Photoredox-Catalyzed Hydrosulfonylation of Arylallenes

Article abstract of DOI:10.1021/acs.joc.9b02960

(Het)Arylallenes undergo hydrosulfonylation under photoredox-catalyzed conditions. The reaction gives vinyl sulfones in a regio- and diastereoselective manner, employing sodium sulfinates as the sulfonyl source and eosin Y as the photocatalyst. Indol-1-yl, pyrrol-1-yl, phenyl, and naphtylallenes might be used. Aliphatic allenes are incompatible with the reaction conditions.

Full text of DOI:10.1021/acs.joc.9b02960

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Article
Photoredox-Catalyzed Hydrosulfonylation of Arylallenes
Olga A. Storozhenko, Alexey A. Festa, Galina I. Detistova, Victor B Rybakov,
Alexey V. Varlamov, Erik V. Van der Eycken, and Leonid G. Voskressensky
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.9b02960 • Publication Date (Web): 24 Dec 2019
Downloaded from pubs.acs.org on December 24, 2019
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Page 1 of 11
The Journal of Organic Chemistry
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Photoredox-Catalyzed Hydrosulfonylation of Arylallenes
Olga A. Storozhenko,† Alexey A. Festa,†,* Galina I. Detistova,† Victor B. Rybakov,^ Alexey V.
Varlamov,† Erik V. Van der Eycken†,‡ and Leonid G. Voskressensky†,*
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†Organic Chemistry Department, Science Faculty, Peoples’ Friendship University of Russia (RUDN University), Moscow,
Russia, Miklukho-Maklaya st., 6, e-mail: lvoskressensky@sci.pfu.edu.ru
^Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory, 1-3, 119991, Moscow (Russia)
‡Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU
Leuven), Celestijnenlaan 200F, B-3001, Leuven, Belgium.
Supporting Information Placeholder
R1
2
(3 equiv)
R SO2Na
R1
Eosin Y (5 mol %)
O
S
DMF-TFE, 2-4 h, rt, N2
green LED
R2
O
24 examples
25-82%
R1 = indol-1-yl, pyrrol-1-yl, phenyl, naphtyl
R2 = aryl, alkyl
ABSTRACT: (Het)Arylallenes undergo hydrosulfonylation under photoredox-catalyzed conditions. The reaction gives vinyl
sulfones in a regio- and diasteroselective manner, employing sodium sulfinates as sulfonyl source, and Eosin Y as photocatalyst.
Indol-1-yl, pyrrol-1-yl, phenyl, and naphtyl allenes might be used. Aliphatic allenes are incompatible with the reaction conditions.
Introduction
OMe O
Cl
The emerging field of photoredox catalysis has become an
indispensable tool for organic synthesis, enabling novel and
intrinsic ways of bond creation.1 Photoredox-catalyzed
reactions proceed mainly through single electron transfer
processes, giving rise to odd electron chemistry. The use of a
renewable resource of visible light to facilitate chemical
reactions allows to perform the transformations under mild
conditions and to evade the use of stoichiometric amounts of
tin, usually employed in free radical chemistry. Beyond Ru-, Ir-,
and Cu-complexes as photocatalysts, the employment of
organic dyes seems a practical and green alternative.2 For
instance, the xanthene dye Eosin Y has a much lower cost and
toxicity, with comparable, and sometimes superior
effectiveness.3
S
O
N
O
H
N
N
A
O
S
N
S
H
O
O
O
Ar
Nrf2 activator
potential therapeutic for
Parkinson's Disease
O
R
NHR
O
K11777
cysteine protease inhibitor
N
H
anti HIV-1
reverse transcriptase inhibitors
Figure 1. Representative biologically active sulfones.
Vinyl sulfones are also widely employed as useful synthetic
intermediates.9 The synthesis of sulfones is a needful task, with
numerous methods developed.10 In general, the preparation of
vinyl sulfones relies on sulfonylation of alkenes through
oxidative11 or cross-coupling reactions,12 decarboxylative
couplings with alkenes13 or alkynes,14 tosylhydrazone
Vinyl sulfones are the sought for compounds for medicine and
biology, as they display extensive biological activity4 and are
excellent substrates for labeling of biomolecules.5 For instance,
K11777 is a renown cysteine protease inhibitor,6 sulfone A is
an Nrf activator with potency to become a therapeutic for
Parkinson’s Disease.7 The combination of the sulfonyl-group
with an indole moiety gives rise to a class of anti HIV-1 reverse
transcriptase inhibitors.8
decompositions,15
SO2
fixation
approaches,16
or
hydrosulfonylation of alkynes.17 The metal free synthesis of
sulfones is also realizable from sulfonate esters.18 The common
drawbacks of these methods are the employment of transition
metal catalysts and/or stoichiometric oxidants, and the use of
sacrificial
groups.
Recently,
photoredox-catalyzed
hydrosulfonylation of alkynes has been reported by Lei and co-
workers.19 Uncommon for radical processes Markovnikov
selectivity has been observed, producing branched vinyl
sulfones B (Scheme 1, equation 1). Allenes are a readily
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available class of compounds, and are widely used in the condition of choice, due to the good yield and the ease of
synthesis of natural products, pharmaceuticals, and materials.20
Therefore, the development of novel methods for selective
allene functionalization is an appealing task for organic
chemists. Free radical transformations of allenes are developing
rapidly,21 and photoredox catalysis poses a sustainable option
for this. However, free radical hydrosulfonylation of allenes has
been realized on few examples (Scheme 1, equation 2).22
Anionic hydrosulfonylation has been developed by Miao, Ren
and co-workers, but is limited to unique highly activated allenes
(Scheme 1, equation 3).23 Herein we report a photoredox-
catalyzed regio- and diastereoselective hydrosulfonylation of
unactivated allenes 1 towards Markovnikov-type vinyl sulfones
2, which we believe excellently complements the existing
methods (Scheme 1, equation 4).
isolation (Table 1, Entry 11). Carrying out the reaction in TFE
solely led to a decreased yield of 38% (Table 1, Entry 12). In
absence of the catalyst the reaction did not start either with or
without light (Table 1, Entries 13 and 14). The structure of
compound 2a was unambiguously determined by single crystal
X-ray diffraction study (for details see CCDC #1922457).
1
2
3
4
5
6
7
8
Table 1. Optimization of hydrosulfonylation of 2-phenyl-N-
(1,2-propadien-1-yl)indole.a
O
9
S
O Na
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Me
(3 equiv)
catalyst
Ph
Ph
Ts
N
N
conditions
25 oC, N2
1a
2a
Scheme 1. Recent examples of vinylsulfone syntheses through
hydrosulfonylation.
Entry
Catalyst
(mol %)
Conditions
Yield 2a,
%
eosin Y (1 mol%)
K2CO3 (1 equiv)
b
2017
Lei,
O
O
R
Ar
S
O
S
uncommon
Markovnikov
selectivity
R
(1)
1
2
Eosin Y (3)
DMF-H2O (3:1), 5 40
h, green LED
DMF, N2, green LED
Ar
OH
OH
B
2016
Lei,
O2
pyridine
O
Ph
O
S
S
Eosin Y (5)
DMF-H2O
equiv), 14 h, green
LED
(5 62
O
R
2 examples
23-34% yields
(2)
(3)
DCE, 45 o
C
Ph
B
R
2016
Miao, Ren
ROC
O
ROC
R
SO2R2
COR
3
Eosin Y (5)
Eosin Y (5)
DMF, 20 h, green
LED
0
0
AcOH
S
or
R2 O Na
SO2R2
solvent
R
R
4c
DMF-H2O
equiv), 14 h, no
light
(5
tunable, but only activated allenes
this work:
R2
O
O
O
eosin Y (5 mol%)
S
Markovnikov
selectivity;
24 examples
R1
S
(4)
R2 O Na
DMF-TFE, N2
green LED
5
Rose Bengal DMF-H2O
(10)
(5 60
R1
1
2
equiv), 1 h, green
regio- and (E)-selective
LED
Results and Discussion
6d
Ru(bpy)3Cl2
6H2O (3)
DMF-H2O
equiv), 10 h, blue
LED
(5 52
Our recent analysis of the impact of photocatalyzed reactions
on the field of indole chemistry uncovered the lack of methods,
where the indole moiety is not modified.24 We became
interested in the outcome of the reaction of 2-phenyl-N-(1,2-
propadien-1-yl)indole 1a under photocatalyzed conditions. We
firstly examined the reaction of 2-phenyl-N-(1,2-propadien-1-
yl)indole 1a with sodium p-tolylsulfinate in the presence of
eosin Y in a DMF-water mixture under visible light irradiation
(Table 1, Entry 1). To our delight, we isolated vinyl sulfone 2a
as the major product in 40% yield. The use of a larger amount
of catalyst and a smaller amount of water (5 equiv) yielded vinyl
sulfone 2a in 62% yield (Table 1, Entry 2). The reaction did not
start without the addition of water (Table 1, Entry 3) or without
irradiation with visible light (Table 1, Entry 4). The use of Rose
Bengal (Table 1, Entry 5) or Ru(bpy)3Cl2 complex (Table 1,
Entry 6) as photocatalyst sped up the formation of 2a, but no
improvement of the yield was observed. Considering water to
be the proton source, basic medium was produced through the
continuous formation of hydroxide anions. We succeeded to
identify 2-phenylindole to be the major by-product of the
reaction. It might arise from the basic hydrolysis of the product
2a. To suppress its formation, we explored various hydrogen
sources. In ethanol the reaction was sluggish, and the target
molecule was isolated in a mere 35% yield (Table 1, Entry 7).
Addition of chloroform (Table 1, Entry 8) instead of water gave
product 2 in 46% yield. Employment of less nucleophilic
alcohols like TFE or HFIP, raised the yield to 61 and 56%,
respectively (Table 1, Entries 9 and 10). The addition of base,
together with the employment of TFE was identified as the
7
8
Eosin Y (5)
Eosin Y (5)
EtOH, 14 h, green 35
LED
DMF-CHCl3
(3:1), 6 h, green
LED
46
9
Eosin Y (5)
Eosin Y (5)
Eosin Y (5)
DMF-TFE (1:0.3), 61
4 h, green LED
10
11e
DMF-HFIP (2:1), 56
5 h, green LED
DMF-TFE (1:0.3), 63
K2CO3, 4 h, green
LED
12
13
14
Eosin Y (5)
No catalyst
No catalyst
TFE, K2CO3, 4 h, 38
green LED
DMF-TFE (1:0.3),
4 h, green LED
0
DMF-TFE (1:0.3),
4 h, no light
aGeneral conditions: allene 1a (0.581 mmol), sodium sulfinate (1.742
mmol), eosin Y (0.029 mmol) and the solvent (0.092 M) under nitrogen
atmosphere were irradiated with one 30W or two 15W 530 nm LED for
1-14 h. bYields after column chromatography. cNo light. dOne 30W 455
nm LED was used. eK2CO3 (2 equiv) was added to the reaction mixture.
0
With the optimized conditions in hand, we determined the scope
of the process. We were pleased to find that indoles bearing a
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methyl-, a bromo-, a methoxy, or a cyano-group gave products
2b-f in 32-43% yields (Scheme 2). Unsubstituted indolyl allene
1
2
3
4
5
6
7
8
Scheme 3. Photoredox-catalyzed hydrosulfonylation of
could be hydrosulfonylated to give product 2h with 42% yield.
The employment of various sulfinates was also possible. Thus,
products 2g, i, k with thienyl or phenyl substituents in the
sulfonyl moiety were synthesized. It is worth noting that
aliphatic sulfinate MeSO2Na was successfully used to produce
the corresponding vinyl sulfone 2j with 39% yield. Indole with
p-tolyl group at C(2) underwent the discovered transformation,
producing a mixture of isomers 2l and 2l’ with moderate 58%
yield. The reaction of N-(allenyl)pyrrole was also successful
and the corresponding product 2n was isolated with 27% yield.
As far as photoredox-catalyzed C(3)-sulfonylation of indoles
was previously reported,25 it is of special interest that in our
reactions no C(3)-sulfonylated indoles were observed.
arylallenes.a
1
(3 equiv)
R SO2Na
R
R
Eosin Y (5 mol %)
DMF-TFE, 2-4h, 25 oC, N2
green LED
O
S
R1
3
O
4
O
S
Ts
SO2Ph
O
b
4a
, 74%
4b
, 78% (81%)
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R2
O
, R2 = Br, 74%
4c
4d
S
2
O
SO2Me
, R = NO2, trace
4e
, 48%
H3C
S
4f
, 82%
O
Ts
Scheme 2. Photoredox-catalyzed hydrosulfonylation of N-(1,2-
4g
, 65%
propadien-1-yl)indoles.a
Ts
4i
, 17%
Ts
Ts
RSO2Na (3 equiv)
MeO
F3C
4h
, 76%
O
N
Eosin Y (5 mol %)
4j
SO2R
, 0%
F3C
N
DMF-TFE, K2CO3 (2 equiv)
3 - 5h, 25 oC, N2
SO2Ph
O
2
S
1
O
S
O
4l
, 74%
R
O
green LED
Me
Br
SO2Ph
N
4k
, 0%
Br
Br
N
, 34%
CN
4m
4n
, 59%
, 69%
N
aGeneral conditions: allene 3 (0.603 mmol), sodium sulfinate (1.810 mmol),
eosin Y (0.0302 mmol), 5.0 mL DMF, and 1.5 mL TFE (1:0.3) under
nitrogen atmosphere were irradiated with one 30W or two 15W 530 nm
LED for 2-4 h (TLC tracking). The products were isolated by column
chromatography. bThe yield of the reaction, performed on 2 mmol scale of
allene.
2d
, 32%
2c
SO2Ph
2b
, 43%
Ts
Ts
MeO
N
Br
N
N
O
S
O
2g
, 29%
2e
, 41%
Ts
2f
, 41%
To clarify the process pathway some control experiments were
performed. Firstly, the reaction of phenylallene 3a in the
presence of D2O was carried out (Scheme 4, eq 1). The resulting
vinyl sulfone showed an incorporated deuterium exclusively in
the methyl group. The analogous outcome was observed for the
reaction of allenyl indole 1m in D2O (Scheme 4, eq 2). When
the water was taken in stoichiometric amount, but not as
solvent, the deuterium could be observed also in α-position (see
Supporting Information). Interestingly, when the reaction was
carried out in the presence of acetic acid, the reaction was faster
and a mixture of regioisomeric vinyl sulfones 4b and 4b’ (2:1)
was formed (Scheme 4, eq 3). The complete quenching of the
reaction in the presence of TEMPO proved the radical nature of
the process (Scheme 4, eq 4). Moreover, the reaction was
significantly inhibited when carried out under oxygen
atmosphere and the target product 2a was formed in trace
amounts as inseparable mixture with numerous by-products
(Scheme 4, eq 5).
S
Ts
MeO
N
2h
2i
2j
, R = p-Tol, 42%
, R = Ph, 30%
, R = Me, 39%
N
SO2R
2k
, 25%
O
S
Me
Me
O
N
N
S
N
Ts
Ts
b
SO2Ph
2m
, 27%
2l+2l' (2.45:1)
, 58%
aGeneral conditions: allene 1 (0.581 mmol), sodium sulfinate (1.742 mmol),
eosin Y (0.029 mmol), K2CO3 (1.161 mmol), 4.850 mL DMF, and 1.455
mL TFE (1:0.3) under nitrogen atmosphere were irradiated with one 30W
or two 15W 530 nm LED for 3-5 h (TLC tracking). The products were
isolated by column chromatography. bThe reaction performed on 4.76 mmol
scale of allene.
To better understand the scope of the discovered process, we
investigated the reaction of 1-phenylpropadiene-1,2 (3a).
Fortunately, employing our optimized conditions, vinyl sulfone
4a was provided with a good yield of 74% (Scheme 3).
Phenylallene 3a reacted smoothly with phenyl-, 4-
bromophenyl-, thien-2-yl-, and methylsulfinates affording
sulfones 4b, c, e, f with 48-82% yields. The interaction of 3a
with sodium p-nitrophenylsulfinate gave target product 4d in
trace amounts. The use of sodium trifluoromethanesulfinate
(Langlois reagent), having higher oxidative potential than
aromatic or aliphatic sulfinates, led to zero conversion of the
starting allene 3a. 4-Methylphenylallene and naphtylallene
could be used successfully to give products 4g and 4h,
respectively. The yield of phenoxy-substituted sulfone 4i was
substantially lower. Finally, we found the reaction scope to be
limited to conjugated allenes only. Thus, the reaction of
benzylallene resulted in a complex inseparable mixture.
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Scheme 4. Control experiments.a
In conclusion, we have elaborated a novel photocatalyzed
1
2
3
4
5
6
7
8
protocol for the hydrosulfonylation of allenes. The reaction
employs readily available sodium sulfinates as sulfonyl source,
and eosin Y as photocatalyst. We successfully applied this
process for the preparation of indolyl- and aryl-substituted
vinylsulfones. The reaction tolerates various sulfinates and
conjugated allenes, while the use of aliphatic allenes has been
found to be a limitation of the method.
PhSO Na
(3 equiv)
2
Eosin Y (5 mol %)
SO2Ph
CH2D
52% (84%)b
DMF-D2O
(1)
5h, 25 oC, N2, green LED
PhSO2Na
3a
(3 equiv)
Eosin Y (5 mol %)
K2CO3 (2 equiv)
indole
40%
N
N
CH2D
(2)
DMF-D2O
5h, 25 oC, N2,green LED
1m
32%
SO2Ph
Ts
Experimental Section
(3 equiv)
PhSO2Na
SO2Ph
(3)
Eosin Y (5 mol %)
9
General Information. All solvents were dried and distilled
according to the standard procedures before use. Reagents and
catalysts were purchased from the commercial sources and used
without additional purification. Sodium sulfinates were
synthesized through the literature procedure.27 1H and 13C NMR
spectra were acquired on 400, 600 MHz spectrometers and
referenced to the residual signals of the solvent (for 1H and 13C).
Chemical shifts are reported in parts per million (δ/ppm).
Coupling constants are reported in Hertz (J/Hz). The peak
patterns are indicated as follows: s, singlet; d, doublet; t, triplet;
q, quadruplet; m, multiplet; dd, doublet of doublets and br s,
broad singlet. Infrared spectra were measured on a FT/IR
instrument. The wavelengths are reported in reciprocal
centimeters (λmax /cm-1). High resolution mass spectra (HRMS)
were obtained by electrospray ionization using a LTQ Orbitrap
Elite ThermoScientific mass spectrometer. The reaction
progress was monitored by TLC and the spots were visualized
under UV light (254 or 365 nm). Column chromatography was
performed using silica gel (230-400 mesh) and mixtures in
different proportions of ethyl acetate with hexane as mobile
phase. Melting points were determined on a SMP-10 apparatus.
DMF-CH3COOH
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59
60
2h, 25 oC, N2, green LED
3a
4b
4b'
, 40%
, 20%
PhSO Na
(3 equiv)
2
Eosin Y (5 mol %)
SO2Ph
(4)
(5)
TEMPO (3 equiv)
DMF-TFE
3a
0%
5h, 25 oC, N2, green LED
(3 equiv)
p-Tol-SO2Na
Ph
Eosin Y (5 mol %)
Ph
N
various
products
N
DMF-TFE
12h, 25 oC, O2, green LED
2a
1a
Ts
trace
aGeneral conditions: allene 3 (0.431 mmol), sodium sulfinate (1.293 mmol),
eosin Y (0.022 mmol), 3.6 mL DMF, 1.6 mL TFE under nitrogen
atmosphere were irradiated with one 30W or two 12W 530 nm LED for 2-
4 h. The products were isolated by column chromatography. bThe yield after
recovering starting allene.
Additional mechanistic investigations to better understand the
reaction have been performed. The photoexcited state of EY has
been found to be quenched by sulfinate. On the opposite, no
fluorescence quenching of EY has been observed with
phenylallene (for more details, see Supporting Information).
Quantum yield of the reaction has been determined to be 0.88
(for more details, see Supporting Information). High photo
effectiveness is in accordance with fast reaction times, but the
chain process is unlikely. According to the literature,26
mechanistic investigations, and the control experiments, we
propose the following mechanism for the allene
hydrosulfonylation. The photoexcited state of EY is reductively
quenched by sodium sulfinate and a sulfonyl radical is
produced. The addition of this sulfonyl radical to the allene
system results in the formation of allyl radical A. It might be
reduced to anion B by the EY anion radical. Further abstraction
of a proton from water or alcohol delivers the final compound
(Scheme 5). The selective formation of 2a in most cases might
be explained by thermodynamically-driven base-catalyzed
isomerization of 2a’.
Synthesis of 2-substituted N-allenylindoles 1a,b
2-Substituted indolylallenes were obtained from corresponding
propargylindoles with KOH and TBAB in toluene. The
alkylation procedure, based on the use of indoles, propargyl
bromide and KOH/DMSO system (see below for 1c-i
compounds) is not selective and leads to the mixtures of the
corresponding propargyl and allenyl indoles.
2-Phenyl-1-propadienyl-1H-indole (1a). To a solution of 2-
phenyl-N-propargyl indole 0.500 g (2.2 mmol) in toluene (27
mL), TBAB 0.071 g (0.1 eq, 0.22 mmol) and KOH 0.121 g (1
eq, 2.2 mmol) were added. The mixture was stirred at rt for 24
h, yield quantitative. Allene was used in the reactions after
filtration and evaporation of the solvent. To obtain the
analytical sample, the crude allene was then chromatographed
through a thin layer of neutralized with Et3N silica, eluent
EtOAc-Hexane 1-10. Yellow oil. Rf = 0.4 (EtOAc – Hexane 1-
Scheme 5. Proposed reaction pathway.
1
20). H NMR (600 MHz, CDCl3) δ 5.55 (d, J = 6.5 Hz, 2H),
EY
6.73 (s, 1H), 7.15 (t, J = 7.5 Hz, 1H), 7.22 (t, J = 7.8 Hz, 1H),
7.25 (t, J = 6.5 Hz, 1H), 7.43 – 7.47 (m, 1H), 7.52 (t, J = 7.6 Hz,
2H), 7.60 -7.62 (m, 3H), 7.78 ppm (d, J = 8.3 Hz, 1H). 13C{1H}
NMR (150 MHz, CDCl3) δ 86.4, 95.9, 103.7, 111.3, 120.5,
120.8, 122.2, 128.2, 128.3, 128.6 (2C), 129.1 (2C), 131.6,
137.0, 139.7, 204.4. HRMS (ESI): m/z [M+H]+ calcd for
C17H14N: 232.1120; found: 232.1121. IR (KBr): 3054 – 3031,
2954 – 2852, 1739 – 1606, 1462, 1378, 745, 698 cm-1.
N
N
N
RSO2
SO2R
B
A
SO2R
green
LED
EY*
ROH
RO
RSO2Na
EY
EY
A
RO
2-(4-Methylphenyl)-1-propadienyl-1H-indole (1b). To
a
N
N
solution of 2-(4-methylphenyl)-N-propargyl indole 0.300 g (1.2
mmol) in toluene (16 mL), TBAB 0.039 g (0.1 eq, 0.12 mmol)
and KOH 0.069 g (1 eq, 1.2 mmol) were added. The mixture
was stirred at rt for 24 h, yield quantitative. Allene was used in
B
SO2R
2a'
2a
SO2R
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The Journal of Organic Chemistry
the reactions after filtration and evaporation of the solvent. To
1666, 1620 – 1580, 1478, 1448, 1247 – 1231, 1152 – 1131,
1029, 799, 716 cm-1.
1
2
3
4
5
6
7
8
obtain the analytical sample, the crude allene was then
chromatographed through a thin layer of neutralized with Et3N
silica, eluent EtOAc-Hexane 1-10. Yellow liquid. Rf = 0.55
(EtOAc – Hexane 1-10). 1H NMR (600 MHz, CDCl3) δ 2.45 (s,
3H), 5.52 (d, J = 6.5 Hz, 2H), 6.63 (s, 1H), 7.08 (t, J = 6.5 Hz,
1H), 7.20 (m, 1H), 7.25 (m, 1H), 7.30 (d, J = 7.8 Hz, 2H), 7.49
(d, J = 7.8 Hz, 2H), 7.64 (d, J = 7.8 Hz, 1H), 7.78 ppm (d, J =
8.1 Hz, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ 21.3, 86.1,
96.8, 103.6, 111.7, 120.5, 120.9, 122.1, 129.0, 129.2 (2C),
129.3, 129.6 (2C), 137.2, 138.1, 140.4, 204.7. HRMS (ESI):
m/z [M+H]+ calcd for C18H16N: 246.1277; found: 246.1269. IR
(KBr): 3094 – 3028, 2972 – 2920, 2859, 1706, 1502, 1458, 1358
– 1322, 823, 787, 748 cm-1.
6-Bromo-1-propadienyl-1H-indole (1g). Yield 0.264 g, 88%,
yellow crystallizing oil. Rf = 0.53 (EtOAc – Hexane 1-10). 1H
NMR (600 MHz, CDCl3) δ 5.66 (d, J = 6.5 Hz, 2H), 6.58 (d, J
= 3.1 Hz, 1H), 7.12 (t, J = 6.5 Hz, 1H), 7.18 (d, J = 3.1 Hz, 1H),
7.26 (dd, J = 1.5, 8.4 Hz, 1H), 7.47 (d, J = 8.4 Hz, 1H), 7.73
ppm (s, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ 88.0, 97.1,
104.1, 113.1, 115.9, 122.2, 123.6, 126.4, 128.2, 136.1, 203.1.
HRMS (ESI): m/z [M+H]+ calcd for C11H9NBr: 233.9913;
found: 233.9919. IR (KBr): 3143 – 3035, 2872 – 2836, 1958,
1875, 1602, 1514, 1463, 1320, 1229, 892, 802, 713 cm-1.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
4-Cyano-1-propadienyl-1H-indole (1h). Yield 0.208, 92%,
white crystals. MP 71 – 72°C. Rf = 0.15 (EtOAc – Hexane 1-
10). 1H NMR (600 MHz, CDCl3) 1H NMR (600 MHz, CDCl3)
δ 5.67 (d, J = 6.5 Hz, 2H), 6.80 (d, J = 3.3 Hz, 1H), 7.18 (t, J =
6.5 Hz, 1H), 7.26 (d, J = 7.8 Hz, 1H), 7.36 (d, J = 3.3 Hz, 1H),
7.49 (d, J = 7.4 Hz, 1H), 7.78 ppm (d, J = 8.4 Hz, 1H). 13C{1H}
NMR (150 MHz, CDCl3) δ 88.3, 96.9, 102.5, 103.4, 114.7,
118.3, 121.8, 125.4, 128.3, 130.5, 134.9, 202.9. HRMS (ESI):
m/z [M+H]+ calcd for C12H9N2: 181.0760; found: 181.0760. IR
(KBr): 3129 – 3088, 3047 – 2981, 2220, 1598, 1518, 1463,
1426, 1330, 1221, 1168, 1053, 899, 747 cm-1.
General procedure for the synthesis of 1-propadienyl-1H-
indoles or pyrroles 1c-i
To a solution of the indole (1.282 mmol, 1 eq) in 2.5 mL of
DMSO, KOH 0.360 g (5 eq) was added and the mixture was
stirred for 45 min. at r.t. Then propargyl bromide (80% solution
in toluene) 0.158 mL (1.1 eq) was added slowly (28-30oC,
exothermic reaction) and resulting brown reaction mixture was
stirred at r.t. for 45 – 60 min (TLC, EtOAc-Hexane 1-10). Upon
completion, reaction mixture was diluted with water and
extracted with Et2O or EtOAc, organic layer was then washed
with water until the neutral reaction of the water layer. Organic
phase was next dried with Na2SO4 and evaporated under
reduced pressure. The residue was then used in the reactions
without further purification. To obtain analytically pure
samples the allenes were rapidly chromatographed through a
thin layer of silica gel, preliminary neutralized with Et3N, eluent
EtOAc-Hexane in proportions 1-20 or 1-10.
3-Methyl-1-propadienyl-1H-indole (1i). Yield 0.206, 95%,
1
yellow oil. Rf = 0.17 (EtOAc – Hexane 1-10). H NMR (600
MHz, DMSO-d6) δ 2.23 (s, 3H), 5.69 (d, J = 6.1 Hz, 2H), 7.06
– 7.08 (m, 1H), 7.10 (c, 1H), 7.15 – 7.18 (m, 1H), 7.49 (d, J =
7.6 Hz, 1H), 7.64 – 7.66 (m, 1H), 7.67 ppm (d, J = 8.1 Hz, 1H).
13C{1H} NMR (150 MHz, DMSO-d6) δ 9.3, 97.4, 110.3, 112.6,
118.9, 119.7, 122.2, 123.3, 129.3, 135.3, 202.4. HRMS (ESI):
m/z [M+H]+ calcd for C12H12N: 170.0964; found: 170.0964. IR
(KBr): 3108 – 3014, 2974 – 2819, 1714 – 1651, 1613, 1462,
1390, 1338, 1227, 1189, 1126 – 1016, 954, 740 cm-1.
1-Propadienyl-1H-indole (1c). Yield 0.185 g, 93%, yellow oil.
1H NMR (40 MHz, CDCl3) δ 5.63 (d, J = 6.4 Hz, 2H), 6.64 (d,
J = 3.2 Hz, 1H), 7.09 – 7.78 (m, 6H). Spectroscopic data are in
accordance with those reported in the lit.28
Synthesis of the various starting arylallenes 3a-h
Propadienylbenzene (3a). Was synthesized from 3-phenyl-1-
propyne according to the literature procedure.29 1H NMR (40
MHz, CDCl3) δ 5.26 (d, J = 6.7 Hz, 2H), 6.18 – 6.49 (m, 1H),
7.31 – 7.58 (m, 5H). Spectroscopic data are in accordance with
those reported in the lit.29
1-propadienyl-1H-pyrrole (1d). Synthesized according to the
literature procedure.28 1.034 mL (14.925 mmol) of pyrrole was
1
used. Yield 0.705 g, 45%, yellow oil. H NMR (40 MHz,
CDCl3) δ 5.57 (d, J = 6.4 Hz, 2H), 6.18 – 6.45 (m, 2H), 6.80 –
7.45 (m, 3H).
2-Propadienylnaphthalene (3b). Was synthesized according to
the literature procedure.30 1H NMR (40 MHz, CDCl3) δ 5.22 (d,
J = 6.7 Hz, 2H), 6.19 – 6.50 (m, 1H), 7.21 – 7.97 (m, 7H).
Spectroscopic data are in accordance with those reported in the
lit.30
5-Methoxy-1-propadienyl-1H-indole (1e). Yield 0.195 g, 82%,
yellow crystallizing liquid. Rf = 0.41 (EtOAc – Hexane 1-10).
1H NMR (600 MHz, CDCl3) δ 3.86 (s, 3H), 5.63 (d, J = 6.6 Hz,
2H), 6.53 (d, J = 3.2 Hz, 1H), 6.90 (dd, J = 2.5, 8.9 Hz, 1H),
7.09 (d, J = 2.5 Hz, 1H), 7.15 – 7.17 (m, 2H), 7.49 ppm (d, J =
8.9 Hz, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ 55.8, 87.7,
97.7, 103.0, 103.6, 110.8, 112.2, 126.3, 129.9, 130.6, 154.6,
203.3. HRMS (ESI): m/z [M+H]+ calcd for C12H12NO:
186.0913; found: 186.0913. IR (KBr): 3154 – 2854, 1723 –
1666, 1620 – 1580, 1478, 1448, 1247 – 1231, 1152 – 1131,
1029, 799, 716 cm-1.
1-Methyl-4-propadienylbenzene (3c). Was synthesized
according to the literature procedure.30 1H NMR (40 MHz,
CDCl3) δ 2.41 (s, 3H), 5.18 (d, J = 6.7 Hz, 2H), 6.07 – 6.39 (m,
1H), 7.23 – 7.32 (m, 4H). Spectroscopic data are in accordance
with those reported in the lit.30
1-Methoxy-4-propadienylbenzene (3d). Was synthesized from
4-methoxystyrene through the literature procedure.30 1H NMR
(40 MHz, CDCl3) δ 3.77 (c, 3H), 5.09 (d, J = 6.7 Hz, 2H), 5.97
– 6.28 (m, 1H), 6.80 (d, J = 8.6 Hz, 2H), 7.23 (d, J = 8.6 Hz,
2H). Spectroscopic data are in accordance with those reported
in the lit.30
5-Bromo-1-propadienyl-1H-indole (1f). Yield 0.261 g, 87%,
yellow crystallizing oil. Rf = 0.47 (EtOAc – Hexane 1-10). 1H
NMR (600 MHz, CDCl3) δ 5.60 (d, J = 6.4 Hz, 2H), 6.50 (d, J
= 3.3 Hz, 1H), 7.11 (t, J = 6.4 Hz, 1H), 7.16 (d, J = 3.3 Hz, 1H),
7.28 (dd, J = 2.0, 8.8 Hz, 1H), 7.40 (d, J = 8.8 Hz, 1H), 7.70
ppm (d, J = 2.0 Hz, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ
87.9, 97.1, 103.3, 111.4, 113.4, 123.4, 124.9, 126.8, 130.8,
133.9, 202.9. HRMS (ESI): m/z [M+H]+ calcd for C11H9NBr:
233.9913; found: 233.9919. IR (KBr): 3154 – 2854, 1723 –
Buta-2,3-dien-1-ylbenzene (3e). The compound was
synthesized from benzylbromide and propargyl bromide
according to the literature procedure.31 1H NMR (100 MHz,
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CDCl3) δ 3.27 – 3.57 (m, 2H), 4.61 – 4.91 (m, 2H), 5.05 – 5,69 C24H22NO2S: 388.1366; found: 388.1360. IR (KBr): 3131 –
1
2
(m, 1H), 7.31 (m, 5H). Spectroscopic data are in accordance
with those reported in the lit.31
3031, 2948 – 2856, 1650, 1596, 1457, 1158, 1122, 1078, 741
cm-1.
3
4
5
6
(Propadienyloxy)benzene (3f). Was synthesized from (prop-2-
3-Methyl-1-[(1E)-2-(phenylsulfonyl)prop-1-en-1-yl]-1H-
indole (2b): A: 0.096 g (0.5681 mmol, 1 eq) of 1i, B: 0.020 g
(0.0284 mmol, 0.05 eq) of EY, C: 0.303 g (1.7043 mmol, 3 eq)
of sodium p-toluene sulfinate, D: 0.157 g (1.1362 mmol, 2 eq
K2CO3, 4.745 mL DMF, 1.424 mL TFE.
yn-1-yloxy)benzene according to the literature procedure.32 1
H
NMR (40 MHz, CDCl3) δ 5.47 (d, J = 6.0 Hz, 2H), 6.61 – 6.93
(m, 1H), 7.03 – 7.27 (m, 5H). Spectroscopic data are in
accordance with those reported in the lit.32
7
8
9
1
1-(Buta-2,3-dien-1-yloxy)-4-(propan-2-yl)benzene (3g). To a
mixture of the alkyne 0.500 g (1 eq, 2.873 mmol),
paraformaldehyde 0.172 g (2 eq, 5.873 mmol) and CuBr 0.205
g (0.5 eq, 1.4365 mmol) in 14 mL of 1,4-dioxane NHiPr2 0.728
mL (1.8 eq, 5.1714 mmol) was added in one portion. The
resulted bright green-yellow mixture was then refluxed for two
hours and after cooling to r.t. was diluted with water and
extracted with Et2O. Organic phase was dried with sodium
sulfate and evaporated under reduced pressure. Flash-
chromatography on silica gel (EtOAc-Hexane 1-10) gave 0.303
g (56%) of pure allene as yellowish oil. Rf = 0.5 (Hexane). 1H
NMR (600 MHz, CDCl3) δ 1.25 (d, J = 6.9 Hz, 6H), 2.80 (spt,
J = 6.9 Hz, 1H), 4.57 (m, 2H), 4.88 (dt, J = 2.5, 6.6 Hz, 2H),
5.42 (m, 1H), 6.88 (d, J = 8.5 Hz, 2H), 7.16 ppm (d, J = 8.5 Hz,
2H). 13C{1H} NMR (150 MHz, CDCl3) δ 24.2 (2C), 33.2, 65.9,
76.4, 87.2, 114.6 (2C), 127.2 (2C), 141.3, 156.4, 209.4. HRMS
(ESI): m/z [M+H]+ calcd for C13H17O: 189.1274; found:
189.1274. IR (KBr): 2960, 2932 – 2869, 1958, 1610, 1511,
1237, 1178, 1018, 847 – 828 cm-1.
Yield 0.078 g (42%), white crystals. MP = 122°C. H NMR
(600 MHz, CDCl3) δ 2.19 (s, 3H), 2.33 (s, 3H), 2.44 (s, 3H),
7.24 (s,1H), 7.26 – 7.30 (m, 1H), 7.33 – 7.39 (m, 3H), 7.56 –
7.60 (m, 2H), 7.82 (d, J = 7.9 Hz, 2H), 8.38 ppm (s, 1H).
13C{1H} NMR (150 MHz, CDCl3) δ 9.7, 12.7, 21.5, 110.0,
117.5, 118.7, 119.3, 122.0, 122.1, 123.8, 127.9 (2C), 129.4,
129.8 (2C), 131.1, 136.9, 137.3, 143.9. HRMS (ESI): m/z
[M+H]+ calcd for C19H20NO2S: 326.1209; found: 326.1209. IR
(KBr): 3162 – 3144, 3054, 2978 – 2926, 2883, 1642, 1596,
1460, 1400, 1351, 1306 – 1289, 1240, 1149, 1120, 1074, 737,
681, 586 cm-1.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
5-Bromo-1-[(1E)-2-(phenylsulfonyl)prop-1-en-1-yl]-1H-indole
(2c): A: 0.137 g (0.5855 mmol, 1 eq) of 1f, B: 0.020 g (0.029
mmol, 0.05 eq) of EY, C: 0.242 g (1.756 mmol, 3 eq) of sodium
p-toluene sulfinate, D: 0.162 g (1.1708 mmol, 2 eq) K2CO3,
4.890 mL DMF, 1.487 mL TFE.
1
Yield 0.094 g (43%), white crystals. MP = 180°C. H NMR
(600 MHz, CDCl3) δ 2.18 (s, 3H), 2.45 (s, 3H), 6.67 (d, J = 3.4
Hz, 1H), 7.36 (d, J = 8.1 Hz, 2H), 7.41 (d, J = 3.4 Hz, 1H), 7.45
(m, 2H), 7.76 (s, 1H), 7.82 (d, J = 8.1 Hz, 2H), 8.31 ppm (s,
1H). 13C{1H} NMR (150 MHz, CDCl3) δ 12.8, 21.6, 107.1,
111.6, 115.7, 122.6, 123.9, 126.2, 126.6, 128.0 (2C), 129.9
(2C), 130.2, 130.8, 135.6, 136.3, 144.4. HRMS (ESI): m/z
[M+H]+ calcd for C18H17NO2SBr: 390.0158; found: 390.0163.
IR (KBr): 3118 – 3029, 2985 – 2857, 1651, 1593, 1520, 1451,
1389, 1302, 1282, 1235, 1150, 1114, 1075, 962, 816, 802, 762,
747, 675, 560 cm-1.
1-propadienyl-4-(trifluoromethyl)benzene
(3h).
Was
synthesized from 4-trifluoromethylstyrene according to the
literature procedure.33 1H NMR (40 MHz, CDCl3) δ 5.32 (d, J =
6.7 Hz, 2H), 6.17 – 6.48 (m, 1H), 7.36 – 7.82 (m, 4H).
Spectroscopic data are in accordance with those reported in the
lit.33
General procedure for the hydrosulfonylation of N-
indolylallenes.
A mixture of an appropriate allene (A g), 5 mol % of EY (B g),
3 eq of a sulfinate (C g) and 2 eq of K2CO3 (D g) in DMF-TFE
mixture (1:0.3) as the solvent under nitrogen atmosphere was
subjected to green light irradiation (green LED) and stirred for
the appropriate time (TLC). Upon the completion, the solvent
was evaporated under reduced pressure and the residue was
chromatographed on silica with EtOAc-Hexane mixtures. After
chromatography the product was crystalized in small amount of
hexane with a few drops of EtOAc and then washed with the
same mixture.
6-Bromo-1-[(1E)-2-(phenylsulfonyl)prop-1-en-1-yl]-1H-indole
(2d): A: 0.137 g (0.5855 mmol, 1 eq) of 1g, B: 0.020 g (0.029
mmol, 0.05 eq) of EY, C: 0.288 g (1.757 mmol, 3 eq) of sodium
benzene sulfinate, D: 0.162 g (1.1708 mmol, 2 eq) K2CO3,
4.890 mL DMF, 1.487 mL TFE.
1
Yield 0.070 g (32%), white crystals. MP = 187°C. H NMR
(600 MHz, CDCl3) δ 2.19 (s, 3H), 6.70 (d, J = 3.3 Hz, 1H), 7.37
(d, J = 8.4 Hz, 1H), 7.40 (d, J = 3.3 Hz, 1H), 7.49 (d, J = 8.4
Hz, 1H), 7.57 – 7.60 (m, 2H), 7.65 (t, J = 7.4 Hz, 1H), 7.75 (s,
1H), 7.96 (d, J = 7.8 Hz, 2H), 8.31 ppm (s, 1H). 13C{1H} NMR
(150 MHz, CDCl3) δ 12.8, 107.8, 113.4, 117.4, 122.2, 122.5,
125.6, 125.8, 127.4, 128.0 (2C), 129.3 (2C), 131.0, 133.4,
137.7, 139.3. HRMS (ESI): m/z [M+H]+ calcd for
C17H15NO2SBr: 376.0001; found: 376.0001. IR (KBr): 3175 –
2980, 1655, 1601, 1521, 1460, 1326, 1293, 1243, 1148, 886,
817, 757, 714, 961, 597, 569 cm-1.
2-Phenyl-1-[(1E)-2-(phenylsulfonyl)prop-1-en-1-yl]-1H-
indole (2a): A: 0.070 g (0.3043 mmol, 1 eq) of 1a, B: 0.0105 g
(0.0152 mmol, 0.05 eq) of EY, C: 0.162 g (0.9129 mmol, 3 eq)
of sodium p-toluene sulfinate, D: 0.084 g (0.6086 mmol, 2 eq)
K2CO3, 2.542 mL DMF, 0.763 mL TFE.
1
Yield 0.074 g (63%), white crystals. MP = 152°C. H NMR
(600 MHz, CDCl3) δ 1.69 (s, 3H), 2.51 (s, 3H), 6.77 (s,1H), 7.18
(d, J = 8.2 Hz, 1H), 7.22 – 7.24 (m, 1H), 7.27 – 7.30 (m, 1H),
7.31 – 7.35 (m, 3H), 7.37 – 7.38 (m, 2H), 7.40 (d, J = 8.1 Hz,
2H), 7.65 (d, J = 7.8 Hz, 1H), 7.80 (d, J = 8.1 Hz, 2H), 8.03
ppm (s, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ 13.2, 21.7,
105.6, 111.0, 121.0, 121.7, 123.1, 128.19, 128.22 (2C), 128.4
(2C), 128.7 (2C), 129.0, 130.0 (2), 132.0, 133.9, 134.6, 136.0,
137.1, 140.6, 144.7. HRMS (ESI): m/z [M+H]+ calcd for
5-Methoxy-1-[(1E)-2-(phenylsulfonyl)prop-1-en-1-yl]-1H-
indole (2e): A: 0.092 g (0.4973 mmol, 1 eq) of 1e, B: 0.017 g
(0.025 mmol, 0.05 eq) of EY, C: 0.266 g (1.492 mmol, 3 eq) of
sodium p-toluene sulfinate, D: 0.137 g (0.9946 mmol, 2 eq)
K2CO3, 4.153 mL DMF, 1.246 mL TFE.
1
Yield 0.077 g (45%), white crystals. MP = 129°C. H NMR
(600 MHz, CDCl3) δ 2.18 (s, 3H), 2.45 (s, 3H), 3.88 (s, 3H),
6.66 (d, J = 3.4 Hz, 1H), 7.00 (dd, J = 2.4, 8.9 Hz, 2H), 7.09 (d,
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J = 2.4 Hz, 1H), 7.35 (d, J = 8.1 Hz, 2H), 7.41 (d, J = 3.4, 1H), 0.05 eq) of EY, C: 0.286 g (1.7421 mmol, 3 eq) of sodium
1
2
3
4
5
6
7
8
7.49 (d, J = 8.9 Hz, 1H), 7.82 (d, J = 8.1 Hz, 2H), 8.34 ppm (s,
1H). 13C{1H} NMR (150 MHz, CDCl3) δ 12.7, 21.6, 55.8,
103.4, 107.7, 110.9, 113.2, 120.2, 125.5, 128.0 (2C), 129.3,
129.9 (2C), 131.3, 131.9, 136.7, 141.1, 156.0. HRMS (ESI):
m/z [M+H]+ calcd for C19H20NO3S: 342.1158; found: 342.1158.
IR (KBr): 3118 – 3029, 2996 – 2845, 1644, 1617, 1596, 1476,
1453, 1407, 1296, 1262, 1148, 1076, 962, 800, 751, 718, 649,
582 cm-1.
benzene sulfinate, D: 0.160 g (1.1614 mmol, 2 eq K2CO3, 4.850
mL DMF, 1.455 mL TFE.
1
Yield 0.051 g (30%), white crystals. MP = 133 °C. H NMR
(600 MHz, CDCl3) δ 2.21 (s, 3H), 6.75 (d, J = 3.3 Hz, 1H), 7.27
– 7.29 (m, 1H), 7.38 (t, J = 7.7 Hz, 1H), 7.44 (d, J = 3.3 Hz,
1H), 7.56 – 7.58 (m, 2H), 7.60 – 7.65 (m, 3H), 7.96 (d, J = 7.8
Hz, 2H), 8.44 ppm (s, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ
12.7, 108.0, 110.1, 120.6, 121.3, 122.5, 123.8, 124.9, 127.9
(2C), 128.6, 129.12 (2C), 131.6, 133.2, 137.0, 139.6. HRMS
(ESI): m/z [M+H]+ calcd for C17H16NO2S: 298.0896; found:
298.0896. IR (KBr): 3167, 3116 – 3050, 3017, 2976, 2917 –
2861, 1650, 1582, 1530, 1463 - 1446, 1409, 1332, 1302, 1242,
1149 – 1116, 1077, 964, 743, 687, 619, 567 cm-1.
1-{(1E)-2-[(4-Methylphenyl)sulfonyl]prop-1-en-1-yl}-1H-
indole-4-carbonitrile (2f): A: 0.090 g (0.500 mmol, 1 eq) of 1h,
B: 0.017 g (0.025 mmol, 0.05 eq) of EY, C: 0.267 g (1.500
mmol, 3 eq) of sodium p-toluene sulfinate, D: 0.138 g (1.00
mmol, 2 eq) K2CO3, 4.176 mL DMF, 1.253 mL TFE.
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Yield 0.069 g (41%), white crystals. MP = 181 – 182°C. H
1-[(1E)-2-(Methylsulfonyl)prop-1-en-1-yl]-1H-indole (2j): A:
0.090 g (0.5807 mmol, 1 eq) of 1a, B: 0.020 g (0.0290 mmol,
0.05 eq) of EY, C: 0.177 g (1.7421 mmol, 3 eq) of sodium
methanesulfinate, D: 0.160 g (1.1614 mmol, 2 eq K2CO3, 4.850
mL DMF, 1.455 mL TFE.
NMR (600 MHz, CDCl3) δ 2.19 (s, 3H), 2.46 (s, 3H), 6.94 (d, J
= 3.4 Hz, 1H), 7.37 (d, J = 8.1 Hz, 2H), 7.40 – 7.43 (m, 1H),
7.57 (d, J = 3.4 Hz, 1H), 7.60 (d, J = 7.5 Hz, 1H), 7.80 (d, J =
8.4, 1H), 7.83 (d, J = 8.1 Hz, 2H), 8.34 ppm (s, 1H). 13C{1H}
NMR (150 MHz, CDCl3) δ 12.8, 21.6, 104.1, 105.8, 114.8,
117.7, 123.4, 125.0, 127.2, 127.8, 128.1 (2C), 130.0 (2C),
130.1, 130.2, 135.9, 136.5, 144.7. HRMS (ESI): m/z [M+H]+
calcd for C19H17N2O2S: 337.1005; found: 337.1002. IR (KBr):
3173, 3123 – 3034, 2988 – 2924, 2871, 2228, 1649, 1595, 1521,
1440, 1408, 1294, 1153, 1076, 749, 660, 598 cm-1.
Yield 0.053 g (39%), yellowish oil. Rf = 0.33 (EtOAc – Hexane
1-2). 1H NMR (600 MHz, CDCl3) δ 2.42 (s, 3H), 3.02 (s, 3H),
6.78 (d, J = 3.4 Hz, 2H), 7.26 – 7.28 (m, 1H), 7.33 – 7.35 (m,
1H), 7.50 (d, J = 3.4 Hz, 1H), 7.53 (d, J = 8.2 Hz, 1H), 7.64 (d,
J =7.7 Hz, 1H), 8.23 ppm (s, 1H). 13C{1H} NMR (150 MHz,
CDCl3) δ 12.9, 41.3, 108.2, 100.0, 121.3, 121.4, 122.5, 123.8,
124.8, 128.5, 132.0, 136.9. HRMS (ESI): m/z [M+H]+ calcd for
C12H14NO2S: 236.0740; found: 236.0740. IR (KBr): 3179 –
2989, 2927, 1654, 1460, 1327, 1295, 1241, 1145, 1102, 966,
774, 743, 561 cm-1.
6-Bromo-1-[(1E)-2-(thiophen-2-ylsulfonyl)prop-1-en-1-yl]-
1H-indole (2g): A: 0.137 g (0.5855 mmol, 1 eq) of 1g, B: 0.020
g (0.029 mmol, 0.05 eq) of EY, C: 0.299 g (1.757 mmol, 3 eq)
of sodium thiophene-2-sulphinate, D: 0.162 g (1.1708 mmol, 2
eq) K2CO3, 4.890 mL DMF, 1.487 mL TFE.
5-Methoxy-1-[(1E)-2-(thiophen-2-ylsulfonyl)prop-1-en-1-yl]-
1H-indole (2k): A: 0.100 g (0.5405 mmol, 1 eq) of 1e, B: 0.019
g (0.027 mmol, 0.05 eq) of EY, C: 0.275 g (1.620 mmol, 3 eq)
of sodium thiophene-2-sulphinate, D: 0.149 g (0.1081 mmol, 2
eq) K2CO3, 4.513 mL DMF, 1.354 mL TFE.
1
Yield 0.065 g (29%), white crystals. MP = 191 – 192°C. H
NMR (600 MHz, CDCl3) δ 2.30 (s, 3H), 6.71 (d, J = 3.4 Hz,
1H), 7.16 – 7.17 (m, 1H), 7.35 (dd, J = 1.3, 8.5 Hz, 1H), 7.42
(d, J = 3.4 Hz, 1H), 7.48 (d, J = 8.5 Hz, 1H), 7.71 – 7.75 (m,
3H), 8.29 ppm (s, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ
12.8, 107.9, 113.4, 117.4, 122.5, 122.7, 125.5, 125.8, 127.5,
127.9, 130.8, 133.9, 134.0, 137.7, 140.8. HRMS (ESI): m/z
[M+H]+ calcd for C15H13NO2S2Br: 381.9566; found: 381.9566.
IR (KBr): 3165, 3113 – 3089, 2978 – 2857, 1650, 1601, 1521,
1461, 1437, 1401, 1326, 1296, 1242, 1148, 1109, 1013, 887,
816, 756, 718, 675, 600, 572 cm-1.
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Yield 0.045 g (25%), white crystals. MP = 158 – 160°C. H
NMR (600 MHz, CDCl3) δ 2.30 (s, 3H), 3.87 (s, 3H), 6.68 (d, J
= 3.4 Hz, 1H), 6.99 (dd, J = 2.4, 8.9 Hz, 2H), 7.09 (d, J = 2.4
Hz, 1H), 7.14 – 7.15 (m, 1H), 7.44 (d, J = 3.4 Hz, 1H), 7.47 (d,
J = 8.9, 1H), 7.69 (d, J = 4.9 Hz, 1H), 7.72 (d, J = 3.8 Hz, 1H),
8.35 ppm (s, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ 12.8,
29.7, 103.5, 108.1, 110.8, 113.2, 120.3, 125.4, 127.7, 129.3,
131.5, 131.9, 133.5, 133.6, 141.3, 156.1. HRMS (ESI): m/z
[M+H]+ calcd for C16H16NO3S2: 334.0566; found: 334.0572. IR
(KBr): 3118 – 3051, 3007 – 2830, 1651, 1614, 1476, 1404,
1269, 1264, 1143 – 1132, 751 – 717, 596, 574 cm-1.
1-{(1E)-2-[(4-Methylphenyl)sulfonyl]prop-1-en-1-yl}-1H-
indole (2h): A: 0.072 g (0.5548 mmol, 1 eq) of 1c, B: 0.019 g
(0.0277 mmol, 0.05 eq) of EY, C: 0.296 g (1.6644 mmol, 3 eq)
of sodium p-toluene sulfinate, D: 0.153 g (1.110 mmol, 2 eq
K2CO3, 4.634 mL DMF, 1.390 mL TFE.
2-(4-Methylphenyl)-1-[(1E)-2-(phenylsulfonyl)prop-1-en-1-
yl]-1H-indole (major) and 2-(4-methylphenyl)-1-{2-[(4-
1
Yield 0.072 g (42%), white crystals. MP = 174 °C. H NMR
(600 MHz, CDCl3) δ 2.20 (s, 3H), 2.45 (s, 3H), 6.74 (d, J = 3.3
Hz, 1H), 7.26 – 7.29 (m, 1H), 7.34 – 7.39 (m, 3H), 7.43 (d, J =
3.3 Hz, 1H), 7.60 (d, J = 8.2 Hz, 2H), 7.64 (d, J = 7.8 Hz, 1H),
7.83 (d, J = 8.2 Hz, 2H), 8.41 ppm (s, 1H). 13C{1H} NMR (150
MHz, CDCl3) δ 12.8, 21.6, 107.8, 110.1, 121.1, 121.3, 122.5,
123.8, 125.0, 128.0 (2C), 128.6, 129.9 (2C), 131.2, 136.6,
137.0, 144.2. HRMS (ESI): m/z [M+H]+ calcd for C18H18NO2S:
312.1053; found: 312.1053. IR (KBr): 3165, 3114 – 3089, 2978
– 2857, 1650, 1601, 1521, 1461 - 1401, 1242, 1148, 1351, 1013,
887, 816, 756, 718, 675, 600, 572 cm-1.
methylphenyl)sulfonyl]prop-2-en-1-yl}-1H-indole
(minor)
(2l+2l’): A: 0.087 g (0.3551 mmol, 1 eq) of 1b, B: 0.012 g
(0.0178 mmol, 0.05 eq) of EY, C: 0.190 g (1.0653 mmol, 3 eq)
of sodium p-toluene sulfinate, D: 0.098 g (0.7102 mmol, 2 eq)
K2CO3, 2.966 mL DMF, 0.890 mL TFE.
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Yield 0.075 g (53%), white crystals. MP = 168°C. H NMR
(600 MHz, CDCl3) δ 1.69 (s, 3H), 2.39 – 2.41 (m, 4.2H), 2.52
(s, 4.2H), 4.91 (s, 0.82H), 5.21 (s, 0.4H), 6.39 (s, 0.4H), 6.57 (s,
0.4H), 6.74 (s, 1H), 6.88 (d, J = 6.4 Hz, 0.4H), 7.07 (d, J = 7.8
Hz, 0.8H), 7.12 – 7.17 (m, 4H), 7.19 (d, J = 8.2 Hz, 1H), 7.22 –
7.24 (m, 1H), 7.26 – 7.30 (m, 3.8H), 7.37 (d, J = 8.1 Hz, 0.8H),
7.41 (d, J = 8.2 Hz, 2H), 7.62 (dd, J = 2.4, 5.6 Hz, 0.4H), 7.65
1-[(1E)-2-(Phenylsulfonyl)prop-1-en-1-yl]-1H-indole (2i): A:
0.090 g (0.5807 mmol, 1 eq) of 1c, B: 0.020 g (0.0290 mmol,
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(d, J = 7.6 Hz, 1H), 7.77 (d, J = 8.1 Hz, 0.4H), 7.82 (d, J = 8.2 mmol, 0.05 eq) of EY, C: 0.440 g (1.810 mmol, 3 eq) of sodium
Hz, 2H), 8.04 ppm (s, 1H). 13C{1H} NMR (150 MHz, CDCl3) δ
13.2, 21.2, 21.61, 21.64, 43.1, 102.6, 105.0, 109.5, 110.9, 120.5,
120.6, 120.8, 121.5, 122.1, 122.9, 124.1, 128.15, 128.18 (2C),
128.2 (2C), 128.3 (2C), 128.7, 129.0 (2C), 129.2 (2C), 129.3
(2C), 129.5, 129.9 (2C), 130.0 (2C), 133.8, 133.4, 134.4, 135.4,
136.0, 137.0, 137.2, 138.0, 140.7, 141.1, 144.5, 144.9, 147.0.
HRMS (ESI): m/z [M+H]+ calcd for C25H23NO2S: 402.1522;
found: 402.1522. IR (KBr): 3080 – 3030, 2992 – 2865, 1651,
1594, 1503, 1454, 1364, 1314, 1161, 1078, 964, 882, 797, 741,
655 cm-1.
4-bromobenzene sulfinate, 5.039 mL DMF, 1.311 mL TFE.
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Yield 0.150 g (74%), white crystals. MP = 122°C. H NMR
(600 MHz, CDCl3) δ 2.13 (s, 3H), 7.38 – 7.44 (m, 5H), 7.70 (d,
J = 8.5 Hz, 2H), 7.80 (d, J = 8.5 Hz, 2H), 7.83 ppm (s, 1H).
13C{1H} NMR (150 MHz, CDCl3) δ 13.2, 128.6, 128.7 (2C),
129.5, 129.6 (2C), 129.7 (2C), 132.5 (2C), 133.5, 136.8, 138.0,
138.2. HRMS (ESI): m/z [M+H]+ calcd for C15H14O2SBr:
336.9892; found: 336.9895. IR (KBr): 3089, 3071, 3030, 2965
– 2922, 1920, 1570, 1466, 1447, 1386, 1309, 1275, 1151, 1103,
1065, 823, 749, 691, 629, 577 cm-1.
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1-[(1E)-2-(Phenylsulfonyl)prop-1-en-1-yl]-1H-pyrrole (2m):
A: 0.500 g (4.760 mmol, 1 eq) of 1d, B: 0.165 g (0.238 mmol,
0.05 eq) of EY, C: 2.342 g (14.280 mmol, 3 eq) of sodium
benzene sulfinate, D: 1.314 g (9.520 mmol, 2 eq) K2CO3, 20 mL
DMF, 6 mL TFE.
(1E)-1-Phenylprop-1-en-2-yl thiophen-2-yl sulfone (4e): A:
0.062 g (0.539 mmol, 1 eq) of 3a, B: 0.019 g (0.02695 mmol,
0.05 eq) of EY, C: 0.275 g (1.6164 mmol, 3 eq) of sodium
tiophene-2-sulfinate, 4.5 mL DMF, 1.35 mL TFE.
Yield 0.069 g (48%), white crystals. MP = 98°C. 1H NMR (600
MHz, CDCl3) δ 2.44 (s, 3H), 7.15 – 7.16 (m, 1H), 7.37 – 7.44
(m, 5H), 7.71 – 7.73 (m, 2H), 7.82 ppm (s, 1H). 13C{1H} NMR
(150 MHz, CDCl3) δ 13.2, 127.8, 128.7 (2C), 129.4, 129.7 (2C),
133.7, 133.9, 134.1, 137.3, 137.8, 140.5. HRMS (ESI): m/z
[M+H]+ calcd for C13H13O2S2: 265.0351; found: 265.0351. IR
(KBr): 3109 – 3036, 2963 – 2923, 1630, 1504, 1401, 1345,
1307, 1228, 1148, 1106, 1090, 1014, 770, 731, 700, 623, 570
cm-1.
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Yield 0.410 g (35%), white crystals. MP = 119°C. H NMR
(600 MHz, CDCl3) δ 2.14 (s, 3H), 6.34 – 6.35 (m, 2H), 7.00 –
7.01 (m, 2H), 7.54 – 7.56 (m, 2H), 7.62 (d, J = 7.5 Hz, 2H), 7.91
(d, J = 7.8 Hz, 2H), 8.03 ppm (s, 1H). 13C{1H} NMR (150 MHz,
CDCl3) δ 12.5, 112.2 (2C), 120.9, 121.9 (2C), 127.8 (2C), 129.2
(2C), 133.2, 135.0, 139.4 ppm. HRMS (ESI): m/z [M+H]+ calcd
for C13H14NO2S: 248.0739 found: 248.0737. IR (KBr): 3173,
3136, 3118, 3086, 3018, 980, 2936, 2872, 1657, 1569, 1542,
1489, 1449, 1335, 1298 – 1282, 1147, 1117, 1074, 1049, 943,
751, 692, 579 cm-1.
[(1E)-2-(Methylsulfonyl)prop-1-en-1-yl]benzene (4f): A: 0.07
g (0.6034 mmol, 1 eq) of 3a, B: 0.021 g (0.03017 mmol, 0.05
eq) of EY, C: 0.185 g (1.81 mmol, 3 eq) of sodium methane
sulfinate, 5.039 mL DMF, 1.511 mL TFE.
General procedure for the hydrosulfonylation of arylallenes
A mixture of an appropriate allene A g, 5 mol % of EY – B g, 3
eq of a sulfinate – C g in DMF-TFE mixture (1:0.3) as the
solvent under nitrogen atmosphere was subjected to green light
irradiation (green led) and stirred for the appropriate time
(TLC). Upon the completion the solvent was evaporated under
reduced pressure and the residue was chromatographed on silica
with EtOAc-Hexane mixtures in different proportions.
Yield 0.097 g (82%), yellowish oil. 1H NMR (600 MHz, CDCl3)
δ 2.33 (s, 3H), 2.97 (s, 3H), 7.38 – 7.45 (m, 5H), 7.64 ppm (s,
1H). 13C{1H} NMR (150 MHz, CDCl3) δ 13.4, 40.3, 128.7 (2C),
129.4, 129.5 (2C), 133.5, 136.7, 137.9. Spectroscopic data are
in accordance with those reported in the lit.36
1-Methyl-4-{[(1E)-1-(4-methylphenyl)prop-1-en-2-
yl]sulfonyl}benzene (4g): A: 0.100 g (0.769 mmol, 1 eq) of 3c,
B: 0.027 g (0.03845 mmol, 0.05 eq) of EY, C: 0.411 g (2.307
mmol, 3 eq) of sodium p-toluene sulfinate, 6.422 mL DMF,
1.927 mL TFE.
1-Methyl-4-{[(1E)-1-phenylprop-1-en-2-yl]sulfonyl}benzene
(4a): A: 0.088 g (0.759 mmol, 1 eq) of 3a, B: 0.026 g (0.0380
mmol, 0.05 eq) of EY, C: 0.405 g (2.276 mmol, 3 eq) of sodium
p-toluene sulfinate, 6.34 mL DMF, 1.9 mL TFE.
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Yield 0.141 g (68%), white crystals. H NMR (600 MHz,
1
Yield 0.143 g (65%), white crystals. MP = 116°C. H NMR
CDCl3) δ 2.12 (s, 3H), 2.45 (s, 3H), 7.34 – 7.43 (m, 7H), 7.81 –
7.82 ppm (m, 3H). 13C{1H} NMR (150 MHz, CDCl3) δ 13.1,
21.6, 128.2 (2C), 128.6 (2C), 129.2, 129.6 (2C), 129.8 (2C),
133.8, 136.0, 137.0, 137.5, 144.2. Spectroscopic data are in
accordance with those reported in the lit.34
(600 MHz, CDCl3) δ 2.11 (s, 3H), 2.38 (s, 3H), 2.44 (s, 3H),
7.22 (d, J = 7.8 Hz, 2H), 7.31 (d, J = 7.8 Hz, 2H), 7.34 (d, J =
8.0 Hz, 2H), 7.78 (s, 1H), 7.80 ppm (d, J = 8.0 Hz, 2H). 13C
{1H} NMR (150 MHz, CDCl3) δ 13.2, 21.3, 21.5, 128.1 (2C),
129.3 (2C), 129.6 (2C), 129.7 (2C), 131.0, 136.2, 136.3, 137.0,
139.5, 144.1. HRMS (ESI): m/z [M+H]+ calcd for C17H19O2S:
287.1100 found: 287.1103. IR (KBr): 3087, 3030, 2984, 2923,
2869, 1916, 1633, 1598, 1511, 1445, 1297, 1148, 1104, 1072,
908, 811, 741, 654, 584 cm-1.
{[(1E)-1-Phenylprop-1-en-2-yl]sulfonyl}benzene (4b): A: 0.09
g (0.776 mmol, 1 eq) of 3a, B: 0.027 g (0.0388 mmol, 0.05 eq)
of EY, C: 0.394 g (2.328 mmol, 3 eq) of sodium benzene
sulfinate, 6.48 mL DMF, 1.94 mL TFE.
1
Yield 0.156 g (78%), white crystals. H NMR (600 MHz,
(1E)-1-(Naphthalen-2-yl)prop-1-en-2-yl phenyl sulfone (4h):
A: 0.075 g (0.4518 mmol, 1 eq) of 3b, B: 0.016 g (0.02259
mmol, 0.05 eq) of EY, C: 0.222 g (1.3554 mmol, 3 eq) of
sodium benzene sulfinate, 3.77 mL DMF, 1.13 mL TFE.
CDCl3) δ 2.13 (s, 3H), 7.38 – 7.43 (m, 5H), 7.55 – 7.58 (m, 2H),
7.63 (t, J = 7.3 Hz, 1H), 7.84 (s, 1H), 7.94 ppm (d, J = 7.7 Hz,
2H). 13C{1H} NMR (150 MHz, CDCl3) δ 13.2, 128.1 (2C),
128.7 (2C), 129.2 (2C), 129.3, 129.6 (2C), 133.3, 133.7, 137.2,
137.5, 139.0. Spectroscopic data are in accordance with those
reported in the lit.35
1
Yield 0.111 g (76%), white crystals. MP = 126°C. H NMR
(600 MHz, CDCl3) δ 2.21 (s, 3H), 2.46 (s, 3H), 7.37 (d, J = 8.0
Hz, 2H), 7.50 (d, J = 8.7 Hz, 1H), 7.53 – 7.55 (m, 2H), 7.85 –
7.88 (m, 6H), 7.97 ppm (s, 1H). 13C{1H} NMR (150 MHz,
CDCl3) δ 13.3, 21.6, 126.4, 126.7, 127.2, 127.7, 128.27 (2C),
128.34 (2C), 129.7, 129.9 (2C), 131.3, 133.0, 133.3, 136.1,
1-Bromo-4-{[(1E)-1-phenylprop-1-en-2-yl]sulfonyl}benzene
(4c): A: 0.07 g (0.6034 mmol, 1 eq) of 3a, B: 0.021 g (0.03017
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The Journal of Organic Chemistry
137.1, 137.7 144.3. HRMS (ESI): m/z [M+H]+ calcd for
C20H19O2S: 323.1100 found: 323.1102. IR (KBr): 3082, 3053,
3027, 2971 – 2924, 1622, 1594, 1493, 1449, 1301, 1143, 1078,
817, 740, 655, 589 cm-1.
3143 – 3036, 2982 – 2802, 1732, 1628, 1574, 1325 – 1266,
1152, 1119, 1071, 1012, 929, 820, 758, 652, 587 cm-1.
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Scale up experiment procedure
{[(1E)-1-Phenylprop-1-en-2-yl]sulfonyl}benzene
(4b).
A
1-Methyl-4-{[(1E)-1-phenoxyprop-1-en-2-yl]sulfonyl}benzene
(4i): A: 0.076 g (0.5757 mmol, 1 eq) of 3f, B: 0.020 g (0.02879
mmol, 0.05 eq) of EY, C: 0.307 g (1.7271 mmol, 3 eq) of
sodium p-toluene sulfinate, 4.634 mL DMF, 1.390 mL TFE.
mixture of phenylallene 3a 0.232 g (2 mmol, 1 eq), 5 mol % of
EY – 0.070 g (0.1 mmol, 0.05 eq), 3 eq of sodium benzene
sulfinate – 0.984 g (6 mmol) in 16.660 mL DMF and 5.000 mL
TFE mixture (1:0.3) as the solvent under nitrogen atmosphere
was subjected to green light irradiation (green led) and stirred
for 5 h (TLC). Upon the completion the solvent was evaporated
under reduced pressure and the residue was chromatographed
on silica with EtOAc-Hexane mixture (1:5) Yield 0.418 g
(81%), white crystals.
Yield 0.028 g (17%), white crystallizing oil. MP = 88-89°C. 1H
NMR (600 MHz, CDCl3) δ 1.92 (s, 3H), 2.45 (s, 3H), 7.09 (d, J
= 8.0 Hz, 2H), 7.20 (t, J = 7.5 Hz, 1H), 7.35 (d, J = 7.9 Hz, 2H),
7.38 – 7.40 (m, 2H), 7.79 (d, J = 8.0 Hz, 2H), 7.82 ppm (s, 1H).
13C{1H} NMR (150 MHz, CDCl3) δ 9.4, 21.6, 115.3, 117.2,
120.2, 124.8, 127.8 (2C), 129.8 (2C), 130.0 (2C), 137.0, 144.0,
151.2, 156.5. HRMS (ESI): m/z [M+H]+ calcd for C16H17O3S:
289.0893 found: 289.0890. IR (KBr): 3092 – 3015, 2961 –
2862, 1658, 1593, 1490, 1305, 1225, 1141, 1077, 765, 665, 603
cm-1.
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ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on the ACS
Publications website.
1-Methoxy-4-{[(1E)-1-(phenyl)prop-1-en-2-
yl]sulfonyl}benzene (4l): A: 0.082 g (0.5616 mmol, 1 eq) of 3d,
B: 0.019 g (0.02808 mmol, 0.05 eq) of EY, C: 0.276 g (2.307
mmol, 3 eq) of sodium benzene sulfinate, 4.690 mL DMF,
1.407 mL TFE.
Control experiments, X-ray crystallography data and copies of 1H
and 13C spectra are provided as Supporting Information.
AUTHOR INFORMATION
Yield 0.121 g (74%), colourless oil. 1H NMR (600 MHz,
CDCl3) δ 2.17 (s, 3H), 3.82 (s, 3H), 6.93 (d, J = 8.6 Hz, 2H),
7.38 (t, J = 8.6 Hz, 2H), 7.52 – 7.54 (m, 2H), 7.60 (t, J = 7.3 Hz,
1H), 7.76 (s, 1H), 7.91 ppm (d, J = 7.7 Hz, 2H). 13C{1H} NMR
(150 MHz, CDCl3) δ 13.2, 55.2, 114.1 (2C), 126.1, 127.9 (2C),
129.0 (2C), 131.4 (2C), 133.0, 134.3, 137.1, 139.3, 160.4.
Spectroscopic data are in accordance with those reported in the
lit.37
Corresponding Author
*lvoskressensky@sci.pfu.edu.ru
*festa_aa@pfur.ru
Author Contributions
The manuscript was written through contributions of all authors.
ORCID
Alexey A. Festa: 0000-0002-5113-1938
Erik V. Van der Eycken: 0000-0001-5172-7208
Leonid G. Voskressensky: 0000-0002-9676-5846
1-[(1E)-2-(phenylsulfonyl)prop-1-en-1-yl]-4-
(trifluoromethyl)benzene (4m): A: 0.067 g (0.3641 mmol, 1 eq)
of 3h, B: 0.013 g (0.0182 mmol, 0.05 eq) of EY, C: 0.179 g
(1.0923 mmol, 3 eq) of sodium benzene sulfinate, 3.050 mL
DMF, 0.900 mL TFE.
ACKNOWLEDGMENT
The publication was prepared with the support of the “RUDN
University Program 5-100” and RFBR Grant 18-33-20040 (Festa
A.A). The X-ray research work was carried out with STOE
STADIVARI PILATUS100 K diffractometer purchased under the
program of MSU development.
Yield 0.082 g (69%), white crystals. MP = 102-103°C. 1H NMR
(600 MHz, CDCl3) δ 2.11 (s, 3H), 7.50 (d, J = 8.1 Hz, 2H), 7.57
– 7.60 (m, 2H), 7.65 – 7.68 (m, 3H), 7.85 (s, 1H), 7.95 ppm (d,
J = 8.1 Hz, 2H). 13C{1H} NMR (150 MHz, CDCl3) δ 13.1, 121.0
(q, JCF = 273.1 Hz), 125.6 (q, JCF = 4.3 Hz, 2C), 128.3 (2C),
129.3 (2C), 129.7 (2C), 130.6 (q, JCF = 33.2 Hz), 133.6, 135.7,
137.3, 138.5, 139.9. HRMS (ESI): m/z [M+H]+ calcd for
C16H14F3O2S: 327.0661 found:327.0661. IR (KBr): 3108 –
3062, 2982 – 2928, 1732, 1615, 1447, 1412, 1328, 1299, 1154
– 1115, 1069, 968, 909, 856, 828, 749, 646, 579 cm-1.
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Yield 0.084 g (59%), white crystals. MP = 121°C. H NMR
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