Transition-Metal-Free HFIP-Mediated Organo Chalcogenylation of Arenes/Indoles with Thio-/Selenocyanates

Article abstract of DOI:10.1021/acs.joc.1c00478

We have developed a protocol for the synthesis of diaryl thio-/selenoethers by the reaction of aryl chalcogenocyanates with electron rich arenes/hetero arenes via HFIP promoted C-H activation. The reaction produces chalcogenides in good to excellent yields under mild conditions without the need of a transition metal as a catalyst. The HFIP-mediated reactions tolerated a wide range of functional groups and set the stage for the synthesis of diversely decorated chalcogenides. A mechanism involving activation of the C-H bond through hydrogen bonding is proposed.

Full text of DOI:10.1021/acs.joc.1c00478

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Transition-Metal-Free HFIP-Mediated Organo Chalcogenylation of
Arenes/Indoles with Thio-/Selenocyanates
Pratibha Kalaramna and Avijit Goswami*
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ABSTRACT: We have developed a protocol for the synthesis of diaryl
thio-/selenoethers by the reaction of aryl chalcogenocyanates with
electron rich arenes/hetero arenes via HFIP promoted C−H activation.
The reaction produces chalcogenides in good to excellent yields under
mild conditions without the need of a transition metal as a catalyst. The
HFIP-mediated reactions tolerated a wide range of functional groups and
set the stage for the synthesis of diversely decorated chalcogenides. A
mechanism involving activation of the C−H bond through hydrogen
bonding is proposed.
coordination of the lone pair of electrons on sulfur with the
transition metal. In this context, we would like to highlight our
previous publications where arylpyridinyl chalcogenides were
constructed via the ruthenium(II)-catalyzed [2+2+2] cyclo-
addition reaction of 1,6-diynes with (hetero)aryl chalcogenated
cyanates under mild reaction conditions (Scheme 1 (a)).16
In order to combat the problem associated with metal-
mediated reactions, metal-free C−H functionalization strat-
egies are gaining attention. Particularly, carbon−chalcogen
bond formations through metal-free strategies emerged as
attractive alternative strategies to the traditional transition-
metal-catalyzed cross-coupling reactions.17 In this connection,
Townsend’s group18 and Braga’s group19 independently
documented the metal-free methodologies to access diaryl
chalcogenides. Townsend et al. established an umpolung
approach to achieve aryl selenides in which aryl selenocyanates
INTRODUCTION
■
Aryl(heteroaryl) chalcogenides have drawn tremendous
attention due to their numerous applications in natural
products, pharmaceuticals, and bioactive molecules.1 Such
classes of compounds and their analogues have been mainly
utilized as pharmaceutical ingredients for antioxidant, anti-
inflammatory, anti-infection, and analgesic activities.2 Unlike
organosulfur compounds, initially, selenium compounds were
considered to be toxic; however, the importance of such
compounds was later recognized after finding the selenium
proteins and enzymes such as glutathione peroxidases (GPx)
and thioredoxin reductases (TR).2b Moreover, C3 selenoether-
linked indoles display unique biological properties as shown in
Figure 1.2c As chalcogen substituted organic compounds are
potential intermediates for many pharmacologically important
substances, the establishment of an efficient synthesis of these
compounds appears to be of great importance. In this context,
it is important to mention that, among many known protocols
for the construction of carbon−X (X = O, S, Se) bonds, the
metal-free carbon−hydrogen bond functionalization is the
most desirable approach.3
The conventional preparation of diaryl sulfides involves a
coupling reaction of various sulfenylating agents such as
sulfonium salts,4 sulfonyl hydrazides,5 disulfides,6 N-thiophtha-
limides,7 sulfenyl halides,8 thiols,9 and arylsulfonyl chlorides10
with phenols/indoles. Analogously, the diaryl selenides can be
obtained by the use of selenolate anions,11 selenite,12 phenyl
tributylstannyl selenide,13 or selenium14 as one of the coupling
partners. At the same time, transition-metal-catalyzed cross-
coupling is one of the traditional strategies for the synthesis of
chalcogenides.15 However, the aformentioned transition-metal-
catalyzed synthetic protocols suffer from several drawbacks,
such as the reactions require expensive and sometimes toxic
transition metals, raising issues of metal contamination and
formation of disulfides as a byproduct due to strong
were treated with electrophiles in the presence of NaBH4
19a,b
(Scheme 1 (b)),18 while Braga et al. used KIO3
and
iodine19c as catalysts to react the dichalcogenides with various
nucleophiles. Miyake et al. developed visible-light-promoted
cross-coupling reaction between thiols and aryl halides for the
construction of C−S bonds in the absence of metal (Scheme 1
(c)).20 In 2019, Radosevich et al. delineated the organo-
phosphorus-catalyzed deoxygenative protocol for sulfenylation
of indoles from arylsulfonyl chlorides (Scheme 1 (d)).3a In the
same year, Kumar and group developed a visible-light-induced
strategy for the organo chalcogenylation (S, Se, Te) of indoles
Received: February 26, 2021
Published: June 30, 2021
https://doi.org/10.1021/acs.joc.1c00478
© 2021 American Chemical Society
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Figure 1. Examples of natural and bioactive (hetero)arenes thio-/selenoethers.
that possess various C−H groups. To achieve more efficient
C−H activation, we focused on highly acidic hexafluoroiso-
propanol (HFIP), which is almost exclusively involved as a
solvent or an additive in the stabilization of cationic
intermediates due to its high polarity and low nucleophilicity.22
Despite the remarkable developments associated with the
HFIP-assisted reactions,23 the construction of C−X bonds in
the presence of HFIP is rare. In the course of our ongoing
studies on aryl chalcogeno-cyanates,16 we would like to report
an operationally simple, yet powerful, protocol for the metal-
free chalcogenations of arenes and indoles with chalcogenated
cyanates by exploiting the hydrogen bonding ability of HFIP.
Scheme 1. Chalcogenylation of (Hetero)arenes
RESULT AND DISCUSSION
■
HFIP is known to mediate C−C and C−heteroatom bond
forming reactions due to its highly polar, strong hydrogen
bond donor (HBD) character and less nucleophilicity. For the
initial screening and optimization of the chalcogenation
reaction conditions, we have chosen HFIP, one of the
strongest HBD solvents to investigate the reaction of phenyl
cyanate 1a with 1,3,5-trimethoxybenzene 4a. Unfortunately,
reaction did not deliver any product at both room temperature
and refluxing conditions (Table 1, entries 1 and 2). We
hypothesized that the stronger HBD capability of HFIP might
not be sufficient to cleave the strongest O−CN bond to
generate an electrophilic aryloxy moiety, which may eventually
introduce the aryloxy group on the arene ring via C−H
activation. With this conclusion, phenyl thiocyanate 2a, having
a relatively weaker S−CN bond was attempted with 4a at 60
°C in DCE using a catalytic amount of HFIP. The reaction
delivered the compound 6aa in 15% yield (Table 1, entry 4).
The same reaction was further conducted in different ratios of
HFIP with other organic solvents to determine the role of
HFIP in promoting the thioarylation (Table 1, entries 5−8). A
significant change in the yield was noticed when HFIP and
DCE were used as a solvent mixture with 1:1 ratio (Table 1,
entry 9). At this point, it is important to mention that, when
HFIP is applied as the only solvent, the above said reaction can
furnish arylthioether 6aa in 80% yield (Table 1, entry 10).
Keeping the aforesaid observation in mind, the reaction of
selenocyanate 3a with arene 4a was performed. To our delight,
unsymmetrical selenoether 7aa was obtained in 89% yield at
with diaryl dichalcogenides under an oxygen atmosphere.3b In
2013, Tian and group disclosed an iodine-catalyzed sulfeny-
lation reaction of indoles with sulfonyl hydrazides (Scheme 1
(d)).5 The direct C−H selenation of indole and imidazopyr-
idine derivatives under aerobic electrolytic conditions employ-
ing an iodide salt as a catalyst has been documented by the
group of Jiang and Sun in 2018 (Scheme 1 (e)).21
It is noteworthy that direct C−H bond functionalization
reactions are restricted owing to two fundamental challenges:
(i) the inert nature of most of the carbon−hydrogen bonds
and (ii) the requirement to control site selectivity in molecules
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a
Table 1. Optimization of the Reaction Conditions
b
entry
PhXCN
solvent
solvent ratio
temp (°C)
time (h)
yield (%)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
1a
1a
2a
2a
2a
2a
2a
2a
2a
2a
2a
3a
3a
3a
3a
3a
3a
HFIP
HFIP
DCE
HFIP:DCE
HFIP:MeOH
HFIP:THF
HFIP:DCE
HFIP:DCE
HFIP:DCE
HFIP
HFIP:DCE
HFIP:DCE
HFIP:DCE
HFIP
tert-BuOH
2,2,2-trifluoroethanol
2,2,2-trifluoroethanol
rt
24
24
24
24
24
24
5
5
4
4
15
10
1.5
1.5
15
1.5
1.5
nr
nr
nr
15
nr
reflux
rt/reflux
60
60
60
60
60
60
60
rt
rt
60
60
70
rt
75
1:9
1:2
1:2
1:4
1:2
1:1
nr
48
65
79
80
75
89
90
90
nr
1:1
1:1
1:1
52
73
a
Optimized reaction conditions: For X = S, 2a (67.5 mg, 0.5 mmol), 4a (100.9 mg, 0.6 mmol), HFIP/DCE (1 mL, 1:1), inert conditions, 60 °C
(oil bath temperature), 4 h. For X = Se, 3a (91.4 mg, 0.5 mmol), 4a (100.9 mg, 0.6 mmol), HFIP/DCE (1 mL, 1:1), inert conditions, rt, 10 h.
b
Isolated yield.
Scheme 2. Transition-Metal-Free Reaction of Aryl Thiocyanates 2 with (Hetero)arenes 4 for the Synthesis of Unsymmetrical
a
Thioethers 6
a
Reaction conditions: 2 (0.5 mmol), 4 (0.6 mmol), HFIP/DCE (1 mL, 1:1), inert conditions, 60 °C (oil bath temperature), 4 h.
room temperature for 5 h under inert conditions (Table 1,
entry 12). In the process to enhance the yield of 7aa, the
reaction was further heated at 60 °C under the same
conditions, and the product was obtained within 1.5 h without
significance enhancement of the yield (Table 1, entry 13). The
reaction was further performed by changing the solvent to tert-
BuOH, and TFE (Table 1, entries 15−17). The result implies
that the strongest H-bonding capability of HFIP with the
nitrogen atom of the nitrile group caused the cleavage of the
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Scheme 3. Transition-Metal-Free Reactions of Aryl Selenocyanates with Heteroarenes for the Synthesis of Unsymmetrical
a
Selenoethers (7)
a
Reaction conditions: 3 (0.5 mmol), 4 (0.6 mmol), HFIP/DCE (1 mL, 1:1), inert conditions, rt, 10 h.
weaker Se−CN bond to form the selenoether 7aa in excellent
yield.
selenocyantes 3 with indoles mediated by HFIP, and the
results are summarized in Scheme 3. A wide range of aryl
selenocyanates (3a−3i) were reacted with commercially
available heteroarenes (4c−4h) to achieve the desired
unsymmetrical diarylselenoether.
To our delight, electron-donating (3a−3c, 3i) and electron-
withdrawing (3e−3g) substituents were well tolerated and the
corresponding diaryl selenides were obtained in excellent
yields. Analogously, it was observed that steric variation on the
aryl selenocyanate counterpart was slightly sensitive to the
reaction efficiency. The hindered ortho-methyl substituted
selenocyanate underwent the reaction and delivered the
corresponding products (7ic, 7id, 7ie, and 7if), albeit with
relatively lower yield. In the course of in-depth studies, next we
devote our attention to investigate the substrate scope with
With the optimized reaction conditions in hand, we
extended our exploration to various aryl thiocyanates 2 with
(hetero)arenes 4 to figure out the substrate scope of the
reaction leading to the unsymmetrical thioethers 6. Employing
this methodology, electron rich arenes and indoles delivered
the diaryl sulfide derivatives 6 in very good yields; however, the
nitro-substituted arylthiocyanate 2c and 3-indole thiocyanate
2d failed to give the desire products under this reaction
conditions. The compound 6aa was isolated as a pure single
crystal, and the structure was unequivocally confirmed by
single crystal X-ray24 analysis (Scheme 2).
Next, we moved to examine the substrate scope for the
synthesis of diarylselenoethers 7 from the reaction of aryl
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Scheme 4. Transition-Metal-Free Reactions of Aryl Selenocyanates with 1,3,5-Trimethoxybenzene for the Synthesis of
a
Unsymmetrical Selenoethers (7)
a
Reaction conditions: 3 (0.5 mmol), 4a (0.6 mmol), HFIP/DCE (1 mL, 1:1), inert conditions, rt, 10 h.
Scheme 5. Preliminary Mechanism Investigation
regard to the indole compounds 4 and found that the metal-
free C−H selenoarylation can lead to the corresponding
selenides 7 using a number of electron rich as well as electron-
withdrawing substituted indoles. The compounds 7id, 7ee,
7ge, and 7eg were isolated as pure single crystals, and their
structures were unequivocally confirmed by single crystal X-
ray24 analysis (Scheme 3).
Besides heteroaromatics, trimethoxybenzene participated
well in this protocol to afford aryl selenides (7aa−7ha) in
high to excellent yields. Electron-donating (3a−3c) and
electron-withdrawing (3e, 3g) substituents were amenable to
the protocol. Unfortunately, compound 7da was not obtained
as aryl selenocyanate 3d remained elusive for arene 4a.
Preferential interaction of HFIP with the nitro group over the
SCN moiety might be the reason for the inertness of nitro-
substituted selenocyanate 3d. The reaction of aliphatic
selenocyanate 3h with 1,3,5-trimethoxybenzene 4a successfully
led to the formation of unsymmetrical selenoether 7ha in 81%
yield. A selenocyanate containing −OH, −OMe, and −CHO
groups (4j) was seen to be compatible with trimethoxybenzene
(Scheme 4). It is noteworthy to mention that selenocyanates
outperform the thiocyanates in terms of substrate scope as well
as the efficiency of the reaction. We surmised that it might be
because the bigger size of selenium allows the facile removal of
the nitrile group by strong H-bonding with HFIP. The HFIP
triggered electrophilic aryl selenocyanates activate the
nucleophilic indole to attack at Se, resulting in the formation
of selenoethers with higher yields.
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To gain more insight into the reaction mechanism, a few
control experiments have been carried out. The model reaction
was performed in the presence of radical inhibitor 2,2,6,6-
tetramethyl-1-piperidinyloxy (TEMPO), and results suggested
that the reaction pathway does not follow the radical pathway
(Scheme 5 (a)). When the solvent was changed to iso-
propanol, the transformation was stopped; this result clearly
indicated the essential presence of HFIP to accomplish the
reaction (Scheme 5 (b)). To illustrate the nature of phenyl
selenocyanate, two reactions were conducted with benzyl
bromide as an electrophile in the presence and absence of
HFIP. Both the experiments ended up with the recovery of
starting materials. The results show the evidence of the
electrophilic nature of phenyl selenocyanate (Scheme 5 (c)
and (d)).
Scheme 6. Probable Mechanism for the Formation of
Compounds 6/7
To get the evidence of H-bonding of the nitrile group with
HFIP, IR data have been taken. The position of the OH bond
of HFIP and the CN group in selenocyanate 3h is observed
observed that reaction of phenyl selenocyanate 3a with arene
4a underwent smoothly to deliver the desired cycloadduct 7aa
in 89% yield (Scheme 7).
at ṽ ̃
= 3435 cm−1 and vbond(CN) = 2149 cm−1, respectively.
During the reaction of selenocyanate 3h with trimethox-
ybenzene 4a in HFIP, a new broad band appeared at frequency
Scheme 7. Gram-Scale Synthesis of Unsymmetrical Selenide
a
7aa
(v bond(CN···H) = 3370 cm−1). and vbond(CN) = 2161 cm−1 (Figure
̃
̃
2). The shift in frequencies might be due to H-bonding.26
a
Reaction conditions: 3a (0.914 g, 5 mmol), 4a (0.907 g, 5.4 mmol),
b
HFIP/DCE (7 mL, 1:1), inert conditions, rt, 5 h. Isolated yield.
CONCLUSIONS
■
In summary, metal-free HFIP-mediated chalcogenation re-
actions (thio- and selenation) between thio-/selenocyanates
with arenes/indoles have been disclosed. The protocol
provides the access to the thio-/selenoethers in good to
excellent yields under mild reaction conditions. The protocol
can also be utilized for the large-scale synthesis of aryl
(hetero)aryl thio-/selenoethers. The said methodology will be
a remarkable example for the HFIP-mediated metal-free C−H
activation reactions.
EXPERIMENTAL SECTION
■
General Information. All chemicals and reagents were purchased
from commercial suppliers and used without further purification. Thin
layer chromatography (TLC) was performed using precoated plates
purchased from E. Merck (silica gel 60 PF254, 0.25 mm). Column
chromatography was performed using E. Merck silica gel 60 (100−
200 mesh). GCMS analyses were carried out on a SHIMADZU
GCMS-QP Ultra 2010 instrument. NMR spectra were recorded in
CDCl3, on a JEOL JNM-ECS spectrometer at operating frequencies
of 400 MHz (1H) or 100 MHz (13C{1H}) as indicated in the
individual spectrum. Chemical shifts (δ) are reported in ppm relative
Figure 2. IR spectra for A = HFIP, B = 3h, and C = During the
reaction of 3h with 4a in HFIP (after 2 h).
On the basis of control experiments, a plausible mechanism
for the chalcogenation is depicted in the Scheme 6. The
hydrogen atom of the hydroxyl group in HFIP forms a strong
H-bond with the nitrogen atom of the thio/selenocyanate
group appended to the aryl ring and, eventually, triggers the
electrophilicity of the sulfur/selenium atom of thio-/
selenocyanates by weakening the X−CN bond. Subsequently,
the nucleophilic indole/arene attacks the electrophilic thio/
seleno center, leading to the formation of the desired product
with the release of a cyanide group (Scheme 6).
1
to the residual solvent (chloroform, δ = 7.26 for H and 77.16 for
proton decoupled 13C{1H} NMR) and coupling constants (J) in Hz.
Multiplicity is tabulated as s for singlet, d for doublet, dd for doublet
of doublet, t for triplet, q for quartet, and m for multiplet. High-
resolution mass spectra (HRMS) were recorded using electron spray
ionization (ESI) methods on a Waters mass spectrometer. Melting
points were determined using a BIBBY-SMP30 melting point meter.
Single crystal X-ray structural data were collected on a CMOS based
Bruker D8 Venture PHOTON 100 diffractometer equipped with in
INCOATEC micro-focus source with graphite monochromated Mo
Kα radiation (λ = 0.71073 Å) operating at 50 kV and 30 mA. All the
aryl thiocyanates (2a−d)25 and aryl selenocyanates (3a−j)18 were
Finally, the gram-scale synthesis of 7aa was performed under
the optimized reaction conditions to illustrate the general
applicability and large-scale productivity of the protocol. It was
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prepared according to the reported literature procedures. The rest of
the chemicals and solvents were purchased from the Sigma, GLR
Innovations, Avra, Spectrochem, and TCI, and used as received.
Experimental Procedures. General Procedure for Sulfenylation
of Arenes/Indoles with Aryl Thiocyanates. A mixture of aryl
thiocyanate (0.5 mmol), arene/indole (0.6 mmol), and HFIP/DCE
(1 mL, 1:1), contained in a Schlenk tube, was stirred at 60 °C (oil
bath temperature) for 4 h. After completion of the reaction checked
by TLC, the solvent was removed under reduced pressure. The crude
reaction mixture was purified through column chromatography over
silica gel using hexane/ethyl acetate as eluents to obtain the desired
product.
5-Bromo-3-(phenylthio)-1H-indole (6ag). White solid (124.7 mg,
82% yield). Rf = 0.40 (EtOAc/Hexane = 2:8). Mp: 140−142 °C. H
NMR (400 MHz, CDCl3): δ 8.30 (bs, 1H), 7.61 (s, 1H), 7.29 (d, J =
2.7 Hz, 1H), 7.19 (m, 1H), 7.13−7.10 (m, 1H), 7.04−7.01 (m, 2H),
6.95−6.92 (m, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 138.8,
135.2, 132.0, 131.0, 128.9, 126.1, 125.9, 125.1, 122.3, 114.5, 113.2,
1
102.7. IR (neat): ṽ = 3408, 2921, 2852, 1580, 1455, 1366, 1206, 1082,
799, 737 cm−1. HRMS m/z: [M + H]+ calcd for C14H12NS79Br
302.9717; found 302.9713. HRMS m/z: [M + H]+ calcd for
C14H12NS81Br 304.9697; found 304.9693.
The values of the characterization data are in accordance with
reported literature data.6b
General Procedure for Selenylation of Arenes/Indoles with Aryl
Selenocyanates. To a Schlenk flask were added aryl selenocyanate
(0.5 mmol), arene/indole (0.6 mmol), and HFIP/DCE (1 mL, 1:1),
and the reaction mixture was allowed to stir at room temperature
under a nitrogen atmosphere. The reaction was monitored by TLC.
After the completion, the mixture was concentrated in vacuo and the
product was purified by column chromatography on silica gel using
hexane/ethyl acetate as eluents to obtain the desired product.
Gram-Scale Synthesis of 7aa. Phenyl selenocyanate 3a (0.914 g, 5
mmol) and arene 4a (0.907 g, 5.4 mmol) were dissolved in HFIP/
DCE (7 mL, 1:1), and the mixture was heated at room temperature
under a nitrogen atmosphere. After completion of the reaction
checked by TLC, evaporation of solvent gave the crude product 7aa
(1.441 g, 89%), which was further purified by column chromatog-
3-(Phenylselanyl)-1H-indole (7ac). White solid (122.4 mg, 90%
yield). Rf = 0.35 (EtOAc/Hexane = 2:8). Mp: 133−135 °C. 1H NMR
(400 MHz, CDCl3): δ 8.41 (bs, 1H), 7.65 (d, J = 8.4 Hz, 1H), 7.47
(d, J = 3.6 Hz, 1H), 7.44 (d, J = 8.4 Hz, 1H), 7.28−7.10 (m, 7H).
13C{1H} NMR (100 MHz, CDCl3): 136.5, 133.9, 131.3, 130.0, 129.0,
128.7, 125.6, 123.0, 121.0, 120.5, 111.4, 98.2. IR (neat): ṽ = 3410,
3123, 3049, 2921, 1646, 1573, 1451, 1236, 1020, 825, 730, 684 cm−1.
HRMS m/z: [M + H]+ calcd for C14H11NSe 273.0057; found
273.0052.
The values of the characterization data are in accordance with
reported literature data.17d
3-(o-Tolylselanyl)-1H-indole (7ic). White solid (121.6 mg, 85%
yield). Rf = 0.36 (EtOAc/Hexane = 2:8). Mp: 109−111 °C. 1H NMR
(400 MHz, CDCl3): δ 8.43 (bs, 1H), 7.52 (d, J = 8.0 Hz, 1H), 7.37−
7.35 (m, 2H), 7.21−7.16 (m, 1H), 7.11−7.03 (m, 2H), 6.95−6.91
(m, 1H), 6.78−6.74 (m, 2H), 2.39 (s, 3H). 13C{1H} NMR (100
MHz, CDCl3): δ 136.5, 136.1, 134.6, 131.6, 130.2, 129.9, 128.0,
1
raphy. The pure compound was analyzed by H NMR and 13C{1H}
NMR and mass spectroscopy.
Characterization Data of Compounds. Phenyl(2,4,6-
trimethoxyphenyl)sulfane (6aa). White solid (109.1 mg, 79%
yield). Rf = 0.20 (EtOAc/Hexane = 2:8). Mp: 105−107 °C. 1H
NMR (400 MHz, CDCl3): δ 7.15 (t, J = 8.2 Hz, 2H), 7.04−7.00 (m,
3H), 6.21 (s, 2H), 3.87 (s, 3H), 3.81 (s, 6H). 13C{1H} NMR (100
MHz, CDCl3): δ 163.0, 162.6, 138.7, 128.6, 125.7, 124.4, 98.6, 91.2,
126.6, 125.4, 123.1, 121.0, 120.5, 111.5, 97.3, 21.4. IR (neat): v =
̃
3406, 2955, 2922, 2852, 1567, 1463, 1237, 1093, 802, 743 cm−1.
HRMS m/z: [M + H]+ calcd for C15H13NSe 287.0213; found
287.0194.
The values of the characterization data are in accordance with
56.4, 55.5. IR (neat): ṽ = 2959, 2931, 2839, 1578, 1455, 1409, 1337,
reported literature data.19b
1226, 1121, 1024, 809 cm−1. HRMS m/z: [M + H]+ calcd for
C15H17O3S 277.0898; found 277.0899.
3-((4-Methoxyphenyl)selanyl)-1H-indole (7cc). White solid
(140.5 mg, 93% yield). Rf = 0.36 (EtOAc/Hexane = 2:8). Mp:
113−115 °C. 1H NMR (400 MHz, CDCl3): δ 8.39 (bs, 1H), 7.57 (d,
J = 8.1 Hz, 1H), 7.38 (d, J = 2.8 Hz, 1H), 7.34 (d, J = 8.1, 1H), 7.19−
7.14 (m, 4H), 7.08 (t, J = 7.6 Hz, 1H), 6.63 (d, J = 8.7 Hz, 2H), 3.64
(s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 158.4, 136.4, 131.2,
130.8, 129.9, 123.3, 123.0, 120.8, 120.5, 114.9, 111.3, 99.6, 55.2. IR
The values of the characterization data are in accordance with
reported literature data.17b
p-Tolyl(2,4,6-trimethoxyphenyl)sulfane (6ba). White solid (111.7
mg, 77% yield). Rf = 0.22 (EtOAc/Hexane = 2:8). Mp: 110−112 °C.
1H NMR (400 MHz, CDCl3): δ 7.10 (d, J = 7.9 Hz, 2 H), 6.95 (d, J =
8.2 Hz, 2H), 6.19 (s, 2H), 3.86 (s, 3H), 3.79 (s, 6H), 2.25 (s, 3H).
13C{1H} NMR (100 MHz, CDCl3): δ 162.9, 162.0, 135.2, 129.6,
(neat): v = 3408, 2956, 2922, 2853, 1488, 1451, 1239, 1094, 1025,
̃
812, 740 cm−1. HRMS m/z: [M + H]+ calcd for C15H14NOSe
304.0241; found 304.0220.
129.3, 126.0, 97.7, 91.2, 56.4, 55.5, 21.1. IR (neat): v = 2961, 2924,
̃
2852, 1588, 1453, 1407, 1333, 1226, 1121, 1021, 806 cm−1. HRMS
m/z: [M + H]+ calcd for C16H19O3S 291.1055; found 291.1052.
The values of the characterization data are in accordance with
reported literature data.17b
The values of the characterization data are in accordance with
reported literature data.17d
3-((4-Bromophenyl)selanyl)-1H-indole (7ec). Brown solid (154.4
mg, 88% yield). Rf = 0.45 (EtOAc/Hexane = 2:8). Mp: 133−135 °C.
1H NMR (400 MHz, CDCl3): δ 8.46 (bs, 1H), 7.58 (d, J = 8.1 Hz,
1H), 7.49 (d, J = 2.6 Hz, 1H), 7.44−7.16 (m, 5H), 7.08 (d, J = 8.3
Hz, 2H). 13C{1H} NMR (100 MHz, CDCl3): δ 136.5, 132.8, 131.9,
131.3, 130.3, 129.7, 123.2, 121.0, 120.3, 119.4, 111.5, 97.9. IR (neat):
(2,4-Dimethoxyphenyl)(phenyl)sulfane (6ab). White solid (87.4
mg, 71% yield). Rf = 0.24 (EtOAc/Hexane = 2:8). Mp: 63−65 °C. 1H
NMR (400 MHz, CDCl3): δ 7.35 (d, J = 8.5 Hz, 1H), 7.23−7.19 (m,
2H), 7.13−7.11 (m, 3H), 6.52−6.48 (m, 2H), 3.83 (s, 3H), 3.81 (s,
3H). 13C{1H} NMR (100 MHz, CDCl3): δ 162.0, 160.5, 137.8, 136.9,
ṽ
= 3380, 3052, 2922, 2853, 1451, 1336, 1069, 1002, 803, 749 cm−1.
128.9, 127.7, 125.5, 112.1, 105.4, 99.3, 56.1, 55.6. IR (neat): ṽ = 3058,
HRMS m/z: [M + H]+ calcd for C14H11NSe79Br 351.9240; found
351.9217. HRMS m/z: [M + H]+ calcd for C14H11NSe81Br 353.9220;
found 353.9204.
3002, 2957, 1593, 1460, 1266, 1150, 1049, 836, 736 cm−1. HRMS m/
z: [M + H]+ calcd for C14H15O2S 247.0793; found 247.0778.
The values of the characterization data are in accordance with
reported literature data.17e
The values of the characterization data are in accordance with
reported literature data.12
3-(Phenylthio)-1H-indole (6ac). White solid (90.0 mg, 80% yield).
1
3-((2-Iodophenyl)selanyl)-1H-indole (7fc). Brown solid (171.1
mg, 87% yield). Rf = 0.48 (EtOAc/Hexane = 2:8). Mp: 160−162 °C.
1H NMR (400 MHz, CDCl3): δ 8.61 (bs, 1H), 7.70 (d, J = 8.0 Hz,
1H), 7.61 (d, J = 7.7 Hz, 1H), 7.51−7.47 (m, 2H), 7.29 (t, J = 8.0 Hz,
1H), 7.19 (t, J = 7.7 Hz, 1H), 6.96 (t, J = 7.7 Hz, 1H), 6.78 (t, J = 7.7
Hz, 1H), 6.67 (d, J = 9.2 Hz, 1H). 13C{1H} NMR (100 MHz,
CDCl3): δ 141.2, 139.1, 136.5, 132.1, 129.8, 128.6, 128.5, 126.7,
Rf = 0.30 (EtOAc/Hexane = 2:8). Mp: 146−148 °C. H NMR (400
MHz, CDCl3): δ 8.42 (bs, 1H), 7.61 (d, J = 8.7 Hz, 1H), 7.50 (d, J =
2.4 Hz, 1H), 7.45 (d, J = 8.3 Hz, 1H), 7.29−7.27 (m, 1H), 7.17−7.14
(m, 3H), 7.13−7.10 (m, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ
139.3, 136.6, 130.8, 129.2, 128.8, 125.8, 124.8, 123.2, 121.0, 119.7,
111.7, 102.9. IR (neat): ṽ = 3405, 2965, 2918, 2820, 1578, 1454,
1406, 1236, 1085, 823, 738 cm−1. HRMS m/z: [M + H]+ calcd for
C14H12NS 226.0690; found 226.0679.
123.3, 121.2, 120.4, 111.5, 100.3, 96.5. IR (neat): ṽ = 3368, 3030,
The values of the characterization data are in accordance with
2927, 2850, 1447, 1331, 1063, 1001, 801, 744 cm−1. HRMS m/z: [M
reported literature data.6b
+ H]+ calcd for C17H16NO2Se 399.9101; found 399.9099.
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Article
Ethyl 4-((1H-Indol-3-yl)selanyl)benzoate (7gc). Gray solid (148.0
mg, 86% yield). Rf = 0.60 (EtOAc/Hexane = 2:8). Mp: 142−144 °C.
1H NMR (400 MHz, CDCl3): δ 8.57 (bs, 1H), 7.70 (d, J = 7.6 Hz,
2H), 7.49 (d, J = 8.2 Hz, 1H), 7.42−7.38 (m, 2H), 7.22−7.14 (m,
4H), 4.23 (q, J = 7.2 Hz, 2H), 1.26 (t, J = 7.0 Hz, 3H). 13C{1H}
NMR (100 MHz, CDCl3): δ 166.7, 141.5, 136.5, 131.7, 129.9, 129.7,
(neat): ṽ = 3316, 2998, 2922, 2840, 1700, 1582, 1484, 1264, 1103,
802, 756 cm−1. HRMS m/z: [M + H]+ calcd for C18H17NO3Se
375.0374; found 375.0353.
5-Chloro-3-(o-tolylselanyl)-1H-indole (7if). Yellow solid (136.4
mg, 85% yield). Rf = 0.38 (EtOAc/Hexane = 2:8). Mp: 96−98 °C. 1H
NMR (400 MHz, CDCl3): δ 8.63 (bs, 1H), 7.57 (d, J = 2.04 Hz, 1H),
7.47 (d, J = 2.5 Hz, 1H), 7.36 (d, J = 8.7 Hz, 1H), 7.21 (d, J = 9.1 Hz,
1H), 7.14−7.12 (m, 1H), 7.03 (t, J = 7.6 Hz, 1H), 6.87 (t, J = 6.8 Hz,
1H), 6.78−6.76 (m, 1H), 2.46 (s, 3H). 13C{1H} NMR (100 MHz,
CDCl3): δ 136.2, 134.9, 134.2, 133.0, 131.6, 130.0, 127.8, 126.9,
127.8, 127.6, 123.3, 121.2, 120.3, 111.6, 96.9, 60.9, 14.4. IR (neat): v
̃
= 3317, 2922, 2852, 1698, 1588, 1455, 1278, 1105, 1014, 844, 755
cm−1. HRMS m/z: [M + H]+ calcd for C17H16NO2Se 346.0346;
found 346.0323.
126.6, 125.6, 123.5, 120.0, 112.6, 97.1, 21.4. IR (neat): ṽ = 3414,
5-Methyl-3-(o-tolylselanyl)-1H-indole (7id). Yellow solid (123.1
mg, 82% yield). Rf = 0.39 (EtOAc/Hexane = 2:8). Mp: 140−142 °C.
1H NMR (400 MHz, CDCl3): δ 8.39 (bs, 1H), 7.43 (d, J = 2.5 Hz,
1H), 7.39−7.34 (m, 2H), 7.11 (t, J = 7.9 Hz, 2H), 7.01 (t, J = 7.4 Hz,
1H), 6.87−6.79 (m, 2H), 2.47 (s, 3H), 2.42 (s, 3H). 13C{1H} NMR
(100 MHz, CDCl3): δ 135.9, 134.9, 134.8, 131.8, 130.5, 130.4, 129.9,
2954, 2923, 2853, 1566, 1454, 1292, 1094, 1032, 892, 797 cm−1.
HRMS m/z: [M + H]+ calcd for C15H12NClSe [M + H]+ 320.9823;
found 320.9803.
3-((4-Bromophenyl)selanyl)-5-chloro-1H-indole (7ef). Brown
solid (173.4 mg, 90% yield). Rf = 0.49 (EtOAc/Hexane = 2:8).
1
Mp: 113−115 °C. H NMR (400 MHz, CDCl3): δ 8.54 (s, 1H),
127.7, 126.6, 125.3, 124.8, 120.1, 111.1, 96.6, 21.6, 21.3. IR (neat): v
̃
= 3398, 2960, 2921, 2852, 1568, 1455, 1260, 1092, 1032, 800 cm−1
.
7.51−7.49 (m, 2H), 7.36 (d, J = 8.3 Hz, 1H), 7.26−7.20 (m, 4H),
7.05 (d, J = 8.3 Hz, 2H). 13C{1H} NMR (100 MHz, CDCl3): δ 134.9,
132.8, 132.5, 132.1, 131.1, 130.3, 128.3, 127.0, 123.7, 119.8, 112.6,
HRMS m/z: [M + H]+ calcd for C16H16NSe 302.0448; found
302.0439.
97.7. IR (neat): ṽ = 3421, 2961, 2922, 2852, 1659, 1447, 1260, 1094,
3-((4-Bromophenyl)selanyl)-5-methyl-1H-indole (7ed). Gray
solid (158.8 mg, 87% yield). Rf = 0.44 (EtOAc/Hexane = 2:8).
797 cm−1. HRMS m/z: [M]+ calcd for C14H9NClSe79Br 384.8772;
found 384.8755. HRMS m/z: [M]+ calcd for C14H9NClSe81Br
386.8752; found 386.8741.
1
Mp: 116−118 °C. H NMR (400 MHz, CDCl3): δ 8.31 (bs, 1H),
7.32−7.29 (m, 2H), 7.23 (d, J = 8.7 Hz, 1H), 7.15−7.12 (m, 2H),
7.02−6.96 (m, 3H), 2.34 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3):
δ 134.8, 133.2, 132.0, 131.6, 130.6, 130.1, 130.0, 124.9, 119.8, 119.3,
The values of the characterization data are in accordance with
reported literature data.3b
Ethyl 4-((5-Chloro-1H-indol-3-yl)selanyl)benzoate (7gf). Brown
solid (166.6 mg, 88% yield). Rf = 0.65 (EtOAc/Hexane = 2:8). Mp:
143−145 °C. 1H NMR (400 MHz, CDCl3): δ 8.66 (bs, 1H), 7.79 (d,
J = 8.2 Hz, 2H), 7.52−7.54 (m, 2H), 7.38 (d, J = 8.7 Hz, 1H), 7.18−
7.24 (m, 3H), 4.32 (q, J = 7.2 Hz, 2H), 1.34 (t, J = 7.2 Hz, 3H).
13C{1H} NMR (100 MHz, CDCl3): δ 166.6, 141.0, 134.9, 133.0,
131.1, 130.0, 127.8, 127.1, 123.6, 119.7, 112.7, 96.7, 61.0, 14.4. IR
111.2, 97.0, 21.6. IR (neat): ṽ = 3397, 2956, 2922, 2853, 1577, 1463,
1260, 1069, 1005, 795 cm−1. HRMS m/z: [M + H]+ calcd for
C15H13NSe79Br 365.9397; found 365.9391. HRMS m/z: [M + H]+
calcd for C15H13NSe81Br 367.9376; found 367.9378.
Ethyl 4-((5-Methyl-1H-indol-3-yl)selanyl)benzoate (7gd). White
solid (150.4 mg, 84% yield). Rf = 0.62 (EtOAc/Hexane = 2:8). Mp:
145−147 °C. 1H NMR (400 MHz, CDCl3): δ 8.69 (bs, 1H), 7.79 (d,
J = 8.8 Hz, 2H), 7.44 (d, J = 2.6 Hz, 1H), 7.35−7.33 (m, 2H), 7.22
(d, J = 8.6 Hz, 2H), 7.09 (d, J = 8.3 Hz, 1H), 4.32 (q, J = 7.1 Hz, 2H),
2.42 (s, 3H), 1.35 (t, J = 7.0 Hz, 3H). 13C{1H} NMR (100 MHz,
CDCl3): δ 166.8, 141.9, 134.8, 131.9, 130.6, 130.0, 129.9, 127.5,
(neat): ṽ = 3294, 2956, 2923, 2853, 1695, 1589, 1565, 1331, 1106,
1013, 887, 798 cm−1. HRMS m/z: [M + H]+ calcd for
C17H15NO2ClSe 379.9957; found 379.9937.
2-((5-Chloro-1H-indol-3-yl)selanyl)-1-phenylethanone (7hf).
Brown solid (142.9 mg, 82% yield). Rf = 0.55 (EtOAc/Hexane =
2:8). Mp: 86−88 °C. 1H NMR (400 MHz, CDCl3): δ 8.44 (bs, 1H),
7.81 (d, J = 7.2 Hz, 2H), 7.54−7.52 (m, 2H), 7.39 (t, J = 8.2 Hz, 2H),
7.27 (s, 1H), 7.21 (d, J = 2.4 Hz, 1H), 7.17−7.15 (m, 1H), 3.92 (s,
2H). 13C{1H} NMR (100 MHz, CDCl3): δ 195.5, 135.4, 134.6, 133.3,
132.8, 131.1, 128.9, 128.6, 126.7, 123.3, 119.5, 112.6, 97.5, 32.5. IR
127.4, 124.8, 119.7, 111.3, 96.0, 60.9, 21.6, 14.4. IR (neat): v = 3382,
̃
2955, 2923, 2854, 1698, 1586, 1461, 1396, 1269, 1175 1104, 1012,
843 754 cm−1. HRMS m/z: [M + H]+ calcd for C18H18NO2Se
360.0503; found 360.0493.
5-Methoxy-3-(o-tolylselanyl)-1H-indole (7ie). Yellow solid (135.9
mg, 86% yield). Rf = 0.40 (EtOAc/Hexane = 2:8). Mp: 78−80 °C. 1H
NMR (400 MHz, CDCl3): δ 8.42 (bs, 1H), 7.42 (d, J = 2.5 Hz, 1H),
7.34 (d, J = 8.6 Hz, 1H), 7.12 (d, J = 7.8 Hz, 1H), 7.03−7.02 (m,
2H), 6.94−6.83 (m, 3H), 3.80 (s, 3H), 2.47 (s, 3H). 13C{1H} NMR
(100 MHz, CDCl3): δ 155.2, 136.0, 132.3, 131.0, 129.9, 127.8, 126.6,
(neat): ṽ = 3421, 2956, 2922, 2852, 1669, 1581, 1374, 1278, 1176,
992, 880, 796 cm−1. HRMS m/z: [M + H]+ calcd for C16H13NOClSe
349.9851; found 349.9841.
5-Bromo-3-(phenylselanyl)-1H-indole (7ag). White solid (161.5
mg, 92% yield). Rf = 0.48 (EtOAc/Hexane = 2:8). Mp: 136−138 °C.
1H NMR (400 MHz, CDCl3): δ 8.47 (bs, 1H), 7.78 (s, 1H), 7.47 (d,
J = 2.3 Hz, 1H), 7.33−7.21 (m, 2H), 7.20−7.17 (m, 2H), 7.16−7.12
(m, 2H). 13C{1H} NMR (100 MHz, CDCl3): δ 135.1, 133.4, 132.4,
132.0, 129.1, 128.7, 126.1, 125.9, 123.1, 114.5, 113.0, 97.9. IR (neat):
125.3, 113.6, 112.3, 101.6, 96.8, 55.9, 21.3. IR (neat): v = 3401, 3054,
̃
2930, 2830, 1623, 1580, 1481, 1454, 1282, 1206, 1163, 917, 837, 790
cm−1. HRMS m/z: [M + H]+ calcd for C16H16NOSe [M + H]+
318.0397; found 318.0388.
3-((4-Bromophenyl)selanyl)-5-methoxy-1H-indole (7ee). White
solid (165.7 mg, 87% yield). Rf = 0.47 (EtOAc/Hexane = 2:8). Mp:
108−110 °C. 1H NMR (400 MHz, CDCl3): δ 8.39 (bs, 1H), 7.46 (d,
J = 2.8 Hz, 1H), 7.33 (d, J = 8.9 Hz, 1H), 7.25−7.22 (m, 2H), 7.06
(d, J = 8.7 Hz, 2H), 7.00 (d, J = 2.8 Hz, 1H), 6.91 (dd, J = 9.9 Hz,
1H), 3.79 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 155.3,
133.1, 132.0, 131.4, 131.1, 130.6, 130.1, 119.4, 113.7, 112.4, 101.4,
ṽ = 3414, 2955, 2922, 2853, 1576,1439, 1397, 1095, 1022, 871, 795
cm−1. HRMS m/z: [M − H]− calcd for C14H9NSe79Br 349.9084;
found 349.9081. HRMS m/z: [M − H]− calcd for C14H9NSe81Br
351.9063; found 351.9070.
The values of the characterization data are in accordance with
reported literature data.17d
5-Bromo-3-(p-tolylselanyl)-1H-indole (7bg). White solid (173.4
mg, 95%, yield). Rf = 0.50 (EtOAc/Hexane = 2:8). Mp: 119−123 °C.
1H NMR (400 MHz, CDCl3): δ 8.51 (bs, 1H), 7.77 (s, 1H), 7.47 (d,
J = 2.5 Hz, 1H), 7.32−7.30 (m, 2H), 7.14 (d, J = 7.7 Hz, 2H), 6.97
(d, J = 8.3 Hz, 2H), 2.24 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3):
δ 135.9, 135.1, 132.3, 132.0, 130.0, 129.4, 129.2, 126.0, 123.1, 114.4,
97.3, 55.9. IR (neat): v = 3390, 3051, 2924, 2827, 1619, 1572, 1449,
̃
1275, 1201, 1069, 803, 785 cm−1. HRMS m/z: [M + H]+ calcd for
C15H13NOSe79Br 381.9346; found 381.9324. HRMS m/z: [M + H]+
calcd for C15H13NOSe81Br 383.9325; found 383.9313.
Ethyl 4-((5-Methoxy-1H-indol-3-yl)selanyl)benzoate (7ge). White
solid (159.0 mg, 85% yield). Rf = 0.64 (EtOAc/Hexane = 2:8). Mp:
144−146 °C. 1H NMR (400 MHz, CDCl3): δ 8.63 (bs, 1H), 7.78 (d,
J = 8.4 Hz, 2H), 7.46 (d, J = 1.8 Hz, 1H), 7.34 (d, J = 8.8 Hz, 1H),
7.22 (d, J = 8.4 Hz, 2H), 6.99 (s, 1H), 6.92 (d, J = 9.8 Hz, 1H), 4.32
(q, J = 7.0 Hz, 2H), 3.79 (s, 3H), 1.34 (t, J = 7.8 Hz, 3H). 13C{1H}
NMR (100 MHz, CDCl3): δ 166.7, 155.3, 141.6, 132.2, 131.4, 130.5,
129.9, 127.6, 127.5, 113.7, 112.4, 101.3, 96.3, 61.0, 55.8, 14.4. IR
112.9, 98.5, 21.0. IR (neat): ṽ = 3414, 2962, 2920, 2850, 1562, 1442,
1259, 1015, 797 cm−1. HRMS m/z: [M + H]+ calcd for
C15H13NSe79Br 365.9397; found 365.9373. HRMS m/z: [M + H]+
calcd for C15H13NSe81Br 367.9376; found 367.9360.
The values of the characterization data are in accordance with
reported literature data.17d
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Article
5-Bromo-3-(o-tolylselanyl)-1H-indole (7ig). Brown solid (162.4
mg, 89%, yield). Rf = 0.51 (EtOAc/Hexane = 2:8). Mp: 94−96 °C.
1H NMR (400 MHz, CDCl3): δ 8.58 (s, 1H), 7.74−7.73 (m, 1H),
7.46 (s, 1H), 7.34−7.33 (m, 2H), 7.13 (d, J = 7.3 Hz, 1H), 7.03 (t, J =
7.7 Hz, 1H), 6.87 (t, J = 7.5 Hz, 1H), 6.78−6.75 (m, 1H), 2.46 (s,
3H). 13C{1H} NMR (100 MHz, CDCl3): δ 136.2, 135.2, 134.2, 132.8,
132.1, 130.0, 127.8, 126.6, 126.1, 125.6, 123.1, 114.5, 113.0, 96.9,
(4-Methoxyphenyl)(2,4,6-trimethoxyphenyl)selane (7ca). Color-
less oil (160.7 mg, 91% yield). Rf = 0.24 (EtOAc/Hexane = 2:8). H
NMR (400 MHz, CDCl3): δ 7.23 (d, J = 8.5 Hz, 2H), 6.71 (d, J = 8.7
Hz, 2H), 6.17 (s, 2H), 3.84 (s, 3H), 3.79 (s, 6H), 3.74 (s, 3H).
13C{1H} NMR (100 MHz, CDCl3): δ 162.8, 161.8, 158.2, 131.9,
1
123.4, 114.5, 98.7, 91.2, 56.4, 55.5, 55.3. IR (neat): v = 2999, 2925,
̃
2838, 1580, 1456, 1225, 1205, 1159, 1030, 811 cm−1. HRMS m/z:
[M + H]+ calcd for C16H19O4Se 355.0449; found 355.0432.
(4-Bromophenyl)(2,4,6-trimethoxyphenyl)selane (7ea). White
solid (168.8 mg, 84% yield). Rf = 0.28 (EtOAc/Hexane = 2:8).
21.4. IR (neat): ṽ = 3394, 2956, 2922, 2853, 1456, 1260, 1033, 866,
793 cm−1. HRMS m/z: [M + H]+ calcd for C15 H12NSe79Br 364.9318;
found 364.9297. HRMS m/z: [M + H]+ calcd for C15 H12NSe81Br
366.9298; found 366.9286.
1
Mp: 100−102 °C. H NMR (400 MHz, CDCl3): δ 7.23 (d, J = 8.3
Hz, 2H), 7.03 (d, J = 8.3 Hz, 2H), 6.20 (s, 2H), 3.86 (s, 3H), 3.78 (s,
The values of the characterization data are in accordance with
reported literature data.3b
6H). 13C{1H} NMR (100 MHz, CDCl3): δ 163.1, 161.8, 132.9, 131.7,
130.4, 119.1, 96.7, 91.2, 56.4, 55.6. IR (neat): v = 2985, 2922, 2853,
̃
5-Bromo-3-((4-methoxyphenyl)selanyl)-1H-indole (7cg). White
solid (177.2 mg, 93%, yield). Rf = 0.53 (EtOAc/Hexane = 2:8). Mp:
135−137 °C. 1H NMR (400 MHz, CDCl3): δ 8.44 (bs, 1H), 7.79 (s,
1H), 7.46 (d, J = 2.5 Hz, 1H), 7.31−7.23 (m, 4H), 6.73 (d, J = 9.5
Hz, 2H), 3.73 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 158.5,
135.5, 135.1, 131.8, 131.5, 125.9, 123.1, 123.0, 114.9, 114.3, 112.9,
1578, 1452, 1250, 1157, 1022, 805, 750 cm−1. HRMS m/z: [M + H]+
calcd for C15H16O3Se79Br 402.9442; found 402.9448. HRMS m/z: [M
+ H]+ calcd for C15H16O3Se81Br 402.9428; found 402.9449.
Ethyl 4-((2,4,6-Trimethoxyphenyl)selanyl)benzoate (7ga). Brown
1
oil (164.0 mg, 83% yield). Rf = 0.30 (EtOAc/Hexane = 2:8). H
NMR (400 MHz, CDCl3): δ 7.78 (d, J = 8.2 Hz, 2H), 7.17 (d, J = 8.2
Hz, 2H), 6.22 (s, 2H), 4.32 (q, J = 7.1 Hz, 2H), 3.88 (s, 3H), 3.78 (s,
6H), 1.35 (t, J = 7.1 Hz, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ
166.7, 163.5, 162.0, 141.4, 129.8, 127.6, 127.2, 95.8, 91.1, 60.8, 56.4,
99.4, 55.4. IR (neat): v = 3414, 2955, 2923, 2852, 1589, 1489, 1455,
̃
1243, 1174, 1097, 883, 796 cm−1. HRMS m/z: [M − H]− calcd for
C15H11NOSe79Br 379.9189; found 379.9176. HRMS m/z: [M − H]−
calcd for C15H11NOSe81Br 381.9169; found 381.9159.
55.5, 14.4. IR (neat): ṽ = 2958, 2928, 2851, 1708, 1582, 1455, 1269,
5-Bromo-3-((4-bromophenyl)selanyl)-1H-indole (7eg). White
solid (197.8 mg, 92%, yield). Rf = 0.58 (EtOAc/Hexane = 2:8).
1159, 1014, 811, 757 cm−1. HRMS m/z: [M + H]+ calcd for
C18H21O5Se 397.0554; found 397.0542.
1
Mp: 140−142 °C. H NMR (400 MHz, CDCl3): δ 8.52 (bs, 1H),
1-Phenyl-2-((2,4,6-trimethoxyphenyl)selanyl)ethanone (7ha).
Yellow solid (147.9 mg, 81% yield). Rf = 0.34 (EtOAc/Hexane =
2:8). Mp: 68−70 °C. 1H NMR (400 MHz, CDCl3): δ 7.84 (d, J = 7.3
Hz, 2H), 7.50 (t, J = 6.0 Hz, 1H), 7.38 (t, J = 9.0 Hz, 2H), 6.08 (s,
2H), 3.96 (s, 2H), 3.81 (s, 3H), 3.69 (s, 6H). 13C{1H} NMR (100
MHz, CDCl3): δ 195.6, 162.8, 161.8, 136.0, 132.8, 128.6, 128.3, 96.8,
7.71 (s, 1H), 7.46 (s, 1H), 7.32 (d, J = 6.7 Hz, 2H), 7.23 (d, J = 7.7
Hz, 2H), 7.04 (d, J = 8.5 Hz, 2H). 13C{1H} NMR (100 MHz,
CDCl3): δ 135.1, 132.6, 132.4, 132.1, 131.6, 130.3, 126.2, 122.9,
119.8, 114.6, 113.0, 97.5. IR (neat): v = 3416, 2959, 2925, 2853,
̃
1675, 1441, 1380, 1291, 1069, 873, 807, 793 cm−1. HRMS m/z: [M −
H]− calcd for C14H8NSe79Br2 427.8189; found 427.8218. HRMS m/
z: [M − H]− calcd for C14H8NSe81Br2 429.8168; found 429.8198.
Ethyl 4-((5-Bromo-1H-indol-3-yl)selanyl)benzoate (7gg). Brown
solid (190.4 mg, 90%, yield). Rf = 0.69 (EtOAc/Hexane = 2:8). Mp:
146−148 °C. 1H NMR (400 MHz, CDCl3): δ 8.61 (bs, 1H), 7.79 (d,
J = 8.5 Hz, 2H), 7.71 (s, 1H), 7.51 (d, J = 2.8 Hz, 1H), 7.35 (s, 2H),
7.19 (d, J = 8.2 Hz, 2H), 4.32 (q, J = 7.0 Hz, 2H), 1.34 (t, J = 7.2 Hz,
3H). 13C{1H} NMR (100 MHz, CDCl3): δ 166.6, 140.8, 135.2, 132.8,
131.7, 130.0, 127.8, 127.7, 126.3, 122.8, 114.6, 113.1, 96.7, 61.0, 14.4.
90.9, 56.1, 55.4, 31.2. IR (neat): ṽ = 2999, 2941, 2839, 1663, 1589,
1459, 1196, 1146, 1063, 818, 751 cm−1. HRMS m/z: [M + H]+ calcd
for C17H19O4Se 367.0449; found 367.0434.
2-Hydroxy-4-methoxy-5-((2,4,6-trimethoxyphenyl)selanyl)-
benzaldehyde (7ja). Yellow solid (198.6 mg, 78% yield). Rf = 0.39
1
(EtOAc/Hexane = 2:8). Mp: 103−105 °C. H NMR (400 MHz,
CDCl3): δ 11.41 (s, 1H), 9.48 (s, 1H), 6.75 (s, 1H), 6.41 (s, 1H),
6.27 (s, 2H), 3.95 (s, 3H), 3.91 (s, 3H), 3.83 (s, 6H). 13C{1H} NMR
(100 MHz, CDCl3): δ 194.1, 163.5, 163.4, 163.0, 162.3, 132.5, 115.9,
IR (neat): v = 3325, 2957, 2923, 2853, 1697, 1586, 1448, 1268, 1105,
̃
1012, 844, 793 cm−1. HRMS m/z: [M + H]+ calcd for
C17H15NO2Se79Br 423.9451; found 423.9431. HRMS m/z: [M +
H]+ calcd for C17H15NO2Se81Br 425.9431; found 425.9420.
3-(p-Tolylselanyl)-1H-indole (7ah). White solid (132.1 mg, 92%,
113.6, 98.9, 94.4, 90.9, 57.2, 56.3, 55.4. IR (neat): v = 3480, 2990,
̃
2940, 2842, 1695, 1480, 1270, 1162, 1012, 813, 756 cm−1. HRMS m/
z: [M + H]+ calcd for C17H18O6Se 398.0269; found 398.0266.
1
yield). Rf = 0.37 (EtOAc/Hexane = 2:8). Mp: 66−68 °C. H NMR
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.joc.1c00478.
■
(400 MHz, CDCl3): δ 7.66 (s, 1H), 7.11−7.39 (m, 9H), 3.83 (s, 3H).
sı
13C{1H} NMR (100 MHz, CDCl3): δ 137.5, 135.7, 134.3, 131.5,
130.8, 129.0, 128.6, 125.6, 122.3, 120.5, 109.5, 95.6, 33.2. IR (neat): v
̃
= 3109, 1573, 1503, 1474, 1236, 1021, 738 cm−1. HRMS m/z: [M +
H]+ calcd for C15H13NSe 287.0213; found 287.0227.
The values of the characterization data are in accordance with
reported literature data.17d
NMR spectra, experimental information, and X-ray data
(PDF)
Phenyl(2,4,6-trimethoxyphenyl)selane (7aa). Yellow oil (140.6
mg, 87% yield). Rf = 0.23 (EtOAc/Hexane = 2:8). H NMR (400
Accession Codes
1
CCDC 1990128, 2035467, 2045884, 2062449, and 2062452
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge via www.ccdc.ca-
m.ac.uk/data_request/cif, or by emailing data_request@ccdc.
cam.ac.uk, or by contacting The Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax:
+44 1223 336033.
MHz, CDCl3): δ 7.19−7.08 (m, 5H), 6.20 (s, 2H), 3.86 (s, 3H), 3.79
(s, 6H). 13C{1H} NMR (100 MHz, CDCl3): δ 163.1, 162.0, 133.6,
128.8, 128.7, 125.3, 97.1, 91.2, 56.4, 55.6. IR (neat): ṽ = 3001, 2920,
2849, 1575, 1452, 1335, 1226, 1160, 1076, 813 cm−1. HRMS m/z:
[M + H]+ calcd for C15H17O3Se 325.0343; found 325.0321.
The values of the characterization data are in accordance with
reported literature data.17d
p-Tolyl(2,4,6-trimethoxyphenyl)selane (7ba). Yellow oil (150.0
1
mg, 89% yield). Rf = 0.24 (EtOAc/Hexane = 2:8). H NMR (400
AUTHOR INFORMATION
Corresponding Author
■
MHz, CDCl3): δ 7.11 (d, J = 8.2 Hz, 2H), 6.94 (d, J = 8.2 Hz, 2H),
6.19 (s, 2H), 3.85 (s, 3H), 3.78 (s, 6H), 2.24 (s, 3H). 13C{1H} NMR
(100 MHz, CDCl3): δ 162.9, 162.0, 135.2, 129.7, 129.6, 129.3, 97.7,
Avijit Goswami − Department of Chemistry, SS Bhatnagar
Block, Main Campus, Indian Institute of Technology Ropar,
Rupnagar, Punjab 140001, India; orcid.org/0000-0003-
2798-1956; Email: agoswami@iitrpr.ac.in
91.1, 56.4, 55.5, 21.1. IR (neat): ṽ = 2960, 2919, 2849, 1583, 1450,
1260, 1223, 1161, 1014, 794 cm−1. HRMS m/z: [M + H]+ calcd for
C16H19O3Se 339.0499; found 339.0486.
9325
https://doi.org/10.1021/acs.joc.1c00478
J. Org. Chem. 2021, 86, 9317−9327

The Journal of Organic Chemistry
Author
Pratibha Kalaramna − Department of Chemistry, SS
Bhatnagar Block, Main Campus, Indian Institute of
Technology Ropar, Rupnagar, Punjab 140001, India
pubs.acs.org/joc
Article
(9) Keshari, T.; Kapoorr, R.; Yadav, L. D. S. Iron(III)-Catalyzed
Radical Cross-Coupling of Thiols with Sodium Sulfinates: A Facile
Access to Thiosulfonates. Synlett 2016, 27, 1878.
(10) Wu, Q.; Zhao, D.; Qin, X.; Lan, J.; You, J. Synthesis of
Di(Hetero)Aryl Sulfides by Directly Using Arylsulfonyl Chlorides as a
Sulfur Source. Chem. Commun. 2011, 47, 9188.
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.joc.1c00478
1
(11) Zhang, Y.; Guo, H. SRN Reaction of Haloarenes With
Benzenethiolate, Benzeneselenolate, Benzenetellurolate Ions Pro-
moted by SmI2. Heteroat. Chem. 2001, 12, 539.
Notes
(12) Cao, Y.; Liu, J.; Liu, F.; Jiang, L.; Yi, W. Copper-catalyzed direct
and odorless selenylation with a sodium selenite-based reagent. Org.
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The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The authors would like to acknowledge DST-SERB, New
Delhi, and CSIR, New Delhi, for financial support and IIT
Ropar for infrastructure and fellowship to P.K.
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