Thermal Transformations of 2,5-Difluoro-3,4,6-trichlorobenzenethiol with Tetrafluoroethylene

Article abstract of DOI:10.1134/S107036322011002X

Abstract: Pyrolysis of a mixture of 2,5-difluoro-3,4,6-trichlorobenzenethiol withtetrafluoroethylene leads to2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]thiophene (the major reaction product) along with2,2,3,3,4,6-hexafluoro-5,7-dichloro-2,3-dihydrobenzo[b]thiophene. Schemes of their formation with the participationof intermediate radicals are proposed. Oxidation of a mixture of the synthesizedcompounds gave 2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]sulfane-1,1-dioxide and2,2,3,3,4,6-hexafluoro-5,7-dichloro-2,3-dihydrobenzo[b]sulfane-1,1-dioxide.

Full text of DOI:10.1134/S107036322011002X

ISSN 1070-3632, Russian Journal of General Chemistry, 2020, Vol. 90, No. 11, pp. 2032–2037. © Pleiades Publishing, Ltd., 2020.
Russian Text © The Author(s), 2020, published in Zhurnal Obshchei Khimii, 2020, Vol. 90, No. 11, pp. 1647–1653.
Thermal Transformations
of 2,5-Difluoro-3,4,6-trichlorobenzenethiol with Tetrafluoroethylene
P. V. Nikul’shina, A. M. Maksimova, and V. E. Platonova,*
a Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences,
Novosibirsk, 630090 Russia
*e-mail: platonov@nioch.nsc.ru
Received July 17, 2020; revised July 17, 2020; accepted July 29, 2020
Abstract—Pyrolysis of a mixture of 2,5-difluoro-3,4,6-trichlorobenzenethiol with tetrafluoroethylene leads
to 2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]thiophene (the major reaction product) along with
2,2,3,3,4,6-hexafluoro-5,7-dichloro-2,3-dihydrobenzo[b]thiophene. Schemes of their formation with the par-
ticipation of intermediate radicals are proposed. Oxidation of a mixture of the synthesized compounds gave
2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]sulfane-1,1-dioxide and 2,2,3,3,4,6-hexafluoro-5,7-
dichloro-2,3-dihydrobenzo[b]sulfane-1,1-dioxide.
Keywords: 2,5-difluoro-3,4,6-trichlorobenzenethiol, tetrafluoroethylene, pyrolysis, 2,2,3,3,4,7-hexafluoro-5,6-di-
chloro-2,3-dihydrobenzo[b]thiophene, 2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]sulfane-1,1-dioxide
DOI: 10.1134/S107036322011002X
Among the reactions of simultaneous pyrolysis of
polyfluoroaromatic compounds and tetrafluoroethylene
in a continuous flow system, the transformations of
polyfluorochlorarenethiols bearing chlorine atoms
in the ortho- and para-positions relative to the thiol
group have been described [1]. The main direction of
pyrolysis of a mixture of polyfluoro-o-chloroarethiols
with tetrafluoroethylene is the unexpected formation of
polyfluoro-2,3-dihydrobenzo[b]thiophene derivatives
through the migration of a sulfur atom. Small amounts
of polyfluoroindanes and isomeric products were also
obtained in which the sulfur atom was in the initial position.
The reactions of 2,3,6-trifluoro-5-chloropyridine-4-thiol
with tetrafluoroethylene at 410–620°C in a continuous
flow system proceeded similarly with the formation of
nitrogen-containing analogs. The pyrolysis products are
apparently formed through the formation of intermediate
radicals, including radical σ-complexes, as well as radical
σ-spirocomplexes [1]. The formation of two isomeric
compounds complicates the isolation of the major isomer
with a migrated sulfur atom. Individual polyfluoro-2,3-
dihydrobenzo[b]thiophenes are difficult to obtain. The
preparation of perfluoro-2,3-dihydrobenzo[b]thiophene
and some of its transformations have been reported
earlier [2]. Pyrolysis of a mixture of 6-(methylsulfanyl)-
octafluoroindane-5-thiol with tetrafluoroethylene
at 420°C afforded individual dodecafluoro-3,5,6,7-
tetrahydro-2H-indene[5,6-b]thiophene [3].
Due to the possibility of rearrangement during the
formation of a polyfluorinated thienyl ring in the synthesis
of polyfluorodihydrobenzo[b]thiophenes, pyrolysis of
a mixture of tetrafluoroethylene and 2,5-difluorinated
o-chlorobenzenethiols bearing the same substituents
at positions 3 and 4 is appropriate. 2,5-difluoro-3,4,6-
trichlorobenzenethiol 1 complies with these requirements.
Therefore, we performed the simultaneous pyrolysis of
thiol 1 with tetrafluoroethylene at different temperatures
in order to obtain 2,2,3,3,4,7-hexafluoro-5,6-dichloro-
2,3-dihydrobenzo[b]thiophene 2.
The starting thiol 1 was obtained in high yield by
reacting available 1,2,4-trifluorotrichlorobenzene [4]
with KSH [5]. Pyrolysis of a mixture of thiol 1 with
tetrafluoroethylene at 600–620°C in a continuous flow
reactor resulted in the formation of compound 2. However,
the formation of another isomer (2,2,3,3,4,6-hexafluoro-
5,7-dichloro-2,3-dihydrobenzo[b]thiophene 3) was
unexpectedly observed. In addition, trace amounts of
1,1,2,2,3,3,4,7-octafluoro-5,6-dichloro-indane 4 were
found in the reaction mixture along with a noticeable
amount of 1,4-difluorotetrachlorobenzene 5 (21%, see
Table 1, entry 1). Among these compounds, 2,2,3,3,4,7-
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THERMAL TRANSFORMATIONS OF 2,5-DIFLUORO-3,4,6-TRICHLOROBENZENETHIOL
2033
Table 1. Pyrolysis of a mixture of 2,5-difluoro-3,4,6-trichlorobenzenethiol with tetrafluoroethylene
Composition of the reaction mixture according to GLC, %
(isolated yield, %)
Entry no.
1, g
2.60
40.30
2.59
τ, min
Т, °C
Yield, g
2
3
4
5
1
2
3
3.7
33.7
4.5
600‒620
510‒530
400‒420
0.68
28.52
1.15
46.1 (10)
56.7 (32)
50 (18)
15.7 (3.5)
20.5 (11.5)
16.1 (6)
2.6 (0.5)
4.7 (2.5)
2.2 (1)
21.3 (4)
5.1 (2)
0.3 (~0.1)
hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]thiophene 2
predominates (yield 10%, 46% in the mixture).Adecrease
in the reaction temperature to 510–530 and 400–420°C
leads to an increase in the yield of compound 2 (32 and
18%) (see Table 1, entries 2, 3) (Scheme 1).
isomeric polyfluorochlorodihydrobenzo[b]thiophenes
in higher yields [1].
It can be assumed (cf. [1]) that the formation
of compound 2 occurs through the 2-(2,5-difluoro-
3,4,6-trichlorophenylsulfanyl)tetrafluoroethyl radical
A (Scheme 2) derived from a 2,5-difluoro-3,4,6-
trichlorobenzenethiyl radical and tetrafluoroethylene.
A thiyl radical can be generated by thermolysis of the
S‒H bond, as well as by the action of a chlorine atom,
which is eliminated from radical σ-complexes. Probably,
the formation of arene 2 also involves the intermediate
[2-(2,5-difluoro-3,4,6-trichlorophenyl)tetrafluoroethane]-
thiyl radical B generated from the σ-spiro complex C.
The latter can be formed as a result of the transformation
of radical A. Radicals A and B undergo intramolecular
cyclization to give radical σ-complexes D and E followed
Pyrolysisofamixtureofthiol1withtetrafluoroethylene
at 600–620°C was accompanied by strong resinification,
which apparently explains the low yield of compound
2 and other reaction products. The strong resinification
is possibly due to a decrease in the thermal stability
of thiol 1 due to the presence of three chlorine
atoms. This assumption is supported by a comparison
with the result of the reaction of 2,4,5-trifluoro-3,6-
dichlorobenzenethiol with tetrafluoroethylene under
similar conditions, which leads to the formation of
Scheme 1.
Scheme 2.
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NIKUL’SHIN et al.
Scheme 3.
Scheme 4.
by elimination of the chlorine atom to form compound
2 (Scheme 2).
reacts with tetrafluoroethylene followed by cyclization
of the polyfluorotrichlorophenylpropyl radical I and
elimination of the chlorine atom from the radical
σ-complex K (Scheme 4).
Presumably, compound 3 is obtained due to the ring
closure in radical A and generation of radical σ-complex
E. Further migration of the fluorine atom leads to the
formation of radical σ-complex G (Scheme 3). A similar
mechanism with the migration of a fluorine atom has
been previously proposed in the case of the reaction of
pentafluorobenzoyl peroxide with hexafluorobenzene [6].
The ring- closure of the radical A through position 2 and
the migration of the fluorine atom is facilitated by the
participation of the vacant d-orbitals of chlorine and sulfur
atoms in the stabilization of the radical σ-complexes
E and G. Elimination of the chlorine atom from the
σ-complex G leads to the formation of compound 3
(Scheme 3).
Taking into account the elimination of the chlorine
atom during the aromatization of σ-complexes D‒G and
K, it can be assumed that compound 5 is formed as a result
of the reaction of thiol 1 with chlorine atoms. Earlier, we
have showed that in the reactions of polyfluoroarenethiols
with PCl5 at ~ 200°C, a substitution of the thiol group by
a chlorine atom occurs readily [8] (Scheme 5).
In order to study the chemical properties and to confirm
the structure of compounds 2 and 3, a ~77:23 mixture
of these compounds was oxidized with H5IO6 in the
presence of CrO3 in acetonitrile. As a result, a mixture of
2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]-
thiophene-1,1-dioxide 6 and 2,2,3,3,4,6-hexafluoro-5,7-
dichloro-2,3-dihydrobenzo[b]thiophene-1,1-dioxide 7 in
approximately the same ratio was obtained (Scheme 6).
Previously, decafluorodiphenylsulfide was oxidized in a
Probably, the formation of compound 4 includes
the incorporation of difluorocarbene generated from
tetrafluoroethylene [7] through the C–S bond of thiol 1
to yield tetrafluorotrichlorobenzyl radical H. The latter
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THERMAL TRANSFORMATIONS OF 2,5-DIFLUORO-3,4,6-TRICHLOROBENZENETHIOL
2035
Scheme 5.
and 6 are comparable; the values of JF4F6 constant in the
spectra of compounds 3 and 7 are close. The chemical
shifts of the F4 atoms in the spectra of compounds 2, 3,
6, 7 are close to each other.
In conclusion, the thermal transformations of
2,5-difluoro-3,4,6-trichlorobenzenethiol in the presence of
tetrafluoroethylene were studied. 2,2,3,3,4,7-Hexafluoro-
5,6-dichloro-2,3-dihydrobenzo[b]thiophene and
2,2,3,3,4,6-hexafluoro-5,7-dichloro-2,3-dihydrobenzo[b]-
thiophene were obtained, the oxidation of which leads to
the formation of the corresponding 2,3-dihydrobenzo[b]-
sulfane-1,1-dioxides.
similar way, and decafluorodiphenylsulfone was obtained
in high yield [9].
Composition and structure of compounds 2, 3, 6,
and 7 were established by means of elemental analysis
data, high-resolution mass spectrometry, and NMR
spectroscopy methods. The regularities observed in the
19F NMR spectra of compounds 2, 3, 6, and 7 are similar
to those in polyfluoro-2,3-dihydrobenzo[b]thiophenes and
their sulfoxides [2].
Chemical shifts of F2 and F3 atoms and spin-spin
coupling constants J(C2F ,C3F ), JF3F4 in the spectra of
compounds 2 and 3 are close to the corresponding values
in the spectra of perfluoro-2,3-dihydrobenzo[b]thiophene
and its 5- and 6-derivatives with O- and S-containing
substituents [2]. Spin-spin coupling constants JF4F7 in
arene 2 and JF4F6 in compound 3 coincide with those
in perfluoro-2,3-dihydrobenzo[b]thiophene [2]. The
signals at 46.8 ppm in the spectrum of compound 2 have
only a doublet constant (JF7F4) in the absence of a triplet
constant, which allows us to assign them to the fluorine
atom at position 7.
EXPERIMENTAL
19F NMR spectra were recorded on a Bruker AV-300
(282.4 MHz) instrument from solutions CCl4–CDCl3
relative to the internal standard—C6F6. Positive values
of chemical shifts correspond to a downfield shift of
the signal from C6F6. 13C NMR spectra (CDCl3) were
recorded on a Bruker AV-300 (75.5 MHz) and Bruker
AV-400 (100.6 MHz) instruments. IR and UV spectra
were registered on a Bruker Vector 22 IR and Hewlett
Packard 8453 UV instruments, respectively. Molecular
masses and elemental composition were determined
from mass spectra taken on a DFS instrument with an
ionization energy of 70 eV. For gas chromatography-
mass spectrometry (GC-MS), a Hewlett Packard HP
5890 chromatograph with an HP 5971 mass selective
detector and an Agilent 6890N chromatograph with an
Agilent 5973N gas chromatography–mass spectrometric
system were used. The energy of ionizing electrons is
70 eV. Gas chromatographic analysis was performed on
a Hewlett Packard HP 5980 instrument equipped with
an HP-5 quartz capillary column (stationary phase—
dimethyldiphenylpolysiloxane), 30 m×0.52 mm/2.6 μm,
and a thermal conductivity detector. Melting points were
determined on a Mettler Toledo FP900 apparatus.
The assignment of signals of fluorine atoms in
positions 4, 7 and 4, 6 in the spectra of compounds 2 and
3 is consistent with calculations using the additive scheme
taking into account the corresponding shifts of fluorine
atoms in perfluoro-2,3-dihydrobenzo[b]thiophene [2] and
the effect of chlorine atoms in pentafluorochlorobenzene
[10].
The chemical shifts of fluorine atoms F2 and F3 and
their coupling constants in the spectra of compounds 6
and 7 are close to the corresponding values in the spectra
of 2,2,3,3-tetrafluoro-2,3-dihydrobenzo[b]thiophene-1,1-
dioxide and its 5-bromo derivative [11]. The values of
JF4F7 and JF3F4 constants in the spectra of compounds 2
Pyrolytic reactions of 2,5-difluoro-3,4,6-trichloro-
benzenethiol 1 with tetrafluoroethylene were carried
out in a reactor consisting of a quartz tube (400×20 mm)
heated in an electric tube furnace. The starting compound
1 was placed into a dropping funnel attached to the quartz
tube of the reactor and melted. Before the start of the
Scheme 6.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 11 2020

2036
NIKUL’SHIN et al.
reaction, the system was purged with argon, then thiol was
supplied simultaneously with a flow of tetrafluoroethylene
(~ 15 L/h). Upon completion of the addition of compound
1 to the reactor, the supply of tetrafluoroethylene was
stopped. The reaction products were collected in a
flask cooled with ice water, then distilled with steam.
The organic layer was separated, dried with CaCl2 and
analyzed by GC-MS, GC and 19F NMR methods. The
reaction conditions, compositions of the mixtures and
the yields are given in Table. The 19F NMR spectra of
the mixtures were used to identify compounds 2, 3, 4.
For identification of arene 5 in the mixture, an authentic
synthesis was performed.
reaction completed, the ampoule was cooled. The mixture
was transferred into the flask under a layer of ice water
(80–100 g). The mixture was stirred for 2 h with the aim
of hydrolysis of phosphorus compounds, then 12.31 g of
Na2CO3 (116.83 mmol) was added. The resulting mixture
was stirred for another 2 h, then distilled with steam.
The organic layer was separated, dried with CaCl2, and
analyzed by GC and 19F NMR. By GC data, content of
compound 5 in the mixture was ~ 98.9%, yield 2.98 g
(88%), mp 74.9‒75.3°C (mp 76.5°C [13]). IR spectrum
(KBr), cm–1: 1632, 1487, 1444, 1394, 1346, 1296, 1252,
1180, 1130, 1117, 912, 879, 729, 633. UV spectrum
(hexane), λmax, нм (ε, L mol–1 cm–1): 207 (2.032), 227
(1.250), 282 (0.162), 290 (0.185). 13C NMR spectrum,
Vacuum distillation (18–20 mmHg) of 26.14 g of
the mixture obtained in entry 2 (see Table 1) yielded a
fraction of 20.32 g of compounds 2 and 3 (bp ~ 105°C,
purity of 91.9% by GC) in a ratio of ~77 : 23 (according
to 19F NMR). For a mixture, it was found m/z 311.8995
[M]+ (calcd. for C8Cl2F6S: 311.8997).
1
δC, ppm: 119.5 m (C2,3,5,6), 151.9 d. d (C1,4, JCF
=
251.0, 4JCF = 5.0 Hz). 19F NMR spectrum: δF 51.2 ppm
[14, 15]. Found, %: С 28.64; Cl 56.15; F 15.51. С6Cl2F4.
Calculated, %: С 28.61; Cl 56.30; F 15.09.
Synthesis of compounds 6 and 7. Oxidation of
a mixture of compounds 2 and 3 (see Table 1, entry
2, distillation) was carried out according to a known
procedure [9]. To 9.76 g of H5IO6 (42.82 mmol) in
35 mL of anhydrous CH3CN was added 0.37 g of CrO3
(1.05 mmol). The mixture was stirred for 30 min at room
temperature, then 1.40 g of a mixture of compounds 2
and 3 in 15 mL of anhydrous CH3CN was added. The
resulting mixture was stirred for 3 h under reflux. After
removal of acetonitrile, ~5 mL of water and 0.57 g of
Na2CO3 (5.38 mmol) were added, and the mixture was
extracted with DCM (3 × 5 mL). The extract was purified
by passing it through silica gel, DCM was distilled off. A
mixture of compounds 6 and 7 (1.18 g, 93.1%, GC) in a
ratio of ~ 75 : 25 (19F NMR) was obtained. 1.01 g of the
mixture was sublimated in a static vacuum (~2 mmHg)
at 150–160°C to give 0.89 g of a mixture of compounds
6 and 7 of 98.0% purity (GC). 0.68 g of the mixture was
recrystallized from ~1.5 mLof hexane at ‒30°C, and then
washed with ~1.5 mL of cold hexane to yield 0.58 g of a
mixture of compounds 6 and 7 (98.4% purity, GC). Mass
spectrum, m/z: 343.8896 [M]+ (calcd for C8Cl2F6O2S:
343.8895). Found, %: C 27.75; Cl 20.46; F 33.30; S
9.35. C8Cl2F6O2S. Calculated, %: C 27.85; Cl 20.55; F
33.04; S 9.29. The NMR spectra recorded for a mixture
of compounds 6 and 7 are given below.
Data of the NMR spectra recorded for a mixture of
compounds 2 and 3. Are given below.
2,2,3,3,4,7-Hexafluoro-5,6-dichloro-2,3-dihydro-
benzo[b]thiophene (2). 13C NMR spectrum, δС, ppm:
14.3 t. d (C3a, 2JCF = 25.0, 2JCF = 20.0 Hz), 117.7 t. t. d
1
2
(C3F2, JCF = 265.0, JCF = 25.0, JCF ~3.0 Hz), 121.2 d
(C5 or C6, JCF = 20.0 Hz), 121.8 d. m (C7a, JCF
~
2
2
22.0 Hz), 127.9 d (C5 or C6, JCF = 20.0 Hz), 128.8 t. t
2
1
2
(C2F2, JCF = 295.0, JCF = 28.0 Hz), 149.3 d. m (C4
1
1
or C7, JCF = 249.0 Hz), 152.2 d. m (C4 or C7, JCF
=
262.0 Hz). 19F NMR spectrum, δF, ppm: 45.6 d. t (F4,
JF F = 15.5, JF F = 10.5 Hz), 46.8 d (F7, JF F = 15.5 Hz),
4 7
4
7 4
51.2 d. t (С3F2, J FF = 10.5, JFF = 2.5 Hz), 68.2 t (С2F2,
4
J
FF = 2.5 Hz).
2,2,3,3,4,6-Hexafluoro-5,7-dichloroр-2,3-dihydro-
benzo[b]thiophene (3). 19F NMR spectrum, δF, ppm:
3
47.4 t. d (F4, JF F = 10.0, JF F = 8.0 Hz), 52.7 d. q (С F2,
4
4 6
6
4
2
6
6 4
JFF = 10.0, JFF ~ JFF ~2.0 Hz), 59.8 d. t (F , JF F = 8.0,
F F ~2.0 Hz), 67.7 t (С2F2, JFF ~2.0 Hz).
6
J
1,1,2,2,3,3,4,7-Octafluoro-5,6-dichloroindane (4).
19F NMR spectrum, δF, ppm: 31.8 quintet (С2F2, JFF
~
4.0 Hz), 47.6 br. s (F4, F7), 54.1 br. s [C1(3)F2] [12]. Mass-
spectrum, m/z: 330 [M]+ (calcd. C9Cl2F8: 330).
1,4-Difluoro-2,3,5,6-tetrachlorobenzene (5). Thiol 1
(3.33 g, 13.35 mmol) was placed into an ampoule, then
5.68 g of PCl5 (27.60 mmol) was added. The resulting
mixture was slowly heated until boiling. Upon completion
of gas evolution, the ampoule was sealed, placed into a
metal casing, and heated at 200‒202°C for 5 h. After the
2,2,3,3,4,7-Hexafluoro-5,6-dichloro-2,3-dihydro-
benzo[b]thiophene-1,1-dioxide (6). 13C NMR spectrum,
1
2
δС, ppm: 108.9 t. t. d (C3F2, JCF = 266.0, JCF = 23.0,
JCF ~2.0 Hz), 113.1 t. t (C2F2, JCF = 305.0, JCF
=
1
2
25.0 Hz), 113.9 t. d (C3a, JCF = 27.0, JCF = 18.0 Hz),
2
2
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THERMAL TRANSFORMATIONS OF 2,5-DIFLUORO-3,4,6-TRICHLOROBENZENETHIOL
2037
2
123.5 d. m (C7a, JCF ~22.0 Hz), 130.4 d. t (C5 or C6,
4. Nikul’shin, P.V., Maksimov, A.M., and Platonov, V.E.,
Russ. J. Org. Chem., 2012, vol. 48, no. 4, p. 536.
https://doi.org/10.1134/ S1070428012040124
2JCF = 19.0, JCF = 1.5 Hz), 131.5 d. t (C5 or C6, JCF
=
=
2
19.0, JCF = 1.5 Hz), 149.6 d. d (C4 or C7, JCF
1
263.0, JCF = 4.0 Hz), 151.9 d. d (C4 or C7, 1JCF = 267.0,
5. Nikul’shin, P.V., Maksimov, A.M., and Platonov, V.E.,
Russ. J. Org. Chem., 2016, vol. 52, no. 1, p. 25.
https://doi.org/10.1134/ S107042801601005X
JCF = 4.0 Hz). 19F NMR spectrum, δF, ppm: 42.4 t (С2F2,
JFF = 5.0 Hz), 49.9 d (F7, JF F = 17.5 Hz), 51.3 d. t (F ,
4
7 4
JF F = 17.5, JF F = 12.5 Hz), 55.8 d. t. d (С3F2, JFF
=
4 7
4
4
6. Vlasova, L.V., Kobrina, L.S., and Yakobson, G.G., Zh.
Org. Khim., 1974, vol. 10, no. 4, p. 787.
2
7
12.5, JFF = 5.0, JFF = 1.0 Hz).
2,2,3,3,4,6-Hexafluoro-5,7-dichloro-2,3-
7. Kirmse, W., Carbene Chemistry, New York: Academic
dihydrobenzo[b]thiophene-1,1-dioxide (7). 19F NMR
Press, 1971.
spectrum, δF, ppm: 42.6 t (С2F2, JFF = 5.0 Hz), 53.3 t. d
8. Nikul’shin, P.V., Maksimov, A.M., and Platonov, V.E.,
Russ. J. Org. Chem., 2016, vol. 52, no. 2, p. 200.
https://doi.org/10.1134/ S1070428016020068
3
(F4, JF F = 12.0, JF F = 10.0 Hz), 56.0 d. t. d (С F2, JFF
=
4
4 6
4
6
2
6
6 4
12.0, JFF = 5.0, JFF = 2.0 Hz), 64.1 d. t (F , JF F = 10.0,
6
JF F = 2.0 Hz).
9. Xu, L., Cheng, J., and Trudell, M.L., J. Org. Chem.,
2003, vol. 68, no. 13, p. 5388.
ACKNOWLEDGMENTS
https://doi.org/10.1021/jo030031n
The authors are grateful to the Chemical Research
Center for Collective Use of the Siberian Branch of RAS for
performing spectral and analytical measurements.
10. Pushkina, L.N., Stepanov, A.P., and Zhukov, V.S., Zh. Org.
Khim., 1972, vol. 8, no. 3, p. 586.
11. Platonov, V.E. and Maksimov, A.M., Heteroatom Chem.,
1992, vol. 3, no. 4, p. 373.
CONFLICT OF INTEREST
No conflict of interest was declared by the authors.
https://doi.org/10.1002/hc.520030411
12. Nikul’shin, P.V., Maksimov, A.M., and Platonov, V.E.,
Russ. J. Appl. Chem., 2010, vol. 83, no. 7, p. 1254.
https://doi.org/10.1134/ S1070427210070165
13. Parshall, G.W., J. Org. Chem., 1962, vol. 27, no. 12,
p. 4649.
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