Isomerization of perfluoro-3,3-diethylindan-1-one into perfluoro-1,3- dimethyl-4-ethyl-1 H-isochromen under the action of antimony pentafluoride

Article abstract of DOI:10.1134/S1070428011020096

The heating of perfluoro-3,3-diethylindan-1-one with SbF₅ at 180°C after treatment of the reaction mixture with anhydrous HF afforded perfluoro-1,3-dimethyl-4-ethylisochromen, and after hydrolysis, perfluoro-1,3-dimethyl-4-ethyl-1H-isochromen-1-ol. The latter under the action of NaHCO₃ converted into 5,6,7,8-tetrafluoro-1,3-bis(trifluoromethyl) -1H-isochromen-1-ol. Both isochromenols reacted with SOCl₂ gave the corresponding polyfluoro-1-chloro-1H-isochromens. On dissolving isochromenols in CF₃SO₃H and isochromens in SbF₅ perfluoro-1,3-dimethyl-4-ethylisochromenyl and 5,6,7,8-tetrafluoro-1,3- bis(trifluoromethyl)isochromenyl cations were generated which by hydrolysis were converted into the corresponding isochromenols.

Full text of DOI:10.1134/S1070428011020096

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol. 47, No. 2, pp. 207213. Pleiades Publishing, Ltd., 2011.
Original Russian Text  Ya.V. Zonov, V.M. Karpova, V.E. Platonov, 2011, published in Zhurnal Organicheskoi Khimii, 2011, Vol. 47, No. 2, pp. 217222.
Isomerization of Perfluoro-3,3-diethylindan-1-one
into Perfluoro-1,3-dimethyl-4-ethyl-1Н-isochromen
under the Action of Antimony Pentafluoride
Ya. V. Zonova,b, V. M. Karpova, and V. E. Platonova
aVorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences,
Novosibirsk, 630090 Russia
e-mail: karpov@nioch.nsc.ru, yzonov@nioch.nsc.ru
bNovosibirsk State University, Novosibirsk, Russia
Received July 7, 2010
Abstract—The heating of perfluoro-3,3-diethylindan-1-one with SbF5 at 180°C after treatment of the reaction
mixture with anhydrous HF afforded perfluoro-1,3-dimethyl-4-ethylisochromen, and after hydrolysis, perfluoro-1,3-
dimethyl-4-ethyl-1Н-isochromen-1-ol. The latter under the action of NaHCO3 converted into 5,6,7,8-tetrafluoro-
1,3-bis(trifluoromethyl)-1Н-isochromen-1-ol. Both isochromenols reacted with SOCl2 gave the corresponding
polyfluoro-1-chloro-1Н-isochromens. On dissolving isochromenols in CF3SO3H and isochromens in SbF5
perfluoro-1,3-dimethyl-4-ethylisochromenyl and 5,6,7,8-tetrafluoro-1,3-bis(trifluoromethyl)isochromenyl cations
were generated which by hydrolysis were converted into the corresponding isochromenols.
DOI: 10.1134/S1070428011020096
We formerly discovered and investigated previously tene [1], 1-alkyl- [5], 1-phenyl-1-ethyl- [6], and 1,1-di-
unknown in perfluoroketones skeleton rearrangements of alkylbenzocyclobutenes [5, 6] effected by the action of
carbonyl derivatives of perfluorinated tetralin [1], indan antimony pentafluoride. It was established that the direc-
[2], 1-methyl- [3] and 1-ethylindans [4], benzocyclobu- tion of the reaction depended on the size of the carbonyl-
Scheme 1.
(1) SbF5, 125°C
(2) H2O
CF3
F3C
C=CFCF3
C2F5
(1) SbF5, 70°C
(2) H2O
CF3
F
F
F
F
F
O
COOH
H2O
O
O
I
_
_F
H2O
CF2
CF3
CF2CF3
F3C
C=CFCF3
C2F5
+
F
+
_
CF3
CFCF3
CF2
F
F
F
F
F
+
_
_F
O
+
F
COF
C O
CO
O
A
F
207

ZONOV et al.
208
containing ring of the substrate and also on the presence
and the position of its perfluoroalkyl substituents. In
particular, the heating of perfluoro-3-ethylindan-1-one (I)
with SbF5 at 70°C resulted in perfluoro-2-(but-2-en-2-yl)
benzoic acid, and at 125°C, in perfluoro-3,4-dimethyl-
isochromen-1-one. The reaction apparently proceeds
through cation А [4] (Scheme 1).
the reaction mixture resulted in perfluoro-1,3-dimethyl-
4-ethyl-1Н-isochromen-1-ol (III). The reaction mixture
contained also a large amount of initial compound II
(Scheme 2). The increased reaction time (74 h) led to the
higher conversion of ketone II, but alongside compounds
II and III the reaction mixture contained a number of
intractable impurities and a small quantity of perfluoro-
1,1-diethylindan (IV).
In contrast to compound I perfluoro-3,3-diethylindan-
1-one (II) treated with SbF5 at 130°C did not suffer the
skeleton rearrangement [2]. This is apparently due to the
presence in the position 3 of ketone II instead of a fluorine
atom of the second perfluoroethyl group preventing the
formation of cation similar to ion А. However formally a
formation of the other cations is possible, e.g., by elimi-
nation of a fluoride ion from the carbon atom of the side
chain of ketone II. It is therefore presumable that under
more severe conditions the five-membered ring of the
diethylindanone II would be able to undergo the skeleton
rearrangements whose mechanism would be different
from the mechanism of the opening of the five-membered
ring in ethylindanone I [4], perfluoro-3-methylindan-1-
one [3], and perfluoroindan-1-one [2].
The heating of diethylindanone II with SbF5 at 180°C
over 27 h followed by treatment of the reaction mixture
with anhydrous HF and then with water led to the forma-
tion of perfluoro-1,3-dimethyl-4-ethylisochromen (V)
alongside initial ketone II and compounds III and IV as
impurities.According to the 19F NMR spectrum the reac-
tion mixture before the treatment with HF contained a salt
of perfluoro-1,3-dimethyl-4-ethylisochromenyl cation
(VI). This cation was also generated from compound V
in SbF5 environment. The hydrolysis of the salt of cation
VI gave alcohol III (Scheme 2).
One among the possible ways of cation VI formation
from ketone II in the presence of SbF5 is presented
in Scheme 2. Initially under the action of SbF5 from
compound II cation B is generated. Then in ion B the
five-membered ring undergoes opening resulting in cation
C that isomerizes into cation D. The intramolecular attack
of the positively charged carbon atom of the allyl system
of ion D on the oxygen atom affords cation E where the
transition of the exocyclic multiple bond С=С into the
In this research we studied the behavior of ketone II in
antimony pentafluoride under more severe conditions than
in [2] in order to elucidate the possibility of its cationoid
skeleton rearrangements.
It was demonstrated that the heating of diethylindanone
II with antimony pentafluoride at 180°C over 15 h in a
nickel pressure reactor with the subsequent hydrolysis of
ring furnishes cation VI
.
Scheme 2.
H2O
C2F5
C2F5
C2F5
O
F5C2 C2F5
F5C2 C2F5
(1) HF
(2) H2O
CF3
CF3
CF3
SbF5
F
F
F
F
+
F
F
+
F
180°C
O
+
O
O
CF3
F CF3
V
HO CF3
III
II
VI
IV
SbF5
_F _
+
CFCF3
+
CFCF3
CFCF3
CF3
CF3CF CF2CF3
±F _
CF2CF3
CFCF3
F
F
F
F
F
F
VI
+
O
+
C O
CF3
CF2
O
B
O
CF3
E
C
D
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 2 2011

ISOMERIZATION OF PERFLUORO-3,3-DIETHYLINDAN-1-ONE
209
Scheme 3.
H
C2F5
O
H
CF3
CF3
CF3
H+
NaHCO3
_O
F
F
F
H2O_CCl4
O
COCF3
HO CF3
HO CF3
H
VII
III
_H+
F3C
H
O
CF2CF3
CFCF3
CF3
H
_
CF3
CF3
O _
O
H2O
_HF
NaHCO3, H2O
_CF3COOH
F
F
F
_F _
F
O
O
CF3
COCF3
COCF3
COCF3
COCF3
G
F
H
The assumed mechanism of the opening of the
five-membered ring in diethylindanone II is unlike
the opening mechanism of the five-membered ring in
ethylindanone I [4]. For instance in diethylketone II
the rupture of the C–C bond occurs in ion B with a
cation center in the side chain (Scheme 2), whereas in
ethylketone I the cleavage of bond occurs in ion А with
a cation center in the benzyl position (Scheme 1). This
mechanism has not been previously observed in the
polyfluorinated indan derivatives, but it is analogous
to the opening mechanism of the four-memebered ring
in the perfluorinated 2,2-diethylbenzocyclobutenone
[6] and 2-alkylbenzocyclobutenes [5], and also in
1,1-dialkylbenzocyclobutenes [7] at the treatment
with antimony pentafluoride. Besides the formolysis
of nonfluorinated (indan-1-yl)methyl tosylate that also
proceeds with the involvement of an intermediate cationoid
species containing an indan frame and a cationic center
in the side chain, resulted not in the opening of the five-
membered ring, but in its extension by the migration of an
aryl group to the cation center with the formation of tetralin
derivatives [8].
The possible way of compound III conversion into
alcohol VII is presented in Scheme 3.Apparently initially
compound III is deprotonated with the opening of the
pyran ring and the elimination of the fluoride ion giving
diketone F. The latter under the reaction conditions trans-
forms into triketone G. Further in compounds G a bond
C–C is ruptured by the type of the haloform cleavage to
give the trifluoroacetic acid and anion H which suffers an
intramolecular cyclization resulting in alcohol VII. The
formation in the reaction of the trifluoroacetic acid was
confirmed by the 19F NMR spectroscopy. The reactions
analogous to the cleavage of triketone G were formerly
observed in the reactions of compounds CHX(COCF3)2
(X = H [9], CF3, COCF3 [10]) with water.
Alcohols III and VII treated with SOCl2 gave
5,6,7,8-tetrafluoro-4-pentafluoroethyl-1,3-bis(trifluoro-
methyl)-1-chloro-1Н-isochromen (VIII) and
5,6,7,8-tetrafluoro-1,3-bis(trifluoromethyl)-1-chloro-
1Н-isochromen (IX) respectively (Scheme 4).
In the antimony pentafluoride medium from
compounds VIII and IX ion VI and 5,6,7,8-tetrafluoro-
1,3-bis(trifluoromethyl)isochromenyl cation (X) are
generated. These cations are also generated at dissolution
of alcohols III and VII in the trifluoromethanesulfonic
acid. Therewith isochromenol VII in CF3SO3H is
completely converted into cation X, and isochromenol
III into cation VI, only partially. On hydrolysis of the
salts of cations VI and X alcohols III and VII form
respectively (Scheme 4).
The attempt to isolate individual alcohol III by
column chromatography on silica gel was unsuccessful
for we failed to elute compound III from the column.
This fact may be due to the lability of compound III
even in the presence of relatively weak bases. Actually,
alcohol III under the action of NaHCO3 in a two-phase
system H2O–CCl4 at room temperature converted
into 5,6,7,8-tetrafluoro-1,3-bis(trifluoromethyl)-1Н-
isochromen-1-ol (VII) (Scheme 3).
Compounds III and VII can formally exist in the cyclic
and/or acyclic III', III', VII', VII' forms (Scheme 5).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 2 2011

ZONOV et al.
Scheme 4.
SbF5
210
R
R
R
+
CF3
CF3
CF3
SOCl2
75oC
CF3SO3H
H2O
F
F
F
O
O
O
Cl CF3
HO CF3
CF3
VIII, IX
III, VII
VI, X
R = C2F5 (III, VI, VIII), H (VII, IX, X).
Scheme 5.
R
R
R
H
CF3
OH
CF3
CF3
CF3
F
F
F
O
O
CF3
HO
CF3
O
O
III, VII
III', VII'
III'', VII''
IR spectra of compounds III and VII in CCl4 and 13C
NMR spectra in CDCl3 do not contain absorption band
or signals characteristic of C=O groups. This means that
compounds III and VII in CCl4 and CDCl3 solutions are
present in the cyclic form.
composition was determined by high resolution mass
spectrometry on instruments Finnigan MAT 8200 and
Thermo Electron Corporation DFS. The GLC analysis
was performed on a chromatograph LKhM-72 (50–
270°С, column 4000 × 4 mm, stationary phase SKFFT-50
on Chromosorb W, the ratio stationary phase–inert carrier
15 : 100, carrier gas helium, flow rate 60 ml/min). GC-
MS analyses were carried out on an instrument Hewlett
Packard G1081A coupled with a gas chromatograph НР
5890 of series II and a mass-selective detector НР 5971
(EI, 70 eV). Capillary column НР 5 (5% phenyl-, 95%
dimethylsiloxane): 30 m × 0.25 mm × 0.25 μm. Carrier
gas helium, flow rate 1 ml/min. The content of compounds
in mixtures (yield) was established from the data of GLC,
GC-MS, and 19F NMR spectra.
The composition and structure of compounds were
established from the data of elemental analysis, high
resolution mass spectrometry, and spectral characteristics.
The assignment of the signals in the 19F NMR spectra of
compounds and cations VI and X was performed from
the chemical shifts of the signals, their fine structure, and
integral intensity. The regularity observed in the spectra of
cations VI and X are in agreement with similar regulari-
ties for the other polyfluoroisochromenyl cations [4, 6].
Reaction of perfluoro-3,3-diethylindan-1-one
(II) with SbF5. а. A mixture of 1.78 g (3.74 mmol) of
compound II [2] and 6.76 g (31.18 mmol) of SbF5 was
heated in a nickel pressure reactor of 10 ml capacity over
15 h at 180°С. Then the mixture was transferred into 5%
water solution of HCl, extracted with CH2Cl2, the extract
was dried with MgSO4. On distilling off the solvent in
a vacuum we obtained 1.64 g of mixture containing
compound II and perfluoro-1,3-dimethyl-4-ethyl-1Н-
isochromen-1-ol (III) in a ratio 78 : 22 (19F NMR data).
EXPERIMENTAL
IR spectra were registered on a spectrophotometer
Bruker Vector 22. UV spectra were taken on a
spectrophotometer Hewlett Packard 8453 19F, 13C, and
1H spectra were recorded on a spectrometer Bruker
AV-300 (operating frequencies 282.4, 75.5, 300 MHz
respectively). The chemical shifts are reported downfield
with respect to C6F6 (19F) and TMS (1H, 13C), internal
references C6F6 and SO2ClF (δF 262.8 ppm), CDCl3
(δC 76.9 ppm), CHCl3 (δH 7.24 ppm). The elemental
b. Similarly to experiment а from 1.8 g (3.78 mmol) of
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 2 2011

ISOMERIZATION OF PERFLUORO-3,3-DIETHYLINDAN-1-ONE
211
compound II and 6.56 g (30.26 mmol) of SbF5 (180°С,
74 h) we obtained 1.69 g of a mixture containing 35% of
ketone II, 50% of compound III, and 7% of perfluoro-
1,1-diethylindanа (IV).
was distilled off in a vacuum. We obtained 0.25 g (84%)
of compound III that was additionally purified by
“sublimation” in a vacuum (40°C, 2 mm Hg). Liquid.
IR spectrum (CCl4), ν, cm–1: 3556 (OH), 1519, 1490
(fluorinated aromatic ring). 1H NMR spectrum (CDCl3),
δ, ppm: 4.44 br.s (1Н, OH). 13C NMR spectrum (CDCl3),
δ, ppm: 96.3 q (C1, 2JCF 37 Hz), 109.5 t (C4, 2JCF 30 Hz),
110.7 m (C4а,8а) and 112.0 d (2JCF 13 Hz), 113.8 t.q
(CF2, 1JCF 260, 2JCF 42 Hz), 119.0 q.t (4-CF3, 1JCF 289,
2JCF 37 Hz), 118.1 q (1,3-CF3, 1JCF 275 Hz) and 121.2 q
(1JCF 290 Hz), 142.1–145.6 (C5,6,7,8), 145.2 q (C3,
2JCF 40 Hz). 19F NMR spectrum (CDCl3), δ, ppm: 13.8
(1F, F7), 14.4 (1F, F6), 28.4 (1F, F8), 31.8 (1F, F5), 64.0
(1F, FB) and 70.1 br.d (1F, FA, CF2), 77.4 br.s (3F, 1-CF3),
88.7 (3F, 4-CF3), 94.8 (3F, 3-CF3); J(FF), Hz: J(8, 1-CF3)
12, J(3-CF3–4-CF3) 8, J(A, 3-CF3) 22, J(B, 3-CF3) 6, J(5,
4-CF3) 31, JA,B 279, JA,5 15, JB,5 54, J5,6 20, J5,7 7, J5,8 12,
J6,7 20, J6,8 8, J7,8 21. Found, %: C 33.20; H 0.07; F 60.23.
C13HF15O2. Calculated, %: C 32.93; H 0.21; F 60.11.
c. A mixture of 5.0 g (10.5 mmol) of compound II
and 13.59 g (62.68 mmol)of SbF5 was heated in a nickel
pressure reactor over 27 h at 180°С. To a part of the
mixture obtained (1.56 g) was added 0.31 g of SO2ClF,
and the 19F NMR spectrum was registered containing
unresolved signals of cation VI. Then the mixture was
treated with 30 ml of anhydrous HF and was poured on
ice, the reaction products were extracted into CH2Cl2.
The organic layer was separated, washed with water,
dried with MgSO4, and the solvent was distilled off.
We obtained 4.35 g of a mixture containing according
to the 19F NMR spectrum compounds II, III, IV, and
perfluoro-1,3-dimethyl-4-ethyl-1Н-isochromen (V)
in the ratio 50 : 2 : 6 : 42. The mixture was subjected to
column chromatography on silica gel (eluent hexane) to
obtain 1.53 g (31%) of compound V and by elution with
CHCl3 1.99 g of ketone II.
Reaction of compound III with NaHCO3. а.
A mixture of 1.19 g of compounds II and III (in molar
ratio 70:30) was dissolved in 15 ml of CCl4, washed
with a saturated water solution of NaHCO3, dried
with MgSO4, and the solvent was distilled off. We
obtained 1.05 g of a mixture containing according to
the 19F NMR data compound II and 5,6,7,8-tetrafluoro-
1,3-bis(trifluoromethyl)-1Н-isochromen-1-ol (VII) in
the ratio 70:30. The mixture was subjected to column
chromatography on silica gel. Elution with CHCl3 yielded
0.7 g of compound II and 0.23 g (86%) of alcohol VII.
The analytical sample of alcohol VII was obtained by
“sublimation” at 90°C in a vacuum (30 mm Hg).
Compound V. Liquid. UV spectrum (hexane), λmax
,
nm (lgε): 221 (3.81), 259 (3.79), 288 (3.59). IR spectrum
(CCl4), ν, cm–1: 1523, 1492 (fluorinated aromatic ring).
13C NMR spectrum (CDCl3), δ, ppm: 104.6 d.q (C1,
2
2
1JCF 242, JCF 41 Hz), 107.5 d.d (C8а, JCF 22, 12 Hz),
110.3 t (C4, 2JCF 30 Hz), 111.4 d (C4а, 2JCF 13 Hz), 113.5 t.q
(CF2, 1JCF 261, 2JCF 43 Hz), 117.8 q (3-CF3, 1JCF 275 Hz),
118.8 q.t (4-CF3, 1JCF 289, 2JCF 37 Hz), 119.4 q.d (1-CF3,
1JCF 289, 2JCF 39 Hz), 142.2 d.d.d (C6,7, 1JCF 263, 2JCF 17,
12 Hz) and 143.9 d.d.d (1JCF 262, 2JCF 18, 12 Hz), 143.7 q
(C3, 2JCF 42 Hz), 143.5 d.d (C5,8, 1JCF 259, 2JCF 13 Hz)
and 145.4 d.d (1JCF 262, 2JCF 13 Hz). 19F NMR spectrum
(CDCl3), δ, ppm: 15.3 (1F, F7), 16.9 (1F, F6), 28.2 (1F,
F8), 32.8 (1F, F5), 46.3 br.s (1F, F1), 64.9 br.d.d (1F, FB)
and 68.4 br.d (1F, FA, CF2), 78.1 br.s (3F, 1-CF3), 88.3
(3F, 4-CF3), 95.1 m (3F, 3-CF3); J(FF), Hz: J(8, 1-CF3)
18, J(3-CF3–4-CF3) 8, J(5, 4-CF3) 30, JA,B 280, JB,5 ~45,
J1,6 3, J1,8 30, J5,6 20, J5,7 8, J5,8 12, J6,7 20, J6,8 9, J7,8 21.
Found M+ 475.9690. C13F16O. Calculated M 475.9688.
b. A solution of 0.26 g (0.55 mmol) of compound III
in 2 ml of CCl4 was washed with a saturated solution
of NaHCO3. The water layer was separated, acidified
with aqueous HCl and extracted with diethyl ether. The
solution in CCl4 and diethyl ether extract were combined
and dried with MgSO4. The obtained mixture according
to 19F NMR spectrum contained equal amounts of
compound VII and CF3COOH. The mixture was washed
with the water solution of NaHCO3, dried with MgSO4,
and the solvent was distilled off to obtain 0.18 g (92%)
of compound VII.
Perfluoro-1,3-dimethyl-4-ethyl-1Н-isochromen-1-
ol (III). In 1.02 g (4.7 mmol) of SbF5 was dissolved 0.3 g
(0.63 mmol) of compound V, and 19F NMR spectrum
was registered containing the signals of cation VI. The
reaction mixture was poured into 45% water solution
of H2SO4 and extracted with CH2Cl2. The solvent was
evaporated from the extract in a vacuum. The residue
was dissolved in 5 ml of hexane, filtered, and the solvent
Compound VII. Liquid. UV spectrum (hexane), λmax
,
nm (log ε): 263 (3.86), 272 (3.81), 292 (3.64), 302 (3.62).
IR spectrum (CCl4), ν, cm–1: 3558 (OH), 3124 (CH),
1520, 1495 (fluorinated aromatic ring). 1H NMR spectrum
(CDCl3), δ, ppm: 6.61 d (1Н, Н4, JH4,F8 2 Hz), 4.59 br.s
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 2 2011

ZONOV et al.
212
(1Н, OH). 13C NMR spectrum (CDCl3), δ, ppm: 95.1 d
JA,B 280, JA,5 18, JB,5 49, J5,6 20, J5,7 7, J5,8 12, J6,7 20,
J6,8 8, J7,8 20. Found M+ 491.9410. C13ClF15O. Calculated
M 491.9398.
(C4, 1JCH 78 Hz), 96.6 q (C1, 2JCF 37 Hz), 106.8 d (C4а,8а
,
2JCF 10 Hz) and 114.2 d (2JCF 15 Hz), 118.5 q (1,3-CF3,
1JCF 272 Hz) and 121.4 q (1JCF 290 Hz), 141.4 q (C3,
2JCF 39 Hz), 141.5 d.d.d (C6,7, 1JCF 258, 2JCF 17, 12 Hz)
Perfluoro-1,3-dimethyl-4-ethylisochromenyl cation
(VI). а. In 1.03 g (4.75 mmol) of SbF5 was dissolved
0.19 g (0.39 mmol) of compound VIII, and 0.29 g
of SO2ClF was added. The 19F NMR spectrum of the
solution obtained contained the signals of cation VI.
The solution was poured into 5% water solution of HCl,
extracted with CCl4, the extract was dried with MgSO4,
and the solvent was distilled off. We obtained 0.16 g of
a mixture that according to the data of GC-MS contained
80% of alcohol III (yield 70%).
and 142.5 d.d.d (1JCF 259, JCF 16, 13 Hz), 142.4 d.d
2
(C5,8, JCF 255, JCF 12 Hz) and 146.3 d.d (1JCF 260,
2JCF 12 Hz). 19F NMR spectrum (CDCl3), δ, ppm: 11.0
(1F, F7), 12.5 (1F, F6), 17.4 (1F, F5), 28.4 (1F, F8), 75.1
(3F, 1-CF3), 89.1 s (3F, 3-CF3); J(FF), Hz: J(8, 1-CF3) 15,
J5,6 20, J5,7 2, J5,8 13, J6,7 20, J6,8 8, J7,8 20, J8,H4 2. Found
M+ 355.9891. C11H2F10O2. Calculated M 355.9895.
1
2
1,3-Bis(trifluoromethyl)-5,6,7,8-tetrafluoro-1-
chloro-1Н-isochromen (IX). To a mixture of 0.1 g
(0.28 mmol) of compound VII and 0.83 g (6.97 mmol)
of SOCl2 was added 2 drops of DMF, and the mixture
was stirred for 9.5 h at 75°C. SOCl2 was distilled off, the
product was obtained by distillation at 70°C in a vacuum
(20 mm Hg). The product was dissolved in CH2Cl2, the
solution was washed with a solution of NaHCO3, dried
with MgSO4, and the solvent was distilled off. Yield
b. To 0.99 g (6.6 mmol) of CF3SO3H was added 0.11 g
19
(0.23 mmol) of alcohol III. The F NMR spectrum of
solution obtained contained the signals of cation VI and
alcohol III in a ratio 65 : 35.
Cation VI. 19F NMR spectrum (SbF5–SO2ClF), δ,
ppm: 35.5 (1F, F7), 48.5 (1F, F5), 59.0 (1F, F8), 69.1 (2F,
CF2), 71.4 (1F, F6), 89.4 (3F, 4-C2F5), 99.4 (3F, 1-CF3),
103.4 (3F, 3-CF3). 19F NMR spectrum (CF3SO3H), δ,
ppm: 35.4 (1F, F7), 47.7 (1F, F5), 57.7 (1F, F8), 69.2 (2F,
CF2), 70.6 (1F, F6), 89.7 (3F, 4-CF3), 99.4 (3F, 1-CF3),
103.6 (3F, 3-CF3); J(FF), Hz: J(8, 1-CF3) 40, J(3-CF3–4-
CF3) 8, J(3-CF3–CF2) 19, J(5, 4-CF3) 31, J(5, CF2) ~60,
J5,6 18, J5,7 15, J5,8 10, J6,7 20, J6,8 34, J7,8 18.
1
0.054 g (51%). H NMR spectrum (CDCl3), δ, ppm:
6.93 d (1Н, Н4 JH4,F8 2 Hz). 19F NMR spectrum (CDCl3),
δ, ppm: 12.7 (1F, F7), 13.3 (1F, F6), 18.6 (1F, F5), 31.5 (1F,
F8), 84.1 (3F, 1-CF3), 89.4 с (3F, 3-CF3); J(FF), Hz: J(8,
1-CF3) 35, J5,6 21, J5,7 4, J5,8 13, J6,7 20, J6,8 9, J7,8 20,
J8,H 2. Found M+ 373.9568. C11HClF10O. Calculated
M 373.9556.
1,3-Bis(trifluoromethyl)-5,6,7,8-tetrafluoro-
isochromenyl cation (X). а. In 2.13 g (9.82 mmol) of
SbF5 was dissolved 0.045 g (0.12 mmol) of compound IX,
and 0.1 g of SO2ClF. was added. The 19F NMR spectrum
of the solution obtained contained the signals of cation X.
The solution was poured in water, extracted with CH2Cl2,
the extract was dried with MgSO4, and the solvent was
distilled off. We obtained 0.031 g (72%) of alcohol VII.
4-Pentafluoroethyl-1,3-bis(trifluoromethyl)-
5,6,7,8-tetrafluoro-1-chloro-1Н-isochromen (VIII).
To 2.57 g of a mixture of compounds II and III (at the
molar ratio 82:18) and 0.66 g of SOCl2 was added 2 drops
of DMF, and the mixture was stirred for 6.5 h at 80°C.
Excess SOCl2 was distilled off in a vacuum to obtain
2.42 g of a mixture containing according to 19F NMR
data compounds II and VIII in a ratio 83:17. With the
use of column chromatography on silica gel (eluent
hexane) we isolated 1.79 g of ketone II and 0.28 g (58%)
of compound VIII. The analytical sample of compound
VIII was obtained by “sublimation” at 90°C in a vacuum
(30 mm Hg). Liquid. UV spectrum (hexane), λmax, nm
(log ε): 213 (4.20), 261 (3.87), 289 (3.56). IR spectrum
(CCl4), ν, cm–1: 1517, 1492 (fluorinated aromatic ring).
19F NMR spectrum (CDCl3), δ, ppm: 14.2 (1F, F6), 14.7
(1F, F7), 30.1 (1F, F8), 33.4 (1F, F5), 63.9 (1FB) and
71.0 br.d (1FA, CF2), 87.0 (3F, 1-CF3), 88.9 (3F, 4-CF3),
94.8 (3F, 3-CF3); J(FF), Hz: J(8, 1-CF3) 40, J(3-CF3–4-
CF3) 8, J(A, 3-CF3) 21, J(B, 3-CF3) 6, J(5, 4-CF3) 30,
b. To 0.90 g (6 mmol) of CF3SO3H was added 0.11 g
(0.31 mmol) of alcohol VII. The 19F NMR spectrum of
the solution obtained contained the signals of cation X
and no signals of alcohol VII. The solution was poured in
water, extracted with CH2Cl2, the extract was dried with
MgSO4, and the solvent was distilled off. We obtained
0.1 g (91%) of alcohol VII.
Cation X. 1H (CF3SO3H, internal reference CH2Cl2,
δH 5.28 ppm from TMS), δ, ppm: 9.45 s (Н4). 19F NMR
spectrum (SbF5–SO2ClF), δ, ppm: 31.2 (1F, F5 or F7),
33.2 (1F, F5 or F7), 51.3 (1F, F8), 60.9 (1F, F6), 96.0 s (3F,
3-CF3), 98.8 (3F, 1-CF3). 19F NMR spectrum (CF3SO3H),
δ, ppm: 31.6 (1F, F5 or F7), 33.2 (1F, F5 or F7), 49.7 (1F,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 2 2011

ISOMERIZATION OF PERFLUORO-3,3-DIETHYLINDAN-1-ONE
tonov, V.E., Zh. Org. Khim., 2008, vol. 44, p. 1675.
213
F8), 59.9 (1F, F6), 96.6 s (3F, 3-CF3), 99.0 (3F, 1-CF3);
J(FF), Hz: J(8, 1-CF3) 35, J5,6 9, J6,7 9, J5,7 10, J5,8 15,
J7,8 15, J6,8 26.
4. Zonov, Ya.V., Karpov, V.M., and Platonov, V.E., J. Fluor.
Chem., 2007, vol. 128, p. 1065.
5. Zonov, Ya.V., Karpov, V.M., and Platonov, V.E., Zh. Org.
Khim., 2010, vol. 46, p. 1512.
ACKNOWLEDGMENTS
6. Zonov, Ya.V., Mezhenkova, T.V., Karpov, V.M., and Pla-
The study was carried out under a financial support
of the Russian Foundation for Basic Research (grant no.
06-03-32170).
tonov, V.E., J. Fluor. Chem., 2008, vol. 129, p. 1206.
7. Karpov, V.M., Mezhenkova, T.V., Platonov, V.E., and
Yakobson, G.G., Izv. AN, SSSR. Ser. khim., 1990, p. 1114.
8. Huisgen, R. and Seidl, G., Chem. Ber., 1963, vol. 96,
p. 2740; Lipovich, V.G., Sakhabutdinov, A.G., and Kal-
echits, I.V., Zh. Org. Khim., 1971, vol. 7, p. 1177.
REFERENCES
1. Zonov, Ya.V., Karpov, V.M., Platonov, V.E., and Gati-
9. Johanson, D.A., Waugh, A.B., Hambley, T.W., and Tay-
lov, Yu.V., Zh. Org. Khim., 2008, vol. 44, p. 212.
lor, J.C., J. Fluor. Chem., 1985, vol. 27, p. 371.
2. Zonov, Ya.V., Karpov, V.M., and Platonov, V.E., J. Fluor.
Chem., 2005, vol. 126, p. 437.
10. Volkonsky, A.Yu. and Rokhlin, E.M., J. Fluor. Chem.,
1984, vol. 26, p. 183.
3. Zonov, Ya.V., Mezhenkova, T.V., Karpov, V.M., and Pla-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 2 2011