Reaction of CBrF2-CBrF2 with hydrazones of aromatic aldehydes. Novel efficient synthesis of fluorocontaining alkanes, alkenes and alkynes

Article abstract of DOI:10.1016/j.jfluchem.2004.04.002

An olefination of hydrazones of aromatic aldehydes by CBrF₂-CBrF₂ under copper catalysis was investigated. In situ prepared aldehydes hydrazones were converted to (3-bromo-2,2,3,3-tetrafluoropropyl)arenes by reaction with CBrF₂-CBrF₂ in the presence of CuCl. Subsequent elimination of HF by sodium hydroxide resulted in stereospecific formation of fluorocontaining alkenes. Elimination proceeds stereoselectively, only Z -isomers of alkenes are formed. Elimination of two molecules of HF from (3-bromo-2,2,3,3-tetrafluoropropyl)arenes by treatment with potassium tert -butoxide leads to formation of (bromodifluoromethyl)alkynes. As a result a simple and efficient transformation of aromatic aldehydes to range of various fluorinated alkanes, alkenes and alkynes was elaborated.

Full text of DOI:10.1016/j.jfluchem.2004.04.002

Journal of Fluorine Chemistry 125 (2004) 1339–1345
Reaction of CBrF2–CBrF2 with hydrazones of aromatic aldehydes
Novel efficient synthesis of fluorocontaining alkanes,
alkenes and alkynes
Valentine G. Nenajdenkoa,*, Georgy N. Varseeva, Vasily N. Korotchenkoa,
Alexey V. Shastinb, Elisabeth S. Balenkovaa
aDepartment of Chemistry, Moscow State University, Leninskie Gory, Moscow 119992, Russia
bInstitute of Problems of Chemical Physics, Chernogolovka, Moscow 142432, Russia
Received 2 February 2004; received in revised form 30 March 2004; accepted 6 April 2004
Available online 17 June 2004
Abstract
An olefination of hydrazones of aromatic aldehydes by CBrF2–CBrF2 under copper catalysis was investigated. In situ prepared aldehydes
hydrazones were converted to (3-bromo-2,2,3,3-tetrafluoropropyl)arenes by reaction with CBrF2–CBrF2 in the presence of CuCl. Subsequent
elimination of HF by sodium hydroxide resulted in stereospecific formation of fluorocontaining alkenes. Elimination proceeds stereo-
selectively, only Z-isomers of alkenes are formed. Elimination of two molecules of HF from (3-bromo-2,2,3,3-tetrafluoropropyl)arenes by
treatment with potassium tert-butoxide leads to formation of (bromodifluoromethyl)alkynes. As a result a simple and efficient transformation
of aromatic aldehydes to range of various fluorinated alkanes, alkenes and alkynes was elaborated.
# 2004 Elsevier B.V. All rights reserved.
Keywords: Perfluoroalkanes; Dibromotetrafluoroethane; Catalysis; Copper; Carbonyl compounds; Olefination
1. Introduction
alkenes by treatment with polyhalogenalkanes in the
presence of catalytic amounts of CuCl. At the presented
paper we investigated the olefination of aromatic aldehydes
(1) with CBrF2–CBrF2, widely used as halogenated fire
agent.
Previously CBrF2–CBrF2 was chemically used as C2-
fluorocontaining block in radical addition reactions to
alkenes and alkynes [11–15]. Some examples of application
of CBrF2–CBrF2 in the nucleophilic substitution have been
described [16–19]. Also this halon was used as bromination
agent for organolithium compounds [20,21].
Fluorine-containing drugs and pesticides have achieved
an increasing interest in modern bioorganic chemistry due to
their remarkable biological activity [1,2]. Extensive studies
have been made to develop a cheap and efficient synthetic
methodology for the synthesis of various organofluorine
compounds. Utilization of new reagents and improved tech-
niques for the selective introduction of fluorine or fluori-
nated synthons has become a major target in organofluorine
chemistry.
We found that in situ-generated hydrazones of aromatic
aldehydes (2) are transformed to (3-bromo-2,2,3,3-tetra-
fluoropropyl)arenes (3) by reaction with CBrF2CBrF2 and
CuCl as a catalyst (Scheme 1). This reaction is the first
example of formation of products without double C–C bond
by the catalytic olefination reaction.
We investigated the reaction of CBrF2–CBrF2 with range
of aromatic aldehydes in the same conditions (ethanol-
ethylenediamine) and found that the corresponding
(3-bromo-2,2,3,3-tetrafluoropropyl)arenes (3a–h) were
obtained in 20–48% yield (Table 1). Both aldehydes bearing
electron-donating and electron-withdrawing groups can be
2. Results and discussion
Recently, we reported a novel catalytic olefination reac-
tion (COR) of aldehydes and ketones [3–10]. It was found
that N-unsubstituted hydrazones of carbonyl compounds
could be smoothly transformed into the various substituted
* Corresponding author. Tel.: þ7-095-9392276; fax: þ7-095-9328846.
E-mail address: nen@acylium.chem.msu.ru (V.G. Nenajdenko).
0022-1139/$ – see front matter # 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2004.04.002

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V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 125 (2004) 1339–1345
Ar
Ar
CF2BrCF2Br
CuCl
H
CF2Br
F
F
N2H5OH
Ar
H
O
NNH2
Ar
+
N
N
H
H
H
H
Ar
3
2
1
4
Scheme 1.
H
CF2Br
F
H
H
Ar
CF2Br
F
F
bulky CF2Br and Ph groups in transition state. It should be
noted that in the case of 4-carbmethoxy substituted alkane
(3h) both trans-esterification and elimination of HF pro-
ceeds simultaneously to form the corresponding 4-car-
bethoxy substituted alkene (5h).
NaOH
EtOH
Ar
3
5
Scheme 2.
Treatment of (3-bromo-2,2,3,3-tetrafluoropropyl)arenes
(3) with more strong base such as t-BuOK leads to elimina-
tion of two molecules of HF (Scheme 3). Corresponding
alkynes (6) bearing CF2Br fragment were obtained as a
result (Table 3). Previously similar alkynes was synthesized
converted to the corresponding (3-bromo-2,2,3,3-tetrafluor-
opropyl)arenes (3a–h) by proposed method. In spite of
moderate yields of target products the procedure is extre-
mely simple and straightforward. Recently we found that
only corresponding sym-azines of carbonyl compounds were
side products of COR. In some cases corresponding sym-
azines (4a–c) were isolated from the reaction mixture. It was
found that total yield of 3 and 4 usually is close to quanti-
tative (Table 1).
Table 2
Synthesis of (3-bromo-2,2,3-trifluoroprop-1-en-1-yl)arenes (5)
Entry
Alkene
Isolated yield (%)
Base-promoted elimination of HF from (3-bromo-2,2,3,3-
tetrafluoropropyl)arenes (3) permits to elaborate also synth-
esis of new types of alkenes and alkynes. We found that
treatment of the range of alkanes (3) with NaOH in ethanol
leads to elimination of HF and formation of corresponding
fluorocontaining alkenes (5) in high to quantitative yield
(Scheme 2). Formation of alkenes (5) proceeds with excel-
lent stereoselectivity, only a Z-isomers of alkenes are
obtained in all cases (Table 2). High diastereoselectivity
can be explained by space hindrance for syn-configuration of
5a
97
5b
95
92
85
88
83
5d
5e
Table 1
Synthesis of (3-bromo-2,2,3,3-tetrafluoropropyl)arenes from aromatic
aldehydes
5f
Entry
Product 3
Isolated yield (%)
3
4
Total
5h
3a
3b
3c
3d
43
30
20
40
51
63
94
93
Table 3
69
89
Synthesis of (3-bromo-3,3-difluoroprop-1-yn-1-yl)arenes (6)
a
a
Entry
Alkene
Isolated yield (%)
6a
6c
6d
80
74
77
a
a
a
a
a
a
a
a
3e
3f
31
39
43
48
3g
3h
6e
6f
85
79
a The yield of corresponding azines was not determined.

V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 125 (2004) 1339–1345
1341
H
H
Ar
CF2Br
F
F
of hydrazine hydrate (2.5 mL, 50 mmol) in EtOH (50 mL)
and the mixture was stirred until aldehyde disappeared (3 h,
TLC monitoring). Then freshly purified CuCl [24] (500 mg,
5 mmol) and 1,2-ethylenediamine (17 mL, 250 mmol) were
added. After 10 min CBrF2–CBrF2 (27 mL, 250 mmol) was
added dropwise. After addition of CBrF2–CBrF2 the reac-
tion mixture was stirred for 5 h at 50 8C, then cooled and
quenched with hydrochloric acid (5%) (500 mL). Reaction
products were extracted with CH2Cl2 (100 mL Â 5).
Extracts were dried over sodium sulphate, CH2Cl2 was
evaporated and the residue was purified by column chro-
matography.
KOtBu
THF
Ar
CF2Br
3
6
Scheme 3.
by Wakselman and coworkers [22] and Fried and coworkers
[23] via the reaction of lithiated alkynes with dibromodi-
fluoromethane. The alkynes have been used in the synthesis
of analogues of biomolecules and interesting starting mate-
rials. Mild conditions, simplicity of the reaction procedure
and high yields of products are significant features of
reaction proposed.
All these classes of fluorinated alkanes and alkenes were
unknown previously. Alkenes (5) and alkynes (6) contains
very active (mobile) bromine in allyl or propargyl position.
We believe that both alkenes and alkynes can be important
precursors for the preparation of functionalized organofluor-
ine compounds via bromine substitution. Reported method
of halons transformation to valuable products of organic
synthesis can be applied as green chemistry process, because
utilization of halogenated hydrocarbons is an actual ecolo-
gical problem.
4.1.1. 1-(3-Bromo-2,2,3,3-tetrafluoropropyl)-4-
chlorobenzene (3a)
Colorless oil; Rf (hexane) 0.4; IR (KBr): v 1500, 1600,
2950; 1H NMR (400 MHz, CDCl3): d 3.26 (2H, t,
J ¼ 18:2 Hz, CH2), 7.15 (2H, d, J ¼ 7:9 Hz, Ar), 7.24
(2H, d, J ¼ 7:9 Hz, Ar); 13C NMR (100 MHz, CDCl3): d
36.07 (t, JCF ¼ 22:9 Hz, CH2), 115.66 (tt, JCF ¼ 254:8 Hz,
JCF ¼ 31:3 Hz, CF2), 117.54 (tt, JCF ¼ 311:3 Hz, JCF
¼
39:7 Hz, CF2Br), 127.95, 128.78, 132.00, 134.26; 19F
NMR (376.27 MHz, CDCl3/CCl3F): d ꢀ65.61 (s, CF2Br),
ꢀ111.13 (t, JHF ¼ 18:2 Hz, CF2). EIMS (probe), 70 eV, m/z
(rel. int.): 304 [M]þ (4), 225 [MꢀBr]þ (1), 205
[MꢀBrꢀHꢀF]þ (2), 185 [MꢀBrꢀ2Hꢀ2F]þ (2), 169
[MꢀClꢀC2F4]þ (2), 125 [MꢀBrꢀC2F4]þ 100. Anal. Calcd.
for C9H6BrClF4: C, 35.38; H, 1.98. Found: C, 35.6; H, 1.9.
3. Conclusion
In summary we elaborated novel efficient one-pot
method for the preparation of unknown class of fluoro-
containing compounds—(3-bromo-2,2,3,3-tetrafluoropro-
pyl)arenes (3)—from aromatic aldehydes. Mild conditions
and simplicity of the reaction procedure are significant
features of the presented method. We investigated synthetic
scope of (3-bromo-2,2,3,3-tetrafluoropropyl)arenes and ela-
borated novel method for synthesis of new fluorinated
alkenes (5) and alkynes (6). Moreover, new unusual route
of the catalytic olefination reaction that leads to saturated
products was found.
4.1.2. 1-(3-Bromo-2,2,3,3-tetrafluoropropyl)-4-
methylbenzene (3b)
Colorless oil; Rf (hexane) 0.45; IR (KBr): n 1500, 1600,
2950. 1H NMR (400 MHz, CDCl3): d 2.37 (3H, s, Me), 3.35
(2H, t, J ¼ 18:2 Hz, CH2), 7.19 (4H, s, Ar); 13C NMR
(100 MHz, CDCl3): d 21.08 (Me), 36.25 (t, JCF
22:9 Hz, CH2), 115.77 (tt, JCF ¼ 254:8 Hz, JCF
¼
¼
31:3 Hz, CF2), 117.84 (tt, JCF ¼ 311:3 Hz, JCF ¼ 39:7 Hz,
CF2Br), 126.40, 129.27, 130.59, 137.83; 19F NMR
(376.27 MHz, CDCl3/CCl3F):
d
ꢀ65.44 (s, CF2Br),
ꢀ111.16 (t, JHF ¼ 18:2 Hz, CF2). EIMS (probe), 70 eV,
m/z (rel. int.): 284 [M]þ (3), 205 [MꢀBr]þ (1), 185
[MꢀBrꢀHꢀF]þ (2), 165 [MꢀBrꢀ2Hꢀ2F]þ (2), 151
[MꢀBrꢀ2Hꢀ2FꢀCH2]þ (1), 133 [MþꢀBrꢀ3Fꢀ3HꢀC]
(1), 105 [MþꢀBrꢀC2F4] (100), 91 [C7H7]þ (3). Anal.
Calcd. for C9H10BrF4: C, 42.13; H, 3.18. Found: C, 42.5;
H, 3.3.
4. Experimental
NMR spectra were recorded on a Varian VXR-400 spec-
trometer in CDCl3 with TMS and CCl3F as an internal
standard. The IR spectra were obtained with UR-20 spectro-
meter. Mass spectra were recorded on a Finnigan SSQ7000
mass spectrometer. Known azines (4a–c) were characterized
by comparison of their spectral and physical data with
literature [3–10]. Column chromatography was performed
on silica gel (63–200 mesh, Merck).
4.1.3. 1-(3-Bromo-2,2,3,3-tetrafluoropropyl)-4-
methoxybenzene (3c)
Colorless oil; Rf (hexane) 0.2; IR (KBr): n 1520, 1600,
1
2850 (CH3O), 2950; H NMR (400 MHz, CDCl3): d 3.31
4.1. General procedure for synthesis of
(3-bromo-2,2,3,3-tetrafluoropropyl)arenes (3a–h)
(2H, t, J ¼ 18:2 Hz, CH2), 3.80 (3H, s, OMe), 6.89 (2H, d,
J ¼ 8:5 Hz, Ar), 7.21 (2H, d, J ¼ 8:5 Hz, Ar); 13C NMR
(100 MHz, CDCl3): d 35.84 (t, JCF ¼ 22:9 Hz, CH2), 55.18
(OMe), 113.99, 115.79 (tt, JCF ¼ 254:8 Hz, JCF ¼ 31:3 Hz,
CF2), 117.83 (tt, JCF ¼ 311:3 Hz, JCF ¼ 39:7 Hz, CF2Br),
A solution of aromatic aldehyde (50 mmol) in EtOH
(100 mL) was added with stirring dropwise to a solution

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V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 125 (2004) 1339–1345
121.38, 131.77, 159.45 (C–OMe); 19F NMR (376.27 MHz,
CDCl3/CCl3F):
JHF ¼ 18:2 Hz, CF2). EIMS (probe), 70 eV, m/z (rel. int.):
300 [M]þ (2), 221 [MꢀBr]þ (1), 201 [MꢀBrꢀHꢀF]þ (1),
181 [MꢀBrꢀ2Hꢀ2F]þ (1), 170 [MꢀBrꢀ2FꢀCꢀH]þ (1),
121 [MꢀBrꢀC2F4]þ (100), 91 [C7H7]þ (4). Anal. Calcd. for
C9H10BrF4O: C, 39.89; H, 3.01. Found: C, 39.6; H, 3.0.
[MꢀBrꢀHꢀF]þ (2), 219 [MꢀBrꢀ2Hꢀ2F]þ (1), 203
[MꢀClꢀBrꢀHF]þ (1), 159 [MꢀBrꢀC2F4]þ (100). Anal.
Calcd. for C9H5BrCl2F4: C, 31.80; H, 1.48. Found: C, 32.0;
H, 1.5.
d
ꢀ65.41 (s, CF2Br), ꢀ111.29 (t,
4.1.7. 1-(3-Bromo-2,2,3,3-tetrafluoropropyl)-3-
nitrobenzene (3g)
Colorless oil; Rf (hexane/CH2Cl2 1/1) 0.6; IR (KBr): n
1480, 1530 (NO2), 1600, 2950; 1H NMR (400 MHz,
CDCl3): d 3.50 (2H, t, J ¼ 17:7 Hz, CH2), 7.55 (1H, dd,
J ¼ 8:2 Hz, J ¼ 7:6 Hz, Ar), 7.64 (1H, d, J ¼ 7:6 Hz, Ar),
8.18 (1H, s, Ar), 8.21 (1H, d, J ¼ 8:2 Hz, Ar); 13C NMR
(100 MHz, CDCl3): d 36.34 (t, JCF ¼ 22:9 Hz, CH2), 115.57
(tt, JCF ¼ 254:8 Hz, JCF ¼ 31:3 Hz, CF2), 117.10 (tt,
JCF ¼ 311:3 Hz, JCF ¼ 39:7 Hz, CF2Br), 123.26, 125.60,
129.60, 131.50, 136.73, 148.31; 19F NMR (376.27 MHz,
4.1.4. 1-Bromo-4-(3-bromo-2,2,3,3-
tetrafluoropropyl)benzene (3d)
Colorless oil; Rf (hexane) 0.45; IR (KBr): n 1510, 1600,
2950. 1H NMR (400 MHz, CDCl3): d 3.33 (2H, t,
J ¼ 18:2 Hz, CH2), 7.16 (2H, d, J ¼ 7:9 Hz, Ar), 7.49
(2H, d, J ¼ 7:9 Hz, Ar); 13C NMR (100 MHz, CDCl3): d
36.20 (t, JCF ¼ 22:9 Hz, CH2), 115.66 (tt, JCF ¼ 254:8 Hz,
JCF ¼ 31:3 Hz, CF2), 117.52 (tt, JCF ¼ 311:3 Hz, JCF
¼
39:7 Hz, CF2Br), 128.48, 130.79, 131.76, 132.32; 19F
NMR (376.27 MHz, CDCl3/CCl3F): d ꢀ65.62 (s, CF2Br),
ꢀ111.10 (t, JHF ¼ 18:2 Hz, CF2). EIMS (probe), 70 eV, m/z
(rel. int.): 348 [M]þ (4), 269 [MꢀBr]þ (1), 249
[MꢀBrꢀHꢀF]þ (2), 218 [MꢀCF2BrꢀH]þ (1), 169
[MꢀBrꢀC2F4]þ (100), 140 [MꢀCF2BrꢀBr]þ (10). Anal.
Calcd. for C9H6Br2F4: C, 30.89; H, 1.73. Found: C, 31.1; H,
1.8.
CDCl3/CCl3F): d ꢀ65.90 (s, CF2Br), ꢀ110.99 (t, JHF ¼
17:7 Hz, CF2). EIMS (probe), 70 eV, m/z (rel. int.): 315
[M]þ (30), 285 (1) [MꢀHF]þ, 269 [MꢀNO2]þ (15), 236
[MꢀBr]þ (2), 205 [MꢀBrꢀFꢀCꢀH]þ (8), 190
[MꢀBrꢀNO2]þ (12), 169 [MꢀNO2ꢀC2F4]þ (38), 136
[MꢀBrꢀC2F4]þ (100), 109 [C7H6F]þ (63), 90 [MꢀBrꢀ
C2F4ꢀNO2]þ (34). Anal. Calcd. for C9H6BrF4NO2: C,
34.60; H, 1.91. Found: C, 34.9; H, 1.9.
4.1.5. 1-(3-Bromo-2,2,3,3-tetrafluoropropyl)-2-
chlorobenzene (3e)
4.1.8. Methyl 4-(3-bromo-2,2,3,3-
tetrafluoropropyl)benzoate (3h)
Colorless oil; Rf (hexane) 0.45; IR (KBr): n 1500, 1600,
2950; 1H NMR (400 MHz, CDCl3): d 3.53 (2H, t,
J ¼ 18:2 Hz, CH2), 7.15–7.23 (2H, m, Ar), 7.29 (1H, d,
J ¼ 8:5 Hz, Ar), 7.35 (1H, dd, J ¼ 7:6 Hz, J ¼ 1:5 Hz, Ar);
13C NMR (100 MHz, CDCl3): d 33.48 (t, JCF ¼ 21:4 Hz,
CH2), 115.69 (tt, JCF ¼ 254:8 Hz, JCF ¼ 31:3 Hz, CF2),
117.63 (tt, JCF ¼ 311:3 Hz, JCF ¼ 39:7 Hz, CF2Br),
126.86, 127.95, 129.59, 129.89, 132.65, 135.63; 19F NMR
Colorless oil; Rf (hexane) 0.2; IR (KBr): n 1510, 1600,
1740 (C¼O), 2950, 2980 (OCH3); 1H NMR (400 MHz,
CDCl3): d 3.33 (2H, t, J ¼ 18:2 Hz, CH2), 3.82 (3H, s,
OCH3), 7.27 (2H, d, J ¼ 8:5 Hz, Ar), 7.92 (2H, d,
J ¼ 8:5 Hz, Ar); 13C NMR (100 MHz, CDCl3): d 36.63
(t, JCF ¼ 22:9 Hz, CH2), 52.10 (OCH3), 115.76 (tt,
JCF ¼ 254:8 Hz, JCF ¼ 31:3 Hz, CF2), 117.48 (tt, JCF
¼
311:3 Hz, JCF ¼ 39:7 Hz, CF2Br), 129.74, 130.04, 130.74,
134.59, 166.58 (C¼O); 19F NMR (376.27 MHz, CDCl3/
CCl3F): d ꢀ65.64 (s, CF2Br), ꢀ110.72 (t, JHF ¼ 18:2 Hz,
CF2). EIMS (probe), 70 eV, m/z (rel. int.): 328 [M]þ (16),
297 [MꢀOCH3]þ (100), 269 [MꢀCO2Me]þ (4), 217
[MꢀBrꢀHꢀOMe]þ (2), 189 [MꢀBrꢀHꢀCO2Me]þ (10),
169 [MꢀBrꢀCO2Meꢀ2HꢀF]þ (20), 149 [MꢀBrꢀC2F4]þ
(34), 121 [C8H6F]þ (23), 109 [C7H6F]þ (31). Anal. Calcd.
for C11H9BrF4O2: C, 40.15; H, 2.76. Found: C, 40.1; H,
2.7.
(376.27 MHz, CDCl3/CCl3F):
d
ꢀ66.04 (s, CF2Br),
ꢀ110.79 (t, JHF ¼ 18:2 Hz, CF2). EIMS (probe), 70 eV,
m/z (rel. int.): 304 [M]þ (1), 225 [MꢀBr]þ (1), 205
[MꢀBrꢀHꢀF]þ (3), 185 [MꢀBrꢀ2Hꢀ2F]þ (2), 169
[MꢀClꢀC2F4]þ (4), 125 [MꢀBrꢀC2F4]þ (100). Anal.
Calcd. for C9H6BrClF4: C, 35.38; H, 1.98. Found: C,
35.1; H, 2.0.
4.1.6. 1-(3-Bromo-2,2,3,3-tetrafluoropropyl)-2,4-
dichlorobenzene (3f)
Colorless oil; Rf (hexane) 0.4; IR (KBr): n 1480, 1600,
2950; 1H NMR (400 MHz, CDCl3): d 3.49 (2H, t,
J ¼ 17:9 Hz, CH2), 7.17 (1H, dd, J ¼ 8:2 Hz, J ¼ 2:1 Hz,
Ar), 7.22 (1H, d, J ¼ 8:2 Hz, Ar), 7.37 (1H, d, J ¼ 2:1 Hz,
4.2. General procedure for synthesis of (3-bromo-2,3,3-
trifluoro-1-propenyl)arenes (5)
A 50% NaOH (0.1 mL, 2.5 mmol) was added to a solution
of alkane (3) (1 mmol) in EtOH (5 mL). The mixture was
refluxed with stirring until alkane disappeared (2–5 h, TLC
monitoring). Then the reaction mixture cooled and quenched
with hydrochloric acid (5%) (50 mL) and extracted with
CH2Cl2 (20 mL Â 3). Extracts were dried over sodium
sulphate, CH2Cl2 was evaporated and the residue was pur-
ified by column chromatography.
Ar); 13C NMR (100 MHz, CDCl3): d 33.06 (t, JCF
22:9 Hz, CH2), 115.81 (tt, JCF ¼ 254:8 Hz, JCF
¼
¼
32:0 Hz, CF2), 117.43 (tt, JCF ¼ 311:3 Hz, JCF ¼ 39:7 Hz,
CF2Br), 126.55, 127.28, 129.75, 133.32, 135.02, 136.34; 19
F
NMR (376.27 MHz, CDCl3/CCl3F): d ꢀ66.15 (s, CF2Br),
ꢀ110.77 (t, JHF ¼ 17:9 Hz, CF2). EIMS (probe), 70 eV, m/z
(rel. int.): 338 [M]þ (1), 259 (1) [MꢀBr]þ, 239

V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 125 (2004) 1339–1345
1343
4.2.1. 1-[(1Z)-3-Bromo-2,3,3-trifluoro-1-propenyl]-4-
chlorobenzene (5a)
4.2.4. 1-[(1Z)-3-Bromo-2,3,3-trifluoro-1-propenyl]-2-
chlorobenzene (5e)
Colorless oil; Rf (hexane) 0.7; IR (KBr): n 1500, 1600,
Colorless oil; Rf (hexane) 0.7; IR (KBr): n 1490, 1600,
1700 (C¼C), 2950. H NMR (400 MHz, CDCl3): d 6.78
1
1
1700 (C¼C), 2950; H NMR (400 MHz, CDCl3): d 6.25
(1H, d, J ¼ 34:9 Hz, ¼CH–), 7.37 (2H, d, J ¼ 8:5 Hz, Ar),
7.50 (2H, d, J ¼ 8:5 Hz, Ar); 13C NMR (100 MHz, CDCl3):
d 107.57–107.63 (m, ¼CH–), 111.77 (td, JCF ¼ 302:2 Hz,
JCF ¼ 44:2 Hz, CF2Br), 128.38 (d, JCF ¼ 4:6 Hz), 129.33,
(1H, d, J ¼ 34:6 Hz, ¼CF–), 7.28–7.33 (2H, m, Ar), 7.41–
7.45 (1H, m, Ar), 7.81–7.83, (1H, m, Ar); 13C NMR
(100 MHz, CDCl3): d 104.60–104.75 (m, ¼CH–), 111.66
(td, JCF ¼ 302:2 Hz, JCF ¼ 42:7 Hz, CF2Br), 127.10, 127.92
(d, JCF ¼ 4:6 Hz), 129.86, 130.51, 130.69 (d, JCF ¼ 7:6 Hz),
134.27, 149.95 (dt, JCF ¼ 268:6 Hz, JCF ¼ 29:0 Hz, ¼CF–);
19F NMR (376.27 MHz, CDCl3/CCl3F): d ꢀ54.45 (d,
JFF ¼ 19:8 Hz, CF2Br), ꢀ124.86 (dt, JHF ¼ 34:6 Hz,
JFF ¼ 19:8 Hz, ¼CF–). EIMS (probe), 70 eV, m/z (rel.
int.): 284 [M]þ (8), 205 [MꢀBr]þ (100), 185
[MꢀBrꢀHꢀF]þ (67), 169 [MꢀBrꢀHꢀCl]þ (35), 151
[MꢀBrꢀClꢀFꢀH]þ (16), 120 [MꢀBrꢀ2FꢀClꢀHꢀC]þ
(8). Anal. Calcd. for C9H5BrClF3: C, 37.86; H, 1.77. Found:
C, 37.7; H, 1.8.
131.09 (d, JCF ¼ 7:6 Hz), 135.85, 149.84 (dt, JCF
¼
267:0 Hz, JCF ¼ 29:0 Hz, ¼CF–); 19F NMR (376.27
MHz, CDCl3/CCl3F): d ꢀ55.48 (d, JFF ¼ 19:8 Hz, CF2Br),
ꢀ124.59 (dt, JHF ¼ 34:9 Hz, JFF ¼ 19:8 Hz, ¼CF–). EIMS
(probe), 70 eV, m/z (rel. int.): 284 [M]þ (3), 205 [MꢀBr]þ
(100), 185 [MꢀBrꢀHꢀF]þ (80), 169 [MꢀBrꢀClꢀH]þ
(43), 151 [MꢀBrꢀClꢀHꢀF]þ (20). Anal. Calcd. for
C9H5BrClF3: C, 37.86; H, 1.77. Found: C, 37.9; H,
1.7.
4.2.2. 1-[(1Z)-3-Bromo-2,3,3-trifluoro-1-propenyl]-4-
methylbenzene (5b)
4.2.5. 1-[(1Z)-3-Bromo-2,3,3-trifluoro-1-propenyl]-2,4-
dichlorobenzene (5f)
Colorless oil; Rf (hexane) 0.75; IR (KBr): n 1500, 1600,
1
1700 (C¼C), 2950; H NMR (400 MHz, CDCl3): d 2.41
Colorless oil; Rf (hexane) 0.7; IR (KBr): n 1480, 1600,
1
(3H, s, Me), 6.29 (1H, d, J ¼ 35:5 Hz, ¼CH–), 7.24 (2H, d,
J ¼ 8:2 Hz, Ar), 7.50 (2H, d, J ¼ 8:2 Hz, Ar); 13C NMR
(100 MHz, CDCl3): d 21.42 (Me), 108.67–108.73 (m,
¼CH–), 112.15 (td, JCF ¼ 302:2 Hz, JCF ¼ 44:1 Hz,
CF2Br), 127.04 (d, JCF ¼ 4:6 Hz), 129.62, 129.78 (d,
JCF ¼ 7:6 Hz), 139.78, 148.76 (dt, JCF ¼ 264:0 Hz,
JCF ¼ 29:0 Hz, ¼CF–); 19F NMR (376.27 MHz, CDCl3/
CCl3F): d ꢀ54.85 (d, JFF ¼ 19:8 Hz, CF2Br), ꢀ126.44 (dt,
JHF ¼ 35:5 Hz, JFF ¼ 19:8 Hz, ¼CF–). EIMS (probe),
70 eV, m/z (rel. int.): 264 [M]þ (3), 185 [MꢀBr]þ
(100), 165 [MꢀBrꢀHꢀF]þ (80), 151 [MꢀBrꢀ
3HꢀFꢀC]þ (10), 145 [MꢀBrꢀ2Hꢀ2F]þ (10), 133
[MꢀBrꢀ2Hꢀ2FꢀC]þ (16), 115 [MþꢀBrꢀHꢀ3FꢀC]
(14). Anal. Calcd. for C10H8BrF3: C, 45.31; H, 3.04.
Found: C, 45.0; H, 3.1.
1700 (C¼C), 2950; H NMR (400 MHz, CDCl3): d 6.70
(1H, d, J ¼ 34:0 Hz, ¼CF–), 7.29 (1H, dd, J ¼ 8:5 Hz,
J ¼ 2:1 Hz, Ar), 7.44 (1H, d, J ¼ 2:1 Hz, Ar), 7.75 (1H,
d, J ¼ 8:5 Hz, Ar); 13C NMR (100 MHz, CDCl3): d 103.73–
103.78 (m, ¼CH–), 111.45 (td, JCF ¼ 302:1 Hz,
JCF ¼ 42:7 Hz, CF2Br), 126.46 (d, JCF ¼ 4:6 Hz), 127.57,
129.77, 131.30 (d, JCF ¼ 7:6 Hz), 134.91, 135.87, 150.44
(dt, JCF ¼ 268:6 Hz, JCF ¼ 29:0 Hz, ¼CF–); 19F NMR
(376.27 MHz, CDCl3/CCl3F):
d
ꢀ55.71 (d, JFF
¼
¼
16:5 Hz, CF2Br), ꢀ123.75 (dt, JHF ¼ 34:0 Hz, JFF
16:5 Hz, ¼CF–). EIMS (probe), 70 eV, m/z (rel. int.): 318
[M]þ (3), 239 [MꢀBr]þ (100), 219 [MꢀBrꢀHꢀF]þ (40),
204 [MꢀClꢀBr]þ (37), 185 [MꢀClꢀBrꢀF]þ (12), 169
[MꢀBrꢀ2Cl]þ (72), 154 [MꢀBrꢀClꢀCꢀ2F]þ (12), 149
[MꢀBrꢀ2ClꢀFꢀH]þ (8), 119 [C8H4F]þ (14). Anal. Calcd.
for C9H5BrClF3: C, 33.79; H, 1.26. Found: C, 33.6; H,
1.3.
4.2.3. 1-Bromo-4-[(1Z)-3-bromo-2,3,3-trifluoro-1-
propenyl] benzene (5d)
Colourless oil; Rf (Hexane) 0.7. IR (KBr); 1500, 1600,
4.2.6. Ethyl 4-[(1Z)-3-bromo-2,3,3-trifluoro-1-
propenyl]benzoate (5h)
1
1700 (C¼C), 2950. H NMR (400 MHz, CDCl3): d 6.24
(1H, d, J ¼ 34:6 Hz, ¼CF–), 7.42 (2H, d, J ¼ 8:8 Hz, Ar),
7.53 (2H, d, J ¼ 8:8 Hz, Ar). 13C NMR (100 MHz,
CDCl3): d 107.68–107.73 (m, ¼CH–), 111.69 (td,
JCF ¼ 302:1 Hz, JCF ¼ 44:7 Hz, CF2Br), 123.85, 128.72
(d, JCF ¼ 4:6 Hz), 131.16 (d, JCF ¼ 7:6 Hz), 132.15,
149.60 (dt, JCF ¼ 265:5 Hz, JCF ¼ 29:0 Hz, ¼CF–). 19F
Colorless oil; Rf (hexane) 0.15; IR (KBr): n 1520, 1600,
1
1700 (C¼C), 1740 (C¼O), 2950, 2990 (OEt); H NMR
(400 MHz, CDCl3): d 1.39 (3H, t, J ¼ 7:0 Hz, CH3), 4.37
(2H, q, J ¼ 7:0 Hz, –CH2O–), 6.32 (1H, d, J ¼ 34:6 Hz,
¼CF–), 7.60 (2H, d, J ¼ 8:2 Hz, Ar), 8.05 (2H, d,
J ¼ 8:2 Hz, Ar); 13C NMR (100 MHz, CDCl3): d 14.22
(CH3), 61.18 (–CH2O–), 107.70–107.95 (m, ¼CF–),
111.52 (td, JCF ¼ 302:1 Hz, JCF ¼ 44:3 Hz, CF2Br),
129.55 (d, JCF ¼ 7:6 Hz), 126.67 (d, JCF ¼ 4:6 Hz),
NMR (376.27 MHz, CDCl3/CCl3F):
d —55.52 (d,
JFF ¼ 19:8 Hz, CF2Br), ꢀ124.69 (dt, JHF ¼ 34:6 Hz,
JFF ¼ 19:8 Hz, ¼CF–). EIMS (probe), 70 eV, m/z (rel.
int.): 328 [M]þ (1), 249 [MꢀBr]þ (24), 229 [MꢀBrꢀ
HꢀF]þ (2), 170 [Mꢀ2Br]þ (100), 151 [Mꢀ2BrꢀFꢀH]þ
(32), 120 [Mꢀ2Brꢀ2FꢀHꢀC]þ (8). Anal. Calcd. for
C9H5Br2F3: C, 32.76; H, 1.53. Found: C, 32.5; H,
1.5.
129.92, 133.93, 150.24 (dt, JCF ¼ 268:6 Hz, JCF
¼
29:0 Hz, ¼CF–), 165.76 (C¼O). 19F NMR (376.27 MHz,
CDCl3/CCl3F): d ꢀ55.54 (d, JFF ¼ 16:5 Hz, CF2Br),
ꢀ122.69 (dt, JHF ¼ 34:6 Hz, JFF ¼ 16:5 Hz, ¼CF–). EIMS
(probe), 70 eV, m/z (rel. int.): 322 [M]þ (1), 277

1344
V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 125 (2004) 1339–1345
[MꢀCO2Et]þ (2), 243 [MꢀBr]þ (13), 215 [MꢀBrꢀ
2Cꢀ5H]þ (3), 198 [MꢀBrꢀOEt]þ (13), 169 [MꢀBrꢀ
OEtꢀCꢀHF]þ (38), 151 [MꢀBrꢀCO2EtꢀHF]þ (100),
119 [C8H5F]þ (9). Anal. Calcd. for C12H10BrF3O2: C,
44.61; H, 3.12. Found: C, 44.4; H, 3.1.
(t, JCF ¼ 289:9 Hz, CF2Br), 117.72, 125.67, 132.07, 135.55;
19F NMR (376.27 MHz, CDCl3/CCl3F): d ꢀ32.46 (s,
CF2Br). EIMS (probe), 70 eV, m/z (rel. int.): 308 [M]þ
(2), 289 [MꢀF]þ (1), 229 [MꢀBr]þ (100), 150
[Mꢀ2BrꢀMe]þ (45), 131 [Mꢀ2BrꢀF]þ (2), 99 [Mꢀ
CF2BrꢀBr]þ (16). Anal. Calcd. for C9H4Br2F2: C, 34.88;
H, 1.30. Found: C, 34.7; H, 1.2.
4.3. General procedure for synthesis of (3-bromo-3,3-
difluoro-1-propynyl)arenes (6)
4.3.4. 1-(3-Bromo-3,3-difluoro-1-propynyl)-2-
chlorobenzene (6e)
A solution of 1 M t-BuOK in THF (3 mL) was added
dropwise to a solution of alkane (3) (1 mmol) in THF (2 mL)
at 0 8C (water bath). The mixture was stirring until alkane
disappeared (3–6 h, TLC monitoring). Then the reaction
mixture quenched with hydrochloric acid (5%) (50 mL) and
extracted with CH2Cl2 (20 mL Â 3). Extracts were dried
over sodium sulphate, CH2Cl2 was evaporated and the
residue was purified by column chromatography.
Colorless oil; Rf (hexane) 0.75; IR (KBr): n 1490, 1600,
2270 (C–C), 2950; 1H NMR (400 MHz, CDCl3): d 7.28 (1H,
ddd, J ¼ 7:9 Hz, J ¼ 7:6 Hz, J ¼ 1:5 Hz, Ar), 7.38 (1H,
ddd, J ¼ 7:9 Hz, J ¼ 7:6 Hz, J ¼ 1:5 Hz, Ar), 7.44 (1H, dd,
J ¼ 7:9 Hz, J ¼ 1:5 Hz, Ar), 7.55 (1H, dd, J ¼ 7:9 Hz,
J ¼ 1:5 Hz, Ar); 13C NMR (100 MHz, CDCl3): d 82.15
(t, JCF ¼ 38:8 Hz, Ar–CBC–CF2Br), 86.50 (t, JCF
¼
6:1 Hz, Ar–CBC–CF2Br), 101.90 (t, JCF ¼ 289:9 Hz,
CF2Br), 119.15, 126.69, 129.71, 131.86, 133.93, 137.11;
19F NMR (376.27 MHz, CDCl3/CCl3F): d ꢀ33.83 (s,
CF2Br). EIMS (probe), 70 eV, m/z (rel. int.): 264 [M]þ
(3), 245 [MꢀF]þ (1), 185 [MꢀBr]þ (100), 166 [MꢀBrꢀF]þ
(6), 150 [MþꢀBrꢀCl]þ (23), 131 [MꢀBrꢀClꢀF]þ (2), 99
[MꢀCF2BrꢀCl]þ (13). Anal. Calcd. for C9H4BrClF2: C,
40.72; H, 1.52. Found: C, 40.5; H, 1.6.
4.3.1. 1-(3-Bromo-3,3-difluoro-1-propynyl)-4-
chlorobenzene (6a)
Colorless oil; Rf (hexane) 0.75; IR (KBr): n 1500, 1600,
1
2270 (C¼C), 2950; H NMR (400 MHz, CDCl3): d 7.39
(2H, d, J ¼ 8:5 Hz, Ar), 7.50 (2H, d, J ¼ 8:5 Hz, Ar); 13C
NMR (100 MHz, CDCl3): d 82.19 (t, JCF ¼ 38:9 Hz, Ar–
CBC–CF2Br), 88.37 (t, JCF ¼ 6:1 Hz, Ar–CBC–CF2Br),
101.94 (t, JCF ¼ 289:9 Hz, CF2Br), 117.55, 129.28,
133.55, 137.53; 19F NMR (376.27 MHz, CDCl3/CCl3F): d
ꢀ32.64 (s, CF2Br). EIMS (probe), 70 eV, m/z (rel. int.): 264
[M]þ (2), 245 [MꢀF]þ (1), 185 [MꢀBr]þ (100), 166
[MꢀBrꢀF]þ (1), 150 [MꢀBrꢀCl]þ (14), 131 [MꢀBrꢀ
ClꢀF]þ (5), 99 [MꢀCF2BrꢀCl]þ (11). Anal. Calcd. for
C9H4BrClF2: C, 40.72; H, 1.52. Found: C, 40.6; H, 1.5.
4.3.5. 1-(3-Bromo-3,3-difluoro-1-propynyl)-2,4-
dichlorobenzene (6f)
Colorless oil; Rf (hexane) 0.7; IR (KBr): n 1480, 1600,
2270 (CBC), 2950; 1H NMR (400 MHz, CDCl3): d 7.27 (1H,
dd, J ¼ 8:5 Hz, J ¼ 1:8 Hz, Ar), 7.46 (1H, d, J ¼ 1:8 Hz,
Ar), 7.48 (1H, d, J ¼ 8:5 Hz, Ar); 13C NMR (100 MHz,
CDCl3): d 85.33 (t, JCF ¼ 6:1 Hz, Ar–CBC–CF2Br), 85.83
4.3.2. 1-(3-Bromo-3,3-difluoro-1-propynyl)-4-
methoxybenzene (6c)
(t, JCF ¼ 38:9 Hz, Ar–CBC–CF2Br), 101.75 (t, JCF ¼
289:9 Hz, CF2Br), 117.72, 127.34, 129.84, 134.46,
137.72, 137.95; 19F NMR (376.27 MHz, CDCl3/CCl3F): d
ꢀ35.73 (s, CF2Br). EIMS (probe), 70 eV, m/z (rel. int.): 298
[M]þ (1), 281 [MꢀF]þ (2), 219 [MꢀBr]þ (100), 184
[MþꢀBrꢀCl]þ (14), 165 [MꢀBrꢀClꢀF]þ (4), 149
[MꢀBrꢀ2Cl]þ (29), 99 [C8H3]þ (3). Anal. Calcd. for
C9H3BrCl2F2: C, 36.04; H, 1.01. Found: C, 35.8; H, 1.1.
Colorless oil; Rf (hexane) 0.15; IR (KBr): n 1520, 1600,
2230 (CBC), 2850 (OCH3), 2950; 1H NMR (400 MHz,
CDCl3): d 3.83 (3H, s, CH3O), 6.89 (2H, d, J ¼ 8:8 Hz,
Ar), 7.47 (2H, d, J ¼ 8:8 Hz, Ar); 13C NMR (100 MHz,
CDCl3): d 55.35 (MeO), 80.26 (t, JCF ¼ 38:2 Hz, Ar–CBC–
CF2Br), 90.59 (t, JCF ¼ 6:1 Hz, Ar–CBC–CF2Br), 102.2 (t,
JCF ¼ 289:9 Hz, CF2Br), 110.64, 114.32, 133.97, 161.55
(C–OMe); 19F NMR (376.27 MHz, CDCl3/CCl3F): d
ꢀ30.86 (s, CF2Br). EIMS (probe), 70 eV, m/z (rel. int.):
260 [M]þ (3), 241 [MꢀF]þ (1), 181 [MꢀBr]þ (100), 166
[MꢀBrꢀMe]þ (13), 150 [MꢀBrꢀOMe]þ (2), 138
[MꢀBrꢀOMeꢀC]þ (22). Anal. Calcd. for C10H7BrF2O:
C, 46.01; H, 2.70. Found: C, 45.9; H, 2.8.
Acknowledgements
Financial support from the Russian Foundation for Basic
Research (Grant No. 03-03-32052) is gratefully acknowl-
edged.
4.3.3. 1-Bromo-4-(3-bromo-3,3-difluoro-1-
propynyl)benzene (6d)
References
Colorless oil; Rf (hexane) 0.75; IR (KBr): 1500, 1600,
2270 (CBC), 2950; 1H NMR (400 MHz, CDCl3): d 7.40 (2H,
d, J ¼ 8:5 Hz, Ar), 7.54 (2H, d, J ¼ 8:5 Hz, Ar); 13C NMR
(100 MHz, CDCl3): d 81.84 (t, JCF ¼ 38:9 Hz, Ar–CBC–
CF2Br), 87.76 (t, JCF ¼ 6:1 Hz, Ar–CBC–CF2Br), 101.90
[1] M. Hudlicky, A.E. Pavlath, Chemistry of Organic Fluorine
Compounds II, American Chemical Society, Washington, DC, 1995.
[2] M. Howe-Grant, Fluorine Chemistry: A Comprehensive Treatment,
Wiley, New York, 1995.

V.G. Nenajdenko et al. / Journal of Fluorine Chemistry 125 (2004) 1339–1345
1345
[3] A.V. Shastin, V.N. Korotchenko, V.G. Nenajdenko, E.S. Balenkova,
Tetrahedron 56 (2000) 6557–6563.
[13] L. Zhang, J. Zhang, Y. Wang, W. Fub, S. Weizbauer, J. Fluorine
Chem. 88 (1998) 153–168.
[4] A.V. Shastin, V.N. Korotchenko, V.G. Nenajdenko, E.S. Balenkova,
Synthesis 14 (2001) 2081–2084.
[14] F.-H. Wu, W.-Y. Huang, J. Fluorine Chem. 110 (2001) 59–61.
[15] P. Tarrant, J.P. Tandon, J. Org. Chem 34 (1969) 864–869.
[16] I. Rico, C. Wakselman, J. Fluorine Chem. 20 (1982) 759–764.
[17] I. Rico, C. Wakselman, J. Fluorine Chem. 20 (1982) 765–770.
[18] A.E. Feiring, E.R. Wonchoba, J. Fluorine Chem. 105 (2000)
129–135.
[5] A.V. Shastin, V.N. Korotchenko, V.G. Nenajdenko, E.S. Balenkova,
Russ. Chem. Bull. 50 (2001) 1401–1404.
[6] A.V. Shastin, V.N. Korotchenko, G.N. Varseev, V.G. Nenajdenko,
E.S. Balenkova, Zh. Org. Khim. 39 (2003) 433–436.
[7] V.N. Korotchenko, A.V. Shastin, V.G. Nenajdenko, E.S. Balenkova,
Org. Biomol. Chem. 1 (2003) 1906–1908.
[19] P. Weiming, Z. Shizheng, J. Guifang, Tetrahedron 57 (2001)
5781–5784.
[8] V.G. Nenajdenko, A.V. Shastin, V.N. Korotchenko, G.N. Varseev,
E.S. Balenkova, Eur. J. Org. Chem. 2 (2003) 302–308.
[9] V.N. Korotchenko, A.V. Shastin, V.G. Nenajdenko, E.S. Balenkova,
Tetrahedron 57 (2001) 7519–7527.
[20] B.L. Finkelstein, J. Org. Chem. 57 (1992) 5538–5540.
[21] S.A. Savage, A.P. Smith, C.F. Fraser, J. Org. Chem. 63 (1998)
10048–10051.
[22] I. Rico, D. Cantacuzene, C. Wakselman, J. Chem. Soc. Perkin Trans.
1 (1982) 1063–1066.
[10] V.G. Nenajdenko, G.N. Varseev, V.N. Korotchenko, A.V. Shastin,
E.S. Balenkova, J. Fluorine Chem. 124 (2003) 115–118.
[11] C.-M. Hu, Y.-L. Qui, F.-L. Quing, J. Fluorine Chem. 51 (1991)
295–298.
[23] P.-Y. Kwok, F.W. Muelner, C.-K. Chen, J. Fried, J. Am. Chem. Soc.
109 (1987) 3684–3692.
[24] D.D. Perrin, W.L.F. Armaredo, Purification of Laboratory Chemi-
cals, Pergamon Press, New York, 1988, p. 322.
[12] C.-M. Hu, Y.-L. Qui, J. Fluorine Chem. 55 (1991) 109–111.