The catalytic olefination reaction of aldehydes and ketones with CBr 3CF3

Article abstract of DOI:10.1016/j.jfluchem.2005.03.020

The new approach of catalytic olefination reaction (COR) has been used to convert aromatic and aliphatic aldehydes and ketones to 2-bromo-3,3,3- trifluoroprop-1-enes by the treatment of corresponding hydrazones with CBr ₃CF₃ under copper(I) catalysis conditions. The reaction proceeds stereoselectively, the target alkenes were obtained in good yields.

Full text of DOI:10.1016/j.jfluchem.2005.03.020

Journal of Fluorine Chemistry 126 (2005) 907–913
www.elsevier.com/locate/fluor
The catalytic olefination reaction of aldehydes
and ketones with CBr3CF3
a
Valentine G. Nenajdenko a, , Georgy N. Varseev ,
*
Alexey V. Shastin b, Elisabeth S. Balenkova a
a Moscow State University, Department of Chemistry, Leninskie Gory, Moscow 119992, Russia
b Institute of Problems of Chemical Physics, Chernogolovka, Moscow Region 142432, Russia
Received 1 February 2005; received in revised form 25 March 2005; accepted 31 March 2005
Available online 23 May 2005
Abstract
The new approach of catalytic olefination reaction (COR) has been used to convert aromatic and aliphatic aldehydes and ketones to 2-
bromo-3,3,3-trifluoroprop-1-enes by the treatment of corresponding hydrazones with CBr3CF3 under copper(I) catalysis conditions. The
reaction proceeds stereoselectively, the target alkenes were obtained in good yields.
# 2005 Elsevier B.V. All rights reserved.
Keywords: Catalysis; Copper; Fluoroalkenes; Carbonyl compounds; Olefination
1. Introduction
bond is very synthetically useful and opens up synthetic
possibilities.
The trifluoromethyl group and its fluorinated homologues
are one of the most important substituents in modern organic
and medicinal chemistry due to their unique stereoelectronic
and biological properties. An unprecedented set of proper-
ties of CF3 or Rf groups is electronegativity, lipophilicity,
high chemical and biological stability and steric volumes
similar to methyl or alkyl groups sterical volume.
At the same time there is very little information about
synthesis and reactions of the substituted analogs of 2-
bromo-3,3,3-trifluoropropene. CBr3–CF3 has never been
used for its preparation. Syntheses of 1-bromo-1-trifluor-
omethylalkenes containing only aliphatic fragments have
been reported. They have been synthesized by base-
promoted elimination of corresponding 1-trifluoromethyl-
1,2-dibromoalkanes [8] or by palladium-catalyzed trifluor-
omethylation of 1,1-dibromalkenes [9]. It is known that
pharmaceutical and agricultural chemicals that contain di-
and trifluoromethyl groups have been the subject of
increased research activity in recent years [10,11].
Commercially available 2-bromo-3,3,3-trifluoropropene
is widely used for the synthesis of many trifluoromethyl
containing compounds. This reagent can be used as the
starting material for trifluoromethylated acetylenes [1],
trifluoromethylated polyfunctionalized cyclopropanes [2],
trifluoromethyl-substituted enamines [3], trifluoromethyl
propargyl alcohols [4], fluorine-containing optically active
allylic alcohols [5], alpha-(trifluoromethyl)styrenes [6],
esters and amides of 2-(trifluoromethyl)acrylic acid [7].
These examples indicate that the combination of trifluor-
omethyl group and bromine in adjacent position of double
Recently, we reported a novel catalytic olefination
reaction (COR) of aldehydes and ketones [12–20]. It was
found that N-unsubstituted hydrazones of carbonyl
compounds could be smoothly transformed into the
various substituted alkenes by treatment with polyhalo-
genalkanes in the presence of catalytic amounts of CuCl.
Based on COR we elaborated a novel approach to synthesis
of dichloroalkenes [12], dibromoalkenes [13] vinylbro-
mides [14] and vinyliodides [15] from aromatic and
heteroaromatic carbonyl precursors as well as aliphatic
* Corresponding author. Tel.: +7 95 9392276; fax: +7 95 9328846.
E-mail addresses: nen@acylium.chem.msu.ru (V.G. Nenajdenko),
shastin@icp.ac.ru (A.V. Shastin).
0022-1139/$ – see front matter # 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2005.03.020

908
V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 126 (2005) 907–913
compounds [16]. We found also COR applicable for the
preparation of fluorocontaining alkenes using such
chlorofluorocarbons as CCl3F [17], CCl3CF3, CCl2FCClF2
[18] and also CBr2F2 [19] and CF2BrCF2Br [20] as C1-
and C2-building blocks.
2. Results and discussion
Previously CBr3CF3 was used as the C2-fluorocontaining
block in the synthesis of 2,2-dibromo-3,3,3-trifluoro-1-
phenylpropan-1-ol by condensation with benzaldehyde [22].
Also it was applied in the synthesis of trifluoromethylpyr-
azoles [23] and in the telomerisation reaction with some
fluorinated alkenes [24]. CBr3CF3 was prepared by AlBr3
promoted isomerisation of the commercially available
CF2BrCF2Br [24]. We found that HalonTM CBr3CF3 under
catalysis of CuCl reacts with hydrazones of aldehydes and
ketones 2 to form 2-bromo-3,3,3-trifluoroprop-1-enes 3
(Scheme 2). These alkenes contain trifluoromethyl group
and bromine atom adjacent at the double bond that can be
useful for synthesis of new trifluoromethyl compounds.
Synthesis of similar 1-bromo-1-trifluoromethylalkenes
containing only aliphatic fragments has been reported by
the base-promoted elimination of corresponding 1-trifluor-
ometyl-1,2-dibromoalkanes [8] or by palladium-catalyzed
trifluoromethylation of 1,1-dibromalkenes [9]. The neces-
sity of using harsh conditions (high temperature and
pressure), dry solvents, expensive and toxic reagents and
also low stereoselectivity are significant disadvantages of
these approaches.
According to the proposed mechanism, the reaction of
copper(II) salt with hydrazone should involve formation of
copper-carbene complex which reacts with polyhalogenalk-
ane to form the desired alkene and copper(II) salt
regeneration. Sym-azine formation is the result of copper-
carbene complex and diazoalkane reaction (Scheme 1)
[18].
The olefination with CBr3CF3 should result in the
interesting substituted analogs of 2-bromo-3,3,3-trifluor-
opropene (vide supra). In accordance with our model of
‘‘catalytic olefination activity’’ [21], CBr3CF3 should be a
very active reagent for catalytic olefination (the most
reactive of all fluorinated compounds which we have used
earlier) and should to provide high yields of desired products
with aldehydes and ketones. The high difference in steric
volumes of CF3 group and bromine atom permit us to hope
for high stereoselectivity of reaction.
In this paper, we have investigated the olefination of
aromatic and aliphatic aldehydes and ketones 1 with
CBr3CF3. This approach would open a new straightforward
way to the synthesis of alkenes having CF3 group and
bromine atom in adjacent positions. The presence of
bromine atom also opens the possibility of functionalization
via organometalic compounds using metallation (lithium-
bromine exchange, for example) or by direct bromine
substitution with different nucleophiles. The functionalized
alkenes prepared bearing trifluoromethyl group should be
very interesting building blocks for many purposes, for
example, Diels–Alder reaction with electron-reach dienes
should be suitable for the synthesis of six-membered cyclic
compounds bearing CF3 group; another possibility is the
construction of CF3-substituted heterocycles.
2.1. Optimization of the reaction conditions
Previously we elaborated two types of solvent and base
systems for the catalytic olefination reaction with various
polyhalogenalkanes [12–19]. DMSO as solvent and aqueous
ammonia as base were found optimal for synthesis of chloro-,
bromo-, and iodo-substituted alkenes [12–16]. However, the
1,2-ethylenediamine-ethanol system is required for activation
of fluorinated compounds in the COR process [17–20].
These two types of solvent and base systems were tested
in the reaction between prepared in situ 4-chlorobenzalde-
hyde hydrazone 2a and CBr3CF3. Using DMSO and aqueous
Scheme 1.

V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 126 (2005) 907–913
909
Scheme 2.
ammonia the desired alkene 3a was obtained in 78% yield.
Main byproduct of the reaction was the corresponding azine
4a, isolated in 20% yield. Under other reaction conditions
(ethanol as solvent and 1,2-ethylenediamine as base) target
alkene 3a was obtained only in 41% yield.
We investigated the dependence of the yield of alkene 3a
on amounts of the catalyst CuCl (Table 1). We found that
10% of catalyst is the optimal. Without copper chloride the
target alkene was obtained only with 34% yield.
bromine atom (ES = À1.16 for CF3 and ES = 0.01 for Br)
[25].
The sym-azines 4 were found to be the only side products
in the COR-process. In some cases corresponding sym-
azines 4a–4c, 4m, 4o were isolated from the reaction
mixture. It was found that total yield of 3 and 4 usually is
close to quantitative (Table 2).
In the case of aryl methyl ketones 1m–1o the carbonyl
group is less reactive and the corresponding hydrazones
could not be prepared and used in situ. We studied an
olefination of ketones by CBr3CF3 using separately prepared
hydrazones. As it is shown in Table 2, hydrazones 2m–2o of
aromatic ketones 2m–2o can be converted into 2-bromo-
3,3,3-trifluoro-1-methylprop-1-enes 3m–3o by treatment
with CBr3CF3 in same conditions (DMSO as a solvent and
aqueous ammonia as a base). The target tetrasubstituted
alkenes are not formed stereoselectively, which can be
explained by steric hindrance of the methyl group in the
reaction of hydrazones with CBr3CF3.
2.2. Synthesis of CF3-alkenes
We have studied the synthetic scope of the method for the
preparation of 2-bromo-3,3,3-trifluoroprop-1-enes 3. Awide
variety of aromatic and aliphatic aldehydes 1a–1l can be
converted smoothly to the corresponding 2-bromo-3,3,3-
trifluoroprop-1-enes 3 (Scheme 2). These results are given in
Table 2. Alkene formation generally proceeds in moderate to
high yield. The COR-process is compatible with many
functional groups, such as hydroxy, alkoxy, carbmethoxy
and nitro. Aromatic compounds containing both electron-
donating and electron-withdrawing substituents, heteroaro-
matic and aliphatic aldehydes can be converted to 2-bromo-
3,3,3-trifluoroprop-1-enes 3. Reaction proceeds stereoselec-
tively and the Z-isomer is formed predominantly. Most of
alkenes were formed with more than 7:1 ratio of isomers. In
the case of thiophene-2-carbaldehyde 2k the Z:E ratio of
alkenes 3k was 14:1. The structure of isomers was
We analysed 19F NMR spectra of alkenes 3a–3o and
found that the chemical shifts of the fluorine in para-
substituted alkenes showed good linear correlations with
Hammett substituent parameters when the s values [25]
were used. Earlier similar regularities were observed for 19
F
NMR spectra of fluorinated alkenes ArC(H) = CClF and
ArC(H) = C(F)CF2Cl.
Table 2
Yields and 19F chemical shifts of 2-bromo-3,3,3-trifluoroprop-1-enes 3a–3o
3
determined on the basis of JC,F in 13C NMR and 19F
R1
R2
19F chemical shifts of 3
chemical shifts of similar compounds ArC(H) = C(Cl)CF3
(3JC,F(Z isomer) = 4.6 Hz and d(19F of Z isomer) < d(19F of
E isomer)). Stereoselectivity of the elaborated method is
much better than in the known method for the synthesis of
similar compounds [9], where the ratio of E:Z isomers is
near 1:1. We believe that the main reason of the Z-selectivity
is high difference in steric volumes of CF3 group and
Alkene Z/E
Azine
Z
E
3
ratio
4
isomer isomer
4-ClC6H4, a
H
H
H
H
H
H
H
H
H
H
H
H
78
74
74
44
60
60
31
69
45
47
61
55
7.5/1 20
8.7/1 22
8.4/1 23
À67.4
À67.1
À66.9
À66.2
À67.6
À67.1
À67.7
À67.1
À66.9
À67.4
À66.2
À67.5
À67.4
À67.1
À66.9
À59.8
À59.7
À59.6
À59.3
À59.9
À59.7
À60.0
À59.7
À59.6
À60.8
À60.00
À60.5
À59.8
À59.7
À59.6
4-MeC6H4, b
4-MeOC6H4, c
4-Me2NC6H4, d
4-CO2MeC6H4, e
4-SMeC6H4, f
4-CF3C6H4, g
4-t-BuC6H4, h
4-OHC6H4, i
2-MeC6H4, j
2-ThC6H4, k
n-C7H15, l
a
4.5/1
a
4.8/1
a
7.7/1
a
5.3/1
Table 1
a
8.8/1
Influence of catalyst amounts on the yield of 3a
a
6.3/1
Amount of
CuCl (%)
Yield of
alkene 3a (%)a
Yield of azine
4a (%)a
Total
a
7.9/1
yield (%)
a
14/1
a
10
1
78
67
35
34
20
30
64
64
98
97
99
98
3/1
4-ClC6H4, m
4-BrC6H4, n
4-OMeC6H4, o
Me 37
Me 34
Me 40
1./1
1/1
1/1
59
a
0.1
0
46
a
aBased on carbonyl compound.
The yield of corresponding azines was not determined.

910
V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 126 (2005) 907–913
3. Experimental
isomer: 1H NMR: d = 7.40 (d, 3JH,H = 8.8 Hz, 2 H, Ar), 7.55
(s, 1 H, –CH ), 7.66 (d, 3JH,H = 8.8 Hz, 2 H, Ar). 13C NMR:
2
d = 108.35 (q, JC,F = 36.6 Hz, CBr), 121.95 (q, JC,F =
1
NMR spectra were recorded on a Varian VXR-400
spectrometer in CDCl3 with TMS and CCl3F as an internal
standard. IR spectra were obtained with UR-20 spectro-
meter. Column and TLC chromatography was performed on
silica gel Merck 60 and Merck 60F254 plates, respectively.
Known azines 4a–4c, 4m, 4o were characterized by
comparison of their spectral and physical data with literature
[12–20]. Hydrazones 2m, [26] 2n, [27] 2o [28] were
prepared by the literature procedures. All new compounds
gave satisfactory 400 MHz 1H NMR (CDCl3, TMDS),
376.29 MHz 19F NMR (CDCl3, CFCl3) and 100 MHz 13C
NMR (CDCl3) and IR spectral data. 19F NMR spectra for
alkenes 3a–3o reported in Table 2.
271.6 Hz, CF3), 128.53 (C1–Ar), 129.32 (Ar), 129.88 (Ar),
135.06 (q, 3JC,F = 4.6 Hz, CH ), 136.45 (C4–Ar). E isomer:
3
1H NMR: d = 7.20 (d, JH,H = 8.5 Hz, 2 H, Ar), 7.34 (d,
3JH,H = 8.5 Hz, 2 H, Ar), 7.45 (s, 1 H, –CH ). 13C NMR:
2
1
d = 109.61 (q, JC,F = 38.2 Hz, CBr), 121.03 (q, JC,F
=
273.2 Hz, CF3), 129.14 (Ar), 130.76 (Ar), 133.88 (C1–Ar),
3
136.64 (C4–Ar), 143.92 (q, JC,F = 3.4 Hz, CH). C9H5
BrClF3 (285.5): calcd. C 37.9, H 1.8; found C 38.0, H 1.9.
3.2.2. 1-[(1E)-2-Bromo-3,3,3-trifluoroprop-1-en-1-yl]-
4-methylbenzene 3b
This compound was obtained as a mixture of Z–E isomers
8.7/1 (after purification); colourless oil (392 mg, 74%); IR
(Nujol): nmax. = 1715 cmÀ1 (C C). Rf (Hexane) 0.7. Z
isomer: 1H NMR: d = 2.47 (s, 3 H, Me), 7.32 (d,
3JH,H = 7.9 Hz, 2 H, Ar), 7.64 (s, 1 H, –CH ), 7.72 (d,
3JH,H = 7.9 Hz, 2 H, Ar). 13C NMR: d = 21.38 (Me), 108.31
3.1. Preparation of 2-bromo-3,3,3-trifluoroprop-1-enes
3a–3l
A solution of aromatic aldehyde (2 mmol) in DMSO
(5 mL) was added dropwise to a solution of 1 M hydrazine
hydrate in DMSO (2 mmol, 2 mL) and the mixture was
stirred until aldehyde disappeared (3 h, TLC monitoring).
Then freshly purified CuCl [29] (20 mg, 0.2 mmol) and
aqueous ammonia (0.7 mL) were added. After 10 min a
solution of CBr3CF3 (was prepared by AlBr3 promoted
isomerisation of the commercially available CF2BrCF2Br
[24]) (1.93 g, 6 mmol) in DMSO (2 mL) was added
dropwise, maintaining the temperature at 20 8C (water
bath). The reaction mixture was stirred for 24 h and
quenched with hydrochloric acid (5%) (100 mL). Reaction
products were extracted with CH2Cl2 (20 mL Â3). Extracts
were dried over sodium sulfate, CH2Cl2 was evaporated and
the residue was purified by column chromatography. E and Z
isomers mixture of alkenes could not be separated by
column chromatography.
2
1
(q, JC,F = 36.6 Hz, CBr), 121.12 (q, JC,F = 271.6 Hz,
CF3), 128.33 (C1–Ar), 129.22 (Ar), 129.66 (Ar), 134.18
3
1
(q, JC,F = 4.6 Hz, CH ), 140.53 (C4–Ar). E isomer: H
3
NMR: d = 2.44 (s, 3 H, Me), 7.32 (d, JH,H = 7.9 Hz, 2 H,
Ar), 7.50 (s, 1 H, –CH ), 7.72 (d, 3JH,H = 7.9 Hz, 2 H, Ar).
13C NMR: d = 21.23 (Me), 109.43 (q, JC,F = 38.2 Hz,
2
1
CBr), 120.58 (q, JC,F = 273.2 Hz, CF3), 129.01 (Ar),
129.54 (Ar), 130.89 (C1–Ar), 139.28 (C4–Ar), 141.68 (q,
3JC,F = 3.4 Hz, CH). C10H8BrF3 (265.1): calcd. C 45.3, H
3.0; found C 45.4, H 3.1.
3.2.3. 1-[(1E)-2-Bromo-3,3,3-trifluoroprop-1-en-1-yl]-
4-methoxylbenzene 3c
This compound was obtained as a mixture of Z–E isomers
8.4/1 (after purification); colourless oil (451 mg, 74%); IR
(Nujol): nmax. = 1720 cmÀ1 (C C). Rf (Hexane) 0.2. Z
isomer: 1H NMR: d = 3.85 (s, 3 H, OMe), 6.95 (d,
3JH,H = 8.8 Hz, 2 H, Ar), 7.53 (s, 1 H, –CH ), 7.75 (d,
3JH,H = 8.8 Hz, 2 H, Ar). 13C NMR: d = 54.24 (OMe),
3.2. Preparation of 2-bromo-3,3,3-trifluoro-1-
methylprop-1-enes 3m–3o
2
106.53 (q, JC,F = 36.6 Hz, CBr), 113.90 (Ar), 121.20 (q,
The freshly purified CuCl [29] (20 mg, 0.2 mmol) and
aqueous ammonia (0.7 mL) were added to a solution of
freshly prepared hydrazone (2 mmol) in DMSO (5 mL).
CBr3CF3 (1.93 g, 6 mmol) in DMSO (2 mL) was added
dropwise, maintaining the temperature at 20 8C (water bath).
The reaction mixture was stirred for 24 h and quenched with
hydrochloric acid (5%) (100 mL). Reaction products were
extracted with CH2Cl2 (20 mL Â3). Extracts were dried over
sodium sulfate, CH2Cl2 was evaporated and the residue was
purified by column chromatography.
1JC,F = 271.6 Hz, CF3), 124.72 (C1–Ar), 131.53 (Ar),
133.57 (q, 3JC,F = 4.6 Hz, CH ), 161.01 (C4–Ar). E isomer:
1H NMR: d = 3.82 (s, 3 H, OMe), 6.89 (d, 3JH,H = 8.8 Hz, 2
3
H, Ar), 7.25 (d, JH,H = 8.8 Hz, 2 H, Ar), 7.43 (s, 1 H, –
2
CH ). 13C NMR: d = 54.27 (OMe), 108.11 (q, JC,F
=
1
38.2 Hz, CBr), 113.73 (Ar), 120.64 (q, JC,F = 273.2- Hz,
CF3), 126.04 (C1–Ar), 130.19 (Ar), 141.35 (q,
3JC,F = 3.1 Hz, CH), 160.28 (C4–Ar). C10H8BrF3O
(281.1): calcd. C 42.7, H 2.9; found C 42.8, H 2.9.
3.2.4. [4-(2-Bromo-3,3,3-trifluoroprop-1-en-1-
yl)phenyl]dimethylamine 3d
3.2.1. 1-(2-Bromo-3,3,3-trifluoroprop-1-en-1-yl)-4-
chlorobenzene 3a
This compound was obtained as a mixture of Z–E isomers
7.5/1 (after purification); colourless oil (444 mg, 78%); IR
(Nujol): nmax. = 1720 cmÀ1 (C C). Rf (Hexane) 0.7. Z
This compound was obtained as a mixture of Z–E isomers
4.5/1 (after purification); colourless oil (259 mg, 44%); IR
(Nujol): nmax. = 1720 cmÀ1 (C C). Rf (Hexane:CH2Cl2 1:1)
1
0.5. Z isomer: H NMR: d = 3.03 (s, 6 H, Me), 6.71 (d,

V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 126 (2005) 907–913
911
3JH,H = 9.1 Hz, 2 H, Ar), 7.47 (s, 1 H, –CH ), 7.75 (d,
3JH,H = 9.1 Hz, 2 H, Ar). 13C NMR: d = 21.38 (Me), 108.33
(Nujol): nmax. = 1720 cmÀ1 (C C). Rf (Hexane) 0.4. Z
isomer: 1H NMR: d = 7.64 (s, 1 H, –CH ), 7.69 (d,
3JH,H = 8.5 Hz, 2 H, Ar), 7.79 (d, 3JH,H = 8.5 Hz, 2 H, Ar). E
isomer: 1H NMR: d = 7.38 (d, 3JH,H = 8.2 Hz, 2 H, Ar), 7.53
(s, 1 H, –CH ), 7.61 (d, 3JH,H = 8.2 Hz, 2 H, Ar). For major
2
1
(q, JC,F = 36.6 Hz, CBr), 121.13 (q, JC,F = 271.6 Hz,
CF3), 128.34 (C4–Ar), 129.22 (Ar), 129.66 (Ar), 134.18
3
(q, JC,F = 4.6 Hz, CH ), 140.53 (C1–Ar). E isomer: H
1
3
NMR: d = 3.00 (s, 6 H, Me), 6.65 (d, JH,H = 8.8 Hz, 2 H,
2
isomer: 13C NMR: d = 108.29 (q, JC,F = 36.6 Hz, CBr),
Ar), 7.24 (d, 3JH,H = 8.8 Hz, 2 H, Ar), 7.37 (s, 1 H, –CH ).
1
112.37 (q, JC,F = 271.6 Hz, CF3), 120.7 (q, JC,F =
1
2
3
271.6 Hz, -CF3), 125.49 (q, JC,F = 4.6 Hz, C3–Ar),
13C NMR: d = 21.23 (Me), 109.79 (q, JC,F = 38.2 Hz,
1
CBr), 120.58 (q, JC,F = 273.2 Hz, CF3), 129.01 (Ar),
3
129.71 (C2–Ar), 133.17 (q, JC,F = 4.6 Hz, CH ), 135.99
129.54 (Ar), 130.89 (C4–Ar), 139.28 (C1–Ar), 141.68 (q,
3JC,F = 3.1 Hz, CH). C11H11BrF3N (294.1): calcd. C 44.9, H
3.8; found C 45.0, H 3.7.
(C4–Ar), 139.80 (C1–Ar). C10H5BrF6 (319.0): calcd. C
37.7, H 1.6; found C 37.9, H 1.6.
3.2.8. 1-(2-Bromo-3,3,3-trifluoroprop-1-en-1-yl)-4-tert-
butylbenzene 3h
3.2.5. Methyl 4-(2-bromo-3,3,3-trifluoroprop-1-en-1-
yl)benzoate 3e
This compound was obtained as a mixture of Z–E isomers
8.8/1 (after purification); colourless oil (392 mg, 69%); IR
(Nujol): nmax. = 1715 cmÀ1 (C C). Rf (Hexane) 0.7. Z
isomer: 1H NMR: d = 1.41 (s, 9 H, Me), 7.52 (d,
3JH,H = 8.5 Hz, 2 H, Ar), 7.63 (s, 1 H, –CH ), 7.76 (d,
3JH,H = 8.5 Hz, 2 H, Ar). E isomer: 1H NMR: d = 1.39 (s, 9
This compound was obtained as a mixture of Z–E isomers
4.8/1 (after purification); colourless oil (371 mg, 60%); IR
(Nujol): nmax. = 1710 cmÀ1 (C C). Rf (Hexane:CH2Cl2 1:1)
0.6. Z isomer: 1H NMR: d = 3.91 (s, 3 H, Me), 7.61 (s, 1 H, –
3
CH ), 7.73 (d, JH,H = 8.5 Hz, 2 H, Ar), 8.06 (d,
3JH,H = 8.5 Hz, 2 H, Ar). 13C NMR: d = 52.22 (Me),
3
H, Me), 7.28 (d, JH,H = 8.5 Hz, 2 H, Ar), 7.53 (s, 1 H, –
3
CH ), 7.44 (d, JH,H = 8.5 Hz, 2 H, Ar).). For mixture of
2
111.89 (q, JC,F = 36.6 Hz, CBr), 120.71 (q, JC,F
1
=
271.6 Hz, CF3), 129.34 (Ar), 129.62 (Ar), 133.51 (q,
isomers 13C NMR: d = 31.10 (Me, Z isomer), 31.10 (Me, E
isomer), 34.91 (CMe3, Z isomer), 108.43 (q, 2JC,F = 36.6 Hz,
3JC,F = 4.6 Hz, CH ), 132.35 (C1–Ar), 136.67 (C4–Ar),
1
166.20 (C O). E isomer: H NMR: d = 3.90 (s, 3 H, Me),
1
CBr, Z isomer), 121.11 (q, JC,F = 271.6 Hz, CF3, Z
7.18 (s, 1 H, –CH ), 7.31 (d, 3JH,H = 8.5 Hz, 2 H, Ar), 7.60
isomer), 125.28 (Ar, E isomer), 125.49 (Ar, Z isomer),
128.27 (C1–Ar, Z isomer), 129.51 (Ar, E isomer), 129.59
3
(d, JH,H = 8.5 Hz, 2 H, Ar). 13C NMR: d = 52.16 (Me),
2
112.35 (q, JC,F = 38.2 Hz, CBr), 120.25 (q, JC,F
1
3
=
(Ar, Z isomer), 134.04 (q, JC,F = 4.6 Hz, CH , Z isomer),
273.2 Hz, CF3), 129.47 (Ar), 129.65 (Ar), 132.07 (C4–
Ar), 138.07 (C1–Ar), 140.32 (q, 3JC,F = 3.1 Hz, CH), 165.80
(C O). C11H8BrF3O2 (309.1): calcd. C 42.8, H 2.6; found C
45.6, H 2.7.
141.6 (q, 3JC,F = 3.1 Hz, CH , E isomer), 153.63 (C4–Ar, E
isomer), 153.63 (C4–Ar, Z isomer). C13H14BrF3 (307.1):
calcd. C 50.8, H 4.6; found C 51.0, H 4.6.
3.2.9. 4-(2-Bromo-3,3,3-trifluoroprop-1-en-
1-yl)phenol 3i
3.2.6. 1-(2-Bromo-3,3,3-trifluoroprop-1-en-1-yl)-4-
(methylthio)benzene 3f
This compound was obtained as a mixture of Z–E isomers
6.3/1 (after purification); colourless oil (240 mg, 45%); IR
(Nujol): nmax. = 1710 cmÀ1 (C C). Rf (Hexane:CH2Cl2 1:1)
This compound was obtained as a mixture of Z–E isomers
7.7/1 (after purification); colourless oil (357 mg, 60%); IR
(Nujol): nmax. = 1720 cmÀ1 (C C). Rf (Hexane) 0.25. Z
isomer: 1H NMR: d = 2.55 (s, 3 H, SMe), 7.31 (d,
3JH,H = 8.5 Hz, 2 H, Ar), 7.58 (s, 1 H, –CH ), 7.72 (d,
3JH,H = 8.5 Hz, 2 H, Ar). 13C NMR: d = 14.92 (SMe), 108.29
1
0.2. Z isomer: H NMR: d = 6.00 (bs, 1 H, OH), 6.90 (d,
3JH,H = 8.8 Hz, 2 H, Ar), 7.51 (s, 1 H, –CH ), 7.70 (d,
3JH,H = 8.8 Hz, 2 H, Ar). E isomer: 1H NMR: d = 5.89 (bs, 1
3
H, OH), 6.84 (d, JH,H = 8.8 Hz, 2 H, Ar), 7.20 (d,
2
1
(q, JC,F = 36.6 Hz, CBr), 121.01 (q, JC,F = 271.6 Hz,
CF3), 125.41 (Ar), 128.54 (C1–Ar), 129.98 (Ar), 133.57
3JH,H = 8.8 Hz, 2 H, Ar), 7.42 (s, 1 H, –CH ). For mixture
of isomers 13C NMR: d = 106.91 (q, 2JC,F = 36.6 Hz, CBr,
Z isomer), 115.29 (Ar, E isomer), 115.46 (Ar, Z isomer),
3
1
(q, JC,F = 4.6 Hz, CH ), 141.95 (C4–Ar). E isomer: H
NMR: d = 2.53 (s, 3 H, SMe), 7.31 (d, 3JH,H = 8.5 Hz, 2 H,
Ar), 7.48 (s, 1 H, –CH ), 7.72 (d, 3JH,H = 8.5 Hz, 2 H, Ar).
1
121.13 (q, JC,F = 271.6 Hz, CF3, Z isomer), 130.41 (q,
4JC,F = 3.1 Hz, C4–Ar, Z isomer), 131.74 (Ar, E isomer),
2
3
131.77 (Ar, Z isomer), 133.45 (q, JC,F = 4.6 Hz, CH , Z
13C NMR: d = 15.05 (SMe), 109.78 (q, JC,F = 36.6 Hz,
1
CBr), 125.48 (Ar), 130.03 (Ar), 120.74 (q, JC,F
=
=
isomer), 156.06 (C1–Ar, E isomer), 156.88 C1–Ar, Z
isomer). C9H6BrF3O (267.0): calcd. C 40.5, H 2.3; found C
40.6, H 2.3.
3
277.7 Hz, CF3), 128.83 (C1–Ar), 140.99 (q, JC,F
3.1 Hz, CH), 141.92 (C4–Ar). C10H8BrF3S (297.1): calcd.
C 40.4, H 2.7; found C 40.6, H 2.8.
3.2.10. 1-(2-Bromo-3,3,3-trifluoroprop-1-en-1-yl)-2-
methylbenzene 3J
This compound was obtained as a mixture of Z–E isomers
7.9/1 (after purification); colourless oil (249 mg, 47%); IR
(Nujol): nmax. = 1720 cmÀ1 (C C). Rf (Hexane) 0.65. Z
3.2.7. 1-(2-Bromo-3,3,3-trifluoroprop-1-en-1-yl)-4-
(trifluoromethyl)benzene 3g
This compound was obtained as a mixture of Z–E isomers
5.3/1 (after purification); colourless oil (198 mg, 31%); IR

912
V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 126 (2005) 907–913
1
isomer: 1H NMR: d = 2.29 (s, 3 H, Me), 7.22–7.33 (m, 3 H,
Ar), 7.54 (d, 3JH,H = 7.6 Hz, 1 H, Ar), 7.70 (s, 1 H, –CH ). E
isomer: 1H NMR: d = 2.27 (s, 3 H, Me), 7.15–7.33 (m, 4 H,
Ar), 7.51 (s, 1 H, –CH ). For major isomer 13C NMR:
CF3), 121.30 (q, JC,F = 273.1 Hz, CF3), 127.87 (Ar),
128.10 (Ar), 128.57 (Ar), 128.87 (Ar), 134.11, 134.17,
138.22, 141.51, 147.16 (C4–Ar), 147.72 (C4–Ar).
C10H7BrClF3 (299.5): calcd. C 40.1, H 2.4; found C 40.2,
H 2.4.
2
d = 19.62 (Me), 112.26 (q, JC,F = 36.6 Hz, CBr), 120.86
CF3), 125.72(Ar), 128.34(Ar),
1
(q, JC,F = 271.6 Hz,
3
129.44(Ar), 130.22(Ar), 134.35 (q, JC,F = 4.6 Hz, CH ),
132.20, 136.66. C10H8BrF3 (265.1): calcd. C 45.3, H 3.0;
found C 45.5, H 3.1.
3.2.14. 1-Bromo-4-(2-bromo-3,3,3-trifluoro-1-
methylprop-1-en-1-yl)benzene 3n
This compound was obtained as a mixture of Z–E isomers
1.3/1 (after purification); colourless oil (234 mg, 34%); IR
(Nujol): nmax. = 1710 cmÀ1 (C C). Rf (Hexane) 0.7. For
mixture of isomers: 1H NMR: d = 2.27 (q, 5JH,F = 2.6 Hz, 3
3.2.11. 2-(2-Bromo-3,3,3-trifluoroprop-1-en-1-
yl)thiophene 3k
This compound was obtained as a mixture of Z–E isomers
14/1 (after purification); colourless oil (314 mg, 61%); IR
(Nujol): nmax. = 1710 cmÀ1 (C C). Rf (Hexane) 0.55. Z
isomer: 1H NMR: d = 7.15 (dd, 3JH,H = 3.8 Hz,
5
H, CH3, Z isomer), 2.29 (q, JH,F = 2.1 Hz, 3 H, CH3, E
3
isomer), 7.02 (d, JH,H = 8.5 Hz, 2 H, Ar), 7.07 (d,
3
3JH,H = 8.5 Hz, 2 H, Ar), 7.49 (d, JH,H = 8.5 Hz, 2 H,
Ar), 7.54 (d, 3JH,H = 8.5 Hz, 2 H, Ar). 13C NMR: d = 22.68
3
3JH,H = 5.0 Hz, 1 H, Ar), 7.47 (d, JH,H = 3.8 Hz, 1 H, Ar),
4
(q, JC,F = 3.1 Hz, Me, Z isomer), 28.31 (Me, E isomer),
7.56 (d, 3JH,H = 5.0 Hz, 1 H, Ar), 7.81 (s, 1 H, –CH ). 13C
2
108.30 (q, JC,F = 36.6 Hz, CBr), 109.53 (q, JC,F
2
2
NMR: d = 105.99 (q, JC,F = 36.6 Hz, CBr), 121.23 (q,
=
36.6 Hz, CBr), 120.60 (q, JC,F = 273.1 Hz, CF3),
1
1JC,F = 271.6 Hz, CF3), 126.90 (Ar), 128.16 (q, JC,F
=
3
1
121.30 (q, JC,F = 273.1 Hz, CF3), 122.24 (Ar), 122.30
4.6 Hz, CH ), 130.07 (Ar), 134.06 (Ar), 135.56 (C-2 Ar).
C7H4BrF3S (257.1): calcd. C 32.7, H 1.6; found C 33.0, H 1.6.
(Ar), 128.15 (Ar), 128.36 (Ar), 131.53, 131.83, 138.72,
142.00, 147.12 (C4–Ar), 147.71 (C4–Ar). C10H7Br2F3
(344.0): calcd. C 34.9, H 2.1; found C 34.5, H 2.2.
3.2.12. (2E)-2-Bromo-1,1,1-trifluorodec-2-ene 3l
This compound was obtained as a mixture of Z–E isomers
3/1 (after purification); colourless oil (300 mg, 55%); IR
(Nujol): nmax. = 1705 cmÀ1 (C C). Rf (Hexane) 0.7. Z
3.2.15. 1-(2-Bromo-3,3,3-trifluoro-1-methylprop-1-en-
1-yl)-4-methoxybenzene 3o
3
isomer: 1H NMR: d = 0.84–0.95 (td, JH,H = 7.0 Hz,
This compound was obtained as a mixture of Z–E isomers
1.3/1 (after purification); colourless oil (236 mg, 40%); IR
(Nujol): nmax. = 1720 cmÀ1 (C C). Rf (Hexane) 0.25. For
mixture of isomers: 1H NMR: d = 2.29 (q, 5JH,F = 2.6 Hz, 3
4JH,H = 1.5 Hz, 3H, –CH3), 1.20–1.50 (m, 10 H, –CH2–),
3
2.24–2.35 (m, 2 H, –CH2–), 6.68 (t, 1 H, JH,H = 7.0 Hz,
CH–).
E
isomer: 1H NMR: d = 0.84–0.95 (td,
3JH,H = 7.0 Hz, JH,H = 1.5 Hz, 3H, –CH3), 1.20–1.50 (m,
10 H, –CH2–), 2.24–2.35 (m, 2 H, –CH2–), 6.44 (t, 1 H,
3JH,H = 7.9 Hz, CH–). For mixture of isomers 13C NMR:
d = 14.02 (CH3), 22.62, 27.51, 28.81 (E isomer), 28.93 (E
isomer), 29.00, 29.13, 29.94 (E isomer), 30.59, 31.71,
4
5
H, CH3, Z isomer), 2.31 (q, JH,F = 2.1 Hz, 3 H, CH3, E
isomer), 3.81 (s, 3 H, OCH3), 3.83 (s, 3 H, OCH3), 6.88 (d,
3
3JH,H = 8.8 Hz, 2 H, Ar), 6.91 (d, JH,H = 8.8 Hz, 2 H, Ar),
7.09 (d, 3JH,H = 8.8 Hz, 2 H, Ar), 7.16 (d, 3JH,H = 8.8 Hz, 2
4
H, Ar). 13C NMR: d = 22.92 (q, JC,F = 3.1 Hz, Me, Z
isomer), 28.62 (Me, E isomer), 55.21 (OMe), 107.33 (q,
2
108.14 (q, JC,F = 38.2 Hz, CBr, E isomer), 111.88 (q,
1
2JC,F = 36.6 Hz, CBr, Z isomer), 120.51 (q, JC,F
=
2
2JC,F = 36.6 Hz, CBr), 108.45 (q, JC,F = 36.6 Hz, CBr),
1
1
113.66 (Ar), 113.81 (Ar), 120.80 (q, JC,F = 271.6 Hz,
271.6 Hz, CF3, Z isomer), 120.96 (q, JC,F = 273.2 Hz,
CF3, E isomer), 138.34 (q, 3JC,F = 4.6 Hz, CH , Z isomer),
3
144.21 (q, JC,F = 3.1 Hz, CH , E isomer). C10H16BrF3
(273.1): calcd. C 44.0, H 5.9; found C 44.1, H 6.0.
1
CF3), 121.54 (q, JC,F = 271.6 Hz, CF3), 127.90 (Ar),
128.16 (Ar), 132.00, 135.43, 148.29, 148.52, 159.35 (C4–
Ar), 159.45 (C4–Ar). C11H10BrF3O (295.1): calcd. C 44.8,
H 3.4; found C 44.5, H 3.5.
3.2.13. 1-(2-Bromo-3,3,3-trifluoro-1-methylprop-1-en-
1-yl)-4-chlorobenzene 3m
This compound was obtained as a mixture of Z–E isomers
1.3/1 (after purification); colourless oil (222 mg, 37%); IR
(Nujol): nmax. = 1710 cmÀ1 (C C). Rf (Hexane) 0.7. 1H
NMR: For mixture of isomers: 1H NMR: d = 2.28 (q,
5JH,F = 2.6 Hz, 3 H, CH3, Z isomer), 2.29 (q, 5JH,F = 2.1 Hz,
3 H, CH3, E isomer), 7.08 (d, 3JH,H = 8.5 Hz, 2 H, Ar), 7.14
Acknowledgment
Financial support from the Russian Foundation for Basic
Research (Grant No. 03-03-32052) is gratefully acknowl-
edged.
3
3
(d, JH,H = 8.5 Hz, 2 H, Ar), 7.33 (d, JH,H = 8.5 Hz, 2 H,
Ar), 7.38 (d, 3JH,H = 8.5 Hz, 2 H, Ar). 13C NMR: d = 22.75
References
4
(q, JC,F = 3.1 Hz, Me, Z isomer), 28.37 (Me, E isomer),
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CBr), 109.63 (q,
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