Hydrosilylation of 3,3,4,4-tetrafluorohexa-1,5-diene and 4-bromo-3,3,4,4-tetrafluorobut-1-ene

Full text of DOI:10.1134/S1070363210060307

ISSN 1070-3632, Russian Journal of General Chemistry, 2010, Vol. 80, No. 6, pp. 1210–1212. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © A.N. Reznikov, L.M. Kogan, N.K. Skvortsov, 2010, published in Zhurnal Obshchei Khimii, 2010, Vol. 80, No. 6, pp. 1042–1044.
LETTERS
TO THE EDITOR
Hydrosilylation of 3,3,4,4-Tetrafluorohexa-1,5-diene
and 4-Bromo-3,3,4,4-tetrafluorobut-1-ene
A. N. Reznikova, L. M. Koganb, and N. K. Skvortsovc
a Samara State Technical University,ul. Molodogvardeiskaya 244, Samara, 443100 Russia
b ZAO “Anles,” St. Petersburg, Russia
c St. Petersburg State Institute of Technology, St. Petersburg, Russia
Received December 3, 2009
DOI: 10.1134/S1070363210060307
Fluoroalkylchlorosilanes are of interest as starting
material for the synthesis of polymeric materials with
some unique properties. The most promising method
for the synthesis of these compounds is organofluorine
hydrosilylation of unsaturated derivatives. However,
the literature on studies of such reactions is rather
limited. Common Spayer or Karsted catalysts are
mentioned in most papers [1–3]. An exception is the
work [4], where Ojima et al. describe in detail the hydro-
silylation of 3,3,3-trifluoropropene and pentafluoro-
styrene catalysed by palladium, rhodium, and ruthe-
nium complexes. When using Rh and Ru catalysts,the
reaction proceeds non-selectively that excludes their
practical application. Addition of chloroosilanes to
fluoroalkenes in the presence of catalysts based on Pt
complexes proceeds with high regioselectivity in
accordance with Farmer rule. The hydrosilylation of
3,3,3-trifluoropropene with methyldichlorosilane forms
the basis for the synthesis of the known SKTFt rubber
of high oil and fuel resistance. The interaction of
3,3,4,4,4-pentafluorobut-1-ene with methyldichloro-
silane was catalysed by Pt complex described in [5].
presence of cis-bis(dibenzyl sulfide)dichloroplatinum(II)
with the formation of 1,6-bis(dimethylchlorosilyl)-3,3,4,4-
tetrafluorohexane III. The hydrosilylation of com-
pound I in this case proceeds in accordance with
Farmer rule.
F
F
+ 2 Me2SiHCl
F
F
I
II
F
F
Cl
Si
Si
Cl
F
F
III
Under controlled hydrolysis bis-chlorosilane III
undergoes intermolecular cyclization to form siloxane
bonds:
F
F
Cl
Si
Si
Cl
F
F
Recently, we reported on the hydrosilylation of 1-
vinyl-2,2,3-trifluoro-3-trifluoromethylcyclobutane with
methyldichlorosilane [6].
III
Si
Si
Si
O
Polyfunctional organofluorosilicon compounds are
promising starting materials in the synthesis of block
copolymers, as well as self cross-linking polysil-
oxanes. For the synthesis of these compounds, we used
3,3,4,4-tetrafluorohexa-1,5-diene and 4-bromo-3,3,4,4-
tetrafluorobut-1-ene.
F
F
F
F
+2H2O
_4HCl
F
F
F
F
O
Si
It has been established that 3,3,4,4-tetrafluorohexa-
1,5-diene I reacts with dimethylchlorosilane II in the
IV
1210

HYDROSILYLATION OF 3,3,4,4-TETRAFLUOROHEXA-1,5-DIENE
1211
The interaction of compound III with an excess of
diethylamine leads to the corresponding bis(diethyl-
amino) derivative V:
reaction mixture was stirred for 1 h, the solvent is
distilled off, and the residue was recrystallized from
petroleum ether. Yield: 0.62 g (32.6%), mp 114°С. H
1
NMR spectrum, δ, ppm: 0.11 s (24Н, СН3Si), 0.73 m
(8H, CH2Si), 1.97 m (8H, CH2CF2). 13C NMR spec-
trum, δС, ppm: –0.36, –0.10 s (CH3Si), 7.50 s (CH2Si),
22.81–25.36 m (CH2CF2). MS CI, m/z (Irel): 79 (18),
99 (15), 103 (5), 151 (100), 155 (28), 578 (25) [M +
H]. EI, m/z (Irel): 59 (10), 73 (8), 77 (20), 79 (35), 99
(5), 103 (12), 118 (5), 151 (100), 155 (15).
F
F
Cl
Si
+ 4Et2NH
Si
Cl
F
F
III
F
F
NEt2
Si
Si
_2Et2NH·HCl
Et2N
1,6-Bis[dimethyl(diethylamino)silyl]-3,3,4,4-tetra-
fluorohexane (V). To a solution of 2.45 g of com-
pound III in 50 ml of diethyl ether a solution of 2.40 g
of diethylamine in 25 ml of ether was added with
stirring at 0°С. The reaction mixture was stirred for 3
h, the precipitated diethylamine hydrochloride was
filtered off. The filtrate was evaporated and the residue
was evacuated at 1 mm Hg for 3 h. Yield: 2.41 g
F
F
V
Hydrosilylation of 4-bromo-3,3,4,4-tetrafluoro-
butene VI with methyldichlorosilane VII proceeds
regioselectively in accordance with Farmer rule and
leads to compound VIII:
1
F
F
Cl
(81.0%). H NMR spectrum, δ, ppm: 0.05 s (12Н,
F
F
СН3Si), 0.70 m. (4H, CH3Si, 4JHF 9.0 Hz), 0.96 t (12Н,
Br
Si
+ Me2SiHCl2
3
СН3, JHH 7.0 Hz) 1.94 m (4H, CH2CF2), 2.77 (4Н,
Br
Cl
F
F
СН2, JHH 6.9 Hz). 13C NMR spectrum, δС, ppm: 6.37 s,
7.79 s, 12.72 s, 15.75 s (CH3), 24.14 m., 39.78 s
(CH2N), 42.85 s, 119.26 t, 124.36 t (CF2).
F
F
VIII
VII
VI
3,3,4,4-tetrafluorohexa-1,5-diene was obtained ac-
cording to [7] by thermolysis of 2,5-diacetoxy-3,3,4,4-
tetrafluorohexane in a nitrogen atmosphere at 460–
480°С, 4-bromo-3,3,4,4-tetrafluorobut-1-ene was ob-
tained by the procedure [8] by dehydrobromination of
1,4-dibromo-1,1,2,2-tetrafluorobutane.
(4-Bromo-3,3,4,4-tetrafluorobutyl)methyldichloro-
silane (VIII). 9.0 g of the compound VI was added
dropwise with stirring to 0.04 g of cis-bis(dibenzyl-
sulfide)dichloroplatinum(II) and 15.0 g of methyldi-
chlorosilane VII placed in a flask equipped with a
reflux condenser. The mixture was boiled for 5 h. The
product was isolated by vacuum distillation. Yield:
1,6-Bis(dimethylchlorosilyl)-3,3,4,4-tetrafluoro-
hexane (III). 2.96 g of diene II was added dropwise
with stirring to 0.04 g of cis-bis(dibenzyl sulfide)
dichloroplatinum(II) and 6.65 g of dimethylchloro-
silane placed in a flask, and the mixture was refluxed
for 2 h. The product was isolated by vacuum distilla-
tion. Yield: 4.71 g (71.5%). mp 37°С, bp 110°С
1
9.69 g (69.2%), bp 78°С (20 mm Hg). H NMR
spectrum, δ, ppm: 0.86 s. (3H, CH3), 1.38 m (2H,
CH2Si, 3JHH 8.4 Hz, 4JHF 4.3 Hz), 2.28 m (2H, CH2CF2,
3
3JHH 8.4 Hz, JHF 18.0 Hz). 13C NMR spectrum, δС,
ppm: 4.59 s (CH3), 11.92 s (CH2Si), 23.97 t (CH2CF2,
2JCF 23.8 Hz), 117.16 m, (CF2, 1JСF 311 Hz, 2JСF 31.4 Hz),
123.3 m (CF2Br, 1JСF 311 Hz, 2JСF 31.4 Hz).
1
(1 mm Hg). H NMR spectrum, δ, ppm: 0.46 s (12Н,
СН3Si), 1.04 m (4H, CH2Si), 2.09 m (4H, CH2CF2).
13C NMR spectrum, δС, ppm: –1.46 s (CH3Si), 6.24 s
(CH2Si), 21.32 m (CH2CF2). RT 12.89. MS CI, m/z
(Irel): 328 [M – CH3] 205 (5), 151 (5), 121 (40), 99
(75), 93 (100), 79 (72). EI, m/z (Irel): 39 (10), 54 (15),
59 (32), 65 (17), 77 (45), 90 (25), 93 (100), 95 (32),
103 (30), 121 (5).
NMR spectra were recorded on a Bruker AC200
[200.13 MHz (1H), 50.32 MHz (13С)] instrument in
CDCl3, using residual signal of deuterated solvent as
reference.
GC–MS analysis of reaction mixtures and isolated
products was performed on a Finnigan Trace DCQ
instrument using capillary column BPX-5 30×0.32
from SGE. Conditions of electron ionization: 70 eV,
ion source temperature 200°С. Conditions of chemical
ionization: 120 eV, ion source temperature 200°С, gas-
reactant isobutane (flow rate 0.4 ml min–1).
2,2,9,9,11,11,18,18-Octamethyl-5,5,6,6,14,14,15,15-
oktafluoro-1,10-dioxa-2,9,11,18-tetra-silacyclo-
octadecane (IV). A solution of 0.12 g of water in
25 ml of ether was added with stirring to 2.26 g of
compound III in 50 ml of diethyl ether at 0°С. The
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 6 2010

1212
REZNIKOV et al.
Chem., 1984, vol. 260, no. 3, p. 335.
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