Acid-promoted cyclization of 2,4-diaryl-1,1,1-trifluorobut-3-en-2-oles and their TMS-ethers into CF3-indenes

Article abstract of DOI:10.1039/c7ob00406k

2,4-Diaryl-1,1,1-trifluorobut-3-en-2-oles and their TMS-ethers in H₂SO₄ at room temperature in just 2 min are quantitatively cyclized into 1-aryl-3-trifluoromethyl-1H-indenes. The reaction proceeds through an intermediate formation o

Full text of DOI:10.1039/c7ob00406k

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Acid-promoted cyclization of 2,4-diaryl-1,1,1-trifluorobut-3-en-2-oles
and their TMS-ethers into CF3-indenes
Matvei Yu. Martynov,a Roman O. Iakovenko,a Anna N. Kazakova,a Irina A. Boyarskaya,a
and Aleksander V. Vasilyev*a,b
aInstitute of Chemistry, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint
Petersburg, 199034, Russia.
bDepartment of Chemistry, Saint Petersburg State Forest Technical University, Institutsky per., 5,
Saint Petersburg, 194021, Russia. E-mail: aleksvasil@mail.ru.
*Corresponding author: A.V. Vasilyev
Keywords: CF3ꢀallyl alcohols, CF3ꢀindenes, Brønsted acids, cyclization, isomerization
Graphical Abstract
CF3
Ar2
CF3
Ar2
CF3
OX
Ar1
Ar2
H2SO4, CH2Cl2
silica gel, EtOAc
r.t., 4 h
isomerization
quantitatively
R1
R1
r.t., just 2 min
cyclization
quantitatively
X = H, SiMe3
17 examples
11 examples
Abstract
2,4ꢀDiarylꢀ1,1,1ꢀtrifluorobutꢀ3ꢀenꢀ2ꢀoles and their TMSꢀethers in H2SO4 at room temperature in
just 2 min are quantitatively cyclized into 1ꢀarylꢀ3ꢀtrifluoromethylꢀ1Hꢀindenes. Reaction proceeds
through an intermediate formation of the corresponding CF3ꢀallyl cations, which are cyclized
regioselectively at the allyl system carbon atom most remote from CF3ꢀgroup. The obtained CF3ꢀ
indenes in solution of EtOAc in the presence of silica gel at room temperature for 4 h are
quantitatively isomerized into 3ꢀarylꢀ1ꢀtrifluoromethylꢀ1Hꢀindenes.
1

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Introduction
Allyl alcohols are valuable synthons in organic chemistry. Recently we have shown1ꢀ3 that
reactions of some trifluoromethyl substituted allyl alcohols with arenes under the action of Brønsted
or Lewis acids have resulted in the formation of trifluoromethylated alkenes, indanes, or indenes.
Synthesis of indenes4ꢀ6 is an actual goal in chemistry, biology, and medicine. For instance, indene
derivatives are widely used as biologically active compounds,7,8 and ligands for metalloꢀ
complexes.9ꢀ12 Introduction of trifluoromethyl group to the indene core may bring new chemical,
biological (lipophilicity and bioavailability), and physical properties to the molecules, due to the
strong electron acceptor character of CF3 group. CF3ꢀIndenes are rather rare objects, there are just a
few reports on their synthesis.13ꢀ17 For instance, Langlois et al showed just one example of BF3ꢀ
promoted cyclization of CF3ꢀallyl alcohol into the corresponding CF3ꢀindene. 13
The main goal of this work was a study of acidꢀpromoted electrophilic transformation of 2,4ꢀ
diarylꢀ1,1,1ꢀtrifluorobutꢀ3ꢀenꢀ2ꢀoles 2 and their TMSꢀethers 1. CF3ꢀTMSꢀethers 1 are easily
available from chalcones by trifluoromethylation of the carbonyl group with CF3TMS followed by
desilylation with SnCl2 or aqueous HCl leading to CF3ꢀallyl alcohols 2 (Scheme 1).
SnCl2, MeCN or
6M HCl, THF
CF3
CF3
OH
Ar1
Ar2
Ar1
Ar2
Ar1
Ar2
CF3SiMe3, CsF
r.t., 24 h
Et2O or MeO(CH2)2OMe
r.t., 4 h
O
OSiMe3
1a-q(82-99 %)
2a-q (61-99 %)
Scheme 1. Synthesis of CF3ꢀTMSꢀethers 1 and the corresponding CF3ꢀalcohols 2 from chalcones
(see substituents R1, R2 in aryl rings Ar1, Ar2, respectively, in Table 1).
Results and Discussion
First, we decided to study plausible reaction cationic intermediates by means of quantum
chemical calculations. One would expect that compounds 1/2 under the action of Brønsted or Lewis
acids could give rise to the corresponding CF3ꢀallyl cations.13 To estimate electronic characteristics
of these cations we carried out DFT calculations of species A generated from 1a/2a by the
protonation of OX group (X = TMS or H), followed by elimination of HOX (Figure 1). The
following parameters were calculated: E - energy of HOMO, LUMO, global electrophilicity index
ω,18,19 natural charges q, contribution of atomic orbital into the molecular orbital k. The calculation
show that carbon C2 bears a large negative charge ꢀ0.21 e, but carbon C4 has a small positive charge
and gives rather big contribution (19.6 %) into LUMO. These data demonstrate that reactive
electrophilic center of cation A should be carbon C4 by both charge and orbital control. Species A
possesses a big value of ω index 7.0 eV, pointing out its high electrophilicity.
2

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q(C2) -0.21 e
k(C2)LUMO 17.7 %
EHOMO -7.51eV
ELUMO -4.80 eV
CF3
OX
1
H+
3
Ph
Ph
4
F3C
2
Ph
q(C4) 0.05 e
k(C4)LUMO 19.6 %
ω 7.0 eV
-HOX
Ph
A
1a (X = SiMe3)
2a (X = H)
Figure 1. Selected electronic characteristics (DFT calculations) of cation A generated from 1a/2a
by protonation of OX group, followed by elimination of HOX (energy of HOMO, LUMO, global
electrophilicity index ω = (EHOMO + ELUMO) 2/8(ELUMO ꢀ EHOMO), natural charges q, contribution of
atomic orbital into the molecular orbital k).
Then we carried out reactions of the series of compounds 1/2 under the action of various
acidic reagents (Table 1). Indeed, the cyclization of 1/2 into CF3ꢀindenes 3 takes place showing that
carbon C4 is a reactive center in the corresponding intermediate cations A. Among all other tested
Brønsted and Lewis acids, the sulfuric acid H2SO4 was found to be one of the best for this
transformation, reaction in this acid took just 2 min (Table 1). Alcohol 2a was not converted in
acetic acid (room temperature, 4 h), and remained unreacted. On the other hand, strong Lewis acids
AlX3 (X = Cl, Br) in reaction with 2a led to complex oligomeric mixtures. The same reaction in
trifluoroacetic needed longer time 1 h (room temperature) and gave 3a in a yield of 88 %. Triflic
acid CF3SO3H (TfOH) may be used as well; indene 3a was formed in 2ꢀ3 min in a yield of 82 % in
this acid. However, we finally chose H2SO4 because it is a cheap and easy to handle reagent.
Both CF3ꢀTMSꢀethers 1 and CF3ꢀallyl alcohols 2 gave the same indenes in the same high
yields (Table 1). In most of the cases, the formation of indenes 3a-q was quantitative (Table 1).
However, in H2SO4 compounds 3h and 3i bearing donating methoxy groups were formed in low
yields of 10 and 20 %, respectively, due to the consequent transformations of these electronꢀrich
indenes in H2SO4. The use of less acidic CF3CO2H resulted in much higher yields of 3h and 3i, 92
and 50 %, respectively (entries 8, 9).
It should be noted that starting compounds 1/2, bearing both electron withdrawing and
donating substituents R1, R2 in aryl rings Ar1, Ar2, respectively, led to the exclusive formation of
indenes 3, formed by the cyclization at carbon C4 in CF3ꢀallyl cations A (see Figure 1). Formation
of alternative indene structures by cyclization at carbon C2 in species A was not observed at all.
This regioselectivity in reactions of CF3ꢀcations A is contrary to not selective behaviour of other
allyl cations without CF3ꢀsubstituent.20
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Table 1. Cyclization of compounds 1/2 in H2SO4 (50 equiv.) at room temperature for 2 min leading
to CF3ꢀindenes 3.
CF3
4
3
5
R1
2
R1
CF3
OX
R2
6
H2SO4, CH2Cl2
r.t., 2 min
1
7
1, X = SiMe3
2, X = H
3
R2
Entry
Starting compounds
Reaction products
R1, R2 in 1/2, R2 in 3
R1
3 (yield, %)a
1/2
R1
H
4ꢀMe
H
4ꢀMe
R2
1
2
3
4
5
6
7
8
H
H
4ꢀMe
4ꢀMe
H
H
6ꢀMe
3a (90)
3b (99)
1a/2a
1b/2b
1c/2c
1d/2d
1e/2e
1f/2f
1g/2g
1h/2h
1i/2i
H
3c (99)
6ꢀMe
6ꢀMeO
H
3d (99)
4ꢀMeO
H
3,4ꢀdi(MeO)
4ꢀMeO
4ꢀMe
3e (97) (97b)
3f (97) (97b)
3g (95) (98b)
3h (10) (92b)
3i (20) (50b)
3j1 (53)
4ꢀMeO
H
4ꢀMeO
3,4ꢀdi(MeO)
H
5,6ꢀdi(MeO)
6ꢀMeO
6ꢀMe
5,6ꢀdi(Me)
6,7ꢀdi(Me)
4,6ꢀdi(Me)
4,7ꢀdi(Me)
4,6,7ꢀ tri(Me)
H
9
10c
3,4ꢀdi(Me)
1j/2j
3j2 (43)
3k (97)
3l (97)
11
12
13
14
15
16
17
2,4ꢀdi(Me)
2,5ꢀdi(Me)
2,4,6ꢀ tri(Me)
H
H
H
1k
1l
1m/2m
1n/2n
1o/2o
1p
3m (97)
H
H
3,4ꢀOCH2O
4ꢀCl
3n (68) (91b)
3o (97)
H
4ꢀF
4ꢀF
3,4ꢀdi(Me)
3,4ꢀdi(MeO)
6ꢀF
6ꢀF
3p (97)
3q (74)d
1q
aIsolated yields.
bYield in reaction in CF3CO2H (50 equiv.), instead of H2SO4, for 5 min.
cTwo regioisomers 3j1 and 3j2 with a ratio 1.25 : 1 and in a total yield of 96 % were obtained.
dThe mixture of isomeric indenes 3q and 4q in a ratio of 8 : 1, respectively, was obtained (see
Scheme 2).
Despite indenes 3 were formed quantitatively without any need of further purification, under
the attempt of their additional column chromatography isolation with silica gel, the isomerization
into other indenes 4 was observed (Scheme 2). Thus, we developed the procedure for this
quantitative isomerization by stirring solution of compounds 3 in EtOAc in the presence of silica
gel at room temperature for 4 h (see Scheme 2 for selected indenes 3/4). As compared with
compounds 3, their isomers 4 should be thermodynamically more stable, because of the additional
conjugation of indene C2=C3 double bond with aryl group Ar2. Some of the indenes 3 were
isomerized very easily. Thus, under the isolation (without column chromatography with silica gel)
4

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of 3q, the additional formation of the corresponding isomeric indene 4q was observed (entry 17,
Table 1). On the other hand, polymethylated indenes 3j2, 3l and 3m, bearing methyl group in
positions 7 of indene system, were not isomerized at all, presumably, because of the steric
hindrance from this methyl substituent. Most likely, the presence of substituent in the indene
position 7 is a crucial point for this isomerization. Any bulky group in this position may disturb a
flat orientation of ring Ar2 relatively to indene plane, that is thermodynamically favorable for
conjugation of their πꢀsystems. Shift of the double bond in indene system with a formation of
isomeric indenes has been also observed under the action of various basic or acidic reagents.13,21ꢀ23
CF3
CF3
silica gel, EtOAc
r.t., 4 h
R1
R1
Ar2
Ar2
quantitatively
3a,c-e,g,i,j1,k,o-q
4a,c-e,g,i,j1,k,o-q
Me
Me
Me
CF3
CF3
Ph
CF3
Me
3j2
Me
3m
Ph
Ph
Me
Me
3l
Compounds 3j2, 3l, 3m are not isomerized
Scheme 2. Isomerization of CF3ꢀindenes 3 into 4 (see substituents R1, R2 in aryl rings Ar1, Ar2,
respectively, in Table 1).
Conclusion
We have found a novel, effective and simple method for the synthesis of two series of
isomeric CF3ꢀindenes based on acid (H2SO4 or CF3CO2H)ꢀpromoted cyclization of 2,4ꢀdiarylꢀ1,1,1ꢀ
trifluorobutꢀ3ꢀenꢀ2ꢀoles or their TMSꢀethers.
Experimental part
Instruments. The NMR spectra of solutions of compounds in CDCl3 were recorded on
Bruker AVANCE III 400 (at 400, 376 and 100 MHz for 1H, 19F and 13C NMR spectra respectively)
1
spectrometer at 25 °C. The residual protonꢀsolvent peak CDCl3 (δ 7.26 ppm) for H NMR spectra
and the carbon signal of CDCl3 (δ 77.0 ppm) for 13C NMR spectra were used as references. 19F
NMR spectra were indirectly referred to the signal of CFCl3 (δ 0.0 ppm). HRMS was carried out at
instruments Bruker maXis HRMSꢀESIꢀQTOF and Varian 902ꢀMS MALDI Mass Spectrometer.
Chromatoꢀmassꢀspectrometry data were obtained at Shimadzu QPꢀ2010 Ultra with a SPBꢀ1
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SULFUR capillary column (30 m × 0.32 mm), thickness of the stationary phase 1.25 ꢁm. The
preparative reactions were monitored by thinꢀlayer chromatography carried out on silica gel plates
(Alugram SIL G/UVꢀ254), using UV light for detection. Preparative TLC was performed on silica
gel Chemapol L 5/40 with petroleum etherꢀethyl acetate mixture eluation.
DFT calculations. All computations were carried out at the DFT/HF hybrid level of theory
using Becke’s threeꢀparameter hybrid exchange functional in combination with the gradientꢀ
corrected correlation functional of Lee, Yang, and Parr (B3LYP) by using GAUSSIAN 2009
program packages.24 The geometries optimization were performed using the 6ꢀ311+G(2d,2p) basis
set (standard 6ꢀ311 basis set added with polarization (d, p) and diffuse functions). Optimizations
were performed on all degrees of freedom and solventꢀphase optimized structures were verified as
true minima with no imaginary frequencies. The Hessian matrix was calculated analytically for the
optimized structures in order to prove the location of correct minima and to estimate the
thermodynamic parameters. Gibbs free energies were calculated for 25°С. Solventꢀphase
calculations used the Polarizable Continuum Model (PCM).
Synthesis and characterizations of compounds 1 and 2.
Trifluoromethylation of chalcones with CF3SiMe3 leading to compounds 1 was carried out
according to the literature procedures.25,26 Detrimethylsilylation of compounds 1 giving alcohols 2
was carried out with aqueous HCl25 or with SnCl2.27
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2,4-diphenylbut-3-en-2-ol (1a). Yield 82 %.
1
Colorless solid. M. p. 49–50°C (oil lit.25,26). H NMR (CDCl3, 400 MHz) δ, ppm: 0.16 s (9H,
SiMe3), 6.56 d (1H, =CH, J 16.3 Hz), 6.71 d (1H, =CH, J 16.3 Hz), 7.29–7.43 m (8Harom.), 7.60–
7.62 m (2Harom.). 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ77.40 s (CF3). HRMS: С19H21F3OSiAg
found 457.0360 [M+Ag]+; calcd. 457.0359.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(4-methylphenyl)-4-phenylbut-3-en-2-ol (1b).
1
Yield 96 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.15 s (9H, SiMe3), 2.39 s (3H, Me),
6.56 d (1H, =CH, J 16.3 Hz), 6.72 d (1H, =CH, J 16.3 Hz), 7.21 d (2Harom., J 8.1 Hz), 7.29–7.43 m
(5Harom.), 7.49 d (2Harom., J 8.1 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 2.2 (SiMe3), 21.2 (Me),
80.0 q (C2, JCꢀF 28.8 Hz), 125.2 q (CF3, JCꢀF 286.8 Hz), 127.0, 127.2, 128.0, 128.7, 128.8, 128.9,
135.2, 135.2, 135.9, 138.5. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ77.57 s (CF3). HRMS:
C20H23F3OSiAg found 471.0517 [M+Ag]+; calcd. 471.0516.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-4-(4-methylphenyl)-2-phenylbut-3-en-2-ol (1c).
Yield 92 %. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 0.16 s (9H, SiMe3), 2.37 s (3H, Me),
6.52 d (1H, =CH, J 16.4 Hz), 6.66 d (1H, =CH, J 16.4 Hz), 7.17 d (2Harom., J 8.0 Hz), 7.31 d
(2Harom., J 8.0 Hz), 7.36–7.43 m (3Harom.), 7.60–7.62 m (2Harom.). 13C NMR (CDCl3, 100
6

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MHz) δ, ppm: 2.2 (SiMe3), 21.4 (Me), 80.1 q (C2, JCꢀF 28.8 Hz), 125.2 q (CF3, JCꢀF 286.6 Hz),
126.0, 126.9, 128.0, 128.1, 128.6, 129.7, 133.1, 135.4, 138.2, 138.8. 19F NMR (CDCl3, 376 MHz) δ,
ppm: ꢀ77.57 s (CF3). HRMS: C20H23F3OSiAg found 471.0507 [M+Ag]+; calcd. 471.0516.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2,4-bis(4-methylphenyl)but-3-en-2-ol (1d).
Yield 99 %. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 0.15 s (9H, SiMe3), 2.36 s (3H, Me),
2.39 s (3H, Me), 6.51 d (1H, =CH, J 16.3 Hz), 6.67 d (1H, =CH, J 16.3 Hz), 7.17 d (2Harom., J 8.0
Hz), 7.20 d (2Harom., J 8.1 Hz), 7.31 d (2Harom., J 8.0 Hz), 7.49 d (2Harom., J 8.1 Hz). 13C NMR
(CDCl3, 100 MHz) δ, ppm: 2.2 (SiMe3), 21.2 (Me), 21.4 (Me), 80.0 q (C2, JCꢀF 28.7 Hz), 125.2 q
(CF3, JCꢀF 286.6 Hz), 126.1, 126.9, 128.1, 128.8, 129.6, 133.2, 135.2, 135.3, 138.4, 138.7. 19F NMR
(CDCl3, 376 MHz) δ, ppm: ꢀ77.75 c (CF3). HRMS: C21H25F3OSiAg found 485.0668 [M+Ag]+;
calcd. 485.0672.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(4-methoxyphenyl)-4-phenylbut-3-en-2-ol
(1e). Yield 98 %. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 0.18 s (9H, SiMe3), 3.83 s (3H,
OMe), 6.46 d (1H, =CH, J 16.3 Hz), 6.64 d (1H, =CH, J 16.3 Hz), 6.91 d (2Harom., J 8.7 Hz), 7.37
d (2Harom., J 8.7 Hz), 7.40–7.42 m (3Harom.), 7.63–7.65 m (2Harom.). 13C NMR (CDCl3, 100
MHz) δ, ppm: 2.2 (SiMe3), 55.4 (OMe), 80.2 q (C2, J 28.8 Hz), 114.4, 124.7, 125.2 q (CF3, J 286.5
Hz), 128.0, 128.2, 128.3, 128.6, 128.6, 135.1, 138.3, 160.2. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ
77.64 c (CF3). HRMS: C20H23F3O2SiAg found 487.0469 [M+Ag]+; calcd. 487.0465.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-4-(4-methoxyphenyl)-2-phenylbut-3-en-2-ol
1
(1f). Yield 99 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.15 s (9H, SiMe3), 3.85 s (3H,
OMe), 6.56 d (1H, =CH, J 16.3 Hz), 6.73 d (1H, =CH, J 16.3 Hz), 6.93 d (2Harom., J 8.6 Hz),
7.30–7.37 m (3Harom.), 7.42–7.44 m (2Harom.), 7.53 d (2Harom., J 8.6 Hz). 13C NMR (CDCl3,
100 MHz) δ, ppm: 2.2 (SiMe3), 55.4 (OMe), 79.8 q (C2, JCꢀF 28.9 Hz), 113.4, 125.2 q (CF3, JCꢀF
286.5 Hz), 127.0, 127.2, 128.7, 128.9, 129.5, 130.0, 135.2, 135.9, 159.9. 19F NMR (CDCl3, 376
MHz) δ, ppm: ꢀ77.73 c (CF3). HRMS: C20H23F3O2SiAg found 487.0477 [M+Ag]+; calcd. 487.0465.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(3,4-dimethoxyphenyl)-2-phenylbut-3-en-2-
1
ol (1g). Yield 99 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.15 s (9H, SiMe3), 3.88 s
(3H, OMe), 3.91 s (3H, OMe), 6.55 d (1H, =CH, J 16.3 Hz), 6.71 d (1H, =CH, J 16.3 Hz), 6.88 d
(1Harom., J 9.0 Hz), 7.14–7.15 m (2Harom.), 7.26–7.43 m (5Harom.). 13C NMR (CDCl3, 100
MHz) δ, ppm: 2.2 s (SiMe3), 56.0 (OMe), 56.0 (OMe), 79.9 q (C2, JCꢀF 28.7 Hz), 110.5, 111.6,
120.8, 125.2 q (CF3, JCꢀF 287.0 Hz), 127.0, 127.0, 128.8, 129.0, 130.4, 135.4, 135.9, 148.5, 149.3.
19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ77.64 c (CF3). HRMS: C21H25F3O2SiAg found 517.0559
[M+Ag]+; calcd. 517.0571.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2,4-bis(4-methoxyphenyl)but-3-en-2-ol (1h).
1
Yield 95 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.14 s (9H, SiMe3), 3.82 s (3H,
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OMe), 3.84 s (3H, OMe), 6.41 d (1H, =CH, J 16.3 Hz), 6.62 d (1H, =CH, J 16.3 Hz), 6.89 d
(2Harom., J 8.7 Hz), 6.92 d (2Harom., J 8.8 Hz), 7.35 d (2Harom., J 8.7 Hz), 7.52 d (2Harom., J
8.8 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 2.2 (SiMe3), 55.4 (OMe), 55.5 (OMe), 79.9 q (C2, JCꢀ
29.0 Hz), 113.4, 114.4, 124.9, 125.3 q (CF3, JCꢀF 286.6 Hz), 128.3, 128.6, 129.5, 130.2, 134.9,
F
19
159.8, 160.2. F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.02 c (CF3). HRMS: C21H25F3O2SiAg found
517.0550 [M+Ag]+; calcd. 517.0571.
Trimethylsilyl
ether
of
(E)-1,1,1-trifluoro-2-(4-methylphenyl)-4-(3,4-
dimethoxyphenyl)but-3-en-2-ol (1i). Yield 99 %. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm:
0.14 s (9H, SiMe3), 2.39 s (3H, Me), 3.89 s (3H, OMe), 3.91 s (3H, OMe), 6.40 d (1H, =CH, J 16.3
Hz), 6.61 d (1H, =CH, J 16.3 Hz), 6.85 d (1Harom., J 8.3 Hz), 6.93 d (1Harom., J 1.9 Hz), 6.96 dd
(1Harom., J 8.3 Hz, J 1.9 Hz), 7.21 d (2Harom., J 8.1 Hz), 7.49 d (2Harom., J 8.1 Hz). 13C NMR
(CDCl3, 100 MHz) δ, ppm: 2.2 (SiMe3), 21.2 (Me), 56.1 (OMe), 56.1 (OMe), 80.1 q (C2, J 28.8
Hz), 104.4, 109.4, 111.4, 120.3, 125.1, 125.2 q (CF3, JCꢀF 286.5 Hz), 128.1, 128.8, 128.9, 135.1,
135.2, 138.4, 149.4, 149.8. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ77.68 (CF3). HRMS:
C22H27F3O3SiAg found 531.0727 [M+Ag]+; calcd. 531.0731.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(3,4-dimethylphenyl)-2-phenylbut-3-en-2-ol
1
(1j). Yield 93 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.15 s (9H, SiMe3), 2.30 s (6H,
2Me), 6.55 d (1H, =CH, J 16.3 Hz), 6.73 d (1H, =CH, J 16.3 Hz), 7.16 d (1Harom., J 7.8 Hz), 7.29–
7.39 m (5Harom.), 7.42–7.44 m (2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 2.2 (SiMe3), 19.6
(Me), 20.2 (Me), 80.0 q (C2, JCꢀF 28.8 Hz), 125.2 q (CF3, JCꢀF 286.7 Hz), 125.5, 127.0, 127.3, 128.7,
128.9, 129.2, 129.4, 135.0, 135.5, 136.0, 136.2, 137.1. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ77.41
c (CF3). HRMS: C21H25F3OSiAg found 485.0668 [M+Ag]+; calcd. 485.0672.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(2,4-dimethylphenyl)-2-phenylbut-3-en-2-ol
1
(1k). Yield 94 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.09 s (9H, SiMe3), 2.33 s (3H,
Me), 2.39 s (3H, Me), 6.47 d (1H, =CH, J 16.4 Hz), 6.67 d (1H, =CH, J 16.4 Hz), 7.01ꢀ7.03 m
(2Harom.), 7.27–7.42 m (5Harom.) , 7.50 d (1Harom., J 7.7 Hz). 13C NMR (CDCl3, 100 MHz) δ,
ppm: 1.8 (SiMe3), 21.0 (Me), 22.6 (Me), 81.0 q (C2, JCꢀF 28.5 Hz), 125.6 q (CF3, JCꢀF 287.4 Hz),
126.2, 126.9, 128.3, 128.5, 128.9, 133.7, 133.8, 134.1, 136.2, 138.0, 138.3. 19F NMR (CDCl3, 376
MHz) δ, ppm: ꢀ74.50 c (CF3). HRMS: C21H25F3OSiAg found 485.0664 [M+Ag]+; calcd. 485.0672.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(2,5-dimethylphenyl)-2-phenylbut-3-en-2-ol
(1l). Yield 97 %. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 0.09 s (9H, SiMe3), 2.36 s (3H,
Me), 2.38 s (3H, Me), 6.47 d (1H, =CH, J 16.4 Hz), 6.68 d (1H, =CH, J 16.4 Hz), 7.08 m
(2Harom.), 7.28–7.37 m (3Harom.), 7.40–7.42 m (3Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm:
1.7 (SiMe3), 21.3 (Me), 22.2 (Me), 81.0 q (C2, JCꢀF 28.6 Hz), 125.5 q (CF3, JCꢀF 287.6 Hz), 126.8,
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128.1, 128.4, 128.8, 129.0, 129.2, 132.8, 134.1, 134.7, 134.9, 136.1, 136.2. 19F NMR (CDCl3, 376
MHz) δ, ppm: ꢀ74.24 c (CF3). HRMS: C21H25F3OSiAg found 485.0662 [M+Ag]+; calcd. 485.0672.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(2,4,6-trimethylphenyl)-2-phenylbut-3-en-2-
1
ol (1m). Yield 99 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.10 s (9H, SiMe3), 2.25 s
(3H, Me), 2.27 s (3H, Me), 2.36 s (3H, Me), 6.48 d (1H, =CH, J 16.4 Hz), 6.69 d (1H, =CH, J 16.4
Hz), 6.97 s (1Harom.), 7.27k–7.43 m (6Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 1.7 (SiMe3),
19.2 (Me), 19.5 (Me), 22.0 (Me), 80.8 q (C2, JCꢀF 28.5 Hz), 125.4 q (CF3, JCꢀF 287.6 Hz), 126.7,
128.2, 128.3, 128.7, 129.6, 133.2, 133.6, 133.9, 134.2, 135.1, 136.1, 136.7. 19F NMR (CDCl3, 376
MHz) δ, ppm: ꢀ74.54 c (CF3). HRMS: C22H27F3OSiAg found 499.0834 [M+Ag]+; calcd. 499.0829.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-4-(3,4-methylenedioxyphenyl)-2-phenylbut-3-
en-2-ol (1n). Yield 99 %. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 0.16 s (9H, SiMe3), 5.98
s (2H, CH2), 6.39 d (1H, =CH, J 16.2 Hz), 6.59 d (1H, =CH, J 16.2 Hz), 6.78 d (1Harom., J 8.0
Hz), 6.83 d (1Harom., J 8.0 Hz), 6.96 s (1Harom.), 7.36–7.42 m (3Harom.), 7.59–7.61 m
(2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 2.2 (SiMe3), 80.1 q (C2, JCꢀF 28.8 Hz), 101.4,
105.9, 108.6, 122.2, 125.2 q (CF3, JCꢀF 286.3 Hz), 125.2, 128.0, 128.1, 128.6, 130.3, 135.2, 138.2,
19
148.3, 148.5. F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ77.59 c (CF3). HRMS: C20H21F3O3SiAg found
501.0252 [M+Ag]+; calcd. 501.0258.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-4-(4-chlorophenyl)-2-phenylbut-3-en-2-ol (1o).
Yield 99 %. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 0.15 s (9H, SiMe3), 6.53 d (1H, =CH,
J 16.3 Hz), 6.67 d (1H, =CH, J 16.3 Hz), 7.34 s (4Harom.), 7.38–7.43 m (3Harom.), 7.59–7.61 m
(2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 2.1 (SiMe3), 80.1 q (C2, JCꢀF 29.0 Hz), 125.1 q
(CF3, JCꢀF 286.8 Hz), 127.9, 128.0, 128.2, 128.2, 128.8, 129.2, 133.9, 134.4, 134.6, 138.0. 19F NMR
(CDCl3, 376 MHz) δ, ppm: ꢀ77.19 c (CF3). HRMS: C21H25F335ClOSiAg found 490.9965 [M+Ag]+;
calcd. 490.9969.
Trimethylsilyl ether of (E)-1,1,1-trifluoro-2-(4-fluorophenyl)-4-(3,4-dimethylphenyl)but-
1
3-en-2-ol (1p). Yield 96 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 0.17 s (9H, SiMe3),
2.28 s (6H, 2Me), 6.50 d (1H, =CH, J 16.4 Hz), 6.61 d (1H, =CH, J 16.4 Hz), 7.05–7.18 m
(5Harom.), 7.59 dd (2Harom., J 8.6 Hz, J 5.5 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 2.1
(SiMe3), 19.6 (Me), 19.8 (Me), 79.8 q (C2, JCꢀF 29.0 Hz), 114.8 d (JCꢀF 21.5 Hz), 124.3, 125.1 q
(CF3, JCꢀF 286.6 Hz), 125.3, 128.3, 130.1 d (J 8.2 Hz) 130.2, 133.2, 134.1 d (JCꢀF 3.1 Hz), 135.9,
137.2, 137.7, 162.9 d (JCꢀF 247.6 Hz). 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ113.96 c (1Farom), ꢀ
77.95 c (CF3). HRMS: C21H24F4OSiAg found 503.0570 [M+Ag]+; calcd. 503.0578.
Trimethylsilyl
ether
of
(E)-1,1,1-trifluoro-2-(4-fluorophenyl)-4-(3,4-
1
dimethoxyphenyl)but-3-en-2-ol (1q). Yield 93 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ,
ppm: 0.16 s (9H, SiMe3), 3.90 s (3H, OMe), 3.91 s (3H, OMe), 6.39 d (1H, =CH, J 16.3 Hz), 6.57 d
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(1H, =CH, J 16.3 Hz), 6.85 d (1Harom., J 8.3 Hz), 6.92 d (1Harom., J 1.9 Hz), 6.96 dd (1Harom., J
8.3 Hz, J 1.9 Hz), 7.05–7.11 m (2Harom.), 7.58 dd (2Harom., J 8.6 Hz, J 5.4 Hz). 13C NMR (CDClꢀ
3, 100 MHz) δ, ppm: 2.1 s (SiMe3), 56.1 (OMe), 56.1 (OMe), 79.8 q (C2, JCꢀF 29.0 Hz), 109.3,
111.4, 114.9 d (JCꢀF 21.5 Hz), 120.4, 124.6, 125.1 q (CF3, JCꢀF 286.3 Hz), 128.6, 130.1 d (JCꢀF 8.3
Hz), 134.0 d (JCꢀF 3.2 Hz), 135.6, 149.4, 150.0, 163.0 d (JCꢀF 247.7 Hz). 19F NMR (CDCl3, 376
MHz) δ, ppm: ꢀ113.88 c (1Farom), ꢀ77.90 c (CF3). HRMS: C21H24F4O3SiAg found 535.0484
[M+Ag]+; calcd. 535.0476.
1
(E)-1,1,1-Trifluoro-2,4-diphenylbut-3-en-2-ol (2a). Yield 95 %. Yellow oil (oil lit.24). H
NMR (CDCl3, 400 MHz) δ, ppm: 2.69 s (1H, OH), 6.73 d (1H, =CH, J 16.1 Hz), 6.89 d (1H, =CH, J
16.1 Hz), 7.28–7.45 m (8Harom.), 7.65–7.67 m (2Harom.). 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ
78.50 c (CF3). HRMS: С16H13F3OAg found 384.9957 [M+Ag]+; calcd. 384.9964.
(E)-1,1,1-Trifluoro-2-(4-methylphenyl)-4-phenylbut-3-en-2-ol (2b). Yield 94 %. Yellow
1
solid. M. p. 53–55°C. H NMR (CDCl3, 400 MHz) δ, ppm: 2.38 s (3H, Me), 2.66 s (1H, OH), 6.72
d (1H, =CH, J 16.1 Hz), 6.89 d (1H, =CH, J 16.1 Hz), 7.23 d (2Harom., J 8.1 Hz), 7.28–7.38 m
(3Harom.), 7.43–7.45 m (2Harom.), 7.54 d (2Harom., J 8.1 Hz). 13C NMR (CDCl3, 100 MHz) δ,
ppm: 21.21 (Me), 77.4 q (C2, JCꢀF 29.0 Hz), 125.2 q (CF3, JCꢀF 286.0 Hz), 126.7, 126.9, 126.9,
127.1, 128.7, 128.9, 129.2, 133.5, 134.6, 135.7, 138.9. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.57
c (CF3). HRMS: С17H15F3OAg found 399.0124 [M+Ag]+; calcd. 399.0120.
(E)-1,1,1-Trifluoro-4-(4-methylphenyl)-2-phenylbut-3-en-2-ol (2c). Yield 92 %. Yellow
1
solid. M. p. 64–66°C. H NMR (CDCl3, 400 MHz) δ, ppm: 2.36 s (3H, Me), 2.67 s (1H, OH), 6.68
d (1H, =CH, J 16.1 Hz), 6.85 d (1H, =CH, J 16.1 Hz), 7.16 d (2Harom., J 8.0 Hz), 7.33 d (2Harom.,
J 8.0 Hz), 7.37–7.44 m (3Harom.), 7.65–7.67 m (2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm:
21.4 (Me), 77.5 q (C2, JCꢀF 29.0 Hz), 125.2 q (CF3, JCꢀF 286.0 Hz), 125.6, 127.0, 127.0, 128.5,
128.9, 129.6, 132.9, 133.6, 137.6, 138.8. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.55 c (CF3).
HRMS: С17H15F3OAg found 399.0110 [M+Ag]+; calcd. 399.0120.
(E)-1,1,1-Trifluoro-2,4-bis(4-methylphenyl)but-3-en-2-ol (2d). Yield 80 %. Yellow solid.
M. p. 49–51°C. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.36 s (3H, Me), 2.38 s (3H, Me), 2.58 s (1H,
OH), 6.66 d (1H, =CH, J 16.1 Hz), 6.84 d (1H, =CH, J 16.1 Hz), 7.16 d (2Harom., J 8.0 Hz), 7.22 d
(2Harom., J 8.1 Hz), 7.32 d (2Harom., J 8.0 Hz), 7.53 d (2Harom., J 8.1 Hz). 13C NMR (CDCl3,
100 MHz) δ, ppm: 21.2 (Me), 21.4 (Me), 77.4 q (C2, JCꢀF 28.6 Hz), 125.3 q (CF3, J 286.2 Hz),
125.7, 126.9, 127.0, 129.2, 129.6, 132.9, 133.5, 134.7, 138.7, 138.8. 19F NMR (CDCl3, 376 MHz) δ,
ppm: ꢀ78.65 c (CF3). HRMS: С18H17F3OAg found 413.0267 [M+Ag]+; calcd. 413.0277.
(E)-1,1,1-Trifluoro-2-(4-methoxyphenyl)-4-phenylbut-3-en-2-ol (2e). Yield 94 %. Yellow
1
oil. H NMR (CDCl3, 400 MHz) δ, ppm: 2.69 s (1H, OH), 3.82 s (3H, OCH3), 6.59 d (1H, =CH, J
16.1 Hz), 6.81 d (1H, =CH, J 16.1 Hz), 6.88 d (2Harom., J 8.8 Hz), 7.35–7.44 m (5Harom.), 7.64–
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7.66 m (2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 55.5 (OMe), 77.5 q (C2, JCꢀF 28.6 Hz),
114.3, 124.4, 125.3 q (CF3, J 285.9 Hz), 127.0, 128.4, 128.4, 128.5, 128.9, 133.3, 137.7, 160.2. 19F
NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.57 c (CF3). HRMS: С17H15F3O2Ag found 415.0089 [M+Ag]+;
calcd. 415.0070.
(E)-1,1,1-Trifluoro-4-(4-methoxylphenyl)-2-phenylbut-3-en-2-ol (2f). Yield 61 %. Yellow
1
oil. H NMR (CDCl3, 400 MHz) δ, ppm: 2.66 s (1H, OH), 3.82 s (3H, OMe), 6.58 d (1H, =CH, J
16.1 Hz), 6.80 d (1H, =CH, J 16.1 Hz), 6.87 d (2Harom., J 8.8 Hz), 7.35–7.43 m (5Harom.), 7.64–
7.65 m (2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 55.5 (OMe), 77.5 q (C2, JCꢀF 28.9 Hz),
114.3, 124.4, 125.3 q (CF3, JCꢀF 286.1 Hz), 127.0, 128.3, 128.4, 128.4, 128.8, 133.3, 137.8, 160.1.
19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.59 c (CF3). HRMS: С17H15F3O2Ag found 415.0073
[M+Ag]+; calcd. 415.0070.
(E)-1,1,1-Trifluoro-2-(3,4-dimethoxyphenyl)-2-phenylbut-3-en-2-ol (2g). Yield 93 %.
1
Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 2.76 s (1H, OH), 3.89 s (3H, OMe), 3.90 s (3H,
OMe), 6.69 d (1H, =CH, J 16.1 Hz), 6.88 d (1H, =CH, J 16.1 Hz), 6.88 d (1Harom., J 8.5 Hz), 7.16
d (1Harom., J 8.5 Hz), 7.19 s (1Harom.), 7.28–7.37 m (3Harom.), 7.43 m (2Harom.). 13C NMR
(CDCl3, 100 MHz) δ, ppm: 56.0 (OMe), 56.1 (OMe), 77.5 q (C2, J 28.6 Hz), 110.3, 110.8, 119.8,
125.3 q (CF3, JCꢀF 286.1 Hz), 126.7, 127.0, 128.8, 128.9, 129.9, 133.7, 135.7, 148.9, 149.5. 19F
NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.54 c (CF3). HRMS: С18H17F3O3Ag found 445.0178 [M+Ag]+;
calcd. 445.0175.
(E)-1,1,1-Trifluoro-2,4-bis(4-methoxyphenyl)but-3-en-2-ol (2h). Yield 99 %. Yellow oil.
1H NMR (CDCl3, 400 MHz) δ, ppm: 2.73 s (1H, OH), 3.81 s (3H, OMe), 3.82 s (3H, OMe), 6.56 d
(1H, =CH, J 16.1 Hz), 6.79 d (1H, =CH, J 16.1 Hz), 6.87 d (2Harom., J 8.7 Hz), 6.92 d (2Harom., J
8.8 Hz), 7.36 d (2Harom., J 8.7 Hz), 7.56 d (2Harom., J 8.8 Hz). 13C NMR (CDCl3, 100 MHz) δ,
ppm: 55.4 (OMe), 55.5 (OMe), 77.2 q (C2, JCꢀF 28.6 Hz), 113.8, 114.3, 124.5, 125.3 q (CF3, JCꢀF
286.0 Hz), 128.3, 128.5, 129.8, 133.1, 159.9, 160.1. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.77 c
(CF3). HRMS: С18H17F3O3Ag found 445.0173 [M+Ag]+; calcd. 445.0175.
(E)-1,1,1-Trifluoro-2-(4-methylphenyl)-4-(3,4-dimethoxyphenyl)but-3-en-2-ol (2i). Yield
1
95 %. Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 2.37 s (3H, Me), 2.71 s (1H, OH), 3.88 s
(3H, OMe), 3.90 s (3H, OMe), 6.55 d (1H, =CH, J 16.0 Hz), 6.79 d (1H, =CH, J 16.0 Hz), 6.83 d
(1Harom., J 8.1 Hz), 6.95–6.97 m (2Harom.), 7.22 d (2Harom., J 8.1 Hz), 7.53 d (2Harom., J 8.1
13
Hz). C NMR (CDCl3, 100 MHz) δ, ppm: 21.2 (Me), 56.1 (OMe), 56.1 (OMe), 77.4 q (C2, J 28.8
Hz), 109.4, 111.3, 120.5, 124.7, 125.3 q (CF3, JCꢀF 285.8 Hz), 126.9, 128.8, 129.2, 133.5, 134.8,
138.8, 149.3, 149.8. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.49 c (CF3). HRMS: С19H19F3O3Ag
found 459.0328 [M+Ag]+; calcd. 459.0332.
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(E)-1,1,1-Trifluoro-2-(3,4-dimethylphenyl)-2-phenylbut-3-en-2-ol (2j). Yield 93 %.
1
Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 2.28 s (3H, Me), 2.30 s (3H, Me), 2.61 s (1H,
OH), 6.70 d (1H, =CH, J 16.1 Hz), 6.89 d (1H, =CH, J 16.1 Hz), 7.17 d (1Harom., J 8.0 Hz), 7.27–
7.36 m (4Harom.), 7.40 s (1Harom.), 7.42–7.44 m (2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm:
19.5 (Me), 20.1 (Me), 77.3 q (C2, JCꢀF 28.8 Hz), 124.3, 125.3 q (CF3, JCꢀF 286.0 Hz), 126.9, 127.0,
127.9, 128.6, 128.8, 129.7, 133.2, 135.1, 135.9, 136.8, 137.4. 19F NMR (CDCl3, 376 MHz) δ, ppm:
ꢀ78.50 c (CF3). HRMS: С18H17F3OAg found 413.0269 [M+Ag]+; calcd. 413.0277.
(E)-1,1,1-Trifluoro-2-(2,4,6-trimethylphenyl)-2-phenylbut-3-en-2-ol (2m). Yield 94 %.
1
Yellow solid. M. p. 66–68°C. H NMR (CDCl3, 400 MHz) δ, ppm: 2.25 s (3H, Me), 2.28 s (3H,
Me), 2.41 s (3H, Me), 2.55 s (1H, OH), 6.67 d (1H, =CH, J 16.2 Hz), 6.75 d (1H, =CH, J 16.2 Hz),
6.99 s (1Harom.), 7.27–7.37 m (3Harom.), 7.42–7.43 m (3Harom.). 13C NMR (CDCl3, 100 MHz) δ,
ppm: 19.3 (Me), 19.6 (Me), 22.0 q (Me, J 1.2 Hz), 78.9 q (C2, JCꢀF 28.6 Hz), 125.7 q (CF3, JCꢀF
286.7 Hz), 126.9, 127.5, 128.6, 128.9, 129.2, 132.8, 133.7, 134.0, 134.5, 135.1, 135.9, 137.4. 19F
NMR (CDCl3, 376 MHz) δ, ppm: ꢀ76.72 c (CF3). HRMS: С19H19F3OAg found 427.0422 [M+Ag]+;
calcd. 427.0433.
(E)-1,1,1-Trifluoro-4-(3,4-methylenedioxyphenyl)-2-phenylbut-3-en-2-ol (2n). Yield 72
%. Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.70 s (1H, OH), 5.97 s (2H, CH2) 6.54 d (1H,
=CH, J 16.0 Hz), 6.77 d (1Harom., J 8.1 Hz), 6.77 d (1H, =CH, J 16.0 Hz), 6.85 dd (1Harom., J 8.1
Hz, J 1.5 Hz), 6.97 d (1Harom., J 1.5 Hz), 7.36–7.43 m (3Harom.), 7.63–7.64 m (2Harom.). 13C
NMR (CDCl3, 100 MHz) δ, ppm: 77.4 q (C2, J 29.2 Hz), 101.4, 106.1, 108.5, 122.2, 124.8, 125.2 q
(CF3, JCꢀF 285.8 Hz), 127.0, 128.5, 128.9, 130.1, 133.4, 137.6, 148.2, 148.4. 19F NMR (CDCl3, 376
MHz) δ, ppm: ꢀ78.57 c (CF3). HRMS: С17H13F3O3Ag found 428.9867 [M+Ag]+; calcd. 428.9863.
(E)-1,1,1-Trifluoro-4-(4-chlorophenyl)-2-phenylbut-3-en-2-ol (2o). Yield 93 %. Yellow
oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.69 s (1H, OH), 6.68 d (1H, =CH, J 16.0 Hz), 6.85 d (1H,
=CH, J 16.0 Hz), 7.30–7.45 m (7Harom.), 7.63–7.65 m (2Harom.). 13C NMR (CDCl3, 100 MHz) δ,
ppm: 77.5 q (C2, JCꢀF 29.1 Hz), 125.1 q (CF3, JCꢀF 286.0 Hz), 126.8, 127.2, 128.3, 128.6, 129.0,
132.5, 134.2, 134.5, 137.4. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ78.40 c (CF3). HRMS:
С16H12F335ClOAg found 418.9557 [M+Ag]+; calcd. 418.9574.
Synthesis and characterizations of indenes 3.
General procedure for cyclization of compounds 1 or 2 into indenes 3 in H2SO4.
1 mL of H2SO4 (95 %) was added at one portion to a solution of 0.1 mmol of compound 1 or
2 in 1 mL of CH2Cl2 at room temperature with vigorous stirring. The reaction mixture was stirred
for 2 min, then poured into 15 mL of water, and extracted with CH2Cl2 (3×15 mL). The combined
extracts were washed with water (3×10 mL), dried over Na2SO4. Evaporation of the solvent under
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reduced pressure gave finally indene 3. Analogously the reactions were carried out in CF3CO2H
(see Table 1).
3-(Trifluoromethyl)-1-phenyl-1H-indene (3a). Yield 90 %. Yellow solid. M. p. 43–45°С
1
(oil lit.13). H NMR (CDCl3, 400 MHz) δ, ppm: 4.74 m (1H, C1H), 7.03 m (1H, =CH), 7.12 d
(2Harom., J 7.6 Hz), 7.28–7.33 m (5Harom.), 7.38 t (1Harom., J 7.4 Hz), 7.57 d (1Harom., J 7.6
Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 55.6 (C1), 121.2, 122.5 q (CF3, J 270.0 Hz), 123.9,
126.6, 127.0, 127.6, 128.03, 129.1, 134.6 q (C3, J 34.3 Hz), 137.1, 138.2, 141.0 q (C2, J 5.0 Hz),
148.0. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ64.05 s (CF3). HRMS (MALDI): C16H12F3
found 261.0886 [М+H]+, calcd. 261.0891.
1
3-(Trifluoromethyl)-6-methyl-1-phenyl-1H-indene (3b). Yield 99 %. Yellow oil. H NMR
(CDCl3, 400 MHz) δ, ppm: 2.36 c (3H, Me), 4.69 m (1H, C1H), 6.95 m (1H, =CH), 7.12 d
(2Harom., J 8.0 Hz), 7.13 c (1Harom.), 7.19 d (1Harom., J 7.8 Hz), 7.28–7.34 m (3Harom.), 7.44 d
(1Harom., J 7.8 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 21.6 (Me) 55.4 (C1), 120.6, 122.6 q
(CF3, J 270.0 Hz), 125.3, 127.5, 128.1, 128.3, 129.1, 134.5 q (C3, J 34.2 Hz), 135.5 d (C3a, J 1.1
Hz), 137.0, 137.4 d (C7a, J 0.8 Hz), 140.0 q (C2, J 5.1 Hz), 148.4. 19F {1H} NMR (CDCl3, 376
MHz) δ, ppm: ꢀ64.07 s (CF3). HRMS (MALDI): C17H14F3 found 275.1042 [М+H]+, calcd.
275.1048.
1
3-(Trifluoromethyl)-1-(4-methylphenyl)-1H-indene (3c). Yield 99 %. Yellow oil. H NMR
(CDCl3, 400 MHz) δ, ppm: 2.34 c (3H, Me), 4.71 m (1H, C1H), 7.00 d (2Harom., J 8.1 Hz), 7.01 m
(1H, =CH), 7.12 d (2Harom., J 8.1 Hz), 7.26–7.32 m (2Harom.), 7.37 t.д (1Harom., J 7.6 Hz, J 1.5
Hz), 7.56 d (1Harom., J 7.6 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 21.2 (Me) 55.3 (C1), 120.9,
122.6 q (CF3, J 270.0 Hz), 124.5, 126.9, 127.4, 127.9, 129.8, 133.9, 134.4 q (C3, J 34.2 Hz), 137.3,
138.2, 141.3 q (C2, J 5.0 Hz), 148.2. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ64.02 s (CF3).
HRMS (MALDI): C17H14F3 found 275.1042 [М+H]+, calcd. 275.1038.
3-(Trifluoromethyl)-6-methyl-1-(4-methylphenyl)-1H-indene (3d). Yield 99 %. Yellow
1
solid. M. p. 101–103°С. H NMR (CDCl3, 400 MHz) δ, ppm: 2.35 c (3H, Me), 2.36 c (3H, Me),
4.66 m (1H, C1H), 6.93 m (1H, =CH), 7.00 d (2Harom., J 7.8 Hz), 7.12 s (1Harom.), 7.13 d
(2Harom., J 7.8 Hz), 7.18 d (1Harom., J 7.9 Hz), 7.43 d (1Harom., J 7.9 Hz). 13C NMR (CDCl3,
100 MHz) δ, ppm: 21.2 (Me), 21.6 (Me), 55.1 (C1), 120.5, 122.6 q (CF3, J 270.0 Hz), 125.3, 127.9,
19
128.2, 129.8, 134.3, 134.3 q (C3, J 34.2 Hz), 135.5, 137.0, 137.2, 140.2 q (C2, J 5.1 Hz). F {1H}
NMR (CDCl3, 376 MHz) δ, ppm: ꢀ64.05 s (CF3). HRMS (MALDI): C18H16F3 found 289.1199
[М+H]+, calcd. 289.1210.
3-(Trifluoromethyl)-6-methoxy-1-phenyl-1H-indene (3e). Yield 97 %. Yellow solid. M. p.
1
77–79°С. H NMR (CDCl3, 400 MHz) δ, ppm: 3.79 c (3H, OMe), 4.69 m (1H, C1H), 6.84 d
(2Harom., J 8.6 Hz), 6.99 m (1H, =CH), 7.01 d (2Harom., J 8.6 Hz), 7.25–7.30 m (2Harom.), 7.37
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m (1Harom.), 7.54 d (1Harom., J 7.5 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 54.9 (C1), 55.4
(OMe), 114.5, 120.9, 122.6 q (CF3, J 270.0 Hz), 124.5, 126.9, 127.4, 128.8, 129.0, 134.3 q (C3, J
34.2 Hz), 138.1, 141.4 q (C2, J 5.0 Hz), 148.3, 159.1. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ
64.03 s (CF3). HRMS (MALDI): C17H14F3O found 291.0991 [М+H]+, calcd. 291.0998.
3-(Trifluoromethyl)-1-(4-methoxyphenyl)-1H-indene (3f). Yield 97 %. Yellow solid. M. p.
1
81–82°С. H NMR (CDCl3, 400 MHz) δ, ppm: 3.79 c (3H, OMe), 4.69 m (1H, C1H), 6.84 d
(2Harom., J 8.7 Hz), 7.00 m (1H, =CH), 7.02 d (2Harom., J 8.7 Hz), 7.25–7.31 m (2Harom.), 7.36
m (1Harom.), 7.55 d (1Harom., J 7.6 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 54.9 (C1), 55.4
(OMe), 114.5, 120.9, 122.6 q (CF3, J 270.0 Hz), 124.5, 126.9, 127.4, 128.8, 129.0, 134.3 q (C3, J
34.2 Hz), 138.1, 141.4 q (C2, J 5.0 Hz), 148.3, 159.1. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ
64.02 s (CF3). HRMS (MALDI): C17H14F3O found 291.0991 [М+H]+, calcd. 291.1002.
3-(Trifluoromethyl)-5,6-dimethoxy-1-phenyl-1H-indene (3g). Yield 95 %. Yellow solid.
M. p. 60–62°С. 1H NMR (CDCl3, 400 MHz) δ, ppm: 3.81 c (3H, OMe), 3.95 c (3H, OMe), 4.65 m
(1H, C1H), 6.84 c (1Harom.), 6.90 m (1H, =CH), 7.05 c (1Harom.), 7.08–7.10 m (2Harom.), 7.27–
7.33 m (3Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 55.6 (C1), 56.3 (OMe), 56.4 (OMe), 104.0,
108.1, 122.6 q (CF3, J 269.9 Hz), 127.5, 128.0, 129.1, 130.8, 134.0 q (C3, J 34.1 Hz), 137.4, 139.8 q
(C2, J 5.2 Hz), 140.9, 149.0. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ63.95 s (CF3). HRMS
(MALDI): C18H16F3O2 found 321.1097 [М+H]+, calcd. 321.1095.
3-(Trifluoromethyl)-6-methoxy-1-(4-methoxyphenyl)-1H-indene (3h). Yield 92 %. Yellow
1
oil. H NMR (CDCl3, 400 MHz) δ, ppm: 3.77 c (3H, OMe), 3.79 c (3H, OMe), 4.63 m (1H, C1H),
6.84 d (2Harom., J 8.6 Hz), 6.85 m (=CH+1Harom.), 6.89 dd (1Harom., J 8.3 Hz, J 2.3 Hz), 7.01 d
(2Harom., J 8.6 Hz), 7.42 d (Harom., J 8.4 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 54.8 (C1),
55.4 (OMe), 55.7 (OMe), 110.9, 113.0, 114.5, 121.4, 122.6 q (CF3, J 269.9 Hz), 129.0, 129.2,
131.0, 133.8 q (C3, J 34.1 Hz), 139.2 q (C2, J 5.1 Hz), 150.4, 159.1, 159.5. 19F {1H} NMR (CDCl3,
376 MHz) δ, ppm: ꢀ64.11 s (CF3). HRMS (MALDI): C18H16F3O2 found 321.1097 [М+H]+, calcd.
321.1115.
3-(Trifluoromethyl)-6-methyl-1-(3,4-dimethoxyphenyl)-1H-indene (3i). Yield 50 %.
Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.44 c (3H, Me), 3.88 c (6H, 2OMe), 4.67 m (1H,
C1H), 6.92 m (1H, =CH), 7.2–7.5 m (6Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 21.4 (Me),
42.2 (C1), 56.1 (2OMe), 111.3, 120.4, 123.5q (CF3, J 273.3Hz), 125.3, 127.6, 129.8, 130.2, 139.2,
139.4 q (C3, J 34 Hz), 140.1q (C2, J 5.0Hz), 148.6. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ
64.04 s (CF3). HRMS (MALDI): C19H18F3O2 found 335.1253 [М+H]+, calcd. 335.1267.
3-(Trifluoromethyl)-5,6-dimethyl-1-phenyl-1H-indene (3j1), and 3-(trifluoromethyl)-6,7-
dimethyl-1-phenyl-1H-indene (3j2). Yield 96 %. Colorless solid. M. p. 85–88°С (for ratio of 3j1
: 3j2 1.25 : 1). Compound 3j1: 1H NMR (CDCl3, 400 MHz) (from spectrum of mixture of isomers)
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δ, ppm: 2.26 s (3H, Me), 2.34 s (3H, Me), 4.67 m (1H, C1H), 6.93 m (1H, =CH), 7.08 c (1Harom.),
7.10–7.12 m (2Harom., J 1.5 Hz), 7.22 d (1Harom., J 7.7 Hz), 7.24–7.31 m (3Harom.). 13C NMR
(CDCl3, 100 MHz) (from spectrum of mixture of isomers, some signals) δ, ppm: 20.1 (Me), 20.2
(Me), 55.2 (C1), 122.64 q (CF3, J 270.0 Hz), 134.5 q (C3, J 34.1 Hz), 140.1 q (C2, J 5.1 Hz). 19F
{1H} NMR (CDCl3, 376 MHz) (from spectrum of mixture of isomers) δ, ppm: ꢀ64.00 s (CF3) Mass
1
spectrum (GCꢀMS), m/z (Iоtн., %): 288 [М]+ (100). Compound 3j2: H NMR (CDCl3, 400 MHz)
(from spectrum of mixture of isomers) δ, ppm: 1.99 c (3H, Me), 2.30 c (3H, Me), 4.72 m (1H, C1H),
6.86 m (1H, =CH), 7.03–7.05 m (2Harom.), 7.24–7.31 m (4Harom.), 7.34 c (1Harom.). 13C NMR
(CDCl3, 100 MHz) (from spectrum of mixture of isomers) δ, ppm: 15.8 (Me), 19.8 (Me), 55.4 (C1),
122.62 q (CF3, J 270.0 Hz), 133.4 q (C3, J 34.1 Hz), 140.9 q (C2, J 5.1 Hz). 19F {1H} NMR (CDCl3,
376 MHz) (from spectrum of mixture of isomers) δ, ppm: ꢀ64.10 s (CF3). For mixture of isomers:
7.24–7.31 m (3Harom.A+4Harom.B). Mass spectrum (GCꢀMS), m/z (Iоtн., %): 288 [М]+ (80). 13C
NMR (CDCl3, 100 MHz) δ, ppm: 118.1, 121.9, 125.7, 127.3, 127.5, 128.0, 129.1, 129.5, 133.4,
135.6, 135.8, 135.9, 136.1, 136.7, 136.8, 137.7, 145.9, 146.1. HRMS (MALDI): C18H16F3 found
289.1199 [М+H]+, calcd. 289.1204 (for mixture of isomers).
3-(Trifluoromethyl)-4,6-dimethyl-1-phenyl-1H-indene (3k). Yield 97 %. Yellow solid. M.
p. 111–113°С. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.35 c (3H, Me), 2.59 c (3H, Me), 4.64 m (1H,
C1H), 7.00 c (1Harom.), 7.03 c (1Harom.), 7.09 m (1H, =CH), 7.15 d (2Harom., J 6.6 Hz), 7.30–
7.37 m (3Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 20.0 q (Me, J 4.7 Hz), 21.2 (Me), 54.6
(C1), 122.9 q (CF3, J 269.4 Hz), 123.1, 127.5, 128.1, 129.1, 131.3, 131.4, 133.8, 134.5 q (C3, J 33.9
Hz), 137.0, 137.8, 141.8 q (C2, J 6.3 Hz), 149.8. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ60.61
s (CF3). HRMS (MALDI): C18H16F3 found 289.1199 [М+H]+, calcd. 289.1214.
1
3-(Trifluoromethyl)-4,7-dimethyl-1-phenyl-1H-indene (3l). Yield 97 %. Yellow oil. H
NMR (CDCl3, 400 MHz) δ, ppm: 2.01 c (3H, Me), 2.55 c (3H, Me), 4.64 m (1H, C1H), 6.98 d
(1Harom., J 7.7 Hz), 7.02–7.05 m (=CH +2Harom.), 7.12 d (1Harom., J 7.7 Hz), 7.23–7.30 m
(3Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 18.7 (Me), 19.8 q (Me, J 4.8 Hz), 54.5 (C1), 122.9
q (CF3, J 269.4 Hz), 127.3, 128.1, 128.6, 129.0, 129.2, 131.1, 131.9, 133.5 q (C3, J 33.9 Hz), 136.3,
137.0, 143.7 q (C2, J 6.4 Hz), 146.9. Спекtр ЯМР 19F {1H} (CDCl3, 376 MHz) δ, ppm: ꢀ60.50 s
(CF3). HRMS (MALDI): C18H16F3 found 289.1199 [М+H]+, calcd. 289.1208.
3-(Trifluoromethyl)-4,6,7-trimethyl-1-phenyl-1H-indene (3m). Yield 97 %. Yellow solid.
M. p. 59–61°С. 1H NMR (CDCl3, 400 MHz) δ, ppm: 1.94 c (3H, Me), 2.26 c (3H, Me), 2.51 c (3H,
Me), 4.65 m (1H, C1H), 6.96 c (1Harom.), 7.02–7.03 m (=CH +2Harom.), 7.21–7.29 m (3Harom.).
13C NMR (CDCl3, 100 MHz) δ, ppm: 15.5 (Me), 19.5 (Me), 19.7 q (Me, J 4.8 Hz), 54.6 (C1), 122.9
q (CF3, J 269.4 Hz), 126.9, 127.2, 128.0, 128.6, 129.0, 132.7, 133.2 q (C3, J 33.8 Hz), 134.9, 135.7,
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137.1, 142.8 q (C2, J 6.4 Hz), 147.2. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ60.69 d (CF3, J 1.8 Hz).
HRMS (MALDI): C19H18F3 found 303.1355 [М+H]+, calcd. 303.1361.
3-(Trifluoromethyl)-1-(3,4-methylenedioxyphenyl)-1H-indene (3n). Yield 91 %. Yellow
oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 4.65 m (1H, C1H), 5.92 m (2H, АВꢀсисtема, CH2), 6.45 d
(1Harom., J 1.7 Hz), 6.67 dd (1Harom., J 7.9 Hz, J 1.7 Hz), 6.76 d (1Harom., J 7.9 Hz), 6.97 m
(1H, =CH), 7.27–7.31 m (2Harom.), 7.36 dt (1Harom., J 7.2 Hz, J 1.8 Hz), 7.53 dd (1Harom., J 7.5
Hz, J 0.8 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 55.2 (C1), 101.3, 108.0, 108.7, 121.0, 121.4,
122.5 q (CF3, J 270.0 Hz), 124.5, 127.0, 127.5, 134.5 q (C3, J 34.2 Hz), 138.1, 141.1 q (C2, J 5.0
Hz), 147.1, 148.1, 148.2. 19F {1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ64.07 s (CF3). HRMS
(MALDI): C17H12F3O2 found 305.0784 [М+H]+, calcd. 305.0792.
1-(4-Chlorophenyl)-3-(trifluoromethyl)-1H-indene (3o). Yield 97 %. Yellow solid. M. p.
1
53–55°С. H NMR (CDCl3, 400 MHz) δ, ppm: 4.71 m (1H, C1H), 7.00 m (1H, =CH), 7.05 d
(2Harom., J 7.7 Hz), 7.28–7.30 m (4Harom.), 7.37ꢀ7.43 m (1Harom.), 7.59 d (1Harom., J 6.9 Hz).
13C NMR (CDCl3, 100 MHz) δ, ppm: 54.9 (C1), 121.1, 122.4 q (CF3, J 270.0 Hz), 124.5, 127.2,
127.7, 129.3, 129.4, 133.5, 135.0 q (C3, J 34.4 Hz), 135.6, 138.1, 140.5 q (C2, J 4.9 Hz), 147.6. 19F
{1H} NMR (CDCl3, 376 MHz) δ, ppm: ꢀ64.04 s (CF3). HRMS (MALDI): C16H11F335Cl found
295.0496 [М+H]+, calcd. 295.0503.
6-Fluoro-3-(trifluoromethyl)-1-(3,4-dimethylphenyl)-1H-indene (3p). Yield 97 %. Yellow
oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.23 s (3H, Me), 2.25 s (3H, Me), 4.65 m (1H, C1H), 6.83ꢀ
6.85 m (2Harom..), 6.97ꢀ6.98 m (1Harom.., C2H), 7.02 dd (1Harom.., 3JHꢀF 8.8 Hz, 4J 2.3 Hz), 7.04ꢀ
7.10 m (2Harom.), 7.47 dd (1Harom., J 7.8 Hz, 4JHꢀF 5.0 Hz).13C NMR (CDCl3, 100 MHz) δ, ppm:
19.5 (Me), 19.9 (Me), 55.3 d (C1, JCꢀF 2.3 Hz), 112.4 d (JCꢀF 23.5 Hz), 114.5 d (JCꢀF 23.5 Hz), 121.8
d (JCꢀF 8.3 Hz), 122.4 q (CF3, JCꢀF 269.9 Hz), 125.4, 129.0, 130.4, 133.4, 133.7 q (C3, JCꢀF 34.5 Hz),
134.1 q (JCꢀF 1.1 Hz), 136.3, 137.6, 141.1 quintet (C4, JCꢀF 4.9 Hz), 150.9 d (JCꢀF 8.3 Hz), 162.6 d
(C6, JCꢀF 246.4 Hz).19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ114.91 td (F, 3JHꢀF 8.8 Hz, 4JHꢀF 5.0 Hz), ꢀ
64.14 s (CF3). HRMS (MALDI): C18H15F4 found 307.1104 [М+H]+, calcd. 307.1089.
6-Fluoro-3-(trifluoromethyl)-1-(3,4-dimethoxyphenyl)-1H-indene
(3q). Yield 74 %.
Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 3.81 s (3H, OMe), 3.86 s (3H, OMe), 4.64 m (1H,
C1H), 6.51 d (1Harom., 4J 2.0 Hz), 6.69 dd (1Harom., 3J 8.2 Hz, 4J 2.0 Hz), 6.81 d (1H, C2H, 3J 8.2
3
4
Hz), 6.97ꢀ6.99 m (1Harom., C2H), 7.01 dd (1Harom., JHꢀF 8.8 Hz, J 2.2 Hz), 7.06 td (1Harom.,
3JHꢀF 8.8 Hz, 4J 2.2 Hz), 7.47 dd (1Harom., 3J 7.7 Hz, 4JHꢀF 4.9 Hz).13C NMR (CDCl3, 100 MHz) δ,
ppm: 55.3 d (C1, JCꢀF 2.4 Hz), 56.1 (2MeO), 110.9, 111.8, 112.3 d (JCꢀF 23.5 Hz), 114.7 d (JCꢀF 23.5
Hz), 120.3, 121.9 d (JCꢀF 8.8 Hz), 122.4 q (CF3, JCꢀF 269.9 Hz), 128.6.4, 133.7 q (C3, JCꢀF 34.6 Hz),
133.9, 140.9 quintet (C4, JCꢀF 4.9 Hz), 148.9, 149.6, 150.5 d (JCꢀF 8.3 Hz), 162.6 d (C6, JCꢀF 246.6
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4
Hz).19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ114.72 td (F, 3JHꢀF 8.8 Hz, JHꢀF 4.9 Hz), ꢀ64.15 s (CF3).
HRMS (MALDI): C18H15F4O2 found 339.1003 [М+H]+, calcd. 339.1018.
Synthesis and characterizations of indenes 4.
General procedure for isomerization of indenes 3 into 4.
A suspension of 4 g of silica gel in a solution of 0.1mmol of indene 3 in 5 mL of EtOAc was
stirred at room temperature for 4 h. The silica gel was filtered off, washed with EtOAc (3×20 mL).
The solutions in EtOAc were combined, and evaporation of the solvent under reduced pressure gave
quantitatively indene 4.
1-(Trifluoromethyl)-3-phenyl-1H-indene (4a). Quantitative yield. Yellow solid. M. p. 50–
52°С (lit.13 m. p. 49–51°С). 1H NMR (CDCl3, 400 MHz) δ, ppm: 4.24 qd (1H, C1H, J 9.4 Hz, J 2.0
Hz), 6.41 d (1H, =CH, J 2.0 Hz), 7.32 t (1Harom., J 7.5 Hz), 7.40–7.50 m (4Harom.), 7.55–7.62 m
(3Harom.), 7.65 d (1Harom., J 7.5 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 52.7 q (C1, J 29.4
Hz), 121.3, 124.8 q (C2, J 2.7 Hz), 124.9, 126.3 q (CF3, J 278.5 Hz), 126.4, 127.8, 128.5, 128.8,
129.5, 134.6, 138.8, 144.2, 149.4. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ67.35 dd (CF3, J 9.3 Hz, J
0.7 Hz). HRMS (MALDI): C16H12F3 found 261.0886 [М+H]+, calcd. 261.0885.
1-(Trifluoromethyl)-3-(4-methylphenyl)-1H-indene (4c). Quantitative yield. Yellow oil. 1H
NMR (CDCl3, 400 MHz) δ, ppm: 2.44 c (3H, Me), 4.24 qd (1H, C1H, J 9.3 Hz, J 2.0 Hz), 6.40 d
(1H, =CH, J 2.0 Hz), 7.30 d (2Harom., J 7.9 Hz), 7.34 t (1Harom., J 7.5 Hz), 7.43 t (1Harom., J 7.5
Hz), 7.52 d (2Harom., J 7.9 Hz), 7.58 d (1Harom., J 7.5 Hz), 7.68 d (1Harom., J 7.5 Hz). 13C NMR
(CDCl3, 100 MHz) δ, ppm: 21.6 (Me), 52.7 q (C1, J 29.5 Hz), 121.3, 124.2 q (C2, J 2.7 Hz), 124.9,
126.3 q (CF3, J 278.5 Hz), 126.4, 127.7, 128.5, 129.5, 131.8, 138.5, 138.9 q (J 1.6 Hz), 144.4,
149.3. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ67.31 d (CF3, J 9.3 Hz). HRMS (MALDI): C17H14F3
found 275.1042 [М+H]+, calcd. 275.1047.
1-(Trifluoromethyl)-5-methyl-3-(4-methylphenyl)-1H-indene (4d). Quantitative yield.
Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.43 c (3H, Me), 2.44 c (3H, Me), 4.21 br. q (1H,
C1H, J 9.2 Hz), 6.38 d (1H, =CH, J 2.1 Hz), 7.16 d (1Harom., J 7.6 Hz), 7.30 d (2Harom., J 7.9
Hz), 7.38 s (2Harom.),7.51 d (2Harom., J 7.9 Hz), 7.55 d (1Harom., J 7.6 Hz). 13C NMR (CDCl3,
100 MHz) δ, ppm: 21.4 (Me), 21.8 (Me), 52.4 (C1, J 29.4 Hz), 122.1, 124.5 q (C2, J 2.8 Hz), 124.6,
126.4 q (CF3, J 278.4 Hz), 127.1, 127.8, 129.5, 131.9, 136.0 q (J 1.8 Hz), 138.4, 138.5, 144.6,
149.3. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ67.49 d (CF3, J 9.4 Hz). HRMS (MALDI): C18H16F3
found 289.1199 [М+H]+, calcd. 289.1209.
1-(Trifluoromethyl)-5-methoxy-3-phenyl-1H-indene (4e). Quantitative yield. Yellow solid.
1
M. p. 77–79°С. H NMR (CDCl3, 400 MHz) δ, ppm: 3.87 c (3H, OMe), 4.23 qd (1H, C1H, J 9.3
Hz, J 2.1 Hz), 6.35 d (1H, =CH, J 2.1 Hz), 7.01 d (2Harom., J 8.8 Hz), 7.33 dt (1Harom., J 7.4 Hz,
J 0.9 Hz), 7.42 t (1Harom., J 7.4 Hz), 7.54–7.58 m (3Harom.), 7.66 d (1Harom., J 7.4 Hz). 13C
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NMR (CDCl3, 100 MHz) δ, ppm: 52.7 q (C1, J 29.4 Hz), 55.5 (OMe), 114.3, 121.3, 123.7 q (C2, J
2.8 Hz), 124.9, 126.3 q (CF3, J 278.5 Hz), 127.2, 128.5, 129.1, 138.9, 144.5, 148.9, 160.0. 19F NMR
(CDCl3, 376 MHz) δ, ppm: ꢀ67.34 d (CF3, J 9.5 Hz). HRMS (MALDI): C17H14F3O found 291.0991
[М+H]+, calcd. 291.0990.
1-(Trifluoromethyl)-5,6-dimethoxy-3-phenyl-1H-indene (4g). Quantitative yield. Yellow
1
solid. M. p. 86–88°С. H NMR (CDCl3, 400 MHz) δ, ppm: 3.89 c (3H, OMe), 3.95 c (3H, OMe),
4.18 br. q (1H, C1H, J 9.3 Hz), 6.32 d (1H, =CH, J 1.9), 7.07 c (1Harom.), 7.22 c (1Harom.), 7.43 t
(1Harom., J 7.3 Hz), 7.49 t (2Harom., J 7.3 Hz), 7.59 d (2Harom., J 7.3 Hz). 13C NMR (CDCl3, 100
MHz) δ, ppm: 52.5 q (C1, J 29.4 Hz), 56.3 (OMe), 56.5 (OMe), 104.9, 108.8, 123.5 q (C2, J 2.8
Hz), 126.3 q (CF3, J 278.5 Hz), 127.7, 128.6, 128.9, 131.3, 135.0, 137.3, 148.4, 149.2, 149.8. 19F
NMR (CDCl3, 376 MHz) δ, ppm: ꢀ67.58 d (CF3, J 9.3 Hz). HRMS (MALDI): C18H16F3O2 found
321.1097 [М+H]+, calcd. 321.1097.
1-(Trifluoromethyl)-5-methyl-3-(3,4-dimethoxyphenyl)-1H-indene (4i). Quantitative yield.
Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 2.42 (3H, Me), 3.95 (3H, OMe), 3.95 (3H, OMe),
4.20 qd (1H, C1H, J 9.3 Hz, J 1.9 Hz), 6.35 d (1H, =CH, J 1.9 Hz), 6.98 d (1Harom., J 8.2 Hz), 7.09
d (1Harom., J 1.9 Hz), 7.14–7.19 m (2Harom.), 7.38 c (1Harom.), 7.54 d (1Harom., J 7.6 Hz). 13C
NMR (CDCl3, 100 MHz) δ, ppm: 21.8 (Me), 52.3 q (C1, J 29.5 Hz), 56.1 (OMe), 56.2 (OMe),
111.2, 111.4, 120.4, 122.0, 124.2 q (C2, J 2.7 Hz), 124.6, 126.3 q (CF3, J 278.4 Hz), 127.2, 127.6,
136.0 d (J 1.9 Hz), 138.5, 144.6, 149.1, 149.3 149.5. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ67.48 d
(CF3, J 9.3 Hz). HRMS (MALDI): C19H18F3O2 found 335.1253 [М+H]+, calcd. 335.1258.
1-(Trifluoromethyl)-5,6-dimethyl-3-phenyl-1H-indene (4j1) was obtained as a mixture
1
with (3j2). Quantitative yield. Yellow oily mixture of isomers. Compound 4j1: H NMR (CDCl3,
400 MHz) (from spectrum of mixture of isomers) δ, ppm: 2.32 c (3H, Me), 2.35 c (3H, Me), 4.19 qd
(1H, C1H, J 9.0 Hz, J 2.0 Hz), 6.33 d (1H, =CH, J 2.0 Hz), 7.27–7.31 m (1Harom.), 7.40–7.50 m
(4Harom.),7.60 d (2Harom., J 8.4 Hz). 13C NMR (CDCl3, 100 MHz) (from spectrum of mixture of
isomers, some signals) δ, ppm: 20.1 (Me), 20.3 (Me), 55.4 q (C1, J 29.4 Hz), 124.0 q (C2, J 2.6 Hz),
126.4 q (CF3, J 278.5 Hz). 19F NMR (CDCl3, 376 MHz) (from spectrum of mixture of isomers) δ,
ppm: ꢀ67.45 d (CF3, J 9.0 Hz). Mass spectrum (GCꢀMS), m/z (Iоtн., %): 288 [М]+ (100). HRMS
(MALDI): C18H16F3 found 289.1199 [М+H]+, calcd. 289.1202 (for mixture of isomers).
1-(Trifluoromethyl)-5,7-dimethyl-3-phenyl-1H-indene (4k). Quantitative yield. Yellow oil.
1H NMR (CDCl3, 400 MHz) δ, ppm: 2.37 c (3H, Me), 2.46 c (3H, Me), 4.25 qd (1H, C1H, J 8.1 Hz,
J 2.1 Hz), 6.39 d (1H, =CH, J 2.1 Hz), 6.98 c (1Harom.), 7.18 c (1Harom.), 7.41ꢀ7.50 m (3Harom.),
7.57ꢀ7.59 m (2Harom.). 13C NMR (CDCl3, 100 MHz) δ, ppm: 20.0 q (Me, J 3.7 Hz), 21.5 (Me),
52.0 q (C1, J 29.2 Hz), 119.9, 125.9 q (C2, J 3.1 Hz), 126.7 q (CF3, J 279.9 Hz), 128.0, 128.5, 128.8,
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129.7, 134.2, 135.0, 135.2, 138.7, 145.3, 149.4. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ63.90 dd
(CF3, J 8.2 Hz, J 1.3 Hz). HRMS (MALDI): C18H16F3 found 289.1199 [М+H]+, calcd. 289.1207.
3-(4-Chlorophenyl)-1-(trifluoromethyl)-1H-indene (4o). Quantitative yield. Yellow solid.
M. p. 49–51°С. 1H NMR (CDCl3, 400 MHz) δ, ppm: 4.25 qd (1H, C1H, J 9.3 Hz, J 2.1 Hz), 6.43 d
(1H, =CH, J 2.1 Hz), 7.35 dt (1Harom., J 7.4 Hz, J 0.9 Hz), 7.41–7.46 m (3Harom.), 7.50–7.55 m
(3Harom.), 7.67 d (1Harom., J 7.4 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 52.8 q (C1, J 29.6
Hz), 121.1, 125.1, 125.2 q (C2, J 2.8 Hz), 126.1 q (CF3, J 278.6 Hz), 126.7, 128.7, 129.1, 129.2,
133.1, 134.6, 138.7, 143.9, 148.4. 19F NMR (CDCl3, 376 MHz) δ, ppm: ꢀ67.23 d (CF3, J 9.3 Hz).
HRMS (MALDI): C16H11F3Cl found 295.0496 [М+H]+, calcd. 295.0496.
5-Fluoro-1-(trifluoromethyl)-3-(3,4-dimethylphenyl)-1H-indene (4p). Quantitative yield.
1
Yellow oil. H NMR (CDCl3, 400 MHz) δ, ppm: 2.36 (3H, Me), 2.37 (3H, Me), 4.22 br. q (1H,
C1H, J 9.1 Hz), 6.47 c (1H, =CH), 7.03 dt (1Harom., J 8.5 Hz, J 2.2 Hz), 7.25–7.35 m (3Harom.),
7.37 c (1Harom.), 7.60 dd (1Harom., J 7.7 Hz, J 5.4 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 19.7
(Me), 20.0 (Me), 52.2 q (C1, J 29.7 Hz), 109.0 d (J 24.2 Hz), 113.0 d (J 23.2 Hz), 125.1, 125.8 d (J
9.3 Hz), 126.0 q (C2, J 2.6 Hz), 126.1 q (CF3, J 278.5 Hz), 128.9, 130.2, 131.6, 134.2 м, 137.4 d (J
25.7 Hz), 146.8 d (J 9.0 Hz), 148.8 d (J 2.9 Hz), 163.6 d (J 245.3 Hz). 19F NMR (CDCl3, 376 MHz)
δ, ppm: ꢀ113.55 – ꢀ113.48 m (1Farom), ꢀ67.52 d (CF3, J 9.1 Hz). HRMS (MALDI): C18H15F4 found
307.1104 [М+H]+, calcd. 307.1107.
5-Fluoro-1-(trifluoromethyl)-3-(3,4-dimethoxyphenyl)-1H-indene (4q). Quantitative yield.
Yellow oil. 1H NMR (CDCl3, 400 MHz) δ, ppm: 3.94 (6H, 2OMe), 4.21 br. q (1H, C1H, J 8.9 Hz),
6.44 d (1H, =CH, J 2.1 Hz), 6.97 d (1Harom., J 8.2 Hz), 7.02 dt (1Harom., J 8.7 Hz, J 2.4 Hz), 7.06
d (1Harom., J 1.9 Hz), 7.14 dd (1Harom., J 8.2 Hz, J 1.9 Hz), 7.26 dd (1Harom., J 9.0 Hz, J 2.4
Hz), 7.58 dd (Harom., J 8.0 Hz, J 5.1 Hz). 13C NMR (CDCl3, 100 MHz) δ, ppm: 52.2 q (C1, J 29.8
Hz), 56.1 (OMe), 56.2 (OMe), 108.9 d (J 24.3 Hz), 110.9, 111.5, 113.1 d (J 23.2 Hz), 120.3, 125.8
q (C2, J 2.6 Hz), 125.9 d (J 9.2 Hz), 126.0 q (CF3, J 278.5 Hz), 126.8, 134.1 м, 146.7 d (J 8.8 Hz),
148.5 d (J 2.9 Hz), 149.6 d (J 44.1 Hz), 163.6 d (J 245.5 Hz). 19F NMR (CDCl3, 376 MHz) δ, ppm:
ꢀ113.31 dt (1Farom, J 9.0 Hz, J 5.1 Hz), ꢀ67.51 d (CF3, J 8.9 Hz). HRMS (MALDI): C18H15F4O2
found 339.1003 [М+H]+, calcd. 339.1009.
Supplementary material: 1H, 13C, 19F NMR spectra of compounds, data on DFT
calculations.
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Acknowledgements
This work was supported by the Russian Scientific Foundation (grant no 14ꢀ13ꢀ00448). Spectral
studies were performed at the Center for Magnetic Resonance, and the Center for Chemical
Analysis and Materials Research of Saint Petersburg State University, Saint Petersburg, Russia.
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