequently derived into various heterocycles and carbocycles.[19] On the other
hand, these compounds are capable of acting as convenient precursors to generate reactive
a-imino metal carbenoid species and undergo subsequent reactions, such as cycliza-
tion,[20] transannulation,[21] denitrogenative reaction,[22] cyclopropanation,[23] aryla-
tion,[24] and X–H insertions (X=C, N, O).[25] Beside of these two fates, other reactions
were seldom reported based on the fragile 1-tosyl-1,2,3-triazole except for the direct desul-
fonylation by using magnesium in methanol,[26] the N2-selective alkylation in the pres-
ence of Au-catalyst or DABCO (1,4-diazabicyclo[2.2.2]octane),[27] and the nucleophilicity
of 1-sulfonyl-1,2,3-triazoles in the presence of Lewis acid.[28] Here we would like to report
an unprecedented and general approach to enol sulfonates through the direct sulfonyla-
tion of 1-sulfonyl-1,2,3-triazoles to enols in the presence of DABCO (Scheme 1).
Results and discussion
We initially started our investigation by choosing 4-phenyl-1-(tosylsulfonyl)-1H-1,2,3-
triazole (1c) to react with 4-hydroxy-2H-chromen-2-one (2a) in the presence of

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Table 1. Optimization of the reaction conditions for the model reaction.a
Entry
Catalyst
Solvent
Temp. (ꢁC)
Time (h)
Yield (%)b
1
2
3
4
5
6
7
8
DBU
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
Toluene
DMF
MeCN
EtOH
DMSO
H2O
DCE
DCE
DCE
DCE
DCE
DCE
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
25
50
70
110
90
90
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
2
7
70
60
81
TEAf
DABCO
NaOH
Trace
Trace
Trace
Trace
Trace
50
NaHCO3
KHCO3
NaOAc
NH4OAc
CsOAc
–
9
10
11c
12d
13e
14
15
16
17
18
19
20
21
22
23
24
25
NRg
52
82
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
DABCO
83
69
NRg
72
70
NRg
NRg
Trace
Trace
70
83
65
82
aReaction conditions: 4-phenyl-1-(tosylsulfonyl)-1H-1,2,3-triazole 1c (0.5 mmol), 4-hydroxy-2H-chromen-2-one 2a
(0.5 mmol), solvent (2 mL), catalyst (2 mol%).
bIsolated yields.
cThe amount of catalyst was 1 mol%.
dThe amount of catalyst was 5 mol%.
eThe amount of catalyst was 10 mol%.
fTEA ¼ Triethylamine.
gNo reaction.
ꢁ
1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in 1,2-dichloroethene (DCE) at 90 C for 5 h,
and to our delight the desired product 3c was harvested in 70% yield as shown in
Table 1 (entry 1). Subsequently, various bases such as organic (e.g., DBU, TEA,
DABCO) and inorganic bases (e.g., NaOH, NaHCO3, KHCO3, NaOAc, NH4OAc,
CsOAc) were tested as the catalysts, organic bases were proved to be the best choice
(Table 1, entries 1–3), and the target product 3c was obtained in the highest yield
(81%) when 1,4-diazabicyclo[2.2.2]octane (DABCO) was chosen as catalyst for this reac-
tion (Table 1, entry 3). Also, among the solvents tested, DCE, toluene, MeCN, and
EtOH were shown to be more effective than the others such as DMF (N,N-dimethylfor-
mamide), DMSO (dimethyl sulfoxide), and H2O (Table 1, entries 14–19), and DCE was
proved to be the best choice (Table 1, entry 3). Moreover, no conversion was observed
when the reaction was performed in the absence of catalyst (Table 1, entry 10). In add-
ition, the yield could not be obvious promoted by increasing or decreasing amount of
catalyst (Table 1, entries 11–13). Furthermore, the effects of the temperature and

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X. HE ET AL.
Table 2. DABCO-catalyzed direct O–H bond sulfonylation of N-sulfonyl-1,2,3-triazoles with 4-hydroxy-
2H-chromen-2-ones.a
Entry
R1
R2
Product
Yield (%)b
1
2
3
4
5
6
7
8
CH3 (1a)
C6H5 (1b)
H (2a)
2a
2a
2a
2a
2a
2a
2a
CH3 (2b)
2b
2b
2b
2b
2b
CH3O (2c)
2c
2c
F (2d)
Cl (2e)
Br (2f)
3a
3b
3c
3d
3e
3f
-
-
3g
3h
3i
3j
3k
3l
3m
3n
3o
3p
3q
3r
80
80
83
80
80
81
NRc
NRc
81
83
85
78
81
83
83
77
80
80
78
75
4-CH3C6H4 (1c)
4-FC6H4 (1d)
4-BrC6H4 (1e)
2,4,6-iPrC6H2 (1f)
4-CH3OC6H4 (1g)
4-CH3CONHC6H4 (1h)
CH3 (1a)
C6H5 (1b)
4-CH3C6H5 (1c)
4-FC6H5 (1d)
9
10
11
12
13
14
15
16
17
18
19
20
4-BrC6H5 (1e)
2,4,6-iPrC6H2 (1f)
CH3 (1a)
4-FC6H5 (1d)
2,4,6-iPrC6H2 (1f)
2,4,6-iPrC6H2 (1f)
2,4,6-iPrC6H2 (1f)
2,4,6-iPrC6H2 (1f)
aReaction conditions: 4-phenyl-1-sulfonyl-1H-1,2,3-triazole 1 (0.5 mmol), 4-hydroxy-2H-chromen-2-one 2 (0.5 mmol), DCE
(2 mL), DABCO (2 mol%), 90 ꢁC for 5 h.
bIsolated yields.
cNo reaction.
reaction time were also investigated (Table 1, entries 20–25). It was found that neither
decreasing nor increasing the reaction temperature or time could improve the yield.
Therefore, the optimal reaction conditions were found to be 2 mol% DABCO as catalyst
ꢁ
with DCE as the solvent at 90 C for 5 h (Table 1, entry 3).
Having identified this acceptable optimization, we then turned to evaluate the scope
of the DABCO-catalyzed direct sulfonylation by utilizing different N-sulfonyl-1,2,3-tria-
zoles and 4-hydroxy-2H-chromen-2-ones, and the results are summarized in Table 2. A
series of 2-oxo-2H-chromen-4-yl-4-sulfonate derivatives were obtained in good yields
(75–85%). For N-sulfonyl-1,2,3-triazoles 1, a set of substrates with aliphatic or aromatic
sulfonyl group could be efficiently sulfonated with 4-hydroxy-2H-chromen-2-one (2a)
to deliver the desired products 3a–3f in good yields (80–83%). Reactions of 4-phenyl-1-
arylsulfonyl-1H-1,2,3-triazoles, which bearing with electron-donating (e.g. –CH3) or
electron-withdrawing groups (e.g. –F, –Br) on the aromatic ring of aryl group (Table 2,
entries 3–5), proceeded well, and almost equal yields were achieved. Notably, substrate
bearing with three sterically demanding isopropyl groups at the 2,4,6-positions of the
benzene ring (1f) was also tolerated to give the corresponding products in 75–83%
yields (Table 2, entries 6, 14, 17–20), the results showed that the steric hindrance did
not influence this reaction obviously. When 4-phenyl-1-arylsulfonyl-1H-1,2,3-triazoles
with a strong electron-donating group (e.g. –OCH3, –NHCOCH3) were subjected to

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Scheme 2. DABCO-catalyzed sulfonylation of 4-phenyl-1-sulfonyl-1H-1,2,3-triazole with other enols.
this reaction, the corresponding products were not obtained (Table 2, entries 7, 8).
4-Hydroxy-2H-chromen-2-ones possessing either electorn-donating (2b, 2c) or electron-
withdrawing substituents (2d–2f) were well tolerated in this sulfonylation (Table 2,
entries 9–20), affording the desired products in good yields (75–85%). This protocol
was tolerant of synthetically valuable functional groups on the phenyl moiety (e.g.,
methoxyl, fluoro, chloro, and bromo groups), which could allow an opportunity for fur-
ther transformations. In addition, all of the products were characterized by IR, 1H
NMR, and 13C NMR spectroscopy and HRMS analysis, and the structures of products
3c was also unambiguously confirmed by X-ray crystallographic analysis (see
Supporting Information, Figure S1).
Next, to further demonstrate the utility of this newly developed protocol, different
enols and ketones containing active methylene were examined (Scheme 2). Gratifyingly,
the reaction worked well with 4-hydroxy-2H-thiochromen-2-one (2g) to provide the
corresponding products 3 s, 3t, and 3 u in 80%, 83%, and 86% yields, respectively
(Scheme 2, Eq (1)). Likewise, reaction of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (2h)
with different 4-phenyl-1-sulfonyl-1H-1,2,3-triazoles were also compatible and gave the
desired products 3v, 3w, and 3x in 85%, 81%, and 81% yields, respectively (Scheme 2,
Eq (2)). It is worth noting that the reaction using 1-(2-hydroxyphenyl)-3-phenylpro-
pane-1,3-dione (2i) with 4-phenyl-1-tosyl-1H-1,2,3-triazole (1c) proceeded well and
gave the desired enol sulfonate product 3y in 78% yield after prolonging the reaction
time to 24 h (Scheme 2, Eq (3)). These results suggested that this direct sulfonylation
would provide a convenient and practical method for the synthesis of a series of
enol sulfonate derivatives by using 4-phenyl-1-sulfonyl-1H-1,2,3-triazoles as
sulfonyl precursors.
Moreover, the sulfonylation process also occurred well with 4-aryl-1-(tosylsulfonyl)-
1H-1,2,3-triazoles (1g–1j) and 4-hydroxy-2H-chromen-2-one (2a), affording the desired
products 3c in 84%, 80%, 81%, and 78% yields, respectively (Scheme 3). It should be
noted that the electronic and steric nature of the Ar group did not show obvious effects
on the yields of product 3c.

6
X. HE ET AL.
Scheme 3. DABCO-catalyzed Sulfonylation of 4-Aryl-1-(tosylsulfonyl)-1H-1,2,3-triazoles and 4-Hydroxy-
2H-chromen-2-one.
Scheme 4. Gram-scale synthesis of this method.
Scheme 5. The cross-coupling transformation of 2-oxo-2H-chromen-4-yl 4-methylbenzenesulfonate 3c.
In addition, we carried out a gram-scale reaction of 4-phenyl-1-(tosylsulfonyl)-1H-
1,2,3-triazole (1c, 5 mmol) to react with 4-hydroxy-2H-chromen-2-one (2a, 5 mmol)
under the standard conditions, and the product 3c was isolated in 80% (1.52 g) yield
(Scheme 4), which showed promise for this synthetic method as a useful tool in prac-
tical synthetic contexts.
Having demonstrated the preparation of the 2-oxo-2H-chromen-4-yl-4-sulfonate
compounds, their reactivity of Pd-catalyzed cross-coupling reactions was then investi-
gated, such as Suzuki-Miyaura, Sonogashira, and Heck coupling reaction. As revealed
from the results depicted in Scheme 5, the generated 2-oxo-2H-chromen-4-yl 4-methyl-
benzenesulfonate (3c) smoothly reacted with phenylboronic acid, phenylacetylene, and

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7
Scheme 6. Proposed mechanism for the synthesis of enol sulfonate derivatives 3.
styrene to obtain the corresponding products in 91%, 90%, and 78% yield, respectively.
Therefore, the generated 2-oxo-2H-chromen-4-yl-4-arylsulfonate compounds from 4-
aryl-1-(tosylsulfonyl)-1H-1,2,3-triazoles and 4-hydroxy-2H-chromen-2-one would be of
profound interest for C–C bond formation, leading to numerous applications in
organic chemistry.
On the basis of the experimental results obtained above, a plausible mechanism was
proposed and described in Scheme 6. Initially, DABCO as a base obtained a proton
from 4-hydroxy-2H-chromen-2-one (2a) to form the intermediate A. Subsequently, the
desired products 3 resulted from nucleophilic substitution of intermediate A as a
nucleophile with N-sulfonyl-1,2,3-triazoles 1. Meanwhile, 4-phenyl-1,2,3-triazole was
released as the byproduct.
Experimental section
General procedure for the synthesis of 2-oxo-2H-chromen-4-yl-4-sulfonates 3
To a stirred solution of N-sulfonyl-1,2,3-triazoles 1 (0.5 mmol), 4-hydroxy-2H-chro-
men-2-one 2 (0.5 mmol) in DCE (2 mL), DABCO (0.01 mmol) was added. The reaction
ꢁ
mixture was heated in an oil bath at 90 C for 5 h. After the reaction completed, the
mixture was cooled to room temperature, extracted with CH2Cl2 (3 ꢂ 10 mL), and
washed with water. The organic layers were combined, dried over Na2SO4, filtered, and
evaporated under vacuum. The residue was further purified by flash column chromatog-
raphy on silica gel (200-300 mesh) with ethyl acetate and petroleum ether (1:4/1:6, v/v)
as the elution solvent to give the desired product 3.
2 -Oxo-2H-chromen-4-yl methanesulfonate (3a)
This compound was purified by column chromatography (ethyl acetate/petroleum ether
1
ꢁ
= 1:6) to afford a white solid in 80% yield; mp 98–99 C; H NMR (CDCl3, 300 MHz)
d 7.75 (d, J = 7.8 Hz, 1H), 7.64 (t, J = 7.2 Hz, 1H), 7.40–7.33 (m, 2H), 6.54 (s, 1H),
3.38 (s, 3H); 13C NMR (CDCl3, 75 MHz) d 160.5, 157.2, 153.5, 133.5, 124.7, 122.9,
117.1, 114.6, 103.4, 39.1; IR (KBr) v 3070, 3034, 1729, 1629, 1606, 1372, 1187, 1175,
1065, 898, 870, 796, 772, 746, 718 cmꢃ1; HRMS (ESI) Calcd for [C10H8O5S þ H]þ
241.0165, Found 241.0165.

8
X. HE ET AL.
General procedure for the synthesis of 4-Phenyl-2H-chromen-2-one 4
To a solution of phenylboronic acid (0.6 mmol), 2-oxo-2H-chromen-4-yl 4-methylben-
zenesulfonate (0.5 mmol), and potassium carbonate (1 mmol) in degassed THF (4 mL)
was added freshly prepared degassed aqueous solution of PdCl2 (2.5 mol%) and 1,10-
ꢁ
bis(diphenylphosphino)ferrocene (dppf) (2.5 mol%). The mixture was stirred at 50 C
under nitrogen atmosphere for 10 h. Upon completion of the reaction, the mixture was
cooled to room temperature, and solvent was removed under reduced pressure. Water
(10 mL) was added to the mixture, and extracted with EtOAc (3 ꢂ 10 mL). The com-
bined organic layer was dried with anhydrous Na2SO4 and the solvent was concentrated
in vacuum. The crude residue was purified by chromatography on silica gel (n-Hexane/
Ethyl Acetate: 9/1) to afford the corresponding product 4 in 91% yield.
4 -Phenyl-2H-chromen-2-one (4)[29]
1
ꢁ
White solid; mp 99–100 C; H NMR (500 MHz, CDCl3) d 7.56–7.52 (m, 4H), 7.50 (d,
J = 7.5 Hz, 1H), 7.46–7.45 (m, 2H), 7.42 (d, J = 10.5 Hz, 1H), 7.23 (t, J = 8.0 Hz, 1H);
13C NMR (100 MHz, CDCl3) d 160.9, 155.8, 154.3, 135.3, 132.0, 129.8, 129.0, 128.5,
127.1, 124.3, 119.1, 117.4, 115.3; HRMS (APCI): [M þ H]þ Calcd for C15H11O2
223.0759; Found 223.0760.
General procedure for the synthesis of 4-(phenylethynyl)-2H-chromen-2-one 5
To a solution of phenylacetylene (0.6 mmol), 2-oxo-2H-chromen-4-yl 4-methylbenze-
nesulfonate (0.5 mmol), CuI (5 mol%) and triethylamine (0.75 mmol) in degassed
acetonitrile (4 mL) was added freshly prepared degassed aqueous solution of PdCl2 (3
mol%) and triphenylphosphine (3 mol%) under nitrogen atmosphere. The mixture
was stirred at 80 ꢁC under nitrogen atmosphere for 8 h. Upon completion of the
reaction, the mixture was cooled to room temperature, and solvent was removed
under reduced pressure. Water (10 mL) was added to the mixture, and extracted with
EtOAc (3 ꢂ 10 mL). The combined organic layer was dried with anhydrous Na2SO4
and the solvent was concentrated in vacuum. The crude residue was purified by chro-
matography on silica gel (n-Hexane/Ethyl Acetate: 10/1) to afford the corresponding
product 5 in 90% yield.
4 -(Phenylethynyl)-2H-chromen-2-one (5)[30]
1
ꢁ
White solid; mp 132–133 C; H NMR (500 MHz, CDCl3) d 7.97 (d, J = 8.0 Hz, 1H),
7.65 (d, J = 7.5 Hz, 2H), 7.57 (t, J = 8.0 Hz, 1H), 7.47–7.42 (m, 3H), 7.36 (t, J = 7.5 Hz,
2H), 6.63 (s, 1H); 13C NMR (125 MHz, CDCl3) d 160.4, 153.7, 137.4, 132.4, 130.3,
128.8, 126.8, 124.6, 121.3, 118.5, 117.2, 102.3, 82.9; HRMS (APCI): [M þ H]þ Calcd for
C17H11O2 247.0754; Found 247.0756.

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General procedure for the synthesis of (E)-4-styryl-2H-chromen-2-one 6
To a solution of styrene (1.5 mmol), 2-oxo-2H-chromen-4-yl 4-methylbenzenesulfonate
(0.5 mmol), and triethylamine (0.75 mmol) in degassed 1,4-dioxane (4 mL) was added
freshly prepared degassed aqueous solution of Pd(OAc)2 (2.5 mol%) and 1,3-bis(diphe-
nylphosphino) propane (dppp) (2.5 mol%) under nitrogen atmosphere. The mixture was
ꢁ
stirred at 85 C under nitrogen atmosphere for 20 h. Upon completion of the reaction,
the mixture was cooled to room temperature, and solvent was removed under reduced
pressure. Water (10 mL) was added to the mixture, and extracted with EtOAc (3 ꢂ 10
mL). The combined organic layer was dried with anhydrous Na2SO4 and the solvent was
concentrated in vacuum. The crude residue was purified by chromatography on silica gel
(n-Hexane/Ethyl Acetate: 10/1) to afford the corresponding product 6 in 78% yield.
(E)-4-Styryl-2H-chromen-2-one (6)[31]
White solid; mp 89–90 ꢁC; 1H NMR (500 MHz, CDCl3) d 7.81 (d, J = 8.0 Hz, 1H), 7.60 (d,
J = 7.0 Hz, 2H), 7.56 (t, J = 8.0 Hz, 1H), 7.43 (t, J = 7.5 Hz, 2H), 7.39 (t, J = 7.5 Hz, 2H),
7.35 (d, J = 8.0 Hz, 2H), 7.32 (t, J = 8.0 Hz, 1H), 6.60 (s, 1H); 13C NMR (125 MHz, CDCl3)
d 161.2, 153.9, 150.4, 137.8, 135.6, 131.9, 129.6, 129.0, 127.5, 124.4, 124.2, 120.3, 118.7,
117.5, 110.5; HRMS (APCI): [M þ H]þ Calcd for C17H13O2 249.0916; Found 249.0918.
Conclusions
In conclusion, a novel and efficient base-catalyzed sulfonylation of N-sulfonyl-1,2,3-tria-
zoles and 4-hydroxy-2H-chromen-2-ones for the synthesis of 2-oxo-2H-chromen-4-yl-4-
arylsulfonates in good yields has been developed. Notably, this is the first example of
the sulfonylation utilizing N-sulfonyl-1,2,3-triazoles as sulfonyl precursors. This metal
and oxidant-free synthetic process works well with a wide range of substrates and can
be safely conducted on a gram scale. The features such as generality, high efficiency
(low catalyst loading), and mild reaction conditions make this method an attractive
alternative for the preparation of organosulfone compounds. Furthermore, this new
reaction can enrich the chemistry of N-sulfonyl-1,2,3-triazole compounds.
1
Full experimental detail, H and 13C NMR spectra. This material can be found via
the “Supplementary Content” section of this article’s webpage.
Funding
The work was partially supported by the National Natural Science Foundation of China [Nos.
21772001, 21702003], the Anhui Provincial Natural Science Foundation [No. 1808085MB41], the
Natural Science Foundation of Education Administration of Anhui Province [No. KJ2016A267],
the Special and Excellent Research Fund of Anhui Normal University, and the Doctoral Scientific
Research Foundation of Anhui Normal University [No. 2016XJJ110].
ORCID
Xinwei He
Yongjia Shang
http://orcid.org/0000-0002-1974-2464
http://orcid.org/0000-0001-9873-9150

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X. HE ET AL.
References
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