Synthesis of 3-selanylbenzo[: B] furans promoted by SelectFluor

Article abstract of DOI:10.1039/d0ra01907k

A simple and practical protocol for the synthesis of 3-selanyl-benzo[b]furans mediated by the SelectFluor reagent was developed. This novel methodology provided a greener alternative to generate 3-substituted-benzo[b]furans via a metal-free procedure unde

Full text of DOI:10.1039/d0ra01907k

RSC Advances
View Article Online
View Journal | View Issue
PAPER
Synthesis of 3-selanylbenzo[b]furans promoted by
SelectFluor®†
Cite this: RSC Adv., 2020, 10, 13975
Maurıcio Carpe Diem Ferreira Xavier,a Eduardo Martarelo Andia Sandagorda,a
´
c
ab
*
Jose Sebastiao Santos Neto, Ricardo Frederico Schumacher
´
˜
a
*
and Marcio Santos Silva
´
A simple and practical protocol for the synthesis of 3-selanyl-benzo[b]furans mediated by the SelectFluor®
reagent was developed. This novel methodology provided a greener alternative to generate 3-substituted-
benzo[b]furans via a metal-free procedure under mild conditions. The intramolecular cyclization reaction
was carried out employing an electrophilic selenium species generated in situ through the reaction
between SelectFluor® and organic diselenides. The formation of this electrophilic selenium species
(RSe-F) was confirmed by heteronuclear NMR spectroscopy, and its reactivity was explored.
Received 28th February 2020
Accepted 30th March 2020
DOI: 10.1039/d0ra01907k
rsc.li/rsc-advances
The benzo[b]furan scaffold is an important structural motif that versatile reactivity.5 From a synthetic point of view, the ease
is present in natural products and in synthetic compounds with cleavage of the Se–Se bond in diselenide compounds can
therapeutic proprieties.1 Substituted benzo[b]furans have generate species with different reactivity, as radical, electro-
shown a broad range of biological activities,2 being found in phile, and nucleophile. This ample usefulness becomes the
a variety of pharmaceutical targets, such as Viibryd® and diselenides in key synthetic intermediates to introduce sele-
Ancoron® (Fig. 1).3 These drugs are used for treatment of nium moiety in organic compounds or to catalyse organic
depression and for cardiac arrhythmias, respectively. An effi- transformations.5,6
cient method to obtain substituted benzo[b]furans is the
Despite the recent advances in the synthesis of 3-selanyl-
intramolecular cyclization reaction between 2-alkynylphenol or benzo[b]furans, new electrophiles and reactional conditions
2-alkynylanisole derivatives with different electrophilic species were explored (Scheme 1).7–9,11–15 Initially, the establishing work
to generate a wide variety of 3-substituted-benzo[b]furans. This by Larock and co-workers toward the synthesis of 3-selanyl-
strategy is especially useful because of the atom-economic
synthesis under mild conditions.4
Organoselenium compounds have attracted great interest
due the large number of biological applications and their
Fig. 1 Substituted benzo[b]furans in commercial drugs.
a
´
´
ˆ
ˆ
´
Laboratorio de Sıntese Organica Limpa – LASOL, Centro de Ciencias Quımicas,
ˆ
Farmaceuticas e de Alimentos – CCQFA, Universidade Federal de Pelotas – UFPel,
˜
˜
Capao do Leao, RS, Brazil. E-mail: silva.ms@ufpel.edu.br; ricardo.schumacher@
ufsm.edu.br
b
´
Departamento de Quımica, Universidade Federal de Santa Maria – UFSM, Santa
Maria, RS, Brazil
´
cDepartamento de Quımica, Universidade Federal de Santa Catarina
– UFSC,
´
Florianopolis, SC, Brazil
† Electronic supplementary information (ESI) available. See DOI:
10.1039/d0ra01907k
Scheme 1 Methodologies to prepare 3-selanyl-benzo[b]furans.
RSC Adv., 2020, 10, 13975–13983 | 13975
This journal is © The Royal Society of Chemistry 2020

View Article Online
RSC Advances
Paper
benzo[b]furans through the intramolecular cyclization of 2-
(phenylethynyl)anisole with PhSeCl in CH2Cl2 at room temper-
ature.7 In 2009, Zeni and co-workers demonstrated the synthesis
of 3-selanyl-benzo[b]furans employing PhSeBr as an active
electrophile.8 A pioneering protocol was reported by Zeni and
co-workers, which employed FeCl3 (1.0 equiv.) and diorganyl
Results and discussion
We commenced optimization of the reaction conditions using
2-phenylalkynylanisole 1a and diphenyl diselenide 2a as stan-
dard substrates. The reaction conditions were investigated as
outlined in Table 1.
diselenides in CH2Cl2 at 45 C.9 Additionally, Lewis acids have
ꢀ
Initially, the reaction was carried out using 0.250 mmol of 1a,
0.125 mmol of 2a and 0.250 mmol of SelectFluor® in MeCN at
room temperature under N2 atmosphere. Aer 2.0 h, the yield of
product 3a was 90% (Table 1, entry 1). When the reaction was
performed under air atmosphere, product 3a was obtained in
just 67% yield (Table 1, entry 2 vs. 1). The reduction of the
amount of MeCN solvent was not benecial for the reaction
(Table 1, entry 3 vs. 1). When the amount of SelectFluor® was
decreased to 0.125 mmol, the reaction performance was similar
to entry 1 (Table 1). When the reaction was carried out with
a small excess of diphenyl diselenide 2a, no effective improve-
ment in the reaction condition was observed (Table 1, entry 5 vs.
1). These outcomes clearly demonstrate that the dependence on
the amount of diorganyl diselenide with SelectFluor® reagent is
not stoichiometric. A solvent evaluation was performed (Table
1, entries 7–12), with DMF demonstrating satisfactory yield but
a longer reaction time (Table 1, entry 8 vs. 1). With DMSO
solvent the formation of product 3a was not detected by TLC
and GC (Table 1, entry 7). With THF, EtOH, PEG-400 and glyc-
erine solvents the yields and reaction times were unsatisfactory
(Table 1, entries 9–11). It is noticeable that this synthetic
protocol is sensitive to water content, since the reaction using
been used as effective catalysts in Se–Se bonding cleavage to
access functionalized selenium compounds.10 Aerward, alter-
native methods were developed, such as the synthesis of 3-
selanyl-benzo[b]furans mediated by PdCl2/I2, I2/water, and CuI
(1.5 equiv.).11–14 More recently, Liu and co-workers reported
a radical cyclization reaction using selenium powder as sele-
nium source and AgNO3 as catalyst in DMSO at 100 C.15
ꢀ
Although, there are different methodologies to prepare 3-
selanyl-benzo[b]furans and other functionalized selenium
compounds through the reaction between diselenides
compounds with oxidant reagents or Lewis acids, alternative
electrophilic selenium species should be employed to avoid
metals and/or toxic reagents.9–15 Furthermore, RSeCl and
RSeBr,7,8 obtained from the reaction of diselenides with SO2Cl2
(or Cl2) and Br2 respectively, are commercially available and
largely used as selenylating agent. However, these species
present a low stability under moisture, and the high nucleo-
philicity of chloride and bromide leaving groups can lead to
undesirable side reactions.
On the other hand, SelectFluor® is a versatile reagent used
for different applications, such as uorination reactions,16 C–H
functionalization17 and organic function transfer.18 In addition,
SelectFluor® has been used as an efficient method for intra-
molecular annulation reactions, due its higher reactivity.19 This
ample application together with the desirable characteristics of
the SelectFluor®, such as the higher stability, non-hydroscopic
solid and hazard-free source of uorine,20 promoted new
possibilities to investigate uorine chemistry. In 2004, Pole-
schner and Seppelt prepared PhSeF derivatives by the reaction
between diorganyl diselenides and XeF2 in CH2Cl2 as a solvent
at ꢁ40 ꢀC.21 The products were characterized by low-
temperature 19F and 77Se NMR, and it was the rst conrma-
tion of this type of electrophilic selenium compound. Although
electrophilic selenium catalysis (ESC) with electrophilic uoride
reagents as oxidants has been demonstrated in the functional-
ization of alkenes,22 fewer knowledge about the reactivity of this
selenium electrophilic species is available in the literature.23
Based on the development of new electrophilic selenium
reagents,9–14,24 herein, we describe a metal-free synthesis of 3-
selanyl-benzo[b]furans under mild conditions using this very
reactive electrophilic selenium species (RSe-F), generated in situ
at room temperature by the reaction of diorganyl diselenides
with SelectFluor® reagent (Scheme 1). Moreover, the higher
reactivity of RSe-F species could be explored for the insertion of
selenium moiety in other building blocks because the envi-
ronmentally friendly reactional condition, and the replacing
chlorine and bromine by the non-nucleophilic uorine counter
ion, can partially circumvented some side reactions.
Table 1 Optimization of the reaction conditions for the synthesis of 3-
phenylselanyl-benzo[b]furan 3aa
#
1
2a (mmol) F® (mmol) Solvent (3.0 mL) Time (h) Yieldb (%)
0.125
0.250
0.250
0.250
0.125
0.125
0.062
0.125
0.250
0.250
0.250
0.250
0.250
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
DMSO
DMF
2
97
67
70
90
92
40
N.R.
79
55
61
57
45
2c 0.125
2
3d 0.125
2
4
5
6
7
8
9
0.125
0.150
0.125
0.125
0.125
0.125
2
2
2
24
24
24
24
24
24
THF
EtOH
PEG-400
Glycerine
10 0.125
11 0.125
12 0.125
a
Reactions performed using 2-phenylalkynylanisole 1a (0.250 mmol)
with diphenyl diselenide 2a and solvent under N2 atmosphere.
b
c
Yields of isolated product.
Reaction performed under air
The reaction was performed using 1.0 mL of
MeCN; N.R. ¼ no reaction.
d
atmosphere.
13976 | RSC Adv., 2020, 10, 13975–13983
This journal is © The Royal Society of Chemistry 2020

View Article Online
Paper
RSC Advances
wet MeCN resulted in yield decrease and the formation of (Scheme 2, 3h) the performance of the reaction remained
seleninic acid was observed by 77Se-{1H} NMR.
suitable.
Similarly, a substrate scope of the 2-organylalkynylanisoles 1
Next, we turned our attention to the reactional scope
(Scheme 2), evaluating different 2-organylalkynylanisoles 1 with was also carried out (Scheme 2). These substrates were prepared
diverse diorganyl diselenides 2 under optimized reaction by the Sonogashira coupling reaction between terminal alkynes
conditions (Table 1, entry 4).
with 2-bromoanisole.7 Once with the 2-organylalkynylanisoles 1
As summarized in Scheme 2, the substitution patterns on the in hands, we started with evaluating the effect of electron-
phenyl moiety were satisfactory in all examples. The presence of donating and electron-withdrawing groups. As can be seen in
methyl substituent, an electron-donating group, at para-posi- Scheme 2, para-methyl (3i) or para-chloride (3j) substituents
tion or ortho and para-positions afforded excellent yields gave a satisfactory efficiency, 67% and 70% of yield, respec-
(Scheme 2, 3b and 3c). The presence of methoxyl group at ortho- tively. When the aryl group was replaced by the alkyl group in
position also provided a satisfactory yield (Scheme 2, product the alkyne reagent the yield was similar (Scheme 2, 3k).
3d). When electron-withdrawing groups were evaluated, the
Aer determining the substrate scope regarding substituted
conversion to the products 3e (para-chloride) and 3f (meta-CF3) diorganyl diselenides 2 and 2-organylalkynylanisoles 1, the
yielded 82% and 85%, respectively (Scheme 2). When we reactivity of others diorganyl dichalcogenides (S and Te) were
examined the presence of pyridyl moiety on the aromatic dis- tested (Scheme 3). Notably, the reaction efficiency was reduced
elenide, a moderate yield was obtained (Scheme 2, 3g). In an employing sulphur or tellurium elements. When diphenyl
attempt to improve the performance of pyridyl moiety, a reac- disulphide was used instead of diselenide, the yield has
tion to obtain the product 3g was carried out in 24 h at room changed to 44% (Scheme 3, 3l). Considering the tellurium atom
ꢀ
temperature or employing heating (oil bath) of 50 C for 2 h. on the electrophilic intramolecular cyclization reaction, the
However, both experimental changes were not affective to yield was just 30% (Scheme 3, 3m). Based on the literature, it is
increase the yield of compound 3g. Furthermore, when the possible to check the higher stability of the S–F bond,25 that
aromatic diselenides were switched for an aliphatic diselenide could explain the lower effectivity of the 3-sulphuryl-benzo[b]
furan 3l synthesis. However, there is not enough data describing
the Te–F bonding stability and reactivity.21,26
To further extend the practicability of this reaction, the
reactivity of the 2-propagylanisole 1e was explored. Thus, the
reaction was carried out using 0.250 mmol of 1e, 0.125 mmol of
2a and 0.250 mmol of SelectFluor® in MeCN at room temper-
ature under N2 atmosphere. Aer 2.0 h, the yield was moderate
1
(Scheme 4, 4a). To our surprise, the H and 13C NMR analyses
have demonstrated altered standard spectra. These outcomes
encouraged us to perform additional analyses to evaluate the
product obtained. Consequently, HRMS (Fig. 2), infrared and
NMR (ESI: 77Se-{1H}, COSY, HSQC and HMBC) analyses were
carried out to check the structural assignment. All these nd-
ings support that a semi-pinacol rearrangement occurred,
which an insertion of the C6H5Se group has occurred followed
by a CH3 group shiing and providing the ketone 4a product
(Scheme 4). Moreover, this reactivity of the 2-propagylanisole 1e
is comparable with the literature, by isomerization27 or addition
of others electrophilic species.28
Scheme 2 Substrate scope for the synthesis of 3-organylselanyl- Scheme 3 Chalcogenide scope for the synthesis of 3-chalcogenyl-
benzo[b]furans 3a–k.
benzo[b]furans 3l–m.
This journal is © The Royal Society of Chemistry 2020
RSC Adv., 2020, 10, 13975–13983 | 13977

View Article Online
RSC Advances
Paper
The reactivity of the 2-phenylalkynylphenol 1d was also
evaluated. According to Scheme 6, it is possible to observe that
the phenol organic functional group is not sensitive to this
higher reactive selenium electrophilic species, which the
product 3a was obtained in 70% of yield.
In order to gain insight into the mechanism, H, 13C-{1H},
1
19F and 77Se-{1H} NMR analyses of a mixture between the
diphenyl diselenide 2a and SelectFluor® were performed
(ESI).30 For this purpose, 0.075 mmol of 2a and 0.150 mmol of
SelectFluor® were solubilized in 1.0 mL of deuterated CD3CN
and the NMR analyses were carried out at 25 ꢀC. It was observed
that a shielding has happened in the 1H and 13C-{1H} NMR
chemical shis of the SelectFluor® reagent, reecting the
leaving of uorine atom. A deshielding was observed in the
aromatic groups of the 2a compound around 1.0 ppm in the 1H
NMR spectrum. Considering the 19F NMR experiment, the
disappearance of 19F NMR chemical shi of the SelectFluor
(ESI: 48.0 ppm) and the arising of a signal at ꢁ182.0 ppm,
suggested the formation of a new uorine compound. Finally,
evaluating the 77Se-{1H} NMR analysis a new signal arisen at
1430.0 ppm, probably related to the Se–F bonding forma-
tion.21,31 When the 19F NMR experiment was performed
employing 0.075 mmol of 2a with 0.075 mmol of SelectFluor®,
similarly to the reaction conditions, a signal at ꢁ46.5 ppm was
detected. But, the 77Se-{1H} NMR experiment did not show new
peak, only regarding to the diphenyl diselenide compound.
Considering the NMR results21,31 and based on the litera-
ture,7–9 we have suggested a plausible mechanism for intra-
molecular cyclization reaction (Scheme 7). We have proposed
two routes, based on the stoichiometric of the reagents, which
both routes have the same intermediate detected by hetero-
nuclear NMR spectroscopy. Initially, the formation of a higher
Scheme 4 Reactivity of 2-propagylanisole 1e in the reaction with the
electrophilic Se–F species.
Fig. 2 HRMS and isotopic distribution of product 4a (up: experimental
analysis; and down: calculated MW + Na+ ¼ 369.0369).
On evaluating the 2-organylalkynylanilines 1f and 1g to
obtain 3-selanylindoles 5a–b, the results were less successful
than the 3-selanyl-benzo[b]furans 3 (Scheme 5). This lower
effectivity was established by a complex mixture of products in
the TLC and 1H NMR analyses, obtaining the indoles 5a and 5b
in just 25% and 20% of yield, respectively. The possible by-
products can be suggested by the higher reactivity of the
indoles with uorine reagents.29 Additionally, a complete
structural elucidation of the product 5b was performed to
undoubtedly conrm the product 5b and obtain information
about 15N NMR chemical shi prole (see ESI†).
reactive selenium electrophilic species
A
(77Se-{1H}
¼
1430.0 ppm and 19F ¼ ꢁ182.0 ppm) is performed by the reaction
between 1.0 equiv. of diselenide compound with 2.0 equiv. of
SelectFluor® reagent (Scheme 7, route A). Next, the electrophilic
selenium A reacts with the 2-organylalkynylanisole 1 to provides
the intermediate B. Therefore, an intramolecular cyclization
occurs by the oxygen attack on the activated triple bond and
producing the 3-selanyl-benzo[b]furans. The CH3 or H leaving
group of the methoxyl or phenol organic function, respectively,
could be favoured by the nucleophilic attack of the nitrogen
atom derived from the SelectFluor® residue. Considering the
route B, a sub stoichiometric amount of SelectFluor® (1.0
equiv.) was employed. To explain the effectiveness of this
experimental condition, the formation of an electrophilic sele-
nium species C (19F ¼ ꢁ46.5 ppm) was suggested, which the
Scheme 6 Synthesis of 3-phenylselanyl-benzo[b]furan 3a employing
Scheme 5 Substrate scope for the synthesis of 3-selanylindoles 5a–b. 2-phenylalkynylphenol 1d.
13978 | RSC Adv., 2020, 10, 13975–13983
This journal is © The Royal Society of Chemistry 2020

View Article Online
Paper
RSC Advances
Experimental section
All commercial reagents and solvents were used without addi-
tional purication. TLC was performed on silica gel plates
(Merck silica gel 60, F254), and the spots were visualized with UV
light (254 and 365 nm) or by charring the plate dipped in
vanillin solution. For the FTIR (Fourier Transform Infrared) in
the attenuated total reection mode (FTIR-ATR), the samples
were submitted to KI and placed on the crystal surface of a FTIR
Bruker Alpha-P spectrometer, obtained at the range of 4000–
1500 cmꢁ1 1H, 13C, 19F, 77Se-{1H}, COSY, HSQC and HMBC
.
NMR spectra were recorded using an NMR spectrometer with
400 MHz (Bruker, Avance III HD model). The probe was a 5 mm
direct F-BBO (uoride broadband observed). Spectra were
recorded in deuterated chloroform at 298 K (25 ꢀC). The re-
ported data include chemical shi (d), multiplicity, coupling
constant (J) in hertz, and integrated intensity. The following
abbreviations were used to explain multiplicities: s ¼ singlet,
d ¼ doublet, dd ¼ doublet of doublet, dt ¼ doublet of triplet, t ¼
triplet, td ¼ triplet of doublet, q ¼ quartet, quint ¼ quintet, sex
¼ sextet and m ¼ multiplet. The 19F NMR chemical shis are
reported in ppm relative to PhCF3 (d ꢁ63 ppm). The 77Se-{1H}
NMR chemical shis are reported in ppm relative to the internal
standard C6H5SeSeC6H5 (d 463 ppm). The NMR pulse sequence
employed for 77Se-{1H} NMR experiments was gated decoupling.
HRMS (m/z) were measured by ESI technique.
Scheme 7 Plausible mechanism routes for the synthesis of 3-organ-
ylselanyl-benzo[b]furans 3.
attack of 2-organylalkynylanisole 1 provides the intermediates A
and B. Consequently, the intermediate B produces the desired
product, and the intermediate A forms the species B, also
resulting the 3-selanyl-benzo[b]furan compound.
Related to the cleavage of the Se–Se bonding for the forma-
tion of the species A, there are some studies that support an
homolytic cleavage.32 Our tests to evaluate this type of cleavage
have demonstrated a yield reduction. Under the standard
reaction conditions, the reaction between 1a and 2a reagents
was performed in the presence of 2,2,6,6-tetramethylpiperidin-
1-oxyl (TEMPO) or benzene-1,4-diol, used as radical inhibitors
(2.0 equiv.). The product yield in each test was 40% and 42%,
respectively. Although, these ndings support an homolytic
cleavage of Se–Se, the higher reactivity of SelectFluor® against
these radical inhibitors limit the conclusions of the reaction
pathway. On the other hand, when we evaluate the mechanism
involved in the ditelluride 2j, a different outcome was provided.
At rst, TEMPO as a radical inhibitor was added, and following
our optimal experimental conditions, no product 3m was ob-
tained. Considering the weak Te–Te bonding and the Te-
oxidation facility,33 this result demonstrated that the reaction
might occurred through a radical pathway.
General protocol for the preparation of 2-alkynylanisoles 1 via
Sonogashira coupling reaction5
To a two-necked round bottom ask containing PdCl2(PPh3)2
(1 mol%) and Et3N (3.0 mL) was added 2-bromoanisole (1.0
mmol) and terminal alkyne (1.5 mmol). The resulting solution
was stirred for 5 minutes at room temperature. Aer this time, it
was added CuI (2 mol%) and the reaction mixture was allowed
to stir at 75 ꢀC for 12 hours. Aer, the mixture was diluted with
ethyl acetate (20.0 mL) and washed with saturated brine (2 ꢂ
20.0 mL). The organic phase was separated, dried over MgSO4
and concentrated under vacuum. The residue was puried by
ash chromatography and eluted with hexane.
General protocol for the preparation of 3-
selanylalkynylanisoles 3
The corresponding diorganyl diselenides (0.125 mmol) was
added to a round bottom ask owed by addition of dry CH3CN
Conclusions
In summary, a simple and efficient protocol for the synthesis of solvent (2.0 mL). To this solution, SelectFluor® (0.250 mmol)
3-selanyl-benzo[b]furans was developed. The methodology was added under N2 atmosphere. As the SelectFluor® was dis-
provided a greener alternative to generate 3-substituted-benzo solved the reaction colour changed from yellow to red-brown.
[b]furans via a metal-free procedure under mild conditions. Aer 5 minutes from the addition of SelectFluor®, a solution
Additionally, we have conrmed the formation of the Se–F of 2-alkynylanisole 1 in dry CH3CN solvent (0.250 mmol in 1.0
bonding, and its reactivity as an electrophilic selenium species mL) was added to the reaction mixture. The reaction colour
was assessed. Compared with traditional methods, this meth- usually changed from red-brown to a clear brown. The reaction
odology is a mild, metal-free and simple tool for the generation progress was monitored by TLC. Aer reaction completion ethyl
of selenium electrophile. These results demonstrate new acetate (20.0 mL) and distilled water (20.0 mL) were added and
possibilities of reaction application, since little information can the aqueous layer was washed with ethyl acetate (2 ꢂ 20.0 mL).
be found in the literature about the reactivity of RSe-F Then, the combined organic layers were washed with distilled
electrophiles.
water (10.0 mL) to remove any remaining organic solvent. Aer
This journal is © The Royal Society of Chemistry 2020
RSC Adv., 2020, 10, 13975–13983 | 13979

View Article Online
RSC Advances
Paper
removal of the solvent, column chromatography was performed CDCl3) d (ppm) ¼ 157.7, 154.2, 132.7, 132.0, 131.5 (q, J ¼ 34.4
using silica gel and either hexane or a mixture of hexane and Hz), 131.4, 129.8, 129.6, 129.5, 128.5, 127.8, 125.6 (q, J ¼ 3.6 Hz),
ethyl acetate depending on the polarity of the product 3. The 125.5, 123.0 (q, J ¼ 272.9), 123.6, 122.9 (q, J ¼ 3.6 Hz), 120.9,
characterization data of synthesized products 3 are described in 111.3, 98.7. MS: m/z (rel intensity) 418 (M+ 35.6), 338 (100.0), 309
the ESI.†
2-Phenyl-3-(phenylselanyl)benzo[b]furan 3a. Yield: 0.084 g
(7.3), 268 (4.3), 241 (6.7), 165 (29.8), 139 (6.1), 115 (3.9).
2-Phenyl-3-(2-pyridylselanyl)benzo[b]furan 3g. Yield: 0.024 g
(97%). White solid, mp ¼ 40–41 ꢀC. 1H NMR (CDCl3, TMS, 400 (40%). Yellow solid, mp ¼ 46 ꢀC. 1H NMR (400 MHz, CDCl3)
MHz) d (ppm) ¼ 8.12 (d, J ¼ 7.2 Hz, 2H), 7.47–7.42 (m, 2H), 7.37– d (ppm) ¼ 8.45 (ddd, J ¼ 4.8, 1.8, 0.8 Hz, 1H), 8.23–8.20 (m, 2H);
7.19 (m, 6H), 7.14 (dt, J ¼ 7.4 and 1.0 Hz, 1H), 7.09–7.02 (m, 3H). 7.60–7.55 (m, 2H), 7.47–7.35 (m, 4H), 7.32–7.29 (m, 2H), 7.01
13C NMR (100 MHz, CDCl3) d (ppm) ¼ 157.2, 154.1, 131.8, 131.3, (ddd, J ¼ 7.4, 4.9, 1 Hz, 1H), 6.9 (dt, J ¼ 8.0, 1.0 Hz). 13C NMR
130.1, 129.3, 129.2, 129.1, 128.4, 127.7, 126.2, 125.2, 123.4, (100 MHz, CDCl3) d (ppm) ¼ 157.6, 157.4, 154.2, 150.0, 136.9,
121.1, 111.1, 99.6. MS: m/z (rel intensity) 350 (M+ 32.4); 270 131.7, 129.9, 129.5, 128.5, 127.8, 125.4, 123.6, 122.9, 121.1,
(100.0), 255 (7.8), 241 (17.0), 165 (28.5), 134 (8.4), 115 (4.5), 77 120.5, 111.3, 99.0. HRMS calculated for C18H13NOSe + Na ¼
(5.4).
2-Phenyl-3-[(4-methylphenyl)selanyl]benzo[b]furan
374.0059, found: 374.0055.
3b.
3-(Butylselanyl)-2-phenylbenzo[b]furan 3h. Yield: 0.066 g
Yield: 0.073 g (81%). Yellow solid, mp ¼ 77 C.2 1H NMR (400 (78%). Yellow oil. 1H NMR (400 MHz, DMSO-d6) d (ppm) ¼ 8.19
MHz, CDCl3) d (ppm) ¼ 8.13 (d, J ¼ 7.2 Hz, 2H), 7.44 (t, J ¼ (d, J ¼ 7.8 Hz, 2H), 7.64 (d, J ¼ 7.8 Hz, 2H), 7.52–7.55 (m, 2H),
8.2 Hz, 2H), 7.38–7.34 (m, 2H), 7.33–7.24 (m, 1H), 7.22 (td, J ¼ 7.47–7.43 (m, 1H), 7.40–7.32 (m, 1H), 2.80 (t, J ¼ 7.2 Hz, 2H),
7.7 Hz and 1.4 Hz, 1H), 7.15–7.11 (m, 3H), 6.88 (d, J ¼ 8.0 Hz, 1.43 (quint, J ¼ 7.1 Hz, 2H), 1.24 (sext, J ¼ 7.3 Hz, 2H), 0.68 (t, J ¼
2H), 2.14 (s, 3H). 13C NMR (100 MHz, CDCl3) d (ppm) ¼ 156.9, 7.3 Hz, 2H). 13C NMR (100 MHz, DMSO-d6) d (ppm) ¼ 155.33,
154.0, 136.1, 131.9, 130.1, 130.0, 129.5, 129.1, 128.4, 127.7, 153.26, 131.88, 129.76, 129.29, 128.65, 127.30, 125.44, 123.58,
ꢀ
127.4, 125.1, 123.3, 121.2, 111.1, 100.1, 20.9.
120.73, 111.31, 99.90, 31.76, 27.65, 21.91, 13.22. EM: m/z (rel
2-Phenyl-3-(mesitylselanyl)benzo[b]furan 3c. Yield: 0.072 g intensity) 330 (M+ 35.3), 274 (11.7), 245 (12.5), 194 (100.0), 165
(77%). Yellow solid, mp ¼ 145–148 ꢀC. 1H NMR (400 MHz, (31.8), 41 (5.9).
CDCl3) d (ppm) ¼ 8.04 (d, J ¼ 7.3 Hz, 2H), 7.40–7.34 (m, 3H),
3-(Phenylselanyl)-2-(4-methylphenyl)benzo[b]furan 3i. Yield:
1
7.29 (m, 1H), 7.10 (dt, J ¼ 1.4 and 8.0 Hz, 1H), 6.93 (dt, J ¼ 7.5 0.060 g (67%). White solid, mp ¼ 62 ꢀC. H NMR (400 MHz,
and 1.0 Hz, 1H), 6.85 (m, 1H), 6.76 (s, 2H), 2.30 (s, 6H), 2.13 (s, CDCl3) d (ppm) ¼ 8.10 (d, J ¼ 8.2 Hz, 2H), 7.55–7.49 (m, 2H),
3H). 13C NMR (100 MHz, CDCl3) d (ppm) ¼ 153.9, 153.4, 142.2, 7.34–7.20 (m, 6H), 7.18–7.10 (m, 3H), 2.39 (s, 3H). 13C NMR (100
138.1, 131.6, 130.6, 128.9, 128.6, 128.3, 127.4, 126.4, 124.6, MHz, CDCl3) d (ppm) ¼ 157.5, 154.0, 139.4, 131.9, 131.5, 129.0,
122.8, 120.6, 110.9, 102.3, 24.1, 20.8. MS: m/z (rel intensity) 392 127.6, 127.3, 126.1, 124.9, 123.3, 121.0, 111.0, 98.8, 21.4. MS: m/z
(M+ 37.9); 311 (2.3); 281 (4.8); 194 (100.0); 165 (33.3); 139 (5.4); (rel intensity) 364 (31), 363 (4), 284 (100), 269 (11), 255 (9), 241
119 (14.8); 91 (16.7); 77 (10.4); 44 (12.2). HRMS calculated for (13), 178 (33), 165 (4), 15 (1), 77 (22).
C
23H20OSe 392.0675, found: 392.0676.
3-(2-Methoxyphenylselanyl)-2-(phenyl)benzo[b]furan
2-(4-Chlorophenyl)-3-(phenylselanyl)benzo[b]furan 3j. Yield:
3d. 0.069 g (70%). Yellow solid, mp ¼ 71–73 ꢀC. 1H NMR (400 MHz,
Yield: 0.063 g (70%). Yellow oil. 1H NMR (400 MHz, CDCl3) CDCl3) d (ppm) ¼ 8.07 (d, J ¼ 8.7 Hz, 2H), 7.44–7.41 (m, 2H),
d (ppm) ¼ 8.19 (d, J ¼ 7.8 Hz, 2H), 7.57–7.52 (m, 2H), 7.43–7.31 7.30 (d, J ¼ 8.7 Hz, 2H), 7.23 (t, J ¼ 7.7 Hz, 1H), 7.19–7.11 (m,
(m, 4H), 7.24–7.21 (m, 1H), 7.10 (t, J ¼ 7.7 Hz, 1H), 6.84 (d, J ¼ 3H), 7.08–7.01 (m, 3H). 13C NMR (100 MHz, CDCl3) d (ppm) ¼
8.1 Hz, 1H), 6.78 (d, J ¼ 7.7 Hz), 6.66 (t, J ¼ 7.5 Hz, 1H), 3.93 (s, 155.9, 154.0, 135.2, 131.8, 131.1, 129.3, 129.2, 128.9, 128.7,
3H). 13C NMR (100 MHz, CDCl3) d (ppm) ¼ 158.0, 156.4, 154.2, 128.5, 126.4, 125.4, 123.5, 121.2, 111.2, 100.2. MS: m/z (rel
132.1, 130.1, 129.2, 128.4, 128.1, 127.8, 126.8, 125.2, 123.4, intensity) 384 (M+ 51.34), 304 (100.0), 281 (7.35), 268 (25.64), 241
121.8, 121.3, 120.6, 111.1, 110.2, 97.8, 55.8. EM: m/z (rel inten- (19.30), 207 (17.43), 199 (16.27), 163 (25.01), 134 (7.98), 73
sity) 380 (M+ 85.4), 300 (100.0), 268 (13.8), 257 (17.0), 207 (14.5), (10.12).
194 (35.7), 165 (64.5), 91 (14.4), 77 (25.6), 63 (12.2). HRMS
calculated for C21H16O2Se + Na ¼ 403.02125, found: 403.0220.
2-(nPentyl)-3-(phenylselanyl)benzo[b]furan 3k. Yield: 0.067 g
(72%). Clear oil. 1H NMR (400 MHz, CDCl3) d (ppm) ¼ 7.47–7.42
3-[(4-Chlorophenyl)selanyl]-2-phenylbenzo[b]furan 3e. Yield: (m, 2H), 7.28–7.22 (m, 4H), 7.18–7.10 (m, 3H), 2.97 (t, J ¼ 7.5 Hz,
1
ꢀ
0.078 g (82%). Yellow solid, mp ¼ 87 C. H NMR (400 MHz, 2H), 1.73 (p, J ¼ 6.8 Hz, 1H), 1.32–1.29 (m, 4H), 0.84 (t, J ¼
CDCl3) d (ppm) ¼ 8.08 (d, J ¼ 7.0 Hz, 2H), 7.46 (d, J ¼ 8.2 Hz, 6.5 Hz, 3H). 13C NMR (100 MHz, CDCl3) d (ppm) ¼ 163.8, 154.4,
1H), 7.40–7.27 (m, 4H), 7.24 (td, 7.7 Hz, 1.4 Hz, 1H), 7.16–7.09 131.8, 130.7, 129.13, 129.10, 126.0, 124.0, 123.0, 120.3, 110.9,
(m, 3H), 7.03–7.00 (m, 2H). 13C NMR (100 MHz, CDCl3) d (ppm) 100.0, 31.3, 27.9, 27.3, 22.3, 13.9. EM: m/z (rel intensity) 344 (M+
¼ 157.3, 154.0, 132.3, 131.5, 130.4, 129.9, 129.5, 129.4, 129.3, 80.1), 287 (36.2), 264 (41.0), 207 (100.0), 178 (33.6), 131 (37.1),
128.4, 127.7, 125.3, 123.5, 120.9, 111.2, 99.3. MS: m/z (rel 115 (8.5), 102 (8.7), 77 (10.0). HRMS calculated for C19H20OSe +
intensity) 384 (M+ 37.2); 304 (100.0), 268 (22.1), 241 (18.6), 165 Na ¼ 367.05764, found: 367.0549.
(38.8), 134 (13.5), 63 (3.7).
2-(4-Chlorophenyl)-3-(phenylselanyl)benzo[b]furan 3l. Yield:
1
2-Phenyl-3-[(3-triuormethylphenyl)selanyl]benzo[b]furan
0.035 g (44%). White solid, mp ¼ 76 ꢀC. H NMR (400 MHz,
3f. Yield: 0.088 g (85%). Yellow solid, mp ¼ 80 ꢀC. 1H NMR (400 CDCl3) d (ppm) ¼ 8.23 (d, J ¼ 7.4 Hz, 2H), 7.56 (d, J ¼ 8.2 Hz,
MHz, CDCl3) d (ppm) ¼ 8.17 (d, J ¼ 7.3 Hz, 2H), 7.61–7.49 (m, 1H), 7.49–7.37 (m, 5H), 7.36–7.28 (m, 2H), 7.24–7.19 (m, 4H).
2H), 7.49–7.32 (m, 7H), 7.26–7.18 (m, 2H). 13C NMR (100 MHz, 13C NMR (100 MHz, CDCl3) d (ppm) ¼ 157.5, 153.9, 136.1, 130.8,
13980 | RSC Adv., 2020, 10, 13975–13983
This journal is © The Royal Society of Chemistry 2020

View Article Online
Paper
RSC Advances
˜
´
129.7, 129.4, 129.0, 128.5, 127.4, 126.5, 125.5, 125.2, 123.4, Coordenaçao de Aperfeiçoamento de Pessoal de Nıvel Superior –
120.4, 111.3, 104.6. MS: m/z (rel intensity) 302 (M+ 100.0), 273 Brasil (CAPES) – Finance Code 001. The publication of this
(10.5), 241 (17.1), 225 (36.0), 197 (32.1), 165 (34.9), 152 (10.8), paper was partially supported by PRPPGI/UFPel and CAPES.
139 (9.5), 105 (32.1), 77 (13.0), 51 (7.6).
2-(Phenyl)-3-(phenylteluryl)benzo[b]furan 3m. Yield: 0.031 g
Notes and references
(30%). Orange solid, mp ¼ 80 C.2 1H NMR (400 MHz, CDCl3)
ꢀ
d (ppm) ¼ 8.12 (d, J ¼ 7.1 Hz, 2H), 7.54–7.53 (m, 2H), 7.47–7.44
(m, 4H), 7.42–7.38 (m, 1H), 7.34 (dt, J ¼ 7.5 and 1.4 Hz, 1H),
7.25–7.23 (m, 1H), 7.18–7.08 (m, 3H). 13C NMR (100 MHz,
CDCl3) d (ppm) ¼ 159.2, 154.6, 134.9, 134.3, 130.6, 129.5, 129.3,
128.5, 128.3, 127.2, 125.2, 123.3, 123.1, 114.8, 111.0, 82.6. EM:
m/z (rel intensity) 400 (M+ 19.7), 270 (100.0), 241 (19.2), 207 (5.7),
193 (5.9), 165 (63.1), 139 (12.4), 115 (8.8), 77 (21.7), 51 (8.4).
4-(2-Methoxyphenyl)-3-methyl-4-(phenylselanyl)but-3-en-2-
one 4a. Yield: 0.037 g (42%). Yellow oil. 1H NMR (400 MHz,
CDCl3) d (ppm) ¼ 7.47 (dd, J ¼ 7.7, 1.8 Hz, 1H11), 7.40 (ddd, J ¼
1 F. M. Dean, The Total Synthesis of Natural Products, Wiley,
New York, 1973, vol. 1; P. Cagniant and D. Cagniant,
Advances in Heterocyclic Chemistry, Academic Press, New
York, 1975; X.-F. Wu and Y. Li, Transition Metal-Catalysed
Benzofuran Synthesis, Elsevier Inc., Amsterdam, 2017;
B. R. Thorat, R. Yamgar and K. More, Review: Synthesis and
Biological Importance of Benzofuran Derivatives, Lambert
Academic Pub., India, 2016; B. A. Keay, J. H. Hopkins and
P. W. Dibble, Furans and their Benzo Derivatives:
Applications, Pergamon Press, Oxford, 2008, pp. 587–616.
2 J. D. Lambert, R. O. Meyers, B. N. Timmermann and
R. T. Dorr, Cancer Lett., 2001, 171, 47; R. Ikeda, T. Nagao,
H. Okabe, Y. Nakano, H. Matsunaga, M. Katano and
M. Mori, Chem. Pharm. Bull., 1998, 46, 871; C. Leung,
J. L. Charlton and C. Cow, Can. J. Chem., 2000, 78, 553;
S. Zacchino, G. Rodriguez, G. Pezzenati, G. Orellana,
R. Enriz and S. M. Gonzalez, J. Nat. Prod., 1997, 60, 659;
D. M. Schultz, J. A. Prescher, S. Kidd, D. Marona-Lewicka,
D. E. Nichols and A. Monte, Bioorg. Med. Chem., 2008, 16,
6242; K. Takahata, H. Tsunekawa, C. Hirami, K. Yoshimi,
S. Shimazu, F. Yoneda, H. Katsuki and A. Akaike, Neurosci.
Res., 2006, 55, S117; Y. Boukharsa, J. Taouk, B. Meddah,
Y. Cherrah, R. Y. Tiendrebeogo, A. Benomar,
M. E. A. Faozi, A. Ibrahimi and M. Ansar, Med. Chem. Res.,
2016, 25, 494; P. Yadav, P. Singh and A. K. Tewari, Bioorg.
Med. Chem., 2014, 24, 2251; R. Romagnoli, C. Lopez-Cara,
I. Castagliuolo, G. Basso, P. G. Baraldi, S. S. Ortega,
S. Mitola, G. Viola, M. K. Salvador, A. Bancale, R. Ronca,
F. Prencipe, E. Hamel, R. Bortolozzi and E. Porcu, J. Med.
Chem., 2015, 58, 3209; L. F. Duncan, G. Wang,
O. V. Ilyichova, M. J. Scanlon, B. Heras and B. M. Abbott,
Molecules, 2019, 24, 3756.
0
8.4 Hz, 7.4 Hz and 1.8 Hz, 1H, H9), 7.28–7.25 (m, 2H14,14 ), 7.19–
0
7.13 (m, 3H15,15 ,16), 6.92–6.86 (m, 2H, H8,10), 3.77 (s, 3H, H12),
2.17 (s, 3H1), 2.04 (s, 3H, H4). 13C NMR (100 MHz, CDCl3)
d (ppm): 194.2 (C2), 158.4 (C7), 146.2 (C6), 133.3 (C9), 131.2 (C11),
0
0
131.1 (C14,14 ), 128.9 (C15,15 ), 127.6 (C5), 127 (C3), 126.3 (C16),
120.3 (C10), 111.4 (C8), 55.7 (C12), 24.9 (C1), 22.6 (C4). MS: m/z (rel
intensity) 346 (19.6), 331 (3.4), 315 (2.9), 265 (3.7), 189 (21.9), 174
(17.8), 158 (20.1), 135 (100.0), 129 (14.1), 105 (3.5), 92 (11.2), 77
(34.4), 51 (4.9). IR (cmꢁ1) 2936, 1636, 1479, 1248, 1016, 734.
HRMS calculated for C18H19O2Se + Na ¼ 369.0360, found:
369.0366.
1-Methyl-2-phenyl-3-(phenylselanyl)indole 5a. Yield: 0.023 g
(25%). Pale yellow oil. 1H NMR (500 MHz, CDCl3) d (ppm) ¼ 7.66
(d, J ¼ 6.5 Hz, 1H), 7.35–7.38 (m, 6H), 7.28–7.31 (m, 1H), 7.18–
7.19 (m, 1H), 7.13–7.14 (m, 2H), 7.02–7.07 (m, 3H), 3.67 (s, 3H).
13C NMR (125 MHz, CDCl3) d (ppm) ¼ 145.8, 137.7, 134.6, 131.2,
130.7, 130.6, 128.8, 128.6, 128.3, 128.1, 125.2, 122.6, 120.8,
120.6, 109.7, 96.3, 31.7. EM: m/z (rel intensity) 363 (M+ 21.0), 283
(100.0), 267 (11.7), 204 (10.8), 190 (3.8), 165 (4.7), 141 (6.3), 77
(5.2).
2-(4-Chlorophenyl)-2-(phenylselanyl)-1-methylindol
5b.
1
ꢀ
Yield: 0.020 g (20%). Yellow solid, mp ¼ 103–104 C. H NMR
(400 MHz, CDCl3) d (ppm) ¼ 7.60 (d, J ¼ 7.9 Hz, 1H, H5), 7.35–
3 P. L. McCormack, Drugs, 2015, 75, 1915; A. Rickli, S. Kopf,
M. C. Hoener and M. E. B. Liechti, J. Pharmacol., 2015, 75,
1915.
4 B. Godoi, R. F. Schumacher and G. Zeni, Chem. Rev., 2011,
111, 2937.
0
0
7.32 (m, 3H, H8,11,11 ), 7.28–7.22 (m, 3H, H7,12,12 ), 7.13 (ddd, J ¼
7.5 Hz, 7.0 Hz and 1.0 Hz, 1H, H6), 7.08–6.99 (m, 5H, H15–17),
3.65 (s, 3H, H1). 13C NMR (100 MHz, CDCl3) d (ppm) ¼ 144.4
0
(C2), 137.7 (C9), 134.8 (C13), 134.3 (C14), 132.0 (C11,11 ), 130.5 (C4),
0
0
0
129.6 (C10), 128.9 (C12,12 ), 128.4 (C15,15 ,16), 128.3 (C15,15 ,16),
125.3 (C17), 122.9 (C7), 121.0 (C6), 120.7 (C5), 109.7 (C8), 96.9
(C3), 31.7 (C1). 15N NMR (40 MHz, CDCl3) d (ppm) ¼ 130 ppm.
EM: m/z (rel intensity) 397 (M+ 23.4), 317 (100.0), 281 (16.7), 267
(8.8), 204 (9.7), 141 (15.1), 77 (3.7).
5 I. Beletskaya, Chem. Rev., 2011, 111, 1596; A. M. Barcellos,
A. L. Abenante and M. T. Sarro, Curr. Org. Chem., 2017, 21,
2044; G. Mugesh, W.-W. Du Mont and H. Sies, Chem. Rev.,
2001, 101, 2125; J. J. Comasseto and R. A. Gariani,
Tetrahedron, 2009, 65, 8447; C. W. Nogueira and
J. B. T. Rocha, Arch. Toxicol., 2011, 85, 1313; G. Perin,
˜
E. J. Lenardao, R. G. Jacob and R. B. Panatieri, Chem. Rev.,
Conflicts of interest
2009, 109, 1277; A. J. Mukeherjee, S. S. Zade, H. B. Singh
and R. B. Sunoj, Chem. Rev., 2010, 110, 4357;
There are no conicts to declare.
˜
E. J. Lenardao, C. Santi and L. Sancineto, New Frontiers in
Organoselenium Compounds, Springer, Switzerland, 2018;
H. Cao, Y. Yang, X. Chen, J. Liu, C. Chen, S. Yuan and
L. Yu, Chin. Chem. Lett., 2020, DOI: 10.1016/
j.cclet.2020.01.027; T. A. C. Goulart, J. A. G. Kazmirski,
Acknowledgements
The authors thank FAPERGS, CNPq and FINEP for their nan-
cial support. This study was nanced in part by the
This journal is © The Royal Society of Chemistry 2020
RSC Adv., 2020, 10, 13975–13983 | 13981

View Article Online
RSC Advances
Paper
D. F. Back and G. Zeni, J. Org. Chem., 2019, 84, 14113;
T. Prochnow, A. Maroneze, D. F. Back and G. Zeni, J. Org.
L. Niu, J. Liu, X.-A. Liang, S. Wang and A. Lei, Nat.
Commun., 2019, 10, 1.
Chem., 2019, 84, 2891; C. Chen, Y. Cao, X. Wu, Y. Cai, 18 Q. Tian, B. Chen and G. Zhang, Green Chem., 2016, 18, 6236;
J. Liu, L. Xu, K. Ding and L. Yu, Chin. Chem. Lett., 2020,
DOI: 10.1016/j.cclet.2019.12.019.
H. Wang, L.-N. Guo and X.-H. Duan, Chem. Commun., 2014,
50, 7382; L. Liu, J. Wang and H. Zhou, J. Org. Chem., 2015, 80,
4749; X. Jiang, J. Yang, F. Zhang, P. Yu, P. Yi, Y. Sun and
Y. Wang, Org. Lett., 2016, 18, 3154; X. Yuan, J.-F. Yao and
Z.-Y. Tang, Org. Lett., 2017, 19, 1410; J. Q. Huang,
Z. Nairoukh and I. Marek, Org. Biomol. Chem., 2018, 16,
1079; Z. Jin, R. S. Hidinger, B. Xu and G. B. Hammond, J.
Org. Chem., 2012, 77, 7725; Y. Liu, X. Chen, J. Zhang and
Z. Xu, Synlett, 2013, 24, 1371.
6 T. Wirth, Organoselenium Chemistry. Synthesis and Reactions,
Wiely-VCH Verlag & Co. KGaA, Weiheim, 2012, p. 462;
D. M. Freudendahl, S. A. Shahzad and T. Wirth, Eur. J. Org.
Chem., 2009, 1649; C. Santi, Organoselenium Chemistry:
Between Synthesis and Biochemistry, Bentham Science,
Sharjah,
e-book,
2014,
DOI:
10.2174/
97816080583891140101; A. D. Sonawane, Y. Kubota and
´
M. Koketsu, J. Org. Chem., 2019, 84, 8602; G. Perin, 19 B. Treguier and S. P. Roche, Org. Lett., 2014, 16, 278; Q. Zhao,
P. C. Nobre, D. H. Mailahn, M. S. Silva, T. Barcellos,
H. Xiang, J.-A. Xiao, P.-J. Xia, J.-J. Wang, X. Chen and
H. Yang, J. Org. Chem., 2017, 82, 9837; J. Zhang, H. Wang,
S. Ren, W. Zhang and Y. Liu, Org. Lett., 2015, 17, 2920;
D. Parmar and M. Rueping, Chem. Commun., 2014, 50,
13928.
˜
R. G. Jacob, E. J. Lenardao, C. Santi and J. A. Roehrs,
Synthesis, 2019, 51, 2293–2304.
7 D. Yue, T. Yao and R. C. Larock, J. Org. Chem., 2005, 70,
10292.
˜
´
8 F. Manarin, J. A. Roehrs, R. M. Gay, R. Brandao, 20 P. T. Nyffeler, S. G. Duron, M. D. Burkart, S. P. Vincent and
P. H. Menezes, C. W. Nogueira and G. Zeni, J. Org. Chem.,
2009, 74, 2153.
C.-H. Wong, Angew. Chem., Int. Ed., 2005, 44, 192.
21 H. Poleschner and K. Seppelt, Chem.–Eur. J., 2004, 10, 6565.
9 R. M. Gay, F. Manarin, C. C. Shneider, D. A. Barancelli, 22 R. Guo, L. Liao and X. Zhao, Molecules, 2017, 22, 835; Z. Tian,
M. D. Costa and G. Zeni, J. Org. Chem., 2010, 75, 5701.
10 L. Yu, J. Meng, L. Xia and R. Guo, J. Org. Chem., 2009, 74,
5087; L. Yu, L. Ren, R. Guo and T. Chen, Synth. Commun.,
Z. Liu, P. Yu and W. Zhang, Chin. J. Appl. Chem., 2016, 33, 10;
L. Shao, Y. Li, J. Lu and X. Jiang, Org. Chem. Front., 2019, 6,
2999.
2011, 41, 1958; L. Yu, L. Ren, R. Yi, Y. Wu, T. Chen and 23 Y. Usuki, M. Iwaoka and S. Tomoda, Chem. Lett., 1992, 8,
R. Guo, J. Organomet. Chem., 2011, 696, 2228. 1507.
11 H.-A. Du, X.-G. Zhang, R.-Y. Tang and J.-H. Li, J. Org. Chem., 24 Selenium and Tellurium Chemistry, Chapter 2: New Selenium
2009, 74, 7844.
Electrophiles and Their Reactivity, ed. J. D. Woollins and R.
S. Laitinen, Springer-Verlag, Berlin, Heidelberg, 2011;
H. Sahoo, G. S. Grandhi, I. Ramakrishna and M. Baidya,
Org. Biomol. Chem., 2019, 17, 10163; V. Kumar, K. Banert,
D. Ray and B. Saha, Org. Biomol. Chem., 2019, DOI:
10.1039/C9OB02235J; G. Perin, L. K. Soares, P. S. Hellwig,
M. S. Silva, J. S. S. Neto, J. A. Roehrs, T. Barcellos and
12 M. Xu, X.-H. Zhang and P. Zhong, Tetrahedron Lett., 2011, 52,
6800.
13 J.-S. Han, Y.-L. Shao, X.-H. Zhang and P. Zhong, Phosphorus,
Sulfur Silicon Relat. Elem., 2013, 188, 1599.
14 J. C. Kazmierczak, A. M. S. Recchi, F. Gritzenco,
E. B. Balbom, T. Barcellos, A. Sperança and B. Godoi, Eur.
J. Org. Chem., 2017, 6382.
˜
E. J. Lenardao, New J. Chem., 2019, 43, 6323; H. A. Goular,
15 C. An, C.-Y. Li, X.-B. Huang, W.-X. Gao, Y.-B. Zhou, M.-C. Liu
and H.-Y. Wu, Org. Lett., 2019, 21, 6710.
J. S. S. Neto, A. M. Barcellos, T. Barcellos, M. S. Silva,
˜
D. Alges, R. G. Jacob, E. J. Lenardao and G. Perin, Adv.
16 J. Bi, Z. Zhang, Q. Liu and G. Zhang, Green Chem., 2012, 14,
Synth. Catal., 2019, 361, 1.
1159; J. W. Kee, H. Shao, C. W. Kee, Y. Lu, H. S. Soo and 25 B. Gao, L. Zhang, Q. Zheng, F. Zhou, L. M. Klivansky, J. Lu,
C. H. Tan, Catal. Sci. Technol., 2017, 7, 848; G. S. Lal,
G. P. Pez and R. G. Syvret, Chem. Rev., 1996, 96, 1737;
B. Lantano and A. Postigo, Org. Biomol. Chem., 2017, 15,
Y. Liu, J. Dong, P. Wu and K. B. Sharpless, Nat. Chem.,
2017, 9, 1083; J. Dong, L. Krasnova, M. G. Finn and
K. B. Sharpless, Angew. Chem., Int. Ed., 2014, 53, 9430.
9954; T. Liang, C. N. Neumann and T. Ritter, Angew. 26 G. W. Fraser and J. B. Millar, J. Chem. Soc., Dalton Trans.,
Chem., Int. Ed., 2013, 52, 8214; A. Lin, C. B. Huehls and
J. Yang, Org. Chem. Front., 2014, 1, 434; N. Naveen and
R. Balamurugan, Org. Biomol. Chem., 2017, 15, 2063; P. Xu,
1974, 2029; J. V. Comasseto, R. L. O. R. Cunha and
G. C. Clososki, Comprehensive Organometallic Chemistry III,
Elsevier Ltd, Netherlands, 2007, vol. 9, pp. 587–648.
S. Guo, L. Wang and P. Tang, Synlett, 2015, 26, 36; 27 X. Gan, Z. Fu, L. Liu, Y. Yan, C. Chen, Y. Zhou and J. Dong,
C. Chatalova-Sazepin, R. Hemelaere, J.-F. Paquin and Tetrahedron Lett., 2019, 60, 150906.
G. M. Sammls, Synthesis, 2015, 47, 2554; D. D'Alonzo, 28 W. Ye, W. Li and J. Zhang, Chem. Commun., 2014, 50, 9879;
M. D. Fenza, G. Palumbo, V. Romanucci, A. Zarrelli,
G. D. Fabio and A. Guaragna, Synthesis, 2017, 49, 998.
17 B. Huang, Y. Zhao, C. Yang, Y. Gao and W. Xia, Org. Lett.,
2017, 19, 3799; S. Sathyamoorthi, Y.-H. Lai, R. M. Bain and
R. N. Zare, J. Org. Chem., 2018, 83, 5681; J. D. Galloway,
D. N. Mai and R. D. Baxter, Org. Lett., 2017, 19, 5772;
Q. Tian, B. Chen and G. Zhang, Green Chem., 2016, 18, 6236.
29 R. Lin, S. Ding, Z. Shi and N. Jiao, Org. Lett., 2011, 13, 4498;
N. Liu, Q.-P. Tian, Q. Yang and S.-D. Yang, Synlett, 2016, 27,
2621; J.-W. Yuan, J.-L. Zhu, B. Li, L.-Y. Yang, P. Mao,
S.-R. Zhang, Y.-C. Li and L.-B. Qu, Org. Biomol. Chem.,
2019, 17, 10178.
13982 | RSC Adv., 2020, 10, 13975–13983
This journal is © The Royal Society of Chemistry 2020

View Article Online
Paper
RSC Advances
30 M. S. Chauhan, G. D. Yadav, F. Hussain and S. Singh, Catal. 32 C. Geng, L. Du, F. Liu, R. Zhu and C. Liu, RSC Adv., 2015, 5,
Sci. Technol., 2014, 4, 3945. 33385.
31 H. Dueck, Sulfur, Selenium and Tellurium NMR, John Wiley & 33 X. Deng, H. Cao, C. Chen, H. Zhou and L. Yu, Sci. Bull., 2019,
Sons Ltd, Oxford, UK, 2007.
64, 1280.
This journal is © The Royal Society of Chemistry 2020
RSC Adv., 2020, 10, 13975–13983 | 13983