Formation of fluorene and anthracene derivatives in reactions of perfluorinated 1-alkyl-1-phenyl- and 1-alkyl-2-phenyl-1,2- dihydrocylobutabenzenes with antimony pentafluoride

Article abstract of DOI:10.1134/S1070428011070098

The reaction of perfluoro(1-methyl-1-phenyl-1,2-dihydrocyclobutabenzene) with SbF₅ at 50°C, followed by hydrolysis, gave perfluoro(1-phenylindan-1-ol), while analogous reaction at 90°C afforded perfluoro[ 10-methylanthracen-9(10H)-one]. Perfluo

Full text of DOI:10.1134/S1070428011070098

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol. 47, No. 7, pp. 1018–1025. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © T.V. Mezhenkova, V.M. Karpov, V.E. Platonov, 2011, published in Zhurnal Organicheskoi Khimii, 2011, Vol. 47, No. 7,
pp. 1004–1011.
Formation of Fluorene and Anthracene Derivatives in Reactions
of Perfluorinated 1-Alkyl-1-phenyl- and 1-Alkyl-2-phenyl-
1,2-dihydrocylobutabenzenes with Antimony Pentafluoride
T. V. Mezhenkova, V. M. Karpov, and V. E. Platonov
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences,
pr. Akademika Lavrent’eva 9, Novosibirsk, 630090 Russia
e-mail: mtv@nioch.nsc.ru
Received December 28, 2010
Abstract—The reaction of perfluoro(1-methyl-1-phenyl-1,2-dihydrocyclobutabenzene) with SbF5 at 50°C,
followed by hydrolysis, gave perfluoro(1-phenylindan-1-ol), while analogous reaction at 90°C afforded per-
fluoro[10-methylanthracen-9(10H)-one]. Perfluoro(1-methyl-2-phenyl-1,2-dihydrocyclobutabenzene) did not
undergo skeletal transformations under analogous conditions, whereas at 200°C it was converted mainly into
perfluoro(9-methylfluoren-9-ol). Perfluoro(1-ethyl-2-phenyl-1,2-dihydrocyclobutabenzene) reacted with SbF5
at 200°C to form perfluoro(9-ethylfluoren-9-ol) together with perfluorinated 9,9-dimethyl- and 9-ethyl-9-
methyl-1,2,3,4-tetrahydro-9H-fluorenes.
DOI: 10.1134/S1070428011070098
Reactions of perfluorinated 1-alkyl- and 1,1- and
1,2-dialkyl-1,2-dihydrocyclobutabenzenes with anti-
mony pentafluoride involve expansion or cleavage of
the four-membered ring with formation of polyfluori-
nated indans, o-alkylstyrenes, or 1,2-dialkylbenzenes
[1]. Perfluoro[1-(2- or 4-ethylphenyl)-1,2-dihydrocy-
clobutabenzenes] [2] and perfluoro(1-ethyl-1-phenyl-
1,2-dihydrocyclobutabenzene) [3] react with SbF5 to
give products of four-membered ring opening, which
then undergo cyclization to anthracene or fluorene
derivatives. On the other hand, no skeletal transforma-
tions of perfluoro(1-phenyl-1,2-dihydrocyclobutaben-
zene) occurs under analogous conditions [2]. Opening
of the four-membered ring in the reaction of perfluoro-
(1,2-diethyl-1-phenyl-1,2-dihydrocyclobutabenzene)
with SbF5 is accompanied by expansion of the six-
membered aromatic ring to seven-membered [4].
With a view to elucidate joint effect of perfluoro-
alkyl and perfluoroaryl groups on the direction of skel-
etal transformations of polyfluorinated cyclobutaben-
zenes, in the present work we studied the behavior of
perfluorinated 1-methyl-1-phenyl-, 1-methyl-2-phenyl-,
and 1-phenyl-2-ethyl-1,2-dihydrocyclobutabenzenes
I–III in antimony pentafluoride.
C6F5H in SbF5 at 25°C, which led to the formation of
a mixture of compounds I and II. It was found that
1,1-isomer I undergoes partial isomerization into
1-(2-methylphenyl)-1-phenylethene (V) [5] during the
process. When a mixture of compounds I and II {gen-
erated together with HF from methylbenzocyclobutene
IV and pentafluorobenzene in the presence of SbF5
[5]} was treated with SbF5 at 50°C, followed by hy-
drolysis, 1,1-isomer I was converted into perfluoro-
(1-phenylindan-1-ol) (VI), while at 90–130°C per-
fluoro[10-methylanthracen-9(10H)-one] (VII) was ob-
tained. The bicyclic skeleton in isomer II remained
intact under analogous conditions; the reaction of II
with SbF5 gave the corresponding salt containing
perfluoro(2-methyl-1-phenyl-1,2-dihydrocyclobuta-
benzen-1-yl) cation (VIII), whose hydrolysis afforded
perfluoro-(2-methyl-1-phenyl-1,2-dihydrocyclobuta-
benzen-1-ol) (IX) (Scheme 1). Cation VIII can also be
generated by dissolution of individual isomer II in the
system SbF5–SO2ClF.
Heating of isomer mixture I/II (obtained as de-
scribed above) with SbF5 at 170°C resulted in only
partial transformation of isomer II. After appropriate
treatment, the product mixture contained mainly com-
pound IX and small amounts of perfluorinated an-
throne VII, perfluoro(2-ethylbenzophenone) (X), and
We previously studied the reaction of perfluoro-
(1-methyl-1,2-dihydrocyclobutabenzene) (IV) with
1018

FORMATION OF FLUORENE AND ANTHRACENE DERIVATIVES
1019
Scheme 1.
3
CF3
CF2
C
2
4
5
F
F
H2O
C6F5
6'
1
F
6
5'
F
CF3
2'
HO C6F5
F
4'
CF3
OH
3'
50°C
VIII
V
F
+
F
F
C6F5
SbF5
SbF5
25°C
VI
IX
CF3
F
CF3
CF3
C6F5
(1) SbF5
(2) H2O 90_130°C
F
F
+
+ HF
F
F
F
F
IX
+
C6F5
O
II
I
VII
X
CF3
CF2CF3
COC6F5
170°C
F
F
F
VII
+
IX
+
+
C6F5H SbF5
CF3
X
XI, XII
F
F
CF3
9
H
CF3
X
F
H
CF3
1
8
F
5
7
6
IV
2
F
F
F
4
F
F
F
+
+
+
3
O
XIII
XIV
XV, XVI
CF3
CF3
200°C
F
F
F
VII
+
XI–XVI
+
XVII
XI, X = OH; XII, XV, X = F; XVI, X = CF3.
Expansion of the four-membered ring in I to five-
membered in the reaction with SbF5 may be ration-
alized in a way similar to that proposed previously for
polyfluoroalkylcyclobutabenzenes [1]. Elimination of
fluoride ion from molecule I by the action of SbF5
gives cation A which undergoes isomerization to
benzyl type cation B via opening of the four-mem-
bered ring (Scheme 2). Addition of fluoride ion to B
yields styrene V [5], and cyclization leads to phenyl-
indanyl cation XVIII. The latter takes up fluoride ion
with formation of perfluoro(1-phenylindan) (XIX),
while hydrolysis of XVIII affords indanol VI [6].
perfluoro(9-methylfluoren-9-ol) (XI); in addition, per-
fluoro(9-methylfluorene) (XII), polyfluorinated
10-methylanthrone XIII, 2,2,3,3,4,5,5,6,6,7,7,8,8-tri-
decafluoro-1,9-bis(trifluoromethyl)-2,3,5,6,7,8-hexa-
hydro-1H-cyclopenta[b]naphthalene (XIV), perfluoro-
(1,2,3,4,5,6,7,8-octahydroanthracene) (XV), and per-
fluoro(9-methyl-1,2,3,4,5,6,7,8-octahydroanthracene)
(XVI) were detected as impurities. Raising the reaction
temperature to 200°C led to complete conversion of
isomeric methylphenylcyclobutabenzenes I and II, and
the product mixture contained fluorenol XI as the
major product together with compounds VII and XII–
XVI and perfluoro(1,9-dimethyl-2,3,5,6,7,8-hexahy-
dro-1H-cyclopenta[b]naphthalene) (XVII) (Scheme 1).
Presumably, change of the reaction direction upon
raising the temperature to 90°C is related to the pres-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 7 2011

MEZHENKOVA et al.
1020
Scheme 2.
CF2
C6F5
CF2
C
C6F5
SbF5
–F–
H2O
C6F5
I
F
F
F
F
VI
F
CF2
A
B
XVIII
F– –F–
F– –F–
C6F5
CF3
CF3
H
CH
HF
SbF5
–F–
C6F5
V
F
F
F
F
F
+
CF3
XX
CF2
XIX
CF3
F
CF3
F
CF3
F
H
CF3
F–
SbF5
H2O
F
F
F
F
F
F
F
F
F
VII
–H+
–F–
ence of HF in the system I–SbF5. By special experi-
ments we showed that the reaction of I with SbF5 in
the absence of HF at both 90°C and 50°C gives
indanol VI rather than anthrone VII. According to our
previous data [5], HF adds to styrene V with formation
of 1,1,1-trifluoro-2-pentafluorophenyl-2-(2-trifluoro-
methyltetrafluorophenyl)ethane (XX). Presumably, the
addition of HF to styrene V with formation of com-
pound XX at 90°C occurs at a much higher rate than
the transformation of V into phenylindan XIX, where-
as compound XX undergoes cyclization as shown in
Scheme 2 to produce anthrone VII as final product.
Analogous mechanism was considered by us previ-
ously while studying cyclization of perfluoro(4-ethyl-
2′-methyldiphenylmethane) to perfluoro(2-ethyl-9,10-
dihydroanthracene) [2]. By special experiment we
showed that anthrone VII is not formed in the reaction
of phenylindan XIX with antimony pentafluoride in
the presence of HF at 130°C.
and XV–XVII [6]. Cation D can also take up fluoride
ion to form styrene E. Addition of HF to E leads to
diarylmethane F, and fluorination of E leads to per-
fluoro(2-ethyldiphenylmethane) (XXI). As shown in
[7], the reaction of XXI with SbF5 generates perfluoro-
(2-ethyldiphenylmethyl) cation (XXII), and hydrolysis
of XXII yields perfluorinated 2-ethylbenzophenone X.
Scheme 3 illustrates possible pathways of transforma-
tion of diarylmethanes F and XXI into reaction prod-
ucts. Benzyl cation G generated from diarylmethane F
undergoes cyclization via attack by the cationic center
on the pentafluorophenyl group, and subsequent addi-
tion of fluoride ion yields structure H. Defluorination
of the latter leads to dihydroanthracene J whose hy-
drolysis leads to anthrone XIII.
The formation of anthrone VII from diarylmethane
XXI may follow an analogous pattern through ben-
zylic cation K along path 1–1a. Concurrent isomeriza-
tion of K according to path 2 gives cation L as a result
of intramolecular attack by the cationic center on the
pentafluorophenyl carbon atom linked to the CF2
group, and ion L is then converted into diarylmethyl
cation M (path 2a). Cyclization of M via attack by the
positively charged ortho-carbon atom in one C6F5 ring
on the other aromatic ring and subsequent elimination
of trifluoromethyl cation produce structure N which
loses fluoride ion (by the action of SbF5), thus gen-
erating perfluoro(9-methylfluoren-9-yl) cation
(XXIII). The latter is stabilized by addition of fluoride
As we already noted (Scheme 1), compound II in
SbF5 gives rise to stable perfluoro(2-methyl-1-phenyl-
1,2-dihydrocyclobutabenzen-1-yl) cation (VIII), so
that skeletal transformations of compound II require
more severe conditions as compared to isomer I. Pre-
sumably, the four-membered ring is opened in cation C
(Scheme 3) to produce benzyl type cation D. Cy-
clization of D, followed by addition of fluoride ion,
can give phenylindan XIX, and reaction of the latter
with SbF5 at 170°C leads to compounds VII, XI–XIII,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 7 2011

FORMATION OF FLUORENE AND ANTHRACENE DERIVATIVES
1021
Scheme 3.
H
CF3
H
CF3
CHCF3
CHFCF3
CF2C6F5
F–
H2O
XIII
F
F
F
F
F
F
F
F
–F–
–F–
–[2F]
CF2C6F5
J
H
G
F
HF
CF2
CF2CF3
CF2CF3
CF=CF2
CFC6F5
CF=CF2
CF2C6F5
F–
[F]
F
II
F
F
F
F
F
–F–
–F–
CFC6F5
XXII
H2O
CF2C6F5
XXI
C6F5
C
D
E
F–
XIX
–F–
X
CF3
CF3
C
CF3
CF3
F
C
C
F–
F
F
F
F
F
F
F
F
–F–
Path 2
CF3
CF2
CF2C6F5
CF3
Path 2a
M
L
K
F–
Path 2b
–CF3
SbF5
XVII
XVI
Path 1
CF3
[F]
F
F
F
CF3
F
CF3
CF3
H
F
F
F–
[F]
HF
N
F
F
F
F
F
F
F
–F–
–F–
Path 1c
O
P
CF3
Path 1b
SbF5
–[2F]
Path 1a
–F–
F
F
XIV
XXIII
CF3
F
CF3
H2O
XI
F–
F
F
F
F
F
F
XII
–F–
–CF3
F–
H2O
H2O
VII
XV
F
F
–F–
ion to give methylfluorene XII or by hydrolysis with
formation of methylfluorenol XI [6]. Cyclization of
cation L can also follow path 2b; addition of fluoride
anion yields compound O whose further transforma-
tions along paths 1b and 1c lead to compound XV and
structures P and XVI, respectively (Scheme 3). Con-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 7 2011

MEZHENKOVA et al.
1022
Scheme 4.
X
C2F51
CF3
C2F5
8
F
5
C2F5
C6F5
C2F5
(1) SbF5, 170°C
(2) H2O
CF2C2F5
C6F5
O
2
3
9
7
6
F
F
F
F
+
F
+
F
F
F
+
OH
C6F5
4
III
XXV
XXVI
XXVII, XXVIII
XXIX
C2F5
C6F5
SbF5
H2O
F
F
XXIV
CF3
CF3
C2F5
(1) SbF5, 200°C
(2) H2O
C6F5H, SbF5
F
F
F
F
III + HF
XV + XXVII + XXVIII + XXIX +
XXX
XXXI
XXVII, X = F; XXVIII, X = OH.
Scheme 5.
CFCF3
CF=CFCF3
CF2CF2CF3
CF2C6F5
CF2CF2CF3
CFC6F5
F–
F–
[F]
III
F
F
F
F
F
–F–
–F–
CFC6F5
C6F5
Q
R
XXXII
XXXIII
H2O
XXVI
XXIX
–F–
F–
CF2CF3
CF2CF3
C
CF2CF3
F
F
CF2CF3
F
F–
–F–
F
F
F
F
F
F
F
CF3
CF2
CF3
F
F
F
XXXIV
T
S
–CF3
CF2CF3
CF2CF3
F–
[F]
F
F
F
F
F
F
F
F
XV
–F–
–CF3CF2
F
F
U
–F–
CF2CF3
F–
F3C
CF2
XXVII
F–
[F]
F
F
F
F
XXXI
H2O
XXVIII
W
Y
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 7 2011

FORMATION OF FLUORENE AND ANTHRACENE DERIVATIVES
1023
affords compound XXXI. Cyclization of cation T,
followed by elimination of pentafluoroethyl cation,
migration of double bonds, and fluorination, results in
formation of compound XV (Scheme 5).
traction of the six-membered ring in P and XVI by the
action of SbF5 produces compounds XIV and XVII;
analogous transformations were observed previously
for perfluorotetralin and perfluoro(5-ethyltetralin) in
antimony pentafluoride [8, 9].
The structure of compounds XIV, XXVII, XXVIII,
and XXXI was determined on the basis of their high-
resolution mass spectra and 19F NMR spectra. The
other products were identified by comparing their 19F
NMR spectra with those of authentic samples (VI, VII,
XI–XIII, XV–XVII, XIX [6], IX [5], XXV [10],
XXIX [3]).
Like methyl-substituted analog II, perfluoro-
(1-ethyl-2-phenyl-1,2-dihydrocyclobutabenzene) (III)
in SbF5 give rise to stable perfluoro(2-ethyl-1-phenyl-
1,2-dihydrocyclobutabenzen-1-yl) cation (XXIV);
after treatment with water, cation XXIV is converted
into perfluoro(2-ethyl-1-phenyl-1,2-dihydrocyclobuta-
benzen-1-ol) (XXV) [10] (Scheme 4). The reaction of
III with SbF5 at 170°C, followed by hydrolysis of the
reaction mixture, gave perfluoro(2-propylbenzophe-
none) (XXVI) together with perfluorinated 9-ethyl-
fluorene XXVII, 9-ethylfluoren-9-ol (XXVIII),
9-ethyl-9-methyl-1,2,3,4-tetrahydro-9H-fluorene
(XXIX), and compound XXV (Scheme 4). Fluorenol
XXVIII was formed as the major product in the reac-
tion of compound III {generated in a mixture with HF
from perfluoro(1-ethyl-1,2-dihydrocyclobutabenzene)
(XXX) and pentafluorobenzene in SbF5 [10]} with
antimony pentafluoride at 200°C, the conversion of III
being complete. In addition, compounds XV, XXVII,
and XXIX and perfluoro(9,9-dimethyl-1,2,3,4-tetra-
hydro-9H-fluorene) (XXXI) were formed.
EXPERIMENTAL
The 19F NMR spectra of reaction mixtures and of
a solution containing cation VIII (SbF5–SO2ClF) were
recorded on Bruker WP-200SY and AC-200 spectrom-
eters (188.3 MHz). The 19F NMR spectra of solutions
of individual compounds XIV, XXVII, XXVIII, and
1
XXXI in CDCl3 and the H NMR spectrum of XIV
were measured on a Bruker AV-300 instrument at
282.4 and 300 MHz, respectively. The chemical shifts
are given relative to C6F6 (19F) and TMS (1H); C6F6
and SO2ClF (δF 262.8 ppm) were used as internal
references for 19F, and 1H chemical shift was measured
relative to the residual proton signal of the solvent
(CHCl3, (δ 7.24 ppm). The elemental compositions
were determined from the high-resolution mass spectra
which were obtained on Finnigan MAT 8200 (XXVII,
XXVIII, XXXI) and Thermo Electron Corporation
DFS instruments (XIV). GLC analysis was performed
on an LKhM-72 chromatograph; 4000×4-mm column
packed with SKTFT-50 on Chromosorb W (15:100);
carrier gas helium, flow rate 60 ml/min; oven tempera-
ture programming from 50 to 270°C.
Possible paths for transformation of perfluoro-
(1-ethyl-2-phenyl-1,2-dihydrocyclobutabenzene) (III)
into compounds XV, XXVI–XXIX, and XXXI are
shown in Scheme 5. Opening of the four-membered
ring is likely to occur in intermediate cation Q which is
thus converted into diarylmethyl cation R; addition of
fluoride ion to the latter and subsequent fluorination
yields perfluoro(2-propyldiphenylmethane) (XXXII).
Hydrolysis of perfluoro(2-propyldiphenylmethyl)
cation (XXXIII) generated from XXXII leads to com-
pound XXVI [7]. Presumably, fluorene derivatives are
formed as a result of cyclization of intermediate diaryl-
methane XXXII. Isomerization of benzyl cation S
derived from XXXII gives cation T which is converted
into perfluoro[1-(2-methylphenyl)-1-phenylpropyl]
cation (XXXIV). The latter was reported by us previ-
ously, and its transformation into compound XXIX
was also considered [3]. Cyclization of XXXIV to
structure U is accompanied by elimination of trifluoro-
methyl cation, and intermediate U in SbF5 gives rise to
ethylfluorenyl cation W. Addition of fluoride ion to
cation W yields ethylfluorene XXVII, hydrolysis of W
leads to fluorenol XXVIII, while isomerization via
1,2-migration of the CF3 group produces cation Y. The
latter takes up fluoride ion, and subsequent fluorination
Reaction of perfluoroinated 1-methyl-1-phenyl-
and 1-methyl-2-phenyl-1,2-dihydrocyclobutaben-
zenes I and II (mixture of isomers) with SbF5.
a. Pentafluorobenzene, 0.45 g (2.68 mmol), was added
over a period of 5 min to a solution of 0.73 g
(2.45 mmol) of perfluoro(1-methyl-1,2-dihydrocyclo-
butabenzene) (IV) in 3.2 g (14.76 mmol) of SbF5
under stirring at 15°C. The mixture was stirred for 2 h
at 15°C and was kept for 15 h at that temperature
without stirring. The resulting mixture of compounds I
and II and HF [5] was stirred for 6 h at 50°C, cooled to
0°C, transferred into an ice–water mixture, and ex-
tracted with methylene chloride. The extract was dried
over MgSO4, and the solvent was distilled off to obtain
1.03 g of a mixture of compounds VI and IX at a ratio
of 9:91 (19F NMR).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 7 2011

MEZHENKOVA et al.
1024
b. A mixture prepared in a similar way from 0.73 g
97.2 (3F, 1-CF3), 107.9 (3F, 9-CF3); J4,5A = 12, J4,5B
=
35, J9,8A = 27, J9,8B = 31 Hz. Found: m/z 541.9754
(2.45 mmol) of compound IV, 0.41g (2.44 mmol) of
pentafluorobenzene, and 3.19 g (14.71 mmol) of SbF5
was heated for 10 h at 90°C in a 10-ml nickel high-
pressure reactor. The mixture was treated as described
above to obtain 0.98 g of a mixture of compounds VII
and IX at a ratio of 11:89 (19F NMR).
[M]+. C16HF19. Calculated: M 541.9769.
Perfluoro(2-methyl-1-phenyl-1,2-dihydrocyclo-
butabenzen-1-yl) cation (VIII). Compound II, 0.21 g
(0.47 mmol), was dissolved in 1.04 g (4.80 mmol) of
SbF5, and 0.27 g of SO2ClF was added. According to
the 19F NMR data, the resulting solution contained
cation VIII, while compound II was absent. 19F NMR
spectrum, δF, ppm: 13.1 (2F, 3′-F, 5′-F), 29.9 (1F, 2-F),
34.8 and 35.3 (1F each, 3-F, 5-F), 59.4 (1F, 2′-F), 59.1
(1F, 6′-F), 68.6 (1F, 6-F), 72.5 (1F, 4′-F), 76.4 (1F,
c. As described above in a, from 0.74 g (2.48 mmol)
of compound IV, 0.41 g (2.44 mmol) of pentafluoro-
benzene, and 3.21 g (14.81 mmol) of SbF5 (10 h,
130°C) we obtained 0.90 g of a mixture of compounds
VII and IX at a ratio of 7:93 (19F NMR).
4-F), 91.1 (3F, CF3); J2,6′ ≈ 50, J3,4 ≈ J4,5 ≈ 18, J4,6
39, J6,2′ = 166 Hz.
=
d. A solution of 0.07 g (0.16 mmol) of isomer mix-
ture I/II (67:33) in 0.6 g (2.77 mmol) of SbF5 was
heated for 10 h at 90°C in a sealed glass ampule. The
mixture was treated as described above in a to isolate
0.06 g of a mixture of compounds VI, IX, and XIX at
a ratio of 60:33:7 (19F NMR).
The solution was cooled to 2°C, poured into an ice–
water mixture, and extracted with chloroform. The ex-
tract was dried over MgSO4, and the solvent was dis-
tilled off to obtain 0.17 g of a mixture of compounds II
and IX at a ratio of 5:95 (19F NMR).
e. As described above in a, from 0.11 g (0.25 mmol)
of a mixture of compounds I, II, and V at a ratio of
60:10:30 and 0.17 g (0.78 mmol) of SbF5 (11 h, 50°C
we obtained 0.10 g of a mixture of compounds VI and
IX at a ratio of 90:10 (19F NMR).
Reaction of perfluoro(1-phenylindan) (XIX) with
SbF5. A nickel high-pressure reactor was charged with
a solution of 1.42 g (4.76 mmol) of perfluoroindan in
7.23 g (33.35 mmol) of SbF5, 0.88 g (5.24 mmol) of
pentafluorobenzene was added, and the mixture was
stirred and kept for 4 h at 22°C. The resulting mixture
containing compound XIX and HF [6] was heated for
15 h at 130°C and cooled to 0°C, 5 ml of anhydrous
hydrogen fluoride was added, and the mixture was
poured into ice water and extracted with chloroform.
The extract was dried over MgSO4, and the solvent
was distilled off to obtain 1.84 g of a mixture contain-
ing 37% of compound XIX and 55% of VI (according
to the GLC and 19F NMR data).
f. As described above in b, from 0.76 g (2.55 mmol)
of compound IV, 0.43 g (2.56 mmol) of pentafluoro-
benzene, and 3.32 g (15.31 mmol) of SbF5 (13 h,
170°C) we obtained 0.89 g of a mixture of compounds
II, VII, and IX–XVI at a ratio of 4:10:61:9:7:1:3:
2:2:1 (19F NMR).
g. As described above in b, from 1.48 g (4.97 mmol)
of compound IV, 0.83 g (4.94 mmol) of pentafluoro-
benzene, and 7.53 g (34.73 mmol) of SbF5 (10 h,
200°C) we obtained 1.49 g of a mixture containing
(according to the GLC and 19F NMR data) 10% of VII,
3% of X, 31% of XI, 6% of XII, 7% of XIII, 12% of
XIV, 5% of XV, 4% of XVI, and 4% of XVII.
Reaction of perfluoro(1-ethyl-2-phenyl-1,2-dihy-
drocyclobutabenzene) (III) with SbF5. a. A mixture
of 1.21 g (2.44 mmol) of compound III and 3.56 g
(16.42 mmol) of SbF5 was heated for 15 h at 170°C in
a 10-ml nickel high-pressure reactor. The mixture was
cooled to 2°C, 2 ml of perfluorobenzene was added,
and the mixture was stirred, poured into an ice–water
mixture, and extracted with methylene chloride. The
extract was dried over MgSO4, and the solvent was
distilled off to isolate 0.97 g of a mixture of com-
pounds XXV–XXIX at a ratio of 51 : 24 : 5 : 9 : 11
(according to the NMR data 19F NMR).
By column chromatography on silica gel using
carbon tetrachloride as eluent we isolated 0.21 g of
a mixture of compounds XII and XIV at a ratio of
44:56, and repeated chromatography on silica gel
using hexane as eluent gave 0.04 g of 2,2,3,3,4,5,5,-
6,6,7,7,8,8-tridecafluoro-1,9-bis(trifluoromethyl)-
2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]naphthalene
1
(XIV) as a liquid. H NMR spectrum: δ 5.0 ppm.
19F NMR spectrum, δF, ppm: 33.8 and 19.0 (1F each,
6-F or 7-F, JAB = 278 Hz), 36.2 and 20.7 (1F each, 7-F
or 6-F, JAB- = 276 Hz), 54.7 and 35.0 (1F each, 2-F,
JAB = 255 Hz), 60.0 (1F, 4-F), 60.5 and 41.4 (1F each,
b. A 10-ml nickel high-pressure reactor was charged
with a solution of 1.57 g (4.51 mmol) of compound
XXX in 6.86 g (31.64 mmol) of SbF5, 0.76 g
(4.52 mmol) of pentafluorobenzene was added, and the
mixture was stirred and kept for 4 h at 25°C. The
3-F, JAB = 270 Hz), 64.6 and 51.1 (1F each, 5-F, JAB
=
300 Hz), 67.5 and 48.0 (1F each, 8-F, JAB = 302 Hz),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 7 2011

FORMATION OF FLUORENE AND ANTHRACENE DERIVATIVES
1025
resulting mixture containing compound III [10] was
heated for 10 h at 200°C, cooled to 2°C, poured into
an ice–water mixture, and extracted with methylene
chloride. The extract was dried over MgSO4, and the
solvent was distilled off to obtain 1.68 g of a mixture
containing (according to the GLC and 19F NMR data)
9% of XV, 4% of XXVII, 44% of XXVIII, 8% of
XXIX, and 8% of XXXI. The product mixture was
subjected to column chromatography on silica gel
using first hexane and then chloroform as eluents to
isolate 0.06 g of perfluoro(9-ethylfluorene) (XXVII),
0.7 g of perfluoro(9-ethylfluoren-1-ol) (XXVIII), and
0.16 g of a mixture of compounds XXIX and XXXI at
a ratio of 1:1 (19F NMR). Repeated chromatography of
the latter (silica gel, hexane) gave 0.05 g of perfluoro-
(9,9-dimethyl-1,2,3,4-tetrahydro-9H-fluorene) (XXXI).
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. 10-03-00120).
REFERENCES
1. Karpov, V.M., Mezhenkova, T.V., Platonov, V.E., and
Yakobson, G.G., J. Fluorine Chem., 1985, vol. 28,
p. 115; Karpov, V.M., Mezhenkova, T.V., Platonov, V.E.,
and Yakobson, G.G., Izv. Akad. Nauk SSSR, Ser. Khim.,
1990, p. 1114; Karpov, V.M., Mezhenkova, T.V., and
Platonov, V.E., Izv. Ross. Akad. Nauk, Ser. Khim., 1992,
p. 1419.
2. Karpov, V.M., Mezhenkova, T.V., Platonov, V.E., and
Sinyakov, V.R., J. Fluorine Chem., 2002, vol. 117, p. 73.
3. Mezhenkova, T.V., Sinyakov, V.R., Karpov, V.M., Plato-
nov, V.E., and Gatilov, Yu.V., J. Fluorine Chem., 2009,
vol. 130, p. 951.
4. Mezhenkova, T.V., Sinyakov, V.R., Karpov, V.M.,
Platonov, V.E., Rybalova, T.V., and Gatilov, Yu.V.,
J. Fluorine Chem., 2008, vol. 129, p. 64.
5. Sinyakov, V.R., Mezhenkova, T.V., Karpov, V.M., Plato-
nov, V.E., Rybalova, T.V., and Gatilov, Yu.V., Russ. J.
Org. Chem., 2003, vol. 39, p. 837.
6. Karpov, V.M., Mezhenkova, T.V., Platonov, V.E., and
Sinyakov, V.R., J. Fluorine Chem., 2001, vol. 107, p. 53.
7. Mezhenkova, T.V., Karpov, V.M., and Platonov, V.E.,
Russ. J. Org. Chem., 2011, vol. 47, p. 1026.
8. Karpov, V.M., Mezhenkova, T.V., Platonov, V.E., and
Yakobson, G.G., Bull. Soc. Chim. Fr., 1986, p. 980.
9. Karpov, V.M., Mezhenkova, T.V., and Platonov, V.E.,
Compound XXVII. mp 69.5–71°C (from hexane).
19F NMR spectrum, δF, ppm: –18.5 (1F, 9-F), 12.1 (2F,
2-F, 7-F), 16.6 (2F, 3-F, 6-F), 28.1 (2F, 1-F, 8-F), 30.3
(2F, 4-F, 5-F), 43.3 (2F, CF2), 82.2 (3F, CF3). Found:
m/z 445.9780 [M]+. C15F14. Calculated: M 445.9776.
Compound XXVIII. mp 80.5–82°C (from hexane).
19F NMR spectrum, δF, ppm: 10.8 (2F, 2-F, 7-F), 13.8
(2F, 3-F, 6-F), 24.3 (2F, 1-F, 8-F), 29.4 (2F, 4-F, 5-F),
43.2 (2F, CF2), 81.7 (3F, CF3). Found: m/z 443.9814
[M]+. C15HF13O. Calculated: M 443.9810.
Compound XXXI. Liquid. 19F NMR spectrum, δF,
ppm: 16.6 (1F, 6-F), 17.7 (1F, 7-F), 26.5 and 29.5 (2F
each, 2-F, 3-F), 31.6 (1F, 5-F), 33.7 (1F, 8-F), 50.5 (2F,
4-F), 52.5 (2F, 1-F), 97.8 (6F, CF3); J1,9 = 13, J4,5 ≈ 35,
Russ. J. Org. Chem., 1997, vol. 33, p. 694.
J5,6 ≈ J6,7 ≈ J7,8 ≈ 20, J5,8 = 15, J5,7 = 8, J6,8 = 9, J8,9
=
10. Sinyakov, V.R., Mezhenkova, T.V., Karpov, V.M., and
Platonov, V.E., Russ. J. Org. Chem., 2007, vol. 43,
p. 1677.
24 Hz. Found: m/z 521.9721[M]+. C15F18. Calculated:
M 521.9712.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 7 2011