Acid-catalyzed polyfluoroarylation of arenes with polyfluorinated mono- and tris(phenoxy)-1-oxaspiro[2.5]octa-4,7-dienes

Article abstract of DOI:10.1007/s11172-011-0307-4

4,5,6,7,8-Pentafluoro-6-pentafluorophenoxy-1-oxaspiro[2.5]octa-4,7-diene and 4,6,8-tri-fluoro-5,6,7-tris(pentafluorophenoxy)-1-oxaspiro[2.5]octa-4,7- diene react with electron-rich arenes in the presence of AlCl₃ or H₂SO₄ to give polyfluorinated phenoxybiaryls.

Full text of DOI:10.1007/s11172-011-0307-4

Russian Chemical Bulletin, International Edition, Vol. 60, No. 10, pp. 2021—2026, October, 2011
2021
Acidꢀcatalyzed polyfluoroarylation of arenes with polyfluorinated
monoꢀ and tris(phenoxy)ꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdienes
V. N. Kovtonyuk and L. S. Kobrina
N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences,
9 prosp. Akad. Lavrent´eva, 630090 Novosibirsk, Russian Federation.
Fax: +7 (383) 330 9752. Eꢀmail: kovtonuk@nioch.nsc.ru
4,5,6,7,8ꢀPentafluoroꢀ6ꢀpentafluorophenoxyꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdiene and 4,6,8ꢀtriꢀ
fluoroꢀ5,6,7ꢀtris(pentafluorophenoxy)ꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdiene react with electronꢀrich
arenes in the presence of AlCl3 or H2SO4 to give polyfluorinated phenoxybiaryls.
Key words: polyfluoroarylation, arylation, biaryls, electrophilic substitution, organofluorine
compounds, oxiranes.
Polyfluorinated cyclohexaꢀ2,5ꢀdienones are conveꢀ
nient synthones for selective synthesis of various organoꢀ
fluorine compounds due to their high and diverse reacꢀ
tivity.1 We have previously shown that they react with
diazomethane at the carbonyl group giving in high yields
fluorineꢀcontaining 1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdienes ("cycloꢀ
hexadienespirooxiranes")2 with the reactive oxirane cycle.
Their interaction with aryl or alkyl isocyanates in the presꢀ
ence of lithium or potassium salts affords polyfluorinated
dihydroꢀ1,3ꢀbenzoxazolꢀ2(3Н)ꢀones in good yields.2
4,5,6,7,8ꢀPentafluoroꢀ6ꢀnitroꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀ
diene in the presence of the AlCl3—αꢀpicoline system in
the reactions with electronꢀrich arenes acts as a pentafluoꢀ
rophenylating agent affording the corresponding pentaꢀ
fluorobiphenyls.3 In this process, nitrocyclohexadieneꢀ
spirooxirane acts as a synthetic equivalent of the pentaꢀ
fluorophenyl cation. A close analog of this process is the
formation of polyfluorinated polynuclear aromatic comꢀ
pounds by the reaction of stable polyfluorinated arenoniꢀ
um ions with aromatic compounds stable in superacidic
media.4 The methods described for the synthesis of fluoꢀ
rineꢀcontaining biphenyls are based on radical reactions,5—8
reactions of nucleophilic substitution of the fluorine atom
in polyfluoroaromatic compounds,9,10 and various crossꢀ
coupling reactions.11—13
So, the decomposition of oxirane 1 by aluminum chloꢀ
ride and αꢀpicoline in a pentafluorobenzene solution
affords a complex mixture in which GC/MS analysis
detected products 2 (21%), 3 (3%), 4 (18%), 5 (5%),
chloropentafluorobenzene (10%), and pentafluoroꢀ
phenol (10%), as well as a number of unidentified comꢀ
pounds (Scheme 1). The reaction in the absence of
αꢀpicoline gave a mixture of products with a similar comꢀ
position. No formation of perfluoroꢀ4ꢀphenoxybiphenyl
(the product of pentafluorobenzene arylation) was obꢀ
served.
The reaction of compound 1 with benzene in the presꢀ
ence of aluminum chloride and αꢀpicoline affords a mixꢀ
ture containing compounds 2 and 4, chloropentafluoꢀ
robenzene, pentafluorophenol, and diphenylmethane, as
well as desired arylation product: 2,3,5,6ꢀtetrafluoroꢀ4ꢀ
pentafluorophenoxybiphenyl (6) (16% yield).
In a similar reaction, more electronꢀrich anisole gives
arylation products 7a,b in an overall yield of 85%.
The main distinction in the behavior of oxirane 1 from
that in the earlier studied reaction of 4,5,6,7,8ꢀpentafluoꢀ
roꢀ6ꢀnitroꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdiene3 is the retention
of the geminal OC6F5 group in the reaction products (biꢀ
phenyls 6 and 7a,b and compounds 2—4). The products in
which this group is absent are formed in a low yield, and
only pentafluorophenol is detected in the reaction with
anisole. It should be mentioned that the use of an αꢀpicoꢀ
line additive in these reactions does not play such a subꢀ
stantial role as in the earlier studied reactions of 4,5,6,7,8ꢀ
pentafluoroꢀ6ꢀnitroꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdiene3: only
slight changes in the ratio of products along with the total
decrease in the yield are observed in the absence of αꢀ
picoline.
In this work, we present the results of studying the
reactions of 4,5,6,7,8ꢀpentafluoroꢀ6ꢀpentafluorophenoxyꢀ
and 4,6,8ꢀtrifluoroꢀ5,6,7ꢀtris(pentafluorophenoxy)ꢀ1ꢀ
oxaspiro[2.5]octaꢀ4,7ꢀdienes with aromatic compounds in
the presence of acidic catalysts.
The direction of the interaction of 4,5,6,7,8ꢀpentafluoroꢀ
6ꢀpentafluorophenoxyꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdiene (1)
with arenes in the presence of aluminum chloride and
αꢀpicoline depends to a substantial extent on the electronic
effect of substituents in the aromatic ring of the substrate.
The formation of products 6 and 7a,b can be described
by Scheme 2 (cf. published data3).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1984—1989, October, 2011.
1066ꢀ5285/11/6010ꢀ2021 © 2011 Springer Science+Business Media, Inc.

2022
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 10, October, 2011
Kovtonyuk and Kobrina
Scheme 1
i. ArH, AlCl3, αꢀpicoline.
Products
6
Ar
Ph
Yield (%)
16
7a
7b
4ꢀMeOC6H4
2ꢀMeOC6H4
54
31
It can be assumed that the reaction proceeds in two
stages. At the first stage, polarized complex A or arenoniꢀ
um ion В interacts with an aromatic substrate to give cycꢀ
lohexadiene С. The formation of cyclohexadiene strucꢀ
tures by the reactions of stable polyfluorinated arenonium
ions with pentafluorobenzene is known.4 Possibly, the aroꢀ
matization of cyclohexadiene С resulting in biaryls 6 and
7a,b, proceeds through arenonium ion D. The retention of
the OC6F5 group in the reaction products can be explained
by the fact that it better stabilizes the cationic centers in
arenonium ion D compared to the fluorine atom. Analoꢀ
gous arguments were used earlier for the explanation of
the easy aromatization of 3ꢀdifluoromethoxyꢀ6ꢀnitroꢀ
hexafluorocyclohexaꢀ1,4ꢀdiene by hydrogen fluoride.14,15
It should be mentioned that the generation of stable polyꢀ
fluorinated arenonium ions by the action of Lewis acid
(SbF5) on fluorineꢀcontaining cyclohexadienes is a comꢀ
monly accepted method.15
1ꢀChloroꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxyꢀ
benzene (4) is formed in the decomposition of oxirane 1
by the action of AlCl3 probably due to the interaction of
arenonium ion В with the chloride anion, whose source is
the [AlCl3F]– anion formed in the reaction. The primary
attack of AlCl3 at the geminal unit CFOC6F5 of spirooxꢀ
irane 1 followed by oxirane ring opening gives chloroꢀ
methyl ether 2. It is known that 1ꢀoxaspiro[2.5]octaꢀ4,7ꢀ
dienꢀ6ꢀones are compounds bearing a similar spirooxirane
cycle and can give both chloroaromatic derivatives16 and
hydroquinone ethers17 under the action of acidic reagents.
Concentrated sulfuric acid turned out to be another
acidic agent catalyzing the formation of polyfluorobiareꢀ
nes from spirooxirane 1 and arenes.
Scheme 2

Polyfluoroarylation of arenes
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 10, October, 2011
2023
The reaction of oxirane 1 with benzene in the presence
of sulfuric acid affords a mixture of products containing
biaryl 6, diphenylmethane, 2,3,5,6ꢀtetrafluoroꢀ4ꢀpentaꢀ
fluorophenoxyphenol (8), 2,3,5,6ꢀtetrafluoroꢀ4ꢀpentaꢀ
fluorophenoxybenzaldehyde (5), and 2,2´,3,3´,4´,5,5´,6,6´ꢀ
nonafluorodiphenyl ether (9) (Scheme 3). The reaction of
oxirane 1 with mesitylene and naphthalene in the presence
of sulfuric acid affords biaryl 10 and a mixture of isomeric
arylnaphthalenes 11a,b, respectively, in good yields.
The formation of biaryls in the reactions of oxirane 1
with aromatic compounds in the presence of sulfuric acid
proceeds, most likely, similarly to the reactions under the
action of aluminum chloride (Scheme 4).
are products of the transformation of oxirane 1 under the
action of sulfuric acid, which was shown by us in a special
experiment. It should be mentioned that the isomerizaꢀ
tion of nonꢀfluorinated 1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdienꢀ6ꢀ
ones under the action of Lewis acids to 4ꢀhydroxybenzꢀ
aldehydes is a wellꢀknown process.18
The OC6F5 group is retained in the formed reaction
products, as well as in case where aluminum chloride
is used as an acidic agent. It could be expected that
the introduction of rather bulky substituents into the poꢀ
sitions adjacent to the geminal unit should increase
the mobility of this group. We synthesized oxirane 12
and studied its reaction with mesitylene in the presence
of sulfuric acid (Scheme 5). It turned out that the major
product of this reaction was also biaryl 13 retaining
Phenoxyphenol 8 formed by the hydrolysis of arenꢀ
onium ion F, phenoxybenzaldehyde 5, and diphenyl ether 9
Scheme 3
i. ArH, H2SO4.
Products
6
ArH
Ph
Yield (%)
18
10
11a
11b
2,4,6ꢀMeC6H2
1ꢀnaphthyl
2ꢀnaphthyl
57
45*
* Overall yield of 11a,b, ratio 11a : 11b = 9 : 1.
Scheme 4

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Russ.Chem.Bull., Int.Ed., Vol. 60, No. 10, October, 2011
Kovtonyuk and Kobrina
Compound 1 (mixture of diastereomers) was synthesized by
a procedure published earlier.2
the OC6F5 group that was in the geminal unit of comꢀ
pound 12.
1ꢀChloromethoxyꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxyꢀ
benzene (2) and 1ꢀchloroꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenꢀ
oxybenzene (4). A. Freshly sublimed AlCl3 (1.51 g, 11.3 mmol)
was added to a solution of αꢀpicoline (0.65 g, 7.0 mmol) in
pentafluorobenzene (4 mL). The solution was stirred for 15—20 min
at room temperature and cooled down to –15 to –20 °С. Then
a solution of oxirane 1 (1.12 g, 2.9 mmol) in pentafluorobenzene
(3 mL) was added dropwise with stirring. The reaction mixture
was slowly heated to room temperature within ~2 h and stirred
for more ~20 h to the complete solidification of the viscous
precipitate that formed. After 10% HCl (40 mL) was added, the
reaction mixture was extracted with CH2Cl2 (3×50 mL). The
extract was dried with CaCl2. A residue (1.32 g) after distillation
of the solvents was chromatographed on a SiO2 column. Elution
with CCl4 gave 0.83 g of a mixture of products containing, acꢀ
cording to the GC/MS data, 1ꢀchloromethoxyꢀ2,3,5,6ꢀtetraꢀ
fluoroꢀ4ꢀpentafluorophenoxybenzene (2) (21%), 1ꢀchloroꢀ2ꢀ
chloromethoxyꢀ3,4,6ꢀtrifluoroꢀ5ꢀpentafluorophenoxybenzene
(3) (3%), chloropentafluorobenzene (10%), 1ꢀchloroꢀ2,3,5,6ꢀ
tetrafluoroꢀ4ꢀpentafluorophenoxybenzene (4) (18%), pentaꢀ
fluorophenol (10%), 2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxyꢀ
benzaldehyde (5) (5%), and other unidentified products.
B. Similarly, from oxirane 1 (0.76 g, 2.0 mmol) and freshly
sublimed AlCl3 (0.81 g, 6.0 mmol) in pentafluorobenzene
(12 mL) a mixture of products was obtained (0.29 g) containing,
according to the GC/MS data, compound 2 (34%), 4 (11%),
pentafluorophenol (~3%), 2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenꢀ
oxybenzaldehyde (5) (23%), and other unidentified products.
The mixtures of products obtained in two experiments were
combined and chromatographed on a SiO2 column (elution with
petroleum ether and then with CCl4). Compound 4 (0.10 g) and
a mixture of compounds 2 and 3 (0.13 g) were isolated. A mixꢀ
ture of compounds 2 and 3 is viscous, partially crystallized at
room temperature and contains, according to the GC/MS data,
~74% of compound 2 (m/z 396 [М]+) and ~15% of compound 3
(m/z 412 [М]+).
Scheme 5
i. (1) C6F5ONa, acetone, 20 °C; (2) CH2N2, Et2O, –15 to +20 °C.
ii. 1,3,5ꢀMe3C6H3, H2SO4.
In summary, 4,5,6,7,8ꢀpentafluoroꢀ6ꢀpentafluoroꢀ
phenoxyꢀ and 4,6,8ꢀtrifluoroꢀ5,6,7ꢀtris(pentafluorophenꢀ
oxy)ꢀ1ꢀoxaspiro[2.5]octaꢀ4,7ꢀdienes (compounds 1
and 12, respectively) in the presence of AlCl3 or H2SO4
can serve as polyfluoroarylating agents for electronꢀ
rich arenes affording polyfluorinated biaryls, and the
OC6F5 group in the geminal unit of reactants 1 and 12
is retained in the reaction products.
Experimental
1
H and 19F NMR spectra (HMDS and С6F6 as internal stanꢀ
Compound 2. 19F NMR (CCl4), δ: 0.3 (2 F, Fmeta); 2.6 (1 F,
Fpara); 5.1 (2 F, Fortho); 5.8 (2 F, F(3), F(5)); 7.4 (2 F, F(2),
F(6)). 1H NMR (CCl4), δ: 5.82 (s, 2 H, OCH2Cl). HR MS, m/z:
395.9598 [М]+; calculated for C13H235ClF9O2: М = 395.9594.
Compound 3. 19F NMR (CCl4), δ: 0.3 (2 F, Fmeta); 2.5 (1 F,
Fpara); 5.8 (2 F, Fortho); 9.1 (1 F, F(3)); 11.2 (1 F, F(4)); 28.8
(1 F, F(6)). The chemical shifts of the fluorine atoms of comꢀ
pound 3 correspond to those calculated using the additive
scheme. 1H NMR (CCl4), δ: 5.86 (s, 2 H, OCH2Cl).
dards) were recorded on a Bruker AV III 400 spectrometer (specꢀ
tra of compounds 7a,b) at frequencies of 400.13 and 376.43 MHz,
respectively, and on a Bruker AV 300 spectrometer (spectra of
other compounds) at frequencies of 300.13 and 282.36 MHz,
1
respectively. Signals in the H and 19F NMR spectra were asꢀ
signed by a comparison with the spectra of pentafluorobiaryls
similar in structure.8,19,20 GC/MS analysis was carried out on
a Hewlett—Packard instrument including an НР 5890 gas
chromatograph (series II) and an НР 5971 massꢀselective detecꢀ
tor (EI, 70 eV). The HP5MS capillary column (diphenylsiloxane
(5%)—dimethylsiloxane (95%), 30 m×0.25 mm×0.25 μm), helium
as a carrier gas (1 mL min–1), temperatureꢀprogrammed mode:
Compound 4. M.p. 69.5—71 °С (petroleum ether). 19F NMR
(CCl4), δ: 0.4 (2 F, Fmeta); 3.0 (1 F, Fpara); 5.8 (2 F, Fortho); 6.2
(2 F, F(3), F(5)); 22.0 (2 F, F(2), F(6)). HR MS, m/z: 365.9494
[М]+; calculated for C1235ClF9O: М = 365.9488.
2,3,5,6ꢀTetrafluoroꢀ4ꢀpentafluorophenoxybiphenyl (6) and 1ꢀ
chloroꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxybenzene (4).
Similarly, from αꢀpicoline (0.78 g, 8.4 mmol), oxirane 1 (1.27 g,
3.3 mmol), and freshly sublimed AlCl3 (1.79 g, 13.4 mmol) in
benzene (10 mL) at 10 °С a mixture was obtained (1.41 g) conꢀ
taining, according to the GC/MS data, chloropentafluorobenꢀ
zene (~1%), pentafluorophenol (~4%), pentafluorobiphenyl
(≤0.2%), 1ꢀchloroꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxyꢀ
benzene (4) (20%), diphenylmethane (12%), 1ꢀchloromethoxyꢀ
2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxybenzene (2) (6%),
2 min at 50 °С, from 50 to 280 °С with a rate of 10 deg min–1
,
5 min at 280 °С, the temperature of the injector 280 °С, the temꢀ
perature of the ion source 175 °С, and the scan rate 1.2 scan s–1
in a mass region of 30—650 amu were used. The empirical comꢀ
position of the obtained biaryls was determined by highꢀresoluꢀ
tion mass spectra (HR MS) detected on a DFS Thermo Scientifꢀ
ic GC/MS mass spectrometer (EI, 70 eV). Elemental analysis
was carried out manually. The molecular weight of diastereoꢀ
mers of oxiranes 12 was determined on a KNAUER osmometer:
found M = 707; calculated M = 708.

Polyfluoroarylation of arenes
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 10, October, 2011
2025
2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxybiphenyl (6) (19%),
and other unidentified products. The obtained mixture of prodꢀ
ucts was chromatographed on a SiO2 column (elution with peꢀ
troleum ether) to give compound 4 (0.23 g, 19%) and biphenyl 6
(0.21 g, 16%).
perature for 5 h. After water (70 mL) was added, the reaction
mixture was extracted with CH2Cl2 (3×50 mL), and the extract
was dried with CaCl2. After the solvents were distilled off, the
residue (1.55 g) was chromatographed on a SiO2 column (elution
with petroleum ether) to give a mixture of products (0.85 g).
Product 10 was isolated by triple crystallization from petroleum
ether in a yield of 0.62 g (57%), m.p. 133—136 °С. 19F NMR
(CCl4), δ: –0.1 (2 F, Fmeta); 2.1 (1 F, Fpara); 4.9 (2 F, Fortho); 5.6
(2 F, F(3), F(5)); 22.1 (2 F, F(2), F(6)). 1H NMR (CCl4), δ: 2.25
(s, 6 H, 2 CH3); 2.41 (3 Н, СН3); 6.86 (s, 2 Н, H(3´), H(5´)).
HR MS, m/z: 450.0658 [М]+; calculated for C21H11F9О:
М = 450.0661.
Compound 6. M.p. 95—96.5 °С (petroleum ether). 19F NMR
(CCl4), δ: 0.0 (2 F, Fmeta); 2.3 (1 F, Fpara); 4.6 (2 F, Fortho); 5.9
1
(2 F, F(3), F(5)); 18.8 (2 F, F(2), F(6)). H NMR (CCl4), δ:
7.36—7.46 (m, 5 Н). HR MS, m/z: 408.0191 [М]+; calculated
for C18H5F9O: М = 408.0191.
4´ꢀMethoxyꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxybiꢀ
phenyl (7a) and 2´ꢀmethoxyꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluoroꢀ
phenoxybiphenyl (7b). Similarly, from oxirane 1 (1.07 g, 2.8 mmol),
freshly sublimed AlCl3 (1.51 g, 11.3 mmol), and αꢀpicoline
(0.65 g, 7.0 mmol) in anisole (6.5 mL) a mixture (2.43 g) was
obtained containing biaryls 7a and 7b (7a : 7b = 56 : 44 accordꢀ
ing to the GC/MS data). The obtained mixture was chromatoꢀ
graphed on a SiO2 column (elution with a mixture of petroleum
ether and CCl4 (gradient from 1 : 1 to 1 : 4)) to give individual
compounds 7a (0.67 g, 54%) and 7b (0.38 g, 31%).
Compound 7a. M.p. 135.5—137.5 °С (petroleum ether).
19F NMR (CCl4—CDCl3 (4 : 1)), δ: 0.0 (2 F, Fmeta); 2.2 (1 F, Fpara);
4.4 (2 F, Fortho); 5.9 (2 F, F(3), F(5)); 18.2 (2 F, F(2), F(6)).
1H NMR (CCl4—CDCl3 (4 : 1)), δ: 3.85 (s, 3 H, OCH3); 6.97
(d, 2 Н, J = 8.8 Hz); 7.34 (d, 2 H, J = 8.8 Hz). HR MS, m/z:
438.0295 [М]+; calculated for C19H7F9O2: М = 438.0297.
Compound 7b. M.p. 69—71 °С (petroleum ether). 19F NMR
(CCl4—CDCl3 (4 : 1)), δ: –0.1 (2 F, Fmeta); 2.0 (1 F, Fpara); 3.7
(2 F, Fortho); 6.0 (2 F, F(3), F(5)); 21.9 (2 F, F(2), F(6)). 1H NMR
(CCl4—CDCl3 (4 : 1)), δ: 3.82 (s, 3 H, OCH3); 6.99 (d, 1 Н,
J = 8.3 Hz); 7.03 (t, 1 Н, J = 7.5 Hz); 7.20 (d, 1 Н, J = 7.5 Hz);
7.41 (dd, 1 Н, J = 8.3 Hz, J = 7.5 Hz). HR MS, m/z: 438.0296
[М]+; calculated for C19H7F9O2: М = 438.0297.
1ꢀ(2,3,5,6ꢀTetrafluorophenylꢀ4ꢀpentafluorophenoxy)naphthꢀ
alene (11a). Concentrated sulfuric acid (2.6 g) was added dropꢀ
wise with stirring to a solution of naphthalene (5.60 g, 44 mmol)
and oxirane 1 (0.83 g, 2.2 mmol) in dichloromethane (10 mL)
cooled to approximately –10 °С. After 30 min, cooling was reꢀ
moved and the reaction mixture was stirred at room temperature
for 1.5 h. After water (50 mL) was added, the reaction mixture
was extracted with CH2Cl2 (3×50 mL) and the extract was dried
with CaCl2. After CH2Cl2 was distilled off, the residue was
chromatographed on a SiO2 column (elution with petroleum
ether) to give naphthalene (4.2 g) and a mixture (0.45 g, 45%).
According to the 19F NMR spectral data, the mixture contained
~90% of αꢀarylnaphthalene 11a and ~10% of βꢀarylnaphthalene
1
11b. H NMR of arylnaphthalenes 11a,b (CCl4), δ: 7.46—7.62
(m); 7.82—8.01 (m). Found (%): С, 58.04; Н, 1.53; F, 37.43.
C22H7F9O. Calculated (%): С, 57.66; Н, 1.54; F, 37.31. HR MS,
m/z: 458.0352 [M]+; calculated for C22H7F9O: M = 458.0348.
Compound 11a. 19F NMR (CCl4), δ: 0.2 (2 F, Fmeta); 2.4
(1 F, Fpara); 6.0 (2 F, Fortho); 5.0 (2 F, F(3), F(5)); 22.9 (2 F, F(2),
F(6)).
Compound 11b. 19F NMR (CCl4), δ: 0.2 (2 F, Fmeta); 2.4
(1 F, Fpara); 6.0 (2 F, Fortho); 4.8 (2 F, F(3), F(5)); 19.0 (2 F,
F(2), F(6)).
2,3,5,6ꢀTetrafluoroꢀ4ꢀpentafluorophenoxybiphenyl (6) and
2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxyphenol (8). Concentratꢀ
ed sulfuric acid (2.0 g) was added dropwise to a solution of oxiꢀ
rane 1 (0.85 g, 2.2 mmol) in benzene (10 mL) cooled to ~6 °С.
The mixture was stirred at room temperature for 2 h. After water
(60 mL) was added, the reaction mixture was extracted with
CH2Cl2 (3×50 mL), and the extract was dried with CaCl2. After
the solvents were distilled off, the residue (1.05 g) was chroꢀ
matographed on a SiO2 column. The consecutive elution with
petroleum ether, CCl4, and CHCl3 gave a mixture of products
2,3,5,6ꢀTetrafluoroꢀ4ꢀpentafluorophenoxyphenol (8) and
2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenoxybenzaldehyde (5).
A freshly prepared and cooled to approximately –10 °С solution
of diazomethane obtained from 0.7 g of NꢀnitrosoꢀNꢀmethylꢀ
urea in diethyl ether (20 mL) was added dropwise with stirring to
a solution of perfluoroꢀ4ꢀphenoxycyclohexaꢀ2,5ꢀdienone (0.73 g,
2.0 mmol) in diethyl ether (10 mL) cooled to approximately
–15 °С. The reaction mixture was stirred for 16 h, gradually
raising the temperature to ambient one. After diethyl ether was
distilled off, concentrated sulfuric acid (2.0 g) was added dropꢀ
wise with stirring to a solution of the residue in CH2Cl2 (5 mL)
cooled to ~0 °С. The mixture was stirred at room temperature
for 20 h. After water (50 mL) was added, the reaction mixture
was extracted with CH2Cl2 (3×50 mL) and the extract was dried
with CaCl2. After the solvent was distilled off, the residue was
chromatographed on a SiO2 column (elution successively with
CCl4 and CHCl3) to give two fractions. According to the
19F NMR spectral data, fraction 1 (0.14 g) contained diphenyl
ether 9 (~15%), phenoxybenzaldehyde 5 (~65%), and other unꢀ
identified products. Signals of compound 5 in the 19F NMR
spectrum of fraction 1 (CHCl3), δ: 0.8 (2 F, Fmeta); 3.9 (1 F,
Fpara); 6.0 (2 F, Fortho); 6.2 (2 F, F(3), F(5)); 17.6 (2 F, F(2),
F(6)). HR MS, m/z: 360 [М]+, 358.9750 [М – 1]+; calculated
for C13HF9O2: М = 360, [М – 1] = 358.9749. Fraction 2 (0.51 g)
contains phenoxyphenol 8, the yield was 73%, m.p. 104—106 °С
(cf. Ref. 22: 106 °С).
1
(0.27 g), which contained, according to the 19F and Н NMR
spectral data, ~4% of diphenyl ether 9, ~70% of biphenyl 6, and
a crystalline product (0.45 g) containing, according to the
19F NMR spectral data, ~95% of phenoxyphenol 8. Diphenyl
ether 9 was identified on the basis of the GC/MS data and a comꢀ
parison with the 19F NMR spectrum of the product described in
the literature.21 Biphenyl 6 (0.16 g, 18%) was isolated by crystalꢀ
lization from petroleum ether. Phenoxyphenol 8 (0.35 g, 45%)
was isolated by sublimation.
Compound 8. M.p. 105—107 °С (sublimation) (cf. Ref. 22:
106 °С). 19F NMR (CHCl3), δ: –0.4 (2 F, Fmeta); –0.3 (2 F, F(2),
F(6)); 1.3 (1 F, Fpara); 2.5 (2 F, F(3), F(5)); 5.3 (2 F, Fortho). MS,
m/z: 348 [М]+.
2´,4´,6´ꢀTrimethylꢀ2,3,5,6ꢀtetrafluoroꢀ4ꢀpentafluorophenꢀ
oxybiphenyl (10). A solution of oxirane 1 (0.90 g, 2.4 mmol) in
mesitylene (4 mL) was added dropwise with stirring to a mixture
of concentrated sulfuric acid (2.0 g) and mesitylene (4 mL) cooled
to approximately –15 °С. The mixture was stirred at room temꢀ

2026
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 10, October, 2011
Kovtonyuk and Kobrina
4,6,8ꢀTrifluoroꢀ5,6,7ꢀtris(pentafluorophenoxy)ꢀ1ꢀoxaspiroꢀ
[2.5]octaꢀ4,7ꢀdiene (12). Sodium pentafluorophenoxide (0.90 g,
4.0 mmol) was added dropwise with stirring at room temperature
to a solution of perfluoroꢀ4ꢀphenoxycyclohexaꢀ2,5ꢀdienone
(0.73 g, 2.0 mmol) in acetone (20 mL). The solution was stirred
for 30 min, and the solvent was distilled off in vacuo (20 Torr,
Тbath ≤ 20 °С). The solid residue was dissolved in diethyl
ether (20 mL). A solution of diazomethane obtained from 0.7 g
of NꢀnitrosoꢀNꢀmethylurea in diethyl ether (20 mL) cooled
to approximately –15 °С was added dropwise with stirring. The
reaction mixture was stirred for 16 h, gradually raising the tempeꢀ
rature to ambient one. After diethyl ether was distilled off, the
residue was chromatographed on a SiO2 column (elution with
CCl4) to give a viscous oil in a yield of 1.15 g (82%). According
to the 19F NMR spectral data, the oil was a mixture of diastereoꢀ
mers 12 in a ratio of 58 : 42. Found (%): С, 42.83; Н, 0.48;
F, 48.31. C25H2F18O4. Calculated (%): С, 42.40; Н, 0.28; F, 48.28.
Diastereomer 1. 19F NMR (CCl4—CDCl3 (4 : 1)), δ: –0.5
(2 F, Fmeta); 0.1 (4 F, Fmeta´); 2.4 (2 F, Fpara´); 4.7 (1 F, Fpara);
5.4 (4 F, Fortho´); 9.8 (2 F, Fortho); 12.7 (2 F, F(4), F(8)); 52.2
(1 F, F(6)).
2. V. N. Kovtonyuk, L. S. Kobrina, O. M. Kataeva, G. Haufe,
Eur. J. Org. Chem., 2005, 1178.
3. V. N. Kovtonyuk, L. S. Kobrina, G. Haufe, Izv. Akad. Nauk,
Ser. Khim., 2008, 1654 [Russ. Chem. Bull., Int. Ed., 2008,
57, 1686].
4. Yu. V. Pozdnyakovich, V. D. Shteingarts, Zh. Org. Khim.,
1977, 13, 1911 [J. Org. Chem. USSR (Engl. Transl.), 1977,
13, 1772].
5. L. S. Kobrina, J. Fluor. Chem., 1989, 42, 301.
6. P. H. Oldham, G. H. Williams, J. Chem. Soc. C, 1970, 1260.
7. D. Kosynkin, T. M. Bockman, J. K. Kochi, J. Am. Chem.
Soc., 1997, 119, 4846.
8. Q.ꢀYu. Chen, Zh.ꢀT. Li, J. Org. Chem., 1993, 58, 2599.
9. A. B. Sigalov, E. S. Petrov, I. P. Beletskaya, Izv. Akad. Nauk
SSSR, Ser. Khim., 1984, 2386 [Bull. Acad. Sci. USSR, Div.
Chem. Sci. (Engl. Transl.), 1984, 33, 2181].
10. M. T. Chaudhry, R. Stephens, J. Chem. Soc., 1963, 4281.
11. R. C. Smith, C. R. Bodner, M. J. Earl, N. C. Sears, N. E.
Hill, L. M. Bishop, N. Sizemore, D. T. Hehemann, J. J.
Bohn, J. D. Protasiewicz, J. Organomet. Chem., 2005,
690, 477.
Diastereomer 2. 19F NMR (CCl4—CDCl3 (4 : 1)), δ: –0.4
(2 F, Fmeta); 0.1 (4 F, Fmeta´); 2.4 (2 F, Fpara´); 4.7 (1 F, Fpara);
5.2 (4 F, Fortho´); 10.3 (2 F, Fortho); 13.8 (2 F, F(4), F(8)); 50.9
(1 F, F(6)).
12. L. D. Field, T. W. Hambley, G. K. Pierens, Tetrahedron,
1990, 46, 7069.
13. W. A. Sheppard, J. Am. Chem. Soc., 1970, 92, 5419.
14. A. A. Shtark, Ph. D. (Chem.) Thesis, Institute of Organic
Chemistry, Siberian Branch of the Russian Academy of Sciꢀ
ences, Novosibirsk, 1976, 144 pp. (in Russian).
15. V. D. Shteingarts, L. S. Kobrina, I. I. Bil´kis, V. F. Starꢀ
ichenko, Khimiya poliftorarenov: mekhanizm reaktsii, interꢀ
mediaty [Chemistry of Polyfluoroarenes: Reaction Mechanism
and Intermediates], Nauka, Sib. Otd., Novosibirsk, 1991, p. 5
(in Russian).
16. B. Eistert, G.Bock, Chem. Ber., 1959, 92, 1247.
17. G. M. Salamonczyk, V. B. Oza, C. J. Sih, Tetrahedron Lett.,
1997, 38, 6965.
18. B. Eistert, H. Fink, A. Müller, Chem. Ber., 1962, 95, 2403.
19. T. Korenaga, T. Kosaki, R. Fukumura, T. Ema, T. Sakai,
Org. Lett., 2005, 7, 4915.
2´,4´,6´ꢀTrimethylꢀ2,6ꢀdifluoroꢀ3,4,5ꢀtris(pentafluorophenꢀ
oxy)biphenyl (13). Concentrated sulfuric acid (2.0 g) was added
dropwise with stirring to a solution of oxirane 12 (1.10 g,
1.6 mmol) in mesitylene (8 mL) cooled to –5 °С. The mixture
was stirred for 1 h, gradually rising the temperature to room
temperature. After water (50 mL) was added, the reaction mixꢀ
ture was extracted with CH2Cl2 (3×50 mL) and the extract was
dried with CaCl2. After the solvent and mesitylene excess were
distilled off, the residue (1.35 g) was chromatographed on a SiO2
column (elution with petroleum ether). According to the 1H NMR
spectral data, the viscous oil isolated (0.91 g) contained ~74% of
biphenyl 13. Biphenyl 13 was obtained by triple crystallization
from petroleum ether in a yield of 0.52 g (42%), m.p. 129—132 °С.
19F NMR (CCl4), δ: 0.1 (4 F, Fmeta´); 0.2 (2 F, Fmeta); 1.3 (2 F,
20. M. Lafrance, D. Shore, K. Fagnou, Org. Lett., 2006, 8, 5097.
21. R. J. Pasquale, C. Tamborski, J. Org. Chem., 1967, 32, 3163.
22. L. Denivelle, HuynhꢀAnhꢀHoa, Bull. Soc. Chim. Fr.,
1974, 487.
F
para´); 1.9 (1 F, Fpara); 3.8 (4 F, Fortho´); 4.8 (2 F, Fortho); 30.7
(2 F, F(2), F(6)). 1H NMR (CCl4), δ: 2.27 (s, 6 H, 2 CH3); 2.44
(s, 3 Н, СН3); 6.88 (s, 2 Н, H(3´), H(5´)). HR MS, m/z: 778.0424
[М]+; calculated for C33H11F17O3: М = 778.0431.
References
1. L. S. Kobrina, Izv. Akad. Nauk, Ser. khim., 2002, 1629 [Russ.
Chem. Bull., Int. Ed., 2002, 51, 1775].
Received July 20, 2010;
in revised form April 22, 2011