Organozinc reagents from polyfluoroarenes: Preparation and reactions with allyl halides. Synthesis of allylpolyfluoroarenes

Article abstract of DOI:10.1134/s1070428008010119

Organozinc compounds of the general formula Ar_FZnX (X = Cl, Ar_F) were synthesized by reactions of Zn with chloropolyfluoroarenes and of Zn/SnCl₂ with polyfluoroarenes. Polyflorinated organozinc compounds reacted with allyl

Full text of DOI:10.1134/s1070428008010119

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 1, pp. 95–102. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © A.S. Vinogradov, V.I. Krasnov, V.E. Platonov, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 1, pp. 101–107.
Dedicated to Full Member of the Russian Academy of Sciences
G.A. Tolstikov on his 75th anniversary
Organozinc Reagents from Polyfluoroarenes:
Preparation and Reactions with Allyl Halides.
Synthesis of Allylpolyfluoroarenes
A. S. Vinogradov, V. I. Krasnov, and V. E. Platonov
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences,
pr. Akademika Lavrent’eva 9, Novosibirsk, 630090 Russia
e-mail: platonov@nioch.nsc.ru
Received August 8, 2006
Abstract—Organozinc compounds of the general formula ArFZnX (X = Cl, ArF) were synthesized by reactions
of Zn with chloropolyfluoroarenes and of Zn/SnCl2 with polyfluoroarenes. Polyflorinated organozinc com-
pounds reacted with allyl chloride and allyl bromide to give the corresponding allyl-substituted polyfluoro-
arenes. The reactions with allyl chloride were carried out in the presence of copper(I) salts (CuCl or CuI).
DOI: 10.1134/S1070428008010119
Introduction of an allyl group into polyfluoroarene
molecules is promising from the viewpoint of syn-
thesis of fluorine-containing analogs of antidepressants
[1] and adsorbent modifiers for chromatography [2].
Methods of introduction of an allyl group are based on
reactions of allyl halides with polyfluoroaromatic
organometallics and of allylmagnesium halides with
polyfluorinated arenes. 1-Allyl-2,3,4,5,6-pentafluoro-
benzene (I) was prepared by reaction of allyl bromide
with the Grignard compound derived from bromo-
pentafluorobenzene (II) [1, 2]. Compound I was also
synthesized in a low yield by cross coupling of iodo-
pentafluorobenzene with allyl bromide in the presence
of activated copper [3]. Pentafluorophenylcopper(I)
obtained from pentafluorophenyllithium by exchange
reaction reacted with allyl bromide and allyl chloride
to give 60–68% of allylpentafluorobenzene (I) [4].
Burton et al. [5] reported on the synthesis of compound
I from the corresponding organocadmium reagent and
allyl bromide in DMF. 1-Allyl-3,5-dichloro-2,4,6-tri-
fluorobenzene was synthesized in a high yield from
tributyl(3,5-dichloro-2,4,6-trifluorophenyl)tin and allyl
chloride [6]. Reactions of polyfluoroarenes with allyl-
magnesium bromide and chloride are characterized by
a poor yield of allylpolyfluoroarenes [7, 8].
examined reactions of allyl chloride and allyl bromide
with organozinc compounds derived from polyfluoro-
arenes. These organometallic reagents were prepared
by treatment of polyfluorinated aromatics with zinc
dust in DMF. From chlorofluoroarenes III–V we thus
obtained mixtures of the corresponding polyfluoroaryl-
zinc chlorides VIa–VIIIa and bis(polyfluoroaryl)zincs
VIb–VIIIb, the former prevailing [9, 10] (Scheme 1).
Scheme 1.
Cl
ZnX
Zn, DMF
F
F
R
R
III–V, X
VIa, VIb, VIIa, VIIb
VIIIa, VIIIb, IXa, IXb
III, VI, R = 4-F; IV, VII, R = 4-CF3; V, VIII, R = 4-Me;
X, XI, R = 3-CF3; X = Cl (a), RC6F4 (b).
Compounds III and IV reacted with zinc in DMF
at 135°C, and these reactions were almost complete in
4 h. By contrast, 1-chloro-2,3,5,6-tetrafluoro-4-methyl-
benzene (V) failed to react under analogous conditions.
Organozinc compounds VIIIa and VIIIb were formed
from arene V only on prolonged heating with zinc dust
at elevated temperature, and the process was accom-
panied by formation of an appreciable amount of
2,3,5,6-tetrafluorotoluene (IX). Presumably, generation
Most of the above reactions involve organolithium
or organomagnesium compounds and ether solvents.
With the goal of obtaining allylpolyfluoroarenes we
95

VINOGRADOV et al.
96
of intermediate radical anions from polyfluoroarenes
III and IV is more facile due to higher electron affinity
of these compounds, as compared to V. This assump-
tion is supported by comparison of the electron affin-
ities of C6F6 and C6F5Cl, C6F6 and C6F5CF3 [11, 12],
and C6H5Cl and o-CH3C6H4Cl [13], as well as by the
electrochemical reduction potentials of C6H5Cl and
p-CH3C6H4Cl [14]. These data indicate that introduc-
tion of a chlorine atom or trifluoromethyl group into
a polyfluoroarene molecule increases the electron af-
finity; therefore, introduction of a methyl group could
reduce the electron affinity.
perature, whereas the reactions with XVII–XIX oc-
curred at 55–65°C (Scheme 2). As above, the products
were mixtures of polyfluoroarylzinc chlorides VIIa,
XVa, XVIa, XXa, and XXIa and bis(polyfluoroaryl)-
zincs VIIb, XVb, XVIb, XXb, and XXIb, the latter
prevailing.
Thus reaction of zinc with chloropolyfluoroarenes
occurred at the C–Cl bond, while perfluoroarenes re-
acted at the C–F bond in the para position (C4–F bond
in pentafluoropyridine); the reactions were accom-
panied by replacement of the halogen atom in the same
position by hydrogen (in most cases, the hydrode-
chlorination products were formed in small amounts).
1-Chloro-2,4,5,6-tetrafluoro-3-trifluoromethylben-
zene (X) gave rise to organozinc compounds XIa and
Xb together with an appreciable amount of 1,2,3,5-tet-
rafluoro-4-trifluoromethylbenzene (XII). Presumably,
apart from atmospheric moisture, dimethylformamide
(solvent) can act as source of hydrogen in the forma-
tion of compound XII. However, this problem requires
special study.
Organozinc compounds C6F5ZnBr (XXIIa) and
VIb obtained from bromopentafluorobenzene (II) and
Zn in DMF reacted with allyl bromide at room tem-
perature to give 1-allyl-2,3,4,5,6-pentafluorobenzene
(I) whose yield reached 55% in 2 days. This reaction
may be regarded as nucleophilic replacement of the
bromine atom in allyl bromide by pentafluorophenyl
group. After treatment of the reaction mixture with
water, pentafluorobenzene (XXIII) was formed as
a result of hydrolysis of unreacted organozinc com-
pound. Compound I was also formed by reaction of
allyl bromide with organozinc derivatives VIa and
VIb obtained from chloropentafluorobenzene (III).
Here, the process was accompanied by formation of
allyl chloride, presumably via replacement of the
bromine atom in allyl bromide by chlorine under the
action of zinc chloride. When a solution of VIa/VIb
and excess allyl bromide was kept for 15 days, the
conversion of the organozinc compounds reached
97%, and the ratio of I to allyl chloride was about 4:1.
Unlike allyl bromide, allyl chloride almost did not
react with organozinc compounds at 20°C, whereas on
heating to 60 or 100°C the yield of I did not exceed
5%. The process can be accelerated by addition of cop-
per(I) salts (CuCl, CuI); in this case, the yield of I
attains ~80%. Presumably, the catalytic effect of Cu(I)
salts originates from their reaction with C6F5ZnX to
The formation of organozinc compounds from
perfluoroarenes involved C–F bonds in the latter and
required the presence of SnCl2 as catalyst. The trans-
formation of pentafluoroarenes XIII and XIV into the
corresponding organozinc compounds XVa/XVb and
XVIa/XVIb was almost complete even at room tem-
Scheme 2.
R
ZnX
Zn, DMF, SnCl2
F
F
R
XIII, XVII, XVIII
VIIa, VIIb, XVa, XVb
XXa, XXb
XIII, XV, R = CN; XVII, VII, R = CF3; XVIII, XX, R =
EtOCO; X = Cl (a), RC6F4 (b).
ZnX
Zn, DMF, SnCl2
F
F
N
N
XIV
XVIa, XVIb
Scheme 3.
X = Cl (a), 2,3,5,6-tetrafluoropyridin-4-yl (b).
ZnX
Cu
CuHlg, DMF
–ZnXHlg
F
F
ZnX
Zn, DMF, SnCl2
F
F
F
F
VIa, VIb
CH2
XIX
XXIa, XXIb
CH2=CHCH2Cl
–CuCl
F
X = Cl (a),
(b).
F
F
I
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ORGANOZINC REAGENTS FROM POLYFLUOROARENES:
97
give organocopper intermediate which reacts with allyl
chloride to afford compound I (Scheme 3).
Cl, C6F5) and allyl chloride, though in a poor yield.
Presumably, ZnI2 acts as a Lewis acid which facilitates
nucleophilic replacement of the chlorine atom in allyl
chloride by pentafluorophenyl group. Also, replace-
ment of the chlorine atom in allyl chloride by iodine by
the action of ZnI2 cannot be ruled out. Allyl iodide is
known to be more reactive than allyl chloride in nu-
cleophilic replacement processes [16, 17].
It is known that copper(I) halides are capable of
reacting with organozinc compounds to form organo-
copper derivatives [15]. Taking into account that the
latter are sensitive to atmospheric oxygen, the reac-
tions of organozinc compounds in the presence of
CuCl and CuI were carried out under argon. Copper(I)
chloride was also used as catalyst to synthesize 1-allyl-
2,3,5,6-tetrafluoro-4-trifluoromethylbenzene (XXIV),
1-allyl-2,3,5,6-tetrafluoro-4-methylbenzene (XXV),
1-allyl-2,3,4,6-tetrafluoro-5-trifluoromethylbenzene
(XXVI), 4-allyl-2,3,5,6-tetrafluorobenzonitrile
(XXVII), and ethyl 4-allyl-2,3,5,6-tetrafluorobenzoate
(XXVIII) in good yields from allyl chloride and
organozinc compounds VIIa/VIIb, VIIIa/VIIIb,
XIa/XIb, XVa/XVb, and XXa/XXb. Despite different
ratios of organozinc reagents VIIa and VIIb obtained
from IV and XVII, they were smoothly converted into
allyl-substituted polyfluoroarene XXIV (Scheme 4).
The chemical shifts of fluorine nuclei in com-
pounds VIa, VIIa, XVa, and XVIa in DMF were con-
sistent with those reported for the same compounds in
DMF–CDCl3 [9]. Signals in the 19F NMR spectra of
VIII, XI, XX, and XXI were assigned taking into
account general relations holding in the spectra of
polyfluoroarylzinc compounds. In particular, fluorine
atoms in the ortho position to zinc are known to
resonate in a considerably weaker field, while the cou-
pling constant J(F2–F3) is known to increase to ~30 Hz
[9, 10, 18]. The assignment of signals to ArFZnCl (a)
and (ArF)2Zn (b) was facilitated by strong difference in
their concentrations, which depended on the amount of
chloride ions added as SnCl2 or ZnCl2 or liberated as
a result of reaction at the C–Cl bond of the poly-
fluorinated substrate.
Scheme 4.
CH2=CHCH2Cl
CuCl, DMF
CH2
ZnX
F
F
EXPERIMENTAL
R
R
VIa, VIb, VIIIa, VIIIb, XIa, XIb
XVa, XVb, XXa, XXb
XXIV–XXVIII
1
The H and 19F NMR spectra were recorded on
1
a Bruker WP-200SY spectrometer at 200 MHz for H
VII, XXIV, R = 4-CF3; VIII, XXV, R = 4-Me; XI, XXVI,
R = 5-CF3; XV, XXVII, R = 4-CN; XX, XXVIII, R =
6-EtOCO; X = Cl (a), RC6F4 (b).
and 188.3 MHz for 19F from reaction mixtures contain-
ing organozinc compounds in DMF or solutions in car-
bon tetrachloride; hexamethyldisiloxane (δ 0.04 ppm
relative to TMS) and C6F6 (δF –162.9 ppm relative to
CCl3F) were used as internal references. The IR spec-
tra were obtained on a Hewlett–Packard Vector-22
instrument. The molecular weights and elemental com-
positions were determined from the high-resolution
mass spectra which were run on a Finnigan MAT 8200
mass spectrometer (electron impact, 70 eV). Gas chro-
matographic–mass spectrometric analysis was per-
formed on a Hewlett–Packard G1081A system consist-
ing of an HP 5890 Series II gas chromatograph and
an HP 5971 mass-selective detector (electron impact,
70 eV; 30-m×0.25-mm HP-5MS capillary column, 5%
of diphenyl- and 95% of dimethylpolysiloxanes; car-
rier gas helium, flow rate 1 ml/min; injector tempera-
ture 280°C, ion source temperature 170°C; a.m.u.
range 30–650). Gas chromatographic analysis was per-
formed on a Hewlett–Packard HP 5980 instrument
equipped with a thermal conductivity detector and
a 30-m×0.52-mm HP-5 quartz capillary column; sta-
Likewise, from allyl chloride and organozinc deriv-
atives XVIa/XVIb and XXIa/XXIb we obtained 4-al-
lyl-2,3,5,6-tetrafluoropyridine (XXIX) and 5-allyl-
nonafluoroindan (XXX), respectively (Scheme 5).
Scheme 5.
ZnX
CH2=CHCH2Cl
CuCl, DMF
CH2
F
F
F
N
N
XVIa, XVIb
XXIX
CH2
CH2=CHCH2Cl
CuCl, DMF
ZnX
F
F
F
XXIa, XXIb
XXX
The use of ZnI2 instead of copper(I) halides also
ensured formation of compound I from C6F5ZnX (X =
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VINOGRADOV et al.
98
tionary phase dimethyldiphenylpolysiloxane, film
thickness 2.6 μm.
amide, 32.3 ml (420 mmol), and compound IV,
10.85 g (43 mmol), were added to 8.43 g (129 mmol)
of zinc dust, and the mixture was stirred for 4 h at
135°C. We isolated 44.84 g of a solution containing
93% of VIIa and VIIb and 7% of 1,2,4,5-tetrafluoro-
3-trifluoromethylbenzene (XXXIV). 19F NMR spec-
trum, δF, ppm: VIIa: 20.5 m (2F, 3-F, 5-F), 48.1 m
Zinc dust according to GOST 12601-76 was used.
Dimethylformamide was dried over solid potassium
hydroxide, distilled under reduced pressure, and stored
over calcium hydride. The starting compounds for the
preparation of organozinc reagents had a purity of
99.1% and higher (II–V, XIII, XIV, XVII), 98%
(XVIII, XIX), and 91% (X); compound X contained
6% of IV and 2% of 1-chloro-3,4,5,6-tetrafluoro-2-tri-
fluoromethylbenzene. Organozinc compounds were
prepared as described below; solutions were separated
from zinc by decanting, and the precipitate was
washed with DMF. The solutions were weighed, and
the concentration of organozinc reagents was calculat-
ed with a correction for their ratio determined on the
basis of the 19F NMR data. The 19F NMR chemical
shifts of XXIII [19], XII, IX [10], 2,3,5,6-tetrafluoro-
benzonitrile (XXXI) [20], 2,3,5,6-tetrafluoropyridine
(XXXII) [21], and 1,1,2,2,3,3,4,6,7-nonafluoroindan
(XXXIII) [22] in the NMR spectra of product mixtures
were consistent with those reported in the literature.
Signals from 19F nuclei in the spectra of allylpoly-
fluoroarenes were assigned on the basis of their fine
structure and calculations of the chemical shifts ac-
cording to the additivity scheme.
4
(2F, 2-F, 6-F), 107.6 t (3F, CF3, JFF = 20 Hz); VIIb:
20.5 m (2F, 3-F, 5-F), 47.7 m (2F, 2-F, 6-F), 107.7 t
4
(3F, CF3, JFF = 21.5 Hz); XXXIV: 26.2 m (2F, 3-F,
4
5-F), 21.4 m (2F, 2-F, 6-F), 107.2 t (3F, CF3, JFF
22 Hz); VIIa:VIIb = 3.4:1.
=
b. Dimethylformamide, 40 ml (520 mmol), and
compound XVII, 19.95 g (84.5 mmol), were added to
30.20 g (462 mmol) of zinc dust and 0.80 g (4.2 mmol)
of SnCl2, and the mixture was stirred for 8 h at 55–
60°C. We isolated 81.00 g of a solution containing
98% of VIIa and VIIb at a ratio of ~1:3.5 and 2% of
XXXIV.
2,3,5,6-Tetrafluoro-4-methylphenylzinc chloride
(VIIIa) and bis(2,3,5,6-tetrafluoro-4-methylphenyl)-
zinc (VIIIb). Dimethylformamide, 10.8 ml
(140 mmol), and compound V, 3.97 g (20 mmol), were
added to 3.92 g (60 mmol) of zinc dust, and the mix-
ture was stirred for 6 h on heating on a sand bath (bath
temperature 135°C). According to the 19F NMR data,
the mixture contained only the initial compound. The
mixture was then heated for 20 h at a bath temperature
of 175–185°C. We isolated 14.17 g of a solution con-
taining 61% of VIIIa and VIIIb, 27% of IX, and 12%
of V. 19F NMR spectrum, δF, ppm: VIIIa (major prod-
uct): 18.3 m (2F, 3-F, 5-F), 44.7 m (2F, 2-F, 6-F);
VIIIb: 18.0 m (2F, 3-F, 5-F), 44.4 m (2F, 2-F, 6-F).
Pentafluorophenylzinc bromide (XXIIa) and bis-
(pentafluorophenyl)zinc (VIb) were obtained from
39.22 g (600 mmol) of zinc dust and 49.39 g
(200 mmol) of compound II in 107.8 ml (1400 mmol)
of DMF at 100°C (2 h; cf. [23]); decantation gave
157.57 g of a solution containing 97% of XXIIa and
VIb and 3% of XXIII. 19F NMR spectrum, δF, ppm:
3
XXIIa: 0.4 m (2F, 3-F, 5-F), 4.6 t (1F, 4-F, JFF
=
2,3,4,6-Tetrafluoro-5-trifluoromethylphenylzinc
chloride (XIa) and bis(2,3,4,6-tetrafluoro-5-tri-
fluoromethylphenyl)zinc (XIb). Following the proce-
dure described above for the synthesis of VIIa/VIIb,
from 7.57 g (90 mmol) of zinc dust and 7.57 g
(30 mmol) of compound X in 16.2 ml (210 mmol) of
DMF we obtained 22.33 g of a solution containing
19 Hz), 46.7 m (2F, 2-H, 6-F); VIb: 0.2 m (2F, 3-F,
3
5-F), 3.8 t (1F, 4-F, JFF = 19 Hz), 46.7 m (2F, 2-F,
6-F); XXIIa:VIb = 1.9:1.
Pentafluorophenylzinc chloride (VIa) and bis-
(pentafluorophenyl)zinc (VIb) were obtained from
39.22 g (0.6 mol) of zinc dust and 40.5 g (0.2 mol) of
compound III [9] in 107.8 ml (1.4 mol) of DMF.
Decantation gave 162.39 g of a solution containing
96% of VIa and VIb and 4% of XXIII. 19F NMR
spectrum, δF, ppm: VIa: 0.5 m (2F, 3-F, 5-F), 4.7 t (1F,
19
67% of XIa and XIb and 15% of XII. F NMR spec-
trum: XIa, δF, ppm: –2.6 d.d.d (1F, 3-F), 24.6 q.d.d.d
(1F, 4-F), 60.2 d.d (1F, 2-F), 73.6 q.d.d (1F, 6-F),
107.5 m (3F, CF3); coupling constants JFF, Hz: 2-F–3-F
31.5, CF3–4-F 23.5, CF3–6-F 21.5, 3-F–4-F 19.0,
3-F–6-F 14.5, 2-F–4-F 9.0, 4-F–6-F 4.0; XIb, δF, ppm:
–2.9 d.d.d (1F, 3-F), 23.8 q.d.d.d (1F, 4-F), 59.7 d.d
(1F, 2-F), 73.1 q.d.d (1F, 6-F), ~107.5 m (3F, CF3);
coupling constants JFF, Hz: 2-F–3-F 32.5, CF3–4-F
23.5, CF3–6-F 21.5, 3-F–4-F 19.0, 3-F–6-F 14.5,
3
4-F, JFF = 19 Hz), 47.2 m (2F, 2-F, 6-F); VIb: 0.3 m
(2F, 3-F, 5-F), 3.9 t (1F, 4-F, 3JFF = 19 Hz), 46.9 m (2F,
2-F, 6-F); VIa:VIb = 4.3:1.
2,3,5,6-Tetrafluoro-4-trifluoromethylphenylzinc
chloride (VIIa) and bis(2,3,5,6-tetrafluoro-4-tri-
fluoromethylphenyl)zinc (VIIb). a. Dimethylform-
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ORGANOZINC REAGENTS FROM POLYFLUOROARENES:
99
4-F); J(6-F,7-F) = 31, J(4-F,7-F) = 23 Hz; XXIa:
XXIb = 1:1.2.
2-F–4-F 9.0, 4-F–6-F 4.0; XIa:XIb = 6.7:1. Apart
from compound XII, the solution also contained other
products which were not identified.
1-Allyl-2,3,4,5,6-pentafluorobenzene (I). a. Allyl
bromide, 1.74 g (14.4 mmol), was added to 11.30 g
(14.0 mmol; hereinafter, the amount of the organozinc
reagent per aromatic ring is given) of a solution con-
taining organozinc compounds XXIIa and VIb, and
the mixture was kept for 2 days at room temperature.
The mixture was treated with 10 ml of water and was
subjected to steam distillation. The organic layer was
separated and dried over MgSO4. We thus isolated
2.13 g of a mixture containing (according to the GLC
data), 60% of I (yield 44%), 28% of XXIII, and 10%
of allyl bromide.
4-Cyano-2,3,5,6-tetrafluorophenylzinc chloride
(XVa) and bis(4-cyano-2,3,5,6-tetrafluorophenyl)-
zinc (XVb). Dimethylformamide, 16.2 ml (210 mmol),
and nitrile XIII, 5.79 g (30 mmol), were added to
5.88 g (90 mmol) of zinc dust and 57 mg (3.0 mmol)
of SnCl2, and the mixture was stirred for 6 h at room
temperature. We isolated 21.80 g of a solution contain-
ing 98% of XVa and XVb and 2% of XXXI. 19F NMR
spectrum, δF, ppm: XVa: 27.6 m (2F, 3-F, 5-F), 48.9 m
(2F, 2-F, 6-F); XVb: 27.4 m (2F, 3-F, 5-F), 48.5 m (2F,
2-F, 6-F); XVa:XVb = 1:1.8.
b. Allyl bromide, 1.74 g (14.4 mmol), was added to
11.60 g of a solution containing 13.7 mmol of organo-
zinc compounds VIa and VIb, and the mixture was
kept for 2 days at room temperature. According to the
19F NMR data, it contained 63% of VIa and VIb, 32%
of I, and 5% of XXIII. The mixture was treated as
described above in a to isolate 2.59 g of a mixture con-
taining (GLC) 29% of I (yield 27%), 43% of XXIII,
20% of allyl bromide, and 5% of allyl chloride.
2,3,5,6-Tetrafluoropyridin-4-ylzinc chloride
(XVIa) and bis(2,3,5,6-tetrafluoropyridin-4-yl)zinc
(XVIb). Dimethylformamide, 8.1 ml (105 mmol), and
compound XIV, 2.54 g (15 mmol), were added to
2.94 g (45 mmol) of zinc dust and 28 mg (1.5 mmol)
of SnCl2, and the mixture was stirred for 12 h at room
temperature. We isolated 10.13 g of a solution contain-
ing 94% of XVIa and XVIb and 2% of XXXII.
19F NMR spectrum, δF, ppm: XVIa: 41.8 m (2F, 3-F,
5-F), 65.5 m (2F, 2-F, 6-F); XVIb: 41.4 m (2F, 3-F,
5-F), 65.1 m (2F, 2-F, 6-F); XVIa:XVIb = 1:1.8.
c. Allyl bromide, 25.41 g (210 mmol), was added to
66.88 g of a solution containing 79 mmol of organo-
zinc compounds VIa and VIb, and the mixture was
kept for 15 days at room temperature. According to the
19F NMR data, the mixture contained 3% of VIa and
VIb, 89% of I, and 8% of XXIII. The mixture was
diluted with 300 ml of water and extracted with carbon
tetrachloride (3×40 ml), and the extract was dried over
4-Ethoxycarbonyl-2,3,5,6-tetrafluorophenylzinc
chloride (XXa) and bis(4-ethoxycarbonyl-2,3,5,6-
tetrafluorophenyl)zinc (XXb). Dimethylformamide,
27 ml (350.9 mmol), and benzoate XVIII, 13.00 g
(54.1 mmol), were added to 17.68 g (270.5 mmol) of
zinc dust and 0.51 g (2.7 mmol) of SnCl2, and the
mixture was stirred for 8 h at 60–65°C. We obtained
44.21 g of a solution containing 98% of XXa and
XXb. 19F NMR spectrum, δF, ppm: XXa: 21.7 m (2F,
3-F, 5-F), 46.9 m (2F, 2-F, 6-F); XXb: 21.5 m (2F, 3-F,
5-F), 46.4 m (2F, 2-F, 6-F); XXa:XXb = 1:4.9.
1
MgSO4. According to the 19F and H NMR data, the
extract contained allyl chloride and compound I at
a ratio of 1:4. A fraction with bp 32–42°C, 0.51 g, was
distilled off; it contained (GLC) 68% of allyl chloride
which was also identified by GC–MS ([M]+ 76).
d. Allyl chloride, 1.10 g (14.4 mmol), was added to
11.60 g of a solution containing 13.7 mmol of organo-
zinc compounds VIa and VIb, and the mixture was
kept for 2 days at room temperature. According to the
19F NMR data, it contained 93% of initial compounds
VIa and VIb and 7% of XXIII. The mixture was
treated as described above in a to isolate 1.59 g of
a mixture containing (GLC) 0.3% of I (yield 0.2%),
74% of XXIII, and 22% of allyl chloride.
1,1,2,2,3,3,4,6,7-Nonafluoroindan-5-ylzinc
chloride (XXIa) and bis(1,1,2,2,3,3,4,6,7-nona-
fluoroindan-5-yl)zinc (XXIb). Dimethylformamide,
16.2 ml (210 mmol), and polyfluoroindan XIX, 8.94 g
(30 mmol), were added to 5.88 g (90 mmol) of zinc
dust and 0.57 g (3 mmol) of SnCl2, and the mixture
was stirred for 16 h at 60–65°C. We obtained 32.85 g
of a solution containing 98% of XXIa and XXIb and
2% of XXXIII. 19F NMR spectrum, δF, ppm: XXIa:
16.6 d.d.m (1F, 7-F), 34.6 m (2F, 2-F), 57.2 m and
57.6 m (2F, 1-F, 3-F), 63.4 d (1F, 6-F), 71.2 d (1F,
4-F); J(6-F,7-F) = 29.5, J(4-F,7-F) = 24 Hz; XXIb:
16.2 d.d.m (1F, 7-F), 34.6 m (2F, 2-F), 57.3 m and
57.7 m (2F, 1-F, 3-F), 62.9 d (1F, 6-F), 70.7 d (1F,
e. Likewise, the reaction at 60°C (20 h) gave 1.40 g
of a mixture containing (GLC) 4.1% of I (yield 2%); in
the reaction carried out at 100°C (4 h), the yield of I
was 5% (fraction 5.1% in the product mixture, accord-
ing to the GLC data).
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VINOGRADOV et al.
100
f. A mixture of 11.60 g of a solution containing
containing (GLC) 95% of XXIV (yield 83%). The
product was purified by vacuum distillation, bp 43–
44°C (3 mm). IR spectrum, ν, cm–1: 3098, 3019, 2990,
2939, 1662, 1642, 1496, 1323, 1218, 1187, 1155, 984.
UV spectrum, λmax, nm (logε): 203 (4.05), 274 (3.33).
13.7 mmol of organozinc compounds VIa and VIb,
1.10 g (14.4 mmol) of allyl chloride, and 47 mg
(1.4 mmol) of ZnI2 was heated for 20 h at 60°C. The
mixture was cooled to room temperature and treated as
described above in a. We isolated 2.0 g of a product
mixture containing (GLC) 42.4% of I (yield 30%),
44% of XXIII, and 6% of allyl chloride.
1H NMR spectrum, δ, ppm: 3.51 d.m (2H, CH2, 3JHH
=
6.3 Hz), 5.08–5.16 m (2H, =CH2), 5.84 m (1H, CH=).
19F NMR spectrum, δF, ppm: 19.5 m (2F, 2-F, 6-F),
20.9 m (2F, 3-F, 5-F), 105.3 t (3F, CF3, 3JFF = 21.5 Hz).
Mass spectrum, m/z (Irel, %): 259 (10), 258 (100) [M]+,
239(30) [M – F]+, 231(31) [M – C2H3]+, 189 (43)
[M – CF3]+. Found, %: C 46.51; H 1.84; F 51.66.
[M]+ 258.02794. C10H5F7. Calculated, %: C 46.53;
H 1.95; F 51.52. M 258.02794.
g. A mixture of 11.60 g of a solution containing
13.7 mmol of organozinc compounds VIa and VIb,
1.10 g (14.4 mmol) of allyl chloride, and 0.27 g
(1.4 mmol) of CuI was heated for 4 h at 60°C under
argon. The mixture was cooled and treated as de-
scribed above in a. We isolated 2.47 g of a product
mixture containing (GLC) 95% of I (yield 82%) and
3% of XXIII.
1-Allyl-2,3,5,6-tetrafluoro-4-methylbenzene
(XXV). The reaction was carried out using 10.72 g of
a solution containing 9.2 mmol of organozinc com-
pounds VIIIa and VIIIb, 1.10 g (14.4 mmol) of allyl
chloride, and 14 mg (0.14 mmol) of CuCl. We isolated
1.89 g of a product mixture containing (GLC) 63.4%
of XXV (yield 64%), 18% of IX, and 10% of V.
Compound XXV was purified by vacuum distillation,
bp 49–51°C (3 mm). UV spectrum, λmax, nm (logε):
h. Following the procedure described above in g but
using 27 mg (0.14 mmol) of CuI we obtained 2.43 g of
a product mixture containing (GLC) 93% of I (yield
79%) and 3% of XXIII.
i. A mixture of 11.60 g of a solution containing
13.7 mmol of organozinc compounds VIa and VIb,
1.10 g (14.4 mmol) of allyl chloride, and 14 mg
(0.14 mmol) of CuCl was heated for 4 h under argon at
a bath temperature of 60–65°C (oil bath). The mixture
was cooled and treated as described above in a. We
isolated 2.45 g of a product mixture containing (GLC)
92% of I (yield 79%) and 4% of XXIII. Compound I
was purified by vacuum distillation, bp 72–76°C
1
207 (4.00), 263 (2.94). H NMR spectrum, δ, ppm:
4
2.25 t (3H, CH3, JHF = 2.1 Hz), 3.41 d.m (2H, CH2,
3JHH = 6.3 Hz), 5.05 m (2H, =CH2), 5.84 m (1H, CH=).
19F NMR spectrum, δF, ppm: 15.8 m (2F, 2-F, 6-F),
17.3 m (2F, 3-F, 5-F). Mass spectrum, m/z (Irel, %): 205
(10), 204 (100) [M]+, 203 (15), 189 (41) [M – CH2]+,
185 (14) [M – F]+, 177 (59) [M – C2H3]+. Found:
[M]+ 204.05525. C10H8F4. Calculated: M 204.05621.
1
(30 mm); published data [2]: bp 148–150°C. H NMR
3
spectrum, δ, ppm: 3.42 d.m (2H, CH2, JHH = 6.3 Hz),
5.02–5.11 m (2H, =CH2), 5.83 m (1H, CH=). 19F NMR
spectrum, δF, ppm: –0.7 m (2F, 3-F, 5-F), 4.7 t (1F, 4-F,
3JFF = 20.5 Hz), 17.7 m (2F, 2-F, 6-F) (cf. [2]).
1-Allyl-2,3,4,6-tetrafluoro-5-trifluoromethyl-
benzene (XXVI). The reaction was carried out with
11.90 g of a solution containing 10.6 mmol of organo-
zinc compounds XIa and XIb, 1.10 g (14.4 mmol) of
allyl chloride, and 14 mg (0.14 mmol) of CuCl. We
isolated 2.18 g of a product mixture containing (GLC)
71.7% of XXVI (yield 66%) and 8% of XII. Com-
pound XXVI was purified by vacuum distillation,
bp 59–61°C (8 mm). IR spectrum, ν, cm–1: 3091, 2990,
2931, 1651, 1627, 1343, 1220, 1182, 1153, 979. UV
spectrum, λmax, nm (logε): 202 (3.75), 267 (2.82).
The other allyl-substituted polufluoroarenes were
synthesized according to similar procedures.
1-Allyl-2,3,5,6-tetrafluoro-4-trifluoromethylben-
zene (XXIV). a. The reaction was carried out using
15.73 g of a solution containing 14.0 mmol of organo-
zinc compounds VIIa and VIIb (prepared according to
method a), 1.15 g (15 mmol) of allyl chloride, and
15 mg (0.15 mmol) of CuCl. We isolated 3.52 g of
a product mixture containing (GLC) 88.3% of XXIV
(yield 86%).
1H NMR spectrum, δ, ppm: 3.43 d.m (2H, CH2, 3JHH
=
6.4 Hz), 5.04–5.13 m (2H, =CH2), 5.83 m (1H, CH=).
19F NMR spectrum, δF, ppm: –0.7 t.d (1F, 3-F),
26.3 q.d.d.d (1F, 4-F), 31.9 d.d.d (1F, 2-F), 42.2 m
(1F, 6-F), 105.4 t (3F, CF3); J(CF3, 4-F) = 23.0,
J(CF3,6-F) = 22.5, J(2-F,3-F) = 21.5, J(3-F,4-F) =
20.5, J(3-F,6-F) = 11.5, J(2-F,4-F) = 9.5, J(2-F,6-F) =
6.0, J(4-F,6-F) = 4.0 Hz. Mass spectrum, m/z (Irel, %):
b. The reaction was carried out using 14.42 g of
a solution containing 14.7 mmol of organozinc com-
pounds VIIa and VIIb (prepared according to method
b), 1.15 g (15 mmol) of allyl chloride, and 15 mg
(0.15 mmol) of CuCl to isolate 3.33 g of a product
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 1 2008

ORGANOZINC REAGENTS FROM POLYFLUOROARENES:
101
259 (10), 258.00 (100) [M]+, 257 (12), 239 (31) [M –
F]+, 237 (8), 231 (69) [M – C2H3]+. Found, %: C 47.27;
H 2.09; F 52.05. [M]+ 238.03015. C10H5F7. Calculated,
%: C 46.53; H 1.95; F 51.52. M 258.02794.
1647, 1595, 1471, 1253, 971. UV spectrum, λmax, nm
1
(logε): 202 (3.73), 265 (3.56), 541 (1.98). H NMR
3
spectrum, δ, ppm: 3.54 d.m (2H, CH2, JHH = 6.3 Hz),
5.12–5.20 m (2H, =CH2), 5.85 m (1H, CH=). 19F NMR
spectrum, δF, ppm: 15.9 m (2F, 3-F, 5-F), 70.9 m (2F,
2-F, 6-F). Mass spectrum, m/z (Irel, %): 192 (9), 191
(100) [M]+, 190 (20) [M – H]+, 172 (50) [M – F]+, 171
(17), 170 (30), 164 (22) [M – C2H3]+. Found, %:
C 51.22; H 2.32; F 39.89; N 7.11. [M]+ 191.03559.
C8H5F4N. Calculated, %: C 50.27; H 2.64; F 39.76;
N 7.33. M 191.03581.
4-Allyl-2,3,5,6-tetrafluorobenzonitrile (XXVII).
The reaction was carried out using 21.80 g of a solu-
tion containing 29.2 mmol of organozinc compounds
XVa and XVb, 2.29 g (30 mmol) of allyl chloride, and
30 mg (0.3 mmol) of CuCl. We isolated 5 g of a prod-
uct containing (GLC) 92.8% of XXVII (yield 74%),
which was purified by vacuum distilation, bp 60–61°C
(3 mm). IR spectrum, ν, cm–1: 3088, 3019, 2987, 2931,
2247, 1656, 1641, 1494, 1313, 1299, 983. UV spec-
trum, λmax, nm (logε): 202 (4.21), 230 (4.32), 236
(4.30), 288 (3.49). 1H NMR spectrum, δ, ppm: 3.54 d.m
5-Allyl-1,1,2,2,3,3,4,6,7-nonafluoroindan (XXX)
was synthesized using 15.56 g of a solution containing
13.8 mmol of organozinc compounds XXIa and XXIb,
1.72 g (22.5 mmol) of allyl chloride, and 22 mg
(0.22 mmol) of CuCl. We isolated 3.60 g of a product
mixture containing (GLC) 87% of XXX (yield 71%)
and 4% of XXXIII. Compound XXX was purified by
vacuum distillation, bp 82–83°C (2 mm). IR spectrum,
ν, cm–1: 3091, 2990, 1643, 1501, 1392, 1330, 1256,
1158, 953. UV spectrum, λmax, nm (logε): 203 (4.12),
3
(2H, CH2, JHH = 6.4 Hz), 5.08–5.18 m (2H, =CH2),
5.85 m (1H, CH=). 19F NMR spectrum, δF, ppm:
20.9 m (2F, 3-F, 5-F), 28.4 m (2F, 2-F, 6-F). Mass spec-
trum, m/z (Irel, %): 216 (10), 215 (100) [M]+, 214 (14),
196 (24) [M – F]+, 194 (29), 188 (53) [M – C2H3]+.
Found: [M]+ 262.06097. C10H5F4N. Calculated:
M 262.06168.
1
273 (3.21). H NMR spectrum, δ, ppm: 3.55 d.m (2H,
CH2, 3JHH = 6.4 Hz), 5.15–5.20 m (2H, =CH2), 5.85 m
(1H, CH=). 19F NMR spectrum, δF, ppm: 20.1 t.t (1F,
7-F), 31.6 quint (2F, 2-F), 35.8 d.d (1F, 6-F), 42.3 d.q
(1F, 4-F), 54.3 m and 54.7 m (2F, 1-F, 3-F); J(6-F,7-F) =
21.0, J(4-F,7-F) = 20.5, J(4-F,6-F) = 8.5, J(3-F,4-F) =
8.0, J(1-F,7-F) = 7.0, J(2-F,1-F) = J(2-F,3-F) = 4.5 Hz.
Mass spectrum, m/z (Irel, %): 321 (17), 320 (100) [M]+,
319 (11), 301 (25) [M – F]+, 293 (43) [M – C2H3]+.
Found, %: C 45.11; H 1.67; F 53.48. [M]+ 320.02436.
C12H5F9. Calculated, %: C 45.02; H 1.57; F 53.41.
M 320.02474.
Ethyl 4-allyl-2,3,5,6-tetrafluorobenzoate
(XXVIII) was synthesized using 12.50 g of a solution
containing 14.7 mmol of organozinc reagents XXa and
XXb, 1.15 g (15 mmol) of allyl chloride, and 15 mg
(0.15 mmol) of CuCl. We isolated 3.54 g of a product
containing (GLC) 94% of XXVIII (yield 87%), which
was purified by vacuum distillation, bp 119–120°C
(6 mm). IR spectrum, ν, cm–1: 3088, 2986, 2939, 2910,
2881, 1742, 1656, 1641, 1486, 1316, 1217, 983. UV
spectrum, λmax, nm (logε): 205 (4.06), 224 (4.01), 275
1
(3.23). H NMR spectrum, δ, ppm: 1.39 t (3H, CH3,
3
3JHH = 7.1 Hz), 3.47 d.m (2H, CH2, JHH = 6.4 Hz),
REFERENCES
4.38 q (2H, OCH2, 3JHH = 7.1 Hz), 5.10 m (2H, =CH2),
5.84 m (1H, CH=). 19F NMR spectrum, δF, ppm:
18.1 m (2F, 3-F, 5-F), 21.4 m (2F, 2-F, 6-F). Mass spec-
trum, m/z (Irel, %): 263 (6), 262 (45) [M]+, 237 (27)
[M – C2H4]+, 218 (17), 217 (100) [M – C2H5O]+.
Found, %: C 55.76; H 3.91; F 29.35. [M]+ 262.06097.
C12H10F4O2. Calculated, %: C 54.97; H 3.84; F 28.98.
M 262.06168.
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 1 2008