Full text of DOI:10.1016/j.jfluchem.2018.07.014

JournalofFluorineChemistry214(2018)24–34
Contents lists available at ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
Carbonylation of polyfluorinated indans, tetralins and perfluoro-2,3-
dihydrobenzofuran under the action of CO/SbF5
⁎
Yaroslav V. Zonova,b, , Victor M. Karpova, Tatyana V. Mezhenkovaa, Vyacheslav E. Platonova
a
N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk 630090, Russia
Novosibirsk State University, Novosibirsk 630090, Russia
b
A R T I C L E I N F O
A B S T R A C T
Keywords:
Carbonylation
Carbocation
Perfluorinated
Carbonyl fluoride
Indan
Tetralin
Carbon monoxide
Antimony pentafluoride
Polyfluorinated indans and tetralins are carbonylated under the action of CO/SbF5 at room temperature and
atmospheric pressure. Perfluoroindan and its 4-CF3, 5-CF3, 5-CH3, 1,1-H,H derivatives add two CO molecules to
form the corresponding dimethyl indan-1,1-dicarboxylates after methanolysis, and/or 1-hydroindan-1-car-
boxylic acids after hydrolysis. 1-X-Perfluoroindans (X]CF3, C2F5, C6F5, H) and 1-X-perfluorotetralins (X]C2F5,
C6F5) add one CO molecule at the 1-position to give the corresponding 1-carbonyl fluorides. Reaction of the
latter with methanol gives methyl esters, whereas hydrolysis is accompanied by decarboxylation. Perfluoro-2,3-
dihydrobenzofuran under the action of CO/SbF5 gives both mono- and dicarbonylation products.
1. Introduction
under the reaction conditions. In the development of this research, in
present article we report on the carbonylation of a number of poly-
Organo-fluorine compounds are essentially important for funda-
mental organic chemistry [1] and its applications, particularly to ma-
terials science, biomedicine and agriculture [1–3]. Therefore, devel-
opment of new approaches for their synthesis is of obvious interest.
Currently, in hydrocarbon chemistry, there are known many carbony-
lation reactions of alcohols, alkyl halides, alkenes etc. proceeding by CO
addition to cations generated from these compounds in acidic systems
and leading to the formation of carboxylic acid derivatives [4–6]. At the
same time for polyfluorinated compounds, despite the variety of reac-
tions of fluorinated cations, such carbonylation reactions have not been
known until our recent reports [7,8]. Some examples of reverse reac-
tions – the decarbonylation of fluorinated acyl halides under the action
of Lewis acids were only observed [9–11].
fluorinated indans and tetralins and perfluoro-2,3-dihydrobenzofuran
under the action of CO/SbF5.
It should be pointed out that in hydrocarbon series it is known only
a few examples of carbonylation of indan and tetralin derivatives at
aliphatic ring and these reactions are catalyzed by palladium-phosphine
complexes. Thus, carbonylation of 1-indanol and 1-tetralol gives 1- and
2-isomers of the corresponding methyl carboxylates [12], and carbo-
nylation of 2-chlorotetralone gives methyl 1-oxotetralin-2-carboxylate
[13]. At the same time, indan1- and tetralin-1-carboxylic acid deriva-
tives, including partially halogenated ones, have been reported to ex-
hibit multiple biological activities [14,15].
2. Results and discussion
We have found that perfluorinated benzocyclobutene and its alkyl
and phenyl derivatives undergo carbonylation and four-membered ring
opening or expansion under the action of carbon monoxide in the
presence of SbF5 resulting in formation of 2-arylalkenoic acid [7],
isochromene [7,8] and indan-2-one derivatives [8]. In these reactions,
irreversible four-membered ring transformations of the products of
the initial CO addition promote the conversion of poly-
fluorobenzocyclobutenes into the final products. A number of fluor-
ocarbonyl derivatives of indan-2-one obtained in these reactions ap-
parently indicate the possibility of carbonylation of indan derivatives
2.1. Reactions of polyfluorinated indans and perfluoro-2,3-
dihydrobenzofuran with CO–SbF5
We have found that perfluoroindan (1) and a number of its deri-
vatives react with carbon monoxide in the presence of SbF5 at room
temperature and atmospheric pressure. In contrast to the carbonylation
of polyfluorobenzocyclobutenes the reaction of indan 1 with CO pro-
ceeds without transformations of the aliphatic ring. Indan 1 adds two
CO molecules to form perfluoroindan-1,1-dicarbonyl difluoride (2)
⁎
Corresponding author at: N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk 630090, Russia.
E-mail address: yzonov@nioch.nsc.ru (Y.V. Zonov).
https://doi.org/10.1016/j.jfluchem.2018.07.014
Received 29 May 2018; Received in revised form 30 July 2018; Accepted 30 July 2018
Availableonline31July2018
0022-1139/©2018PublishedbyElsevierB.V.

Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
Scheme 1. Carbonylation of perfluoroindan.
(Scheme 1), but complete conversion is not achieved and the reaction
mixture contains compounds 1 and 2 in about equal amounts. The in-
crease in the reaction time from 5 to 28.5 h does not increase the degree
of conversion. Variation of SbF5 amount in the range of 0.5–7.6 mol
equivalent also does not lead to significant changes in the result. When
the reaction mixture is treated with methanol, compound 2 is trans-
formed into dimethyl perfluoroindan-1,1-dicarboxylate (3), whereas
the reaction with water gives 1-hydroperfluoroindan-1-carboxylic acid
(4) which is a decarboxylation product of the corresponding 1,1-di-
carboxylic acid.
Heteroatomic analog of perfluoroindan (1) – perfluoro-2,3-dihy-
drobenzofuran (5), also reacts with CO–SbF5 (Scheme 2). Under the
action of excess of SbF5 compound 5 is completely converted into a salt
of perfluoro-2,3-dihydrobenzofuran-3-yl cation (6) which adds one CO
molecule to form perfluoro-3-fluorocarbonyl-2,3-dihydrobenzofuran-3-
yl cation (7). Treatment of the reaction mixture containing salts of
cations 6 and 7 with HF-pyridine (Olah’s reagent) and then with water
gives mainly perfluoro-2,3-dihydrobenzofuran-3-carboxylic acid (8)
along with perfluoro-2,6-dihydrobenzofuran-3-carboxylic acid (9) and
the starting compound. Acids 8 and 9 are converted by treatment with
PCl5 and then with methanol into corresponding methyl esters 11 and
12 which are separated chromatographically (Scheme 2).
Treatment of the salt of cation 6 with water leads to a mixture of
perfluoro-2,3-dihydrobenzofuran-3-one (10) and compound 5. Ketone
10 is also synthesized in the reaction of compound 5 with CF3COOH
and SbF5 in a good yield.
Whereas in the excess of SbF5 compound 5 undergoes mono-
carbonylation, in the presence of 0.5 mol equivalent of SbF5 it adds two
CO molecules to form, after methanolysis of the reaction mixture, di-
methyl perfluoro-2,3-dihydrobenzofuran-3,3-dicarboxylate (13) along
with the starting compound and only small amounts of mono-
carbonylation product 11 (Scheme 2).
Interaction of perfluorinated 4-methyl- (14) and 5-methylindans
(15) with CO proceeds analogously to perfluorindan (1) in the presence
of excess of SbF5 to give, after hydrolysis of the reaction mixtures, 1-
hydroperfluoro-4-methylindan-1-carboxylic (16) and 1-hydroperfluoro-
6-methylindan-1-carboxylic (17) acids (Scheme 3). The degree of con-
version of indans 14 and 15 is lower than that of perfluoroindan (1) and
does not increase with increase of the reaction time. The carbonylation
proceeds regioselectively at the CF2 group which is in the meta-position
Scheme 2. Carbonylation of perfluoro-2,3-dihydrobenzofuran.
25

Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
Scheme 3. Carbonylation of perfluorinated 4- and 5-methylindans.
to the CF3 group, that is in accordance with the larger relative stability
of the corresponding perfluoromethylindan-1-yl cations that do not
contain electron-withdrawing CF3 group in the resonance positions
[16,17].
from 5 to 27.5 h and apparently corresponds to the thermodynamic
control of the reaction.
Analogously, 1,1-dihydroperfluoroindan (25) in the presence of
0.5 mol equivalent of SbF5 undergoes dicarbonylation to give, after
methanolysis of the reaction mixture, mainly dimethyl 3,3-dihy-
droperfluoroindan-1,1-dicarboxylate (26) along with the starting com-
pound (Scheme 5). 1-Hydroperfluoroindan (27) reacts with CO in ex-
cess of SbF5 to form a salt of (1-hydroperfluoroindan-1-yl)(oxo)methyl
cation (28), its hydrolysis gives acid 4. The reaction proceeds with
complete conversion of compound 27.
Perfluorinated 1-alkylindans in the system CO–SbF5 are also selec-
tively carbonylated at the 1-position. Thus, reaction of perfluoro-1-
ethylindan (29) with CO–SbF5 and subsequent water treatment gives
perfluoro-1-ethylindan-1-carbonyl fluoride (30) with minor admixtures
(Scheme 6). The degree of conversion of indan 29 exceeds 90% and
depends a little on amount of SbF5 in the range of 0.5–7.6 mol
equivalent. Analogously reaction of perfluoro-1-methylindan (31) with
CO–SbF5 gives perfluoro-1-methylindan-1-carbonyl fluoride (32). The
conversion of methylindan 31 is complete, apparently due to less steric
hindrance to CO addition in comparison with ethylindan 29, but car-
bonyl fluoride 32 is less stable to hydrolysis than compound 30, as a
result, the reaction mixture after water treatment contains admixture of
1-hydroperfluoro-1-methylindan (33) (about its formation see below).
5-Methylperfluoroindan (18) under the action of excess of SbF5 is
completely converted into a salt of 6-methylperfluoroindan-1-yl cation
(19), which does not add CO under these conditions (Scheme 4). Iso-
meric 5-methylperfluoroindan-1-yl cation (20) is not reliably detected
in a solution by NMR. Nevertheless hydrolysis of the reaction mixture
leads to 6-methylperfluoroindan-1-one (21) together with a small
amount of 5-methylperfluoroindan-1-one (22) and starting compound
18. A mixture of ketones 21 and 22 is also synthesized in the reaction of
compound 18 with CF3COOH and SbF5, where cation 20 makes con-
siderable contribution to the formation of product 22 (Scheme 4).
Decrease in the amount of SbF5 facilitates the carbonylation of
indan 18. Thus, its reaction with CO and 1 mol equivalent of SbF5 gives,
after hydrolysis, a mixture of 1-hydro-6-methylperfluoroindan-1-car-
boxylic (23) and 1-hydro-5-methylperfluoroindan-1-carboxylic (24)
acids along with 6-methylperfluoroindan-1-one (21) and the starting
compound. In contrast to regioselective carbonylation of perfluorinated
methylindans 14 and 15, the reaction of compound 18 proceeds via
both cations 19 and 20 in an almost equal proportion. The ratio of
products 23 and 24 does not change with increase in the reaction time
Scheme 4. Reactions of 5-methylperfluoroindan with CO and CF3COOH in the presence of SbF5.
26

Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
Scheme 5. Carbonylation of 1,1-dihydroperfluoroindan and 1-hydroperfluoroindan.
In contrast to ethylindan 29, carbonylation of perfluoro-1-pheny-
Perfluoro-1,1-diethylindan, in contrast to the indans described
above, practically does not undergo carbonylation in the system
CO–SbF5 that is apparently due to steric hindrance to CO addition
caused by the presence of two C2F5 groups.
lindan (34) in the presence of excess of SbF5 does not occur, reaction
equilibrium is shifted to the formation of stable perfluoro-1-pheny-
lindan-1-yl cation [18], whereas the reaction in the presence of 1 mol
equivalent of SbF5 and subsequent treatment with water gives per-
fluoro-1-phenylindan-1-carbonyl fluoride (35) (Scheme 6). Conversion
of phenylindan 34 is incomplete and in addition the reaction mixture
contains perfluoro-1-phenylindan-1-ol (36) as a product of hydrolysis of
the corresponding cation.
Treatment of the reaction mixtures containing carbonyl fluorides
32, 30 and 35 with methanol yields the corresponding methyl esters
37, 38 and 39 (Scheme 6, the yields are given relative to the starting
compounds 29, 31, 34), while the hydrolysis of compounds 32, 30 and
35 in a mixture of 5% hydrochloric acid and Et2O leads to the formation
of the corresponding 1-hydro-1-R-perfluoroindans 33, 40 and 41,
which are the products of decarboxylation of corresponding acids. In
the case of hydrolysis of phenyl derivative 35, admixture of perfluoro-3-
phenylindene (42) is also formed. Indene 42 has been also synthesized
in a separate experiment from compound 41 with triethylamine in a
good yield.
2.2. Reactions of polyfluorinated tetralins with CO–SbF5
Perfluorotetralin, as well as its 6-CF3 and 6-CH3 derivatives in
contrast to indans 1, 6, 9 do not form carbonylation products in the
system CO–SbF5. At the same time perfluoro-1-ethyltetralin (43) adds a
CO molecule at the 1-position to form perfluoro-1-ethyltetralin-1-car-
bonyl fluoride (44) with ∼50% conversion of compound 43 (Scheme
7).
Variation of SbF5 amount in the range of 1–7.8 mol equivalent and
the reaction time from 5.5 to 28.5 h do not lead to significant changes in
the result, but further decrease of SbF5 amount appreciably hampers the
reaction of ethyltetralin 43 with CO. Treatment of compound 44 with
methanol yields the corresponding methyl ester 45, whereas its hy-
drolysis leads to the formation of 1-hydroperfluoro-1-ethyltetralin (46).
It should be noted that in the reaction of ethyltetralin 43 with CO,
Scheme 6. Carbonylation of perfluoro-1-R-indans (R = C2F5, CF3, C6F5).
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Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
Scheme 7. Carbonylation of perfluorinated 1-ethyl- and 1,4-diethyltetralins.
Scheme 8. Carbonylation of perfluoro-1-phenyltetralin.
the 1,4-isomer of compound 44 is not detected. At the same time, in the
irreversible reaction of compound 43 with tetrafluoroethylene in the
presence of SbF5, only perfluoro-1,4-diethyltetralin (47) is formed [19],
whereas regioselectivity in the reactions of ethylindan 29 with
CF2=CF2 [19] and with CO is the same.
Perfluoro-1,4-diethyltetralin (47) in the reaction with CO in excess
of SbF5 gives mainly monocarbonylated product, that is converted into
methyl perfluoro-1,4-diethyltetralin-1-carboxylate (48) by treatment
with methanol (Scheme 7).
Reaction of perfluoro-1-phenyltetralin (49) with CO in the presence
of excess of SbF5 does not occur, a salt of perfluoro-1-phenyltetralin-1-
yl cation [18] is the only product of the reaction. When 1 mol equiva-
lent of SbF5 is used, carbonylation of phenyltetralin 49 proceeds in a
substantially lower extent in comparison with phenylindan 34. Treat-
ment of the reaction mixture with water gives a mixture containing only
5% of perfluoro-1-phenyltetralin-1-carbonyl fluoride (50) along with
perfluoro-1-phenyltetralin-1-ol (51) and the starting compound
(Scheme 8).
dihydronaphthalene (52).
2.3. Structure of compounds
The structures of the compounds were established by HRMS, ele-
mental analysis and spectral characteristics. Assignment of signals in
the NMR spectra of compounds was made on the basis of chemical shifts
of the signals, their fine structure and integral intensities. Compounds
36, 51 [18], 52 [20] were identified by comparison of the 19F NMR
data with data for authentic samples. Assignment of signals in the 19F
NMR spectra of cations 19, 6 and 7 was made by analogy with per-
fluorinated indan-1-yl [21] and 1-phenylindan-1-yl [18] cations. The
structures of the cations were additionally confirmed by the structures
of the corresponding products of fluorine anion addition and/or hy-
drolysis.
3. Conclusion
In contrast to the ethyl derivative 44, hydrolysis of compound 50
with H2O-Et2O leads to the formation of perfluoro-4-phenyl-1,2-
We have found the possibility of carbonylation of polyfluorinated
indans and tetralins in the system CO–SbF5. 1-X-Perfluoroindans
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Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
(X]CF3, C2F5, C6F5, H) and 1-X-perfluorotetralins (X]C2F5, C6F5) add
one CO molecule to the 1-position. Polyfluoroindans without the CFX
fragment at the benzylic position give products of dicarbonylation to
form polyfluorinated indan-1,1-dicarbonyl difluorides, whereas per-
fluorotetralin and its 6-CF3 and 6-CH3 derivatives do not produce car-
bonylation products. For perfluoro-2,3-dihydrobenzofuran, formation
of both mono- and dicarbonylation products are possible. The degree of
conversion into carbonylation products can be influenced by the
amount of SbF5, electronic and sterical factors.
of compounds 1, 4, 1k in the ratio 43:46:11.
3 Compound 1 (1.27 g, 4.24 mmol) and SbF5 (0.92 g, 4.26 mmol)
(molar ratio, 1:1) according to procedure A (5.5 h) gave a mixture of
compounds 1, 4, 1k in the ratio 42:55:3. The residue obtained after
evaporation on watch glass was sublimed (110 °C, 1 Torr) to give
0.63 g of acid 4 (yield 49%).
4 Compound 1 (1.11 g, 3.71 mmol) and SbF5 (0.40 g, 1.83 mmol)
(molar ratio, 1:0.5) according to procedure A (28.5 h) gave a mix-
ture of compounds 1, 4, 1k in the ratio 44:51:5.
5 Compound 1 (1.16 g, 3.90 mmol) and SbF5 (0.42 g, 1.94 mmol)
(molar ratio, 1:0.5) according to procedure A (5.5 h) gave a mixture
of compounds 1, 4, 1k in the ratio 45:53:2.
4. Experimental
Analytical and spectral measurements were carried out in the Multi-
Access Chemical Research Center SB RAS. IR spectra were taken on a
Bruker Vector 22 IR spectrophotometer. 19F and 1H NMR spectra were
recorded on a Bruker AV 300 instrument (282.4 MHz and 300 MHz,
respectively), 13C NMR spectra were recorded on a Bruker DRX-500
instrument (125.8 MHz). Chemical shifts are given in δ ppm from CCl3F
4.2.1. Perfluoroindan-1,1-dicarbonyl difluoride (2)
19F NMR (SbF5): δ 42.5 (br s, 2 F, COF), –104.1 (br s, 2 F, CF2-3),
–112.6 (br s, 2 F, CF2-2), –132.9 (br s, 1 F, F-7), –136.7 (br s, 1 F, F-4),
–142.0 (br s, 1 F) and –143.6 (br s, 1 F, F-5 and F-6).
(
19F) and TMS (1H, 13C), J values in Hz; C6F6 and SO2ClF (–162.9 and
4.2.2. Dimethyl perfluoroindan-1,1-dicarboxylate (3)
99.9 ppm from CCl3F), CHCl3 (7.24 ppm from TMS), CDCl3 (76.9 ppm
ppm from TMS) were used as internal standards. The molecular masses
of the compounds were determined by high-resolution mass-spectro-
metry on a Thermo Electron Corporation DFS instrument (EI 70 eV).
Contents of products in the reaction mixtures were established by 19F
NMR spectroscopic data.
Antimony pentafluoride was distilled at atmospheric pressure (bp
142–143 °C); carbon monoxide was prepared by decomposition of
formic acid in concentrated sulfuric acid and it was additionally dried
with the latter. The starting compounds were obtained according to
Refs.: compounds 1, 5, 14, 15 [19]; 18 [22]; 25 [23]; 27 [24]; 29, 43,
47 [25]; 31 [26]; 34, 49 [18]. The reactions were carried out in
glassware at atmospheric pressure.
mp 94–94.5 оC (hexane). IR (KBr) ν, cm–1: 2959 (CeH), 1765 (C]
O), 1518 [fluorinated aromatic ring (FAR)]. 1H NMR (CDCl3): δ 3.87 (s,
CH3). 19F NMR (CDCl3): δ –107.0 (m, 2 F, CF2-3), –117.9 (t, 2 F, CF2-2),
–133.6 (ddd, 1 F, F-7), –141.1 (dddt, 1 F, F-4), –145.4 (ddd, 1 F, F-6),
–149.2 (ddd, 1 F, F-5); J2,3 = 4.5, J3,4 = 7, J4,5 = 21, J4,6 = 7,
J4,7 = 16, J5,6 = 19, J5,7 = 7, J6,7 = 20.5. HRMS m/z, 378.0135 (M+).
Calcd. for C13H6F8O4 = 378.0133. Anal. Calcd for C13H6F8O4: C, 41.29;
H, 1.60; F, 40.19%. Found: C, 41.34; H, 2.21; F, 40.20%.
4.2.3. 1-Hydroperfluoroindan-1-carboxylic acid (4)
mp 106–107.5 оC (hexane). IR (KBr) ν, cm–1: 1740 (C = O), 1525
(FAR). 1H NMR (CDCl3): δ 10.8 (br s, 1H, COOH), 4.61 (dd, 1H, H-1). 19
F
NMR (CDCl3): δ –106.5 (dm, 1 FA, CF2-3), –109.7 (dm, 1 FB, CF2-3),
–112.2 (dddd, 1 FA, CF2-2), –120.0 (dddd, 1 FB, CF2-2), –138.4 (ddd, 1 F,
F-7), –140.3 (dddt, 1 F, F-4), –145.8 (dddm, 1 F, F-6), –149.7 (dddm, 1 F,
4.1. Typical procedures
F-5); JH(1)–F(2A)
= 14, JH(1)–F(2B) = 6.5, J2A,2B = 242, J2A,3A and
Procedure A. A mixture of compound and SbF5 was intensively
stirred in 10 mL round bottom flask under CO atmosphere at room
temperature. The mixture was treated with cold 5% hydrochloric acid
and extracted with CH2Cl2 [or mixture CH2Cl2–Et2O (3:1) in experi-
ments 4.2.(2–5), 4.3., 4.4., 4.5.(2,3), 4.11.]. The extract was dried over
MgSO4 and 19F NMR spectrum was recorded.
J2A,3B = 4 and 2, J2B,3A and J2B,3B = 4.5 and 3, J3A,3B = 260, J3,4 = 7,
J4,5 = 20.5, J4,6 = 7.5, J4,7 = 16.5, J5,6 = 19, J5,7 = 5.5, J6,7 = 20.
HRMS m/z, 305.9916 (M+). Calcd. for C10H2F8O2 = 305.9922.
4.3. Reaction of perfluoro-2,3-dihydrobenzofuran (5) with CO–SbF5
Procedure B. A mixture of compound and SbF5 was intensively
stirred in 10 mL round bottom flask under CO atmosphere at room
temperature. The mixture was poured into cold CH3OH (10–20 mL per
1 g of SbF5), kept at room temperature for 1 h, diluted with 5–10 vo-
lumes of 5% hydrochloric acid and extracted with CH2Cl2. The extract
was dried over MgSO4 and 19F NMR spectrum was recorded.
It should be noted that after treatment with water or methanol, in
the reaction mixtures obtained by carbonylation of indans 1, 25, 29,
tetralin 43 and compound 5, small amounts of the corresponding ke-
tones are present: perfluoroindan-1-one (1k), 3,3-dihydroper-
fluoroindan-1-one (25k), perfluoro-3-ethylindan-1-one (29k), per-
fluoro-4-ethyltetralin-1-one (43k) and ketone 10, respectively.
Compounds 1k, 29k [27], 43k [28] were identified by comparison of
the 19F NMR data with data for authentic samples.
1 A mixture of compound 5 (0.65 g, 2.46 mmol) and SbF5 (3.28 g,
15.13 mmol) (molar ratio, 1:6.1) was intensively stirred 5.5 h under
CO atmosphere at room temperature. According to 19F NMR the
resulting solution contained a mixture of salts of cations 6 and 7 in
the ratio 70:30. The solution stirred under CO atmosphere for 5 h
more, then it was poured into Teflon vessel with HF-pyridine
(10 ml) cooled down to −15 °C, kept at room temperature for 0.5 h,
treated with water, extracted with mixture CH2Cl2–Et2O (3:1). The
solution contained compounds 5, 8, 9, 10 in the ratio 15:68:13:4.
The solvents were rotary evaporated, the residue was dissolved in
CH2Cl2 and extracted with aqueous solution of NaHCO3. The aqu-
eous extract was acidified with HCl, extracted with mixture
CH2Cl2–Et2O (3:1) dried over MgSO4. The solvents were rotary
evaporated, the residue was sublimed (100 °C, 3 Torr) to give 0.43 g
of acids 8 and 9 in the ratio 84:16 (yield 60%). Reaction of the
mixture of acids 8 and 9 dissolved in CCl4 (3 mL) with PCl5 (0.4 g) at
room temperature (20 h) and then with CH3OH (4 mL) (0.5 h),
subsequent water treatment, extraction with CH2Cl2 and silica gel
column chromatography (mixture CCl4–CHCl3 (1:1) as eluent) gave
0.28 g of ester 11 (yield 37%) and 0.063 g of ester 12 (yield 8%).
2 Compound 5 (0.86 g, 3.26 mmol) and SbF5 (0.35 g, 1.61 mmol)
(molar ratio, 1:0.5) according to procedure B (5 h) gave a mixture of
compounds 5, 10, 11, 13 in the ratio 45:4:4:47. Silica gel column
chromatography (CHCl3 as eluent) gave 0.41 g of product 13 (yield
36%).
4.2. Reaction of perfluoroindan (1) with CO–SbF5
1 Compound 1 (0.73 g, 2.46 mmol) and SbF5 (4.02 g, 18.57 mmol)
(molar ratio, 1:7.6) according to procedure B (5 h) gave a mixture of
compounds 1, 3, 1k in the ratio 51:44:5. According to 19F NMR the
SbF5 solution before hydrolysis contained compounds 1 and 2 in
approximately equal amounts. Silica gel column chromatography
(CHCl3 as eluent) gave 0.30 g of product 3 (yield 32%).
2 Compound 1 (0.70 g, 2.35 mmol) and SbF5 (3.56 g, 16.44 mmol)
(molar ratio, 1:7) according to procedure A (28.5 h) gave a mixture
29

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JournalofFluorineChemistry214(2018)24–34
4.3.1. Perfluoro-3-fluorocarbonyl-2,3-dihydrobenzofuran-3-yl cation (7)
19F NMR (SbF5): δ 45.4 (d, 1 F, COF), –29.1 (m, 1 F, F-6), –95.5 (s,
2 F, CF2), –97.2 (dd, 1 F, F-4), –133.0 (br s, 1 F) and –143.6 (br s, 1 F, F-
5 and F-7); J4,COF = 53, J4,6 = 48.
4.5. Reaction of perfluoro-2,3-dihydrobenzofuran (5) with CF3COOH–SbF5
A mixture of compound 5 (1.24 g, 4.7 mmol), CF3COOH (0.75 g,
6.58 mmol) and SbF5 (3 g, 13.86 mmol) (molar ratio, 1:1.4:3) was kept
at 20 °C for 1 h. The mixture was treated with cold 5% hydrochloric
acid and extracted with CH2Cl2 and dried over MgSO4. Solvent rotary
evaporation gave 2.44 g ketone 10 (yield 79%).
4.3.2. Perfluoro-2,3-dihydrobenzofuran-3-carboxylic acid (8) and
perfluoro-2,6-dihydrobenzofuran-3-carboxylic acid (9)
Mixture of two isomers, ratio 8:9 = 84:16, liquid. 1H NMR (CDCl3):
δ 10.5 (br s, COOH).
4.5.1. Perfluoro-2,3-dihydrobenzofuran-3-one (10)
Liquid. IR (film) ν, cm–1: 1780, 1773 (C = O), 1539, 1501 (FAR). 19
F
Isomers 8: 19F NMR (CDCl3): δ –80.6 (dd, 1 FA, CF2-2), –86.1 (dd,
1 FB, CF2-2), –138.8 (dddd, 1 F, F-4), –145.3 (dddd, 1 F, F-6), –158.2 (m,
1 F, F-3), –158.5 (dd, 1 F, F-7), –160.7 (ddd, 1 F, F-5); J2A,2B = 142,
NMR (CDCl3): δ –92.0 (s, 2 F, CF2-2), –132.2 (ddd, 1 F, F-4), –134.3
(ddd, 1 F, F-6), –158.7 (ddd, 1 F, F-7), –159.7 (ddd, 1 F, F-5);
J4,5 = 21.5, J4,6 = 11.5, J4,7 = 16, J5,6 = 19.5, J5,7 = 1, J6,7 = 19.5.
HRMS m/z, 241.9796 (M+). Calcd. for C8F6O2 = 241.9797.
J2A,3 = 2, J2B,3
= 4, J3,4 = 3.5, J3,5 = 2, J3,6 = 4.5, J4,5 = 21.5,
J4,6 = 6, J4,7 = 14.5, J5,6 = 19, J6,7 = 19.5.
Isomers 9: 19F NMR (CDCl3): δ –69.7 (td, 2 F, CF2-2), –110.0 (dddt,
2 F, CF2-6), –141.4 (tdd, 1 F, F-5), –142.0 (tdd, 1 F, F-4), –156.3 (ttdd,
1 F, F-7); J2,6 = 6.5, J2,7 = 6.5, J4,5 = 3.5, J4,6 = 9.5, J4,7 = 1.5,
J5,6 = 22, J5,7 = 3.5, J6,7 = 21.
4.6. Reaction of perfluoro-4-methylindan (14) with CO–SbF5
Compound 14 (0.84 g, 2.42 mmol) and SbF5 (3.57 g, 16.49 mmol)
(molar ratio, 1:6.8) according to procedure A (6 h) gave a mixture of
compounds 14 and 16 in the ratio 77:23. The residue obtained after
evaporation on watch glass was sublimed (110 °C, 3 Torr) to give 0.16 g
of acid 16 (yield 19%).
4.3.3. Methyl perfluoro-2,3-dihydrobenzofuran-3-carboxylate (11)
Liquid. IR (film) ν, cm–1: 2966 (CH); 1782 (C = O), 1535, 1504
(FAR). 1H NMR (CDCl3): δ 3.94 (s, CH3). 19F NMR (CDCl3): δ –80.6 (dd,
1 FA, CF2-2), –86.2 (dd, 1 FB, CF2-2), –138.9 (dddd, 1 F, F-4), –146.0
(dddd, 1 F, F-6), –157.6 (m, 1 F, F-3), –159.0 (dd, 1 F, F-7), –161.0 (ddd,
1 F, F-5); J2A,2B = 142, J2A,3 = 2, J2B,3 = 4, J3,4 = 3.5, J3,5 = 2,
J3,6 = 4.5, J4,5 = 21.5, J4,6 = 6, J4,7 = 14.5, J5,6 = 19.5, J6,7 = 19.5.
HRMS m/z, 303.9964 (M+). Calcd. for C10H3F7O3 = 303.9965.
4.6.1. 1-Hydroperfluoro-4-methylindan-1-carboxylic acid (16)
mp 94–95.5 оC (hexane-CCl4). IR (KBr) ν, cm–1: 1742 (C = O), 1632,
1526, 1485 (FAR). 1H NMR (CDCl3): δ 9.7 (br s, 1H, COOH), 4.63 (dd,
1H, H-1). 19F NMR (CDCl3): δ –58.7 (dt, 3 F, CF3), –104.8 (dqm, 1 FA,
CF2-3), –109.4 (dqm, 1 FB, CF2-3), –112.2 (ddt, 1 FA, CF2-2), –120.7
(ddt, 1 FB, CF2-2), –126.7 (qdd, 1 F, F-5), –127.5 (dd, 1 F, F-7), –148.5
(dd, 1 F, F-6); JH(1)–F(2A) = 14.5, JH(1)–F(2B) = 6, J2A,2B = 241, J2A,3A
=
4.3.4. Methyl perfluoro-2,6-dihydrobenzofuran-3-carboxylate (12)
Liquid. IR (film) ν, cm–1: 2965 (CH); 1742 (C = O), 1693, 1651
(C = C). 1H NMR (CDCl3): δ 3.93 (s, CH3). 19F NMR (CDCl3): δ –69.7
(td, 2 F, CF2-2), –108.8 (dddt, 2 F, CF2-6), –142.2 (tdd, 1 F, F-4), –143.9
(tdd, 1 F, F-5), –155.7 (ttdd, 1 F, F-7); J2,6 = 7, J2,7 = 7, J4,5 = 4,
J4,6 = 9.5, J4,7 = 2, J5,6 = 22, J5,7 = 2.5, J6,7 = 21. 13C NMR (CDCl3): δ
J2A,3B = 2.5, J2B,3A = J2B,3B = 3.5, J3A,3B = 266, J = 14.5, J
F(3A)–CF3
= 15, J5,6 = 19.5, J5,7 = 15, J6,7 = 20.5, JCF3–F(5) = 20.5.
F(3B)–CF3
HRMS m/z, 355.9885 (M+). Calcd. for C11H2F10O2 = 355.9890.
4.7. Reaction of perfluoro-5-methylindan (15) with CO–SbF5
1
2
2
157.5 (s, C=O), 142.2 (dtd, JCF = 287, JCF = 25, JCF = 5, C-5),
Compound 15 (0.84 g, 2.42 mmol) and SbF5 (3.53 g, 16.42 mmol)
(molar ratio, 1:6.7) according to procedure A (6 h) gave a mixture of
compounds 15, 17 in the ratio 70:30. The residue obtained after eva-
poration on watch glass was sublimed (110 °C, 3 Torr) to give 0.23 g of
acid 17 (yield 27%).
1
2
3
136.4 (ddt, JCF = 272, JCF = 14.5, JCF = 7.5, C-4), 132.4 (dtd,
2JCF = 8.5, JCF = 8.5, JCF = 8.5, C-7a), 130.5 (dtm, JCF = 279,
3
3
1
2JCF = 24.5, C-7), 129.1 (t, JCF = 266, C-2), 128.8 (d, JCF = 25.5, C-
1
2
2
1
2
3a), 125.4 (tm, JCF ∼ 30, C-3), 108.6 (ttd, JCF = 238, JCF = 23.5,
3JCF = 6, C-6), 53.4 (s, CH3). HRMS m/z, 303.9961 (M+). Calcd. for
C
10H3F7O3 = 303.9965.
4.7.1. 1-Hydroperfluoro-6-methylindan-1-carboxylic acid (17)
mp 110–112 оC (CCl4). IR (KBr) ν, cm–1: 1751 (C = O), 1510 (FAR).
1H NMR (CDCl3): δ 8.4 (br s, 1H, COOH), 4.62 (dd, 1H, H-1). 19F NMR
(CDCl3): δ –58.0 (dd, 3 F, CF3), –107.3 (dm, 1 FA, CF2-3), –112.1 (dm,
1 FB, CF2-3), –111.9 (dddd, 1 FA, CF2-2), –115.8 (qd, 1 F, F-7), –120.3
(dddd, 1 FB, CF2-2), –128.5 (qd, 1 F, F-5), –141.3 (ddt, 1 F, F-4);
JH(1)–F(2A) = 14, JH(1)–F(2B) = 6, J2A,2B = 242, J2A,3A and J2A,3B = 3.5
and 2, J2B,3A and J2B,3B = 4 and 3, J3A,3B = 264, J3,4 = 6.5, J4,5 = 20.5,
J4,7 = 20.5, JCF3–F(5) = 22, JCF3–F(7) = 23. HRMS m/z, 355.9886 (M+).
Calcd. for C11H2F10O2 = 355.9890.
4.3.5. Dimethyl perfluoro-2,3-dihydrobenzofuran-3,3-dicarboxylate (13)
Liquid. IR (film) ν, cm–1: 2964 (CeH), 1761 (C]O), 1531, 1502
(FAR). 1H NMR (CDCl3): δ 3.87 (s, CH3). 19F NMR (CDCl3): δ –73.1 (s,
2 F, CF2-2), –137.7 (ddd, 1 F, F-4), –150.6 (ddd, 1 F, F-6), –160.2 (ddd,
1 F, F-7), –162.0 (ddd, 1 F, F-5); J4,5 = 21.5, J4,6 = 5, J4,7 = 14,
J5,6 = 19.5, J5,7 = 1.5, J6,7 = 20.5. HRMS m/z, 344.0113 (M+). Calcd.
for C12H6F6O5 = 344.0114.
4.4. Reaction of perfluoro-2,3-dihydrobenzofuran (5) with SbF5
4.8. Reaction of 5-methylperfluoroindan (18) with CO–SbF5
A solution of compound 5 (0.15 g, 0.55 mmol) in SbF5 (1.24 g,
5.73 mmol) (molar ratio, 1:10.4) was prepared. According to 19F NMR
the solution contained a salt of cation 6. The mixture was treated with
cold 5% hydrochloric acid, extracted with CH2Cl2 and dried over
MgSO4. Solvent rotary evaporation gave 0.11 g of a mixture of com-
pounds 5 and 10 in the ratio 15:85.
1 Compound 18 (0.26 g, 0.87 mmol) and SbF5 (1.15 g, 5.33 mmol)
(molar ratio, 1:6.1) according to procedure A (5.5 h) gave after
solvent rotary evaporation a mixture of compounds 18, 21, 22 in the
ratio 17:78:5. According to 19F NMR the SbF5 solution before hy-
drolysis contained a salt of cation 19 without significant admixtures.
2 Compound 18 (0.97 g, 3.29 mmol) and SbF5 (0.71 g, 3.3 mmol)
(molar ratio, 1:1) according to procedure A (5 h) gave a mixture of
compounds 18, 21, 23, 24 in the ratio 40:9:24:27. The residue ob-
tained after solvent evaporation on watch glass was sublimed
(110 °C, 1 Torr) and recrystallized from CCl4-hexane mixture to give
0.31 g of acids 23 and 24 mixture (yield 31%) in the ratio 42:58.
4.4.1. Perfluoro-2,3-dihydrobenzofuran-3-yl cation (6)
19F NMR (SbF5): δ –24.3 (br s, 1 F, F-3), –47.2 (br s, 1 F, F-6), –98.5
(m, 1 F, F-4), –98.9 (d, 2 F, CF2), –139.9 (br s, 1 F) and –144.3 (br s, 1 F,
F-5 and F-7); J2,3 = 15.
30

Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
3 Compound 18 (0.79 g, 2.67 mmol) and SbF5 (0.58 g, 2.66 mmol)
(molar ratio, 1:1) according to procedure A (27.5 h) gave a mixture
of compounds 18, 21, 23, 24 in the ratio 36:9:26:29.
4.10.1. Dimethyl 3,3-dihydroperfluoroindan-1,1-dicarboxylate (26)
mp 59.5–60.5 оC. IR (KBr) ν, cm–1: 2962 (CeH), 1749 (C]O), 1512
(FAR). 1H NMR (CDCl3): δ 3.83 (s, 3H, CH3), 3.64 (tm, 2H, CH2). 19F
NMR (CDCl3): δ –101.2 (t, 2 F, CF2-2), –135.8 (ddd, 1 F, F-7), –141.9
(ddd, 1 F, F-4), –152.9 (ddd, 1 F, F-5), –154.8 (dddt, 1 F, F-6); JH(3)–F(2)
4.8.1. 6-Methylperfluoroindan-1-yl cation (19)
1H NMR (SbF5): δ 1.69 (s, CH3). 19F NMR (SbF5): δ –9.6 (dddt, 1 F,
F-1), –29.1 (ddd, 1 F, F-5), –50.5 (dd, 1 F, F-7), –105.6 (s, 2 F, CF2-3),
=
13.5, JH(3)–F(6)
J5,7 = 5.5, J6,7 = 21. HRMS m/z, 342.0323 (M+). Calcd. for
13H8F6O4 = 342.0321. Anal. Calcd for C13H8F6O4: C, 45.63; H, 2.36;
= 2, J4,5 = 21, J4,6 = 2, J4,7 = 16, J5,6 = 19,
C
–113.6 (d, 2 F, CF2-2), –121.6 (dd, 1 F, F-4); J1,2 = 20, J1,4 = 24, J1,5
38, J1,7 = 76, J4,5 = 22, J5,7 = 69.
=
F, 33.31%. Found: C, 45.14; H, 2.47; F, 33.38%.
4.10.2. 3,3-Dihydroperfluoroindan-1-one (25k)
4.8.2. 1-Hydro-6-methylperfluoroindan-1-carboxylic acid (23) and 1-
hydro-5-methyl-perfluoroindan-1-carboxylic acid (24)
mp 97–98 оC (hexane). IR (KBr) ν, cm–1: 2995, 2958 (CeH), 1747
(C] O), 1514 (FAR). 1H NMR (CDCl3): δ 3.64 (tm, CH2). 19F NMR
(CDCl3): δ –110.8 (t, 2 F, CF2-2), –135.5 (ddd, 1 F, F-7), –139.7 (ddd,
1 F, F-5), –141.5 (ddd, 1 F, F-4), –153.0 (dddt, 1 F, F-6); JH(3)–F(2) = 12,
JH(3)–F(6) = 2, J4,5 = 20, J4,6 = 3.5, J4,7 = 18, J5,6 = 18.5, J5,7 = 11.5,
Mixture of two isomers, ratio 23:24 = 42:58, mp 98–103 оC (CCl4-
hexane). IR (KBr) ν, cm–1: 1745 (C = O), 1502 (FAR). HRMS m/z,
302.0168 (M+). Calcd. for C11H5F7O2 = 302.0172. Anal. Calcd for
C
11H5F7O2: C, 43.73; H, 1.67; F, 44.01%. Found: C, 43.54; H, 1.43; F,
J6,7 = 20.5.
HRMS
m/z,
239.9998
(M+).
Calcd.
for
44.66%.
C9H2F6O = 240.0004.
Isomers 23: 1H NMR (CDCl3): δ 7.9 (br s, COOH), 4.53 (dd, 1H, H-
1), 2.31 (dd, 3H, CH3). 19F NMR (CDCl3): δ –105.9 (dm, 1 FA, CF2-3),
–110.8 (dm, 1 FB, CF2-3), –111.8 (dddd, 1 FA, CF2-2), –120.2 (dm, 1 FB,
CF2-2), –120.6 (ddq, 1 F, F-7), –132.6 (ddq, 1 F, F-5), –145.5 (ddt, 1 F,
F-4); JH(1)–F(2A) = 14.5, JH(1)–F(2B) = 6, JCH3–F(5) = 2, JCH3–F(7) = 2,
J2A,2B = 241, J2A,3A and J2A,3B = 4 and 2, J3A,3B = 259, J3,4 = 6.5,
J4,5 = 21, J4,7 = 19.5, J5,7 = 7.5.
4.11. Reaction of 1-hydroperfluoroindan (27) with CO–SbF5
Compound 27 (0.48 g, 1.7 mmol) and SbF5 (2.1 g, 9.7 mmol) (molar
ratio, 1:5.7) according to procedure A (2.5 h) gave a solution of acid 4
with small admixtures (∼5%). According to 19F NMR the SbF5 solution
before hydrolysis contained a salt of cation 28. The solvent was rotary
evaporated and the residue was sublimed (120 °C, 3 Torr) to give 0.41 g
of acid 4 (yield 79%).
Isomers 24: 1H NMR (CDCl3): δ 7.9 (br s, COOH), 4.58 (dd, 1H, H-
1), 2.29 (dd, 3H, CH3). 19F NMR (CDCl3): δ –106.6 (dm, 1 FA, CF2-3),
–110.0 (dm, 1 FB, CF2-3), –112.0 (dddd, 1 FA, CF2-2), –120.0 (dddd,
1 FB, CF2-2), –121.8 (ddtq, 1 F, F-4), –128.3 (ddq, 1 F, F-6), –144.0 (dd,
1 F, F-7); JH(1)–F(2A) = 14, JH(1)–F(2B) = 6.5, JCH3–F(4) = 2, JCH3–F(6) = 2,
J2A,2B = 241, J2A,3A and J2A,3B = 4 and 2, J2B,3A and J2B,3B = 5 and 3,
J3A,3B = 258, J3,4 = 7, J4,6 = 9, J4,7 = 19.5, J6,7 = 20.5.
4.11.1. (1-Hydroperfluoroindan-1-yl)(oxo)methyl cation (28)
1H NMR (SbF5): δ 5.57 (s, H-1). 19F NMR (SbF5): δ –99.2 (d, 1 FA,
CF2-2), –99.9 (d, 1 FA, CF2-3), –100.6 (d, 1 FB, CF2-2), –102.3 (d, 1 FB,
CF2-3), –130.9 (br s, 1 F) and –132.0 (br s, 1 F, F-4 and F-7), –136.5 (br
s, 1 F) and –136.7 (br s, 1 F, F-5 and F-6); J2A,2B = 238, J3A,3B = 262.
4.9. Reaction of 5-methylperfluoroindan (18) with CF3COOH–SbF5
4.12. Reaction of perfluoro-1-ethylindan (29) with CO–SbF5
A mixture of compound 18 (2.75 g, 9.35 mmol), CF3COOH (1.32 g,
11.58 mmol) and SbF5 (6.40 g, 29.56 mmol) (molar ratio, 1:1.2:3.2)
was kept at 20 °C for 2 h. The mixture was treated with cold 5% hy-
drochloric acid and extracted with CH2Cl2 and dried over MgSO4.
Solvent rotary evaporation gave 2.44 g of crude mixture of ketones 21
and 22. Vacuum distillation gave 1.97 g mixture of ketones 21 and 22
(yield 77%) in the ratio 66:34.
1 Compound 29 (0.76 g, 1.9 mmol) and SbF5 (3.11 g, 14.36 mmol)
(molar ratio, 1:7.6) according to procedure A (4.5 h) gave a mixture
of compounds 29, 30, 29k in the ratio 7:89:4. Solvent rotary eva-
poration gave 0.67 g of product, which was dissolved in 5 mL
CH3OH and kept at room temperature for 5.5 h. Silica gel column
chromatography (eluent – hexane, then CCl4) gave 0.57 g of ester 38
(yield 69%).
2 Compound 29 (0.74 g, 1.85 mmol) and SbF5 (0.2 g, 0.92 mmol)
(molar ratio, 1:0.5) according to procedure A (5 h) after solvent
rotary evaporation gave 0.73 g of product 30 (yield 87%), which
contained admixtures of indane 29 (4%) and ketone 29k (2%). The
product was dissolved in the mixture of 5% hydrochloric acid (4 mL)
and Et2O (4 mL) and kept at room temperature for 23 h. Silica gel
column chromatography (CCl4 as eluent) gave 0.54 g of compound
40 (yield 77%).
4.9.1. 6-Methylperfluoroindan-1-one (21) and 5-methylperfluoroindan-1-
one (22)
Mixture of two isomers, ratio 21:22 = 66:34, liquid, bp 72 °C
(6 Torr). IR (KBr) ν, cm–1: 1771 (C = O), 1499 (FAR). HRMS m/z,
272.0065 (M+). Calcd. for C10H3F7O = 272.0067.
Isomers 21: 1H NMR (CDCl3): δ 2.40 (ddt, CH3). 19F NMR (CDCl3): δ
–110.4 (m, 2 F, CF2-3), –112.1 (ddm, 1 F) and –118.0 (ddm, 1 F, F-5 and
F-7), –126.2 (t, 2 F, CF2-2), –142.2 (ddt, 1 F, F-4); JCH3–F(5) = 2,
JCH3–F(7)
= 2, JCH3–F(3) = 1, J2,3 = 3, J3,4 = 6.5, J4,5 = 20.5,
J4,7 = 20.5, J5,7 = 14.5.
4.12.1. Perfluoro-1-ethylindan-1-carbonyl fluoride (30)
Isomers 22: 1H NMR (CDCl3): δ 2.46 (dd, CH3). 19F NMR (CDCl3): δ
–110.1 (m, 2 F, CF2-3), –118.3 (ddtq, 1 F, F-4), –126.0 (t, 2 F, CF2-2),
Liquid. IR (film) ν, cm–1: 1865 (C = O), 1521 (FAR). 19F NMR
(CDCl3): δ 41.0 (m, 1 F, COF), –80.7 (m, 3 F, CF3), –99.0 (dm, 1 FA, CF2-
3), –105.9 (dm, 1 FA, CF2-2), –110.9 (dm, 1 FA, CF2-1α), –112.4 (dm,
1 FB, CF2-1α), –112.4 (dm, 1 FB, CF2-3), –117.8 (dm, 1 FB, CF2-2),
–128.9 (m, 1 F, F-7), –138.3 (ddddd, 1 F, F-4), –142.5 (dddm, 1 F, F-6),
–143.9 (ddd, 1 F, F-5); J1αА,1αB = 289, J2A,2B = 251, J3A,3B = 259, J4,3A
and J4,3B = 10 and 3.5, J4,5 = 21, J4,6 = 8.5, J4,7 = 15.5, J5,6 = 19.5,
J5,7 = 9.5, J6,7 = 20. HRMS m/z, 425.9719 (M+). Calcd. for
–126.3 (ddq, 1 F, F-6), –138.1 (dd, 1 F, F-7); JCH3–F(4) = 2, JCH3–F(6)
2, J2,3 = 3, J3,4 = 7, J4,6 = 9.5, J4,7 = 21, J6,7 = 20.5.
=
4.10. Reaction of 1,1-dihydroperfluoroindan (25) with CO–SbF5
Compound 25 (0.8 g, 3.06 mmol) and SbF5 (0.33 g, 1.53 mmol)
(molar ratio, 1:0.5) according to procedure B (2.5 h) gave a mixture of
compounds 25, 26, 25k in the ratio 32:60:8. Silica gel column chro-
matography (eluent – CCl4, then CHCl3) gave 0.53 g of ester 26 (yield
44%) and after additional sublimation (90 °C, 10 Torr) 0.046 g of ke-
tone 25k (yield 6%).
C
12F14O = 425.9720.
4.12.2. Methyl perfluoro-1-ethylindan-1-carboxylate (38)
Liquid. IR (CCl4) ν, cm–1: 2959 (CH); 1773 (C = O), 1518 (FAR). 1
H
NMR (CDCl3): δ 3.94 (s, CH3). 19F NMR (CDCl3): δ –80.8 (m, 3 F, CF3),
31

Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
–100.3 (dm, 1 FA, CF2-3), –108.5 (d, 1 FA, CF2-2), –110.7 (dm, 1 FA, CF2-
1α), –111.3 (dm, 1 FB, CF2-1α), –112.5 (dm, 1 FB, CF2-3), –119.1 (dm,
1 FB, CF2-2), –128.8 (m, 1 F, F-7), –140.4 (ddddd, 1 F, F-4), –144.8
(dddm, 1 F, F-6), –146.7 (ddd, 1 F, F-5); J1αА,1αB = 288, J2A,2B = 250,
J3A,3B = 259, J4,3A and J4,3B = 9.5 and 3.5, J4,5 = 21, J4,6 = 7.5,
J4,7 = 15.5, J5,6 = 19.5, J5,7 = 9, J6,7 = 20. HRMS m/z, 437.9922
(M+). Calcd. for C13H3F13O2 = 437.9920.
7:55:38. The solvents was rotary evaporated, the residue was dis-
solved in 5 mL CH3OH and kept at room temperature for 28 h. Silica
gel column chromatography (eluent – CCl4, then CHCl3) and va-
cuum sublimation (110 °C, 1 Torr) gave 0.22 g of ester 39 (yield
45%).
2 Compound 34 (0.64 g, 1.43 mmol) and SbF5 (0.32 g, 1.45 mmol)
(molar ratio, 1:1) according to procedure A (49 h, 0.6 mL C6F6 was
added as a solvent) gave a mixture of compounds 34, 35, 36 in the
ratio 8:59:33. The solvent was rotary evaporated, the residue was
dissolved in the mixture of 5% hydrochloric acid (4 mL) and Et2O
(4 mL) and kept at room temperature for 48 h. Resulting mixture
contained compounds 34, 36, 41, 42 in the ratio 8:33:49:10. Silica
gel column chromatography (CCl4 as eluent) gave 0.26 g of com-
pound 41 (yield 43%).
4.12.3. 1-Hydroperfluoro-1-ethylindan (40)
Liquid. 1H NMR (CDCl3): δ 4.45 (ddd, J = 18.5, J = 14.5, J = 8, H-
1). 19F NMR (CDCl3): δ –83.8 (m, 3 F, CF3), –100.3 (dm, 1 FA, CF2-3),
–108.0 (dm, 1 FA, CF2-2), –112.4 (dm, 1 FA, CF2-1α), –118.2 (dm, 1 FB,
CF2-1α), –119.5 (dm, 1 FB, CF2-3), –123.7 (dm, 1 FB, CF2-2), –135.4 (m,
1 F, F-7), –139.4 (ddddd, 1 F, F-4), –145.2 (dddm, 1 F, F-6), –147.6
(ddd, 1 F, F-5); J1αА,1αB = 284, J2A,2B = 250, J3A,3B = 260, J4,3A and
J4,3B = 10 and 4, J4,5 = 21, J4,6 = 7.5, J4,7 = 16.5, J5,6 = 19, J5,7 = 7,
J6,7 = 20. HRMS m/z, 379.9959 (M+). Calcd. for C11HF13 = 379.9965.
4.14.1. Perfluoro-1-phenylindan-1-carbonyl fluoride (35)
19F NMR (CDCl3): δ 33.6 (m, 1 F, COF), –96.7 (dm, 1 FA, CF2-3),
–110.3 (dm, 1 FA, CF2-2), –113.9 (dm, 1 FB, CF2-3), –124.9 (dm, 1 FB,
CF2-2), –136.6 (m, 1 F, F-7), –137.8 (ddddd, 1 F, F-4), –138.1 (br.s, 2 F,
F-ortho), –143.5 (dddm, 1 F, F-6), –145.9 (ddd, 1 F, F-5), –148.3 (tt, 1 F,
F-para), –159.7 (m, 2 F, F-meta); Jpara,meta = 21, Jpara,ortho = 4,
J2A,2B = 243, J3A,3B = 260, J4,3A and J4,3B = 9.5 and 3.5, J4,5 = 21,
J4,6 = 8, J4,7 = 15.5, J5,6 = 18.5, J5,7 = 7.5, J6,7 = 20.5.
4.13. Reaction of perfluoro-1-methylindan (31) with CO–SbF5
1 Compound 31 (0.64 g, 1.84 mmol) and SbF5 (0.2 g, 0.92 mmol)
(molar ratio, 1:0.5) according to procedure A (3 h) gave a mixture of
compounds 32 and 33 in the ratio 90:10. The solvent was rotary
evaporated, the residue was dissolved in the mixture of 5% hydro-
chloric acid (4 mL) and Et2O (4 mL) and kept at room temperature
for 23 h. Silica gel column chromatography (CCl4 as eluent) gave
0.40 g of compound 33 (yield 66%).
2 Compound 31 (0.81 g, 2.33 mmol) and SbF5 (0.25 g, 1.17 mmol)
(molar ratio, 1:0.5) according to procedure B (3.5 h) gave after silica
gel column chromatography (CCl4 as eluent) 0.76 g of compound 37
(yield 84%).
4.14.2. Methyl perfluoro-1-phenylindan-1-carboxylate (39)
mp 88.5–89.5 оC. IR (CCl4) ν, cm–1: 2964 (CH); 1768 (C = O), 1520,
1500 (FAR). 1H NMR (CDCl3): δ 3.79 (s, CH3). 19F NMR (CDCl3): δ
–97.5 (dm, 1 FA, CF2-3), –108.9 (dm, 1 FA, CF2-2), –113.4 (dm, 1 FB,
CF2-3), –125.6 (dm, 1 FB, CF2-2), –137.7 (m, 1 F, F-7), –139.0 (br.s, 2 F,
F-ortho), –139.6 (ddddd, 1 F, F-4), –145.5 (dddm, 1 F, F-6), –148.7 (ddd,
1 F, F-5), –150.8 (tt, 1 F, F-para), –161.3 (m, 2 F, F-meta);
Jpara,meta = 21.5, Jpara,ortho = 4, J2A,2B = 242, J3A,3B = 258, J4,3A and
J4,3B = 9 and 3, J4,5 = 21, J4,6 = 7, J4,7 = 16, J5,6 = 19, J5,7 = 6.5,
4.13.1. Perfluoro-1-methylindan-1-carbonyl fluoride (32)
In the mixture with compound 33, ratio 32:33 = 90:10. 19F NMR.
(CDCl3): δ 41.7 (m, 1 F, COF), –66.1 (m, 3 F, CF3), –101.6 (dm, 1 FA,
CF2-3), –110.8 (dm, 1 FB, CF2-3), –110.9 (dm, 1 FA, CF2-2), –120.4 (dm,
1 FB, CF2-2), –132.7 (m, 1 F, F-7), –138.2 (ddddd, 1 F, F-4), –142.2
(dddm, 1 F, F-6), –144.4 (ddd, 1 F, F-5); J2A,2B = 250, J3A,3B = 261,
J4,3A and J4,3B = 8.5 and 5, J4,5 = 21, J4,6 = 8.5, J4,7 = 15.5, J5,6 = 19,
J5,7 = 8.5, J6,7 = 20.
J6,7 = 20.5.
HRMS
m/z,
485.9923
(M+).
Calcd.
for
C
17H3F13O2 = 485.9920.
4.14.3. 1-Hydroperfluoro-1-phenylindan (41)
mp 58–59.5 оC. 1H NMR (CDCl3): δ 4.45 (t, J = 11.5, H-1). 19F NMR
(CDCl3): –104.5 (dm, 1 FA, CF2-3), –111.8 (dm, 1 FA, CF2-3), –115.4
(dm, 1 FB, CF2-2), –119.3 (dm, 1 FB, CF2-2), –139.4 (ddddd, 1 F, F-4),
–139.6 (br.m, 1 F, F-ortho), –141.9 (br.d, 1 F, J ∼ 22, F-ortho), –141.8
(ddd, 1 F, F-7), –145.4 (dddm, 1 F, F-6), –150.1 (dddm, 1 F, F-5), –150.7
(tt, 1 F, F-para), –160.7 (m, 2 F, F-meta); Jpara,meta = 21, Jpara,ortho = 3,
J2A,2B = 236, J3A,3B = 261, J4,3A and J4,3B = 8 and 5.5, J4,5 = 21,
J4,6 = 7.5, J4,7 = 16.5, J5,6 = 19, J5,7 = 4.6, J6,7 = 20. HRMS m/z,
427.9862 (M+). Calcd. for C15HF13 = 427.9865.
4.13.2. 1-Hydroperfluoro-1-methylindan (33)
Liquid. 1H NMR (CDCl3): δ 4.41 (dq, H-1). 19F NMR (CDCl3): δ –67.0
(m, 3 F, CF3), –101.6 (dm, 1 FA, CF2-3), –110.5 (ddm, 1 FA, CF2-2),
–116.8 (dm, 1 FB, CF2-3), –125.7 (dqm, 1 FB, CF2-2), –136.9 (ddqd, 1 F,
F-7), –139.4 (ddddd, 1 F, F-4), –144.9 (dddm, 1 F, F-6), –147.9 (dddm,
1 F, F-5); JH–CF3 = 7.5, JH–
= 14.5, J2A,2B = 251, J3A,3B = 261,
F(2A)
JF(2B)–CF3 = 14, J4,3A and J4,3B = 9 and 4.5, J4,5 = 20.5, J4,6 = 8,
J4,7 = 16.5, J5,6 = 19, J5,7 = 6.5, J6,7 = 20, JCF3–F(7) = 15.5. HRMS m/
z, 329.9889 (M+). Calcd. for C10HF11 = 329.9889.
4.15. Synthesis of perfluoro-3-phenylindene (42)
A mixture of compound 41 (0.24 g, 0.56 mmol), NEt3 (0.17 g,
1.68 mmol) and CHCl3 (1 mL) was kept at room temperature for 21 h
and washed with 5% hydrochloric acid. Silica gel column chromato-
graphy (hexane as eluent) gave 0.2 g of compound 42 (yield 87%).
4.13.3. Methyl perfluoro-1-methylindan-1-carboxylate (37)
Liquid. IR (film) ν, cm–1: 2968 (CH); 1771 (C = O), 1521 (FAR). 1
H
NMR (CDCl3): δ 3.93 (s, CH3). 19F NMR (CDCl3): δ –65.8 (m, 3 F, CF3),
–103.7 (dm, 1 FA, CF2-3), –110.5 (dm, 1 FB, CF2-3), –113.5 (dm, 1 FA,
CF2-2), –121.4 (dm, 1 FB, CF2-2), –133.0 (dqdd, 1 F, F-7), –140.3
(ddddd, 1 F, F-4), –144.4 (dddm, 1 F, F-6), –147.2 (ddd, 1 F, F-5);
J2A,2B = 249, J3A,3B = 260, J4,3A and J4,3B = 8 and 5.5, J4,5 = 21,
J4,6 = 7.5, J4,7 = 16, J5,6 = 19, J5,7 = 8, J6,7 = 20, JCF3–F(7) = 18.5.
HRMS m/z, 387.9946 (M+). Calcd. for C12H3F11O2 = 387.9952.
4.15.1. Perfluoro-3-phenylindene (42)
Liquid. 19F NMR (CDCl3): δ –125.2 (dm, 2 F, CF2-1), –127.8 (m, 1 F,
F-2), –135.5 (m, 1 F, F-7), –137.3 (m, 2 F, F-ortho), –147.2 (m, 1 F, F-4),
–147.6 (m, 1 F, F-5), –150.7 (tt, 1 F, F-para), –153.6 (m, 1 F, F-6),
–161.1 (m, 2 F, F-meta); Jpara,meta = 21, Jpara,ortho = 3, J1,2 = 13.5.
HRMS m/z, 407.9804 (M+). Calcd. for C15F12 = 407.9803.
4.14. Reaction of perfluoro-1-phenylindan (34) with CO–SbF5
4.16. Reaction of perfluoro-1-ethyltetralin (43) with CO–SbF5
1 Compound 34 (0.45 g, 1 mmol) and SbF5 (0.23 g, 1.07 mmol) (molar
ratio, 1:1.1) according to procedure A (28 h, 0.5 mL C6F6 was added
as a solvent) gave a mixture of compounds 34, 35, 36 in the ratio
1 Compound 43 (0.83 g, 1.85 mmol) and SbF5 (3.11 g, 14.36 mmol)
(molar ratio, 1:7.8) according to procedure A (5.5 h) gave a mixture
of compounds 43, 44, 43k in the ratio 43:50:7. Solvent rotary
32

Y.V. Zonov et al.
JournalofFluorineChemistry214(2018)24–34
evaporation gave 0.81 g of product, which was dissolved in 5 mL
290, CF2), –116.9 (dm, 1 FA) and –136.2 (br d, 1 FB, JA,B = 270, CF2),
–126.3 (br m, 1 F) and –129.5 (m, 1 F, F-4, F-8), –145.9 (br s, 1 F) and
–147.1 (td, 1 F, 3J = 21, 4J = 9, F-6, F-7), –175.7 (br s, 1 F, F-4). HRMS
m/z, 568.9845 ([M-F]+). Calcd. for C16H3F18O2 = 568.9840. Anal.
Calcd for C16H3F19O2: C, 32.67; H, 0.51; F, 61.37%. Found: C, 32.26; H,
0.74; F, 61.19%.
CH3OH and kept at room temperature for 24 h. Silica gel column
chromatography (eluent – hexane, then CCl4) gave 0.4 g (yield 44%)
of mixture of ester 45 and ketone 43k in the ratio 89:11.
2 Compound 43 (0.6 g, 1.33 mmol) and SbF5 (1.95 g, 8.98 mmol)
(molar ratio, 1:6.7) according to procedure A (28.5 h) gave a mix-
ture of compounds 43, 44, 43k in the ratio 41:42:16. Solvent rotary
evaporation gave 0.55 g of product, which was dissolved in the
mixture of 5% hydrochloric acid (4 mL) and Et2O (4 mL) and kept at
room temperature for 5 days. Silica gel column chromatography
(hexane as eluent) gave 0.114 g of compound 46 (yield 20%).
3 Compound 43 (0.66 g, 1.47 mmol) and SbF5 (0.32 g, 1.49 mmol)
(molar ratio, 1:1) according to procedure A (6 h) gave 0.64 g of a
mixture of compounds 43, 44, 43k in the ratio 52:42:5.
4.18. Reaction of perfluoro-1-phenyltetralin (49) with CO–SbF5
Compound 49 (0.53 g, 1.07 mmol) and SbF5 (0.23 g, 1.08 mmol)
(molar ratio, 1:1) according to procedure A (48 h, 0.5 mL C6F6 was
added as a solvent) gave a mixture of compounds 49, 50, 51 in the ratio
69:5:26. 19F NMR (CDCl3) spectrum of the mixture contained multiplet
signal at 39.1 ppm corresponding to the COF-group of compound 50,
most of its other signals were overlapped with signals of compounds 49
and 51. The solvent was rotary evaporated, the residue was dissolved in
the mixture of 5% hydrochloric acid (4 mL) and Et2O (4 mL) and kept at
room temperature for 3 days. Resulting mixture contained compounds
49, 51, 52 in the ratio 69:26:5. Silica gel column chromatography (CCl4
as eluent) gave 0.34 g of mixture of compounds 49 and 52 in the ratio
95:5.
4 Compound 43 (0.73 g, 1.62 mmol) and SbF5 (0.17 g, 0.8 mmol)
(molar ratio, 1:0.5) according to procedure A (5.5 h) gave 0.69 g of a
mixture of compounds 43, 44, 43k in the ratio 81:14:5.
4.16.1. Perfluoro-1-ethyltetralin-1-carbonyl fluoride (44)
19F NMR (CDCl3): δ 42.7 (m, 1 F, COF), –76.7 (m, 3 F, CF3), –101.5
(dm, 1 FA) and –105.3 (dm, 1 FB, JA,B = 287, CF2), –102.6 (br d, 1 FA)
and –113.8 (br d, 1 FB, JA,B ∼ 290, CF2), –112.1 (br s, 2 F, CF2), –125.7
(m, 1 F, F-8), –130.5 (br d, 1 FA) and –140.5 (br d, 1 FB, JA,B ∼ 270,
CF2), –133.3 (ddddd, 1 F, F-5), –144.0 (dddm, 1 F, F-7), –144.5 (ddd,
1 F, F-6); J5,4A and J5,4B = 42 and 10, J5,6 = 21, J5,7 = 9.5, J5,8 = 11.5,
J6,7 = 20.5, J6,8 = 10, J7,8 = 20.5.
Acknowledgments
The authors gratefully acknowledge the Russian Foundation for
Basic Researches (project no. 16-03-00348) for financial support. Y.V.Z.
thanks the Russian Foundation for Basic Researches (project no. 16-33-
00121) for financial support. The authors are grateful to the Multi-
Access Chemical Research Center of SB RAS for spectral and analytical
measurements.
4.16.2. Methyl perfluoro-1-ethyltetralin-1-carboxylate (45)
Liquid (for mixture with ketone 43k, ratio 45:43k = 89:11). IR
(CCl4) ν, cm–1: 2959 (CH); 1769, 1782 (C = O), 1528, 1489 (FAR). 1H
NMR (CDCl3): δ 3.92 (s, CH3). 19F NMR (CDCl3): δ –76.3 (m, 3 F, CF3),
–101.7 (dm, 1 FA) and –105.3 (dm, 1 FB, JA,B = 284, CF2), –102.2 (br d,
1 FA) and –116.5 (br d, 1 FB, JA,B ∼ 290, CF2), –111.6 (br d, 1 FA) and
–114.6 (br d, 1 FB, JA,B ∼ 290, CF2), –126.3 (m, 1 F, F-8), –130.2 (br d,
1 FA) and –142.6 (br d, 1 FB, JA,B ∼ 270, CF2), –135.5 (ddddd, 1 F, F-5),
–146.1 (ddd, 1 F, F-7), –147.4 (ddd, 1 F, F-6); J5,4A and J5,4B = 46 and
10, J5,6 = 21, J5,7 = 8.5, J5,8 = 10, J6,7 = 20.5, J6,8 = 9.5, J7,8 = 20.1.
HRMS m/z, 487.9886 (M+). Calcd. for C14H3F15O2 = 487.9888
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