Phenyl(fluoro)dichlorosilane: A new synthon for the preparation of compounds containing chiral silicon atom

Full text of DOI:10.1134/S0012500811080015

ISSN 0012ꢀ5008, Doklady Chemistry, 2011, Vol. 439, Part 2, pp. 219–222. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © S.V. Basenko, M.G. Voronkov, L.E. Zelenkov, A.I. Albanov, 2011, published in Doklady Akademii Nauk, 2011, Vol. 439, No. 4, pp. 485–488.
CHEMISTRY
Phenyl(fluoro)dichlorosilane:
A New Synthon for the Preparation
of Compounds Containing Chiral Silicon Atom
S. V. Basenko, Academician M. G. Voronkov, L. E. Zelenkov, and A. I. Albanov
Received March 15, 2011
DOI: 10.1134/S0012500811080015
Compounds containing asymmetric silicon atom
have long attracted the attention of researchers [1–4].
The known methods of synthesis of chiral silicon comꢀ
pounds containing simultaneously two different haloꢀ
gen atoms are based either on the treatment of hydroꢀ
carbylfluorosilanes with aluminum chloride [5] and
their analogs containing Si–H bonds with copper
chloride [6], or irradiation of reaction mixtures of
hexafluoroꢀ and pentafluorochlorobenzene [7] or 1,4ꢀ
dichlorotetrafluorobenzene [8] with trichloroꢀ and
methyldichlorosilanes by accelerated electrons.
We have found a simplest and convenient method
for the synthesis of compounds of such a type. It is
based on the displacement of one of the chlorine
atoms in phenyl(fluoro)dichlorosilane (I) by OR,
OC(O)R, OSiMe3, NHSiMe3, OSiMe2OSiMe3, and
other groups. All compounds resulting from this reacꢀ
tion were previously unknown.
The alcoholysis of synthon
I (molar ratio 1 : 1,
20
°
C) leads to the corresponding phenyl(alkoxy)fluoꢀ
rochlorosilane in 55–63% yield.
SiFCl2
+ ROH
I
FSiClOR
+ HCl
(R = Me, Et, tꢀBu, nꢀOct).
The reaction of compound
I
with trimethyl(acyꢀ 1 : 1, 20°C) for 2–3 h results in phenyl(acyloxy)fluoꢀ
loxy)silanes or carboxylic acid anhydrides (molar ratio rochlorosilanes in 27–59% yield.
F
F
O
Cl
Cl
+ R1Cl
Si
O C(O)R
+
R
Si
Cl
OR1
(R1 = –SiMe3, –C(O)R; R = H, CF3, CCl3, CH2Cl, CH2Br,
CH3, CMe3, C(Me)=CH2, CH=CH2Me, CH=CH2Ph, Ph).
Favorskii Institute of Chemistry, Siberian Branch,
Russian Academy of Sciences, ul. Favorskogo 1, Irkutsk, 664033 Russia
219

220
BASENKO et al.
When compound
I
reacts with hexamethyldisiꢀ nyl(trimethylsiloxy)fluorochlorosilane forms in
loxane (molar ratio 1 : 1, 20°C) for 14 h, pheꢀ 55–60% yield
SiFCl2
Cl
F
Si
OSiMe3
+ (Me3Si)2O
+ MeSiCl,
whereas the reaction with tetramethyldisiloxane under similar conditions leads to phenyl(dimethylsiloxy)fluoꢀ
rochlorosilane in 30% yield.
SiFCl2
+ (HMe2Si)2O
Cl
F
+ Me3SiCl.
Si
OSiMe2H
The reaction of compound
I
with octamethyltrisiꢀ nyl(pentamethyldisiloxanyl)fluorochlorosilane
in
loxane (molar ratio 1 : 1, 20
°
C) gives rise to pheꢀ 27% yield.
SiFCl2
+ (Me3SiO)2SiMe2
F
.
SiOSiMe2OSiMe3 + Me3SiCl
Cl
A simple mixing of compound
yldisilazane (molar ratio 1 : 1, 20
I
with hexamethꢀ tatively phenyl(trimethylsilylamino)fluorochlorosiꢀ
°
C) yields quantiꢀ lane.
SiFCl2
+ (Me3Si)2NH
Cl
F
+ Me3SiCl.
Si
NHSiMe3
The major product of hydrolysis of compound
1,3ꢀdiphenylꢀ1,3ꢀdifluoroꢀ1,3ꢀdichlorodisiloxane
(rather than the corresponding silanol) containing two
I
is
The obtained chiral compounds can be used for the
synthesis of new molecules containing asymmetric silꢀ
icon atom. For example, the reaction of phenyl(triꢀ
methylsiloxy)fluorochlorosilane with hexamethyldisiꢀ
chiral silicon atoms. The cohydrolysis of compound
I
with phenyldifluorochloroꢀ or phenyltrichlorosilane also
makes it possible to obtain corresponding asymmetric
1,3ꢀdiphenylꢀ1,1,3ꢀtrifluoroꢀ1ꢀchlorodisiloxane and
1,3ꢀdiphenylꢀ3ꢀfluoroꢀ1,1,3ꢀtrichlorodisiloxane.
lazane (molar ratio 1 : 1, 20 C) smoothly leads to preꢀ
°
viously unknown phenyl(trimethylsiloxy)(trimethylꢀ
silylamino)fluorosilane in 91% yield.
OSiMe3
F
OSiMe3
F
+ (Me3Si)2NH
+ Me3SiCl.
Si
Si
Cl
NHSiMe3
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2011

PHENYL(FLUORO)DICHLOROSILANE
221
It should be noted that the reaction of 1ꢀphenylꢀ1ꢀ methyldisiloxane does not lead to the above product
fluoroꢀ1ꢀchloroꢀ3,3,3ꢀtrimethyldisilazane with hexaꢀ under studied conditions.
NHSiMe3
F
NHSiMe3
F
+ (Me3Si)2O
×
Si
Si
+ Me3SiCl.
OSiMe3
Cl
The peculiarity of the all above reactions is that
they readily occur even at ambient temperature.
Ethoxy(phenyl)fluorochlorosilane PhSiFCl(OEt).
Ethanol (3.81 mL, 0.0653 mol) was added dropwise
with vigorous stirring into a cooled to 0–5 C flask
°
All phenyl(fluoro)chloroacyloxysilanes presented
in the table show 29Si chemical shifts in the range
38.0–39.8 ppm, 19F chemical shifts are from –128.39
to –130.09 ppm, and 29Si–19F spin–spin coupling
constants are within 296.0–304.0 Hz. The range of
variation of the spectral parameters is negligible, howꢀ
ever, it should be noted that the utmost positions of the
ranges are occupied by the compounds with directly
opposite electronic effects; i.e., electronꢀdonating
substituents in phenyl(fluoro)chloroacyloxysilanes
lead to the strengthening of weak intramolecular interꢀ
containing 10 mL (0.0653 mol) of PhSiFCl2. After the
addition was completed, dry argon was passed through
the mixture to remove HCl residues and the mixture
reached ambient temperature. Then, the mixture was
distilled in vacuum (12 mmHg) to give 8.41 g (63%) of
PhSiFCl(OEt), bp 82–85 C (12 mmHg) (the paramꢀ
°
eters of NMR spectra see in the table).
Parameters of 19F, 29Si NMR spectra of phenyl(fluoro)chloꢀ
roorganylsilanes
action (C=O
→
Si), thus increasing the shielding of
δSi,
ppm
δF,
ppm
JF–Si
Hz
,
Compound
PhSiFClOC(O)H
the silicon atom and decreasing the 29Si–19F spin–
spin coupling constants [9].
–39.3 –128.55 298.7
–39.8 –129.98 296.4
The substitution of acyl group by alkoxy in pheꢀ
nyl(fluoro)chlorosilanes leads to an upfield shift of 29Si
resonances by 1–3 ppm, while the substitution of
alkoxy by siloxy group results in an upfield shift by
10 ppm.
PhSiFClOC(O)CH3
PhSiFClOC(O)C(CH3)3
PhSiFClOC(O)Ph
–
–130.09
–
–38.2 –129.61 296.0
–39.2 –129.30 298.7
–39.3 –129.30 298.7
–38.4 –128.39 304.0
–38.0 –128.57 303.4
–38.9 –129.81 295.4
PhSiFClOC(O)CH2Cl
PhSiFClOC(O)CH2Br
PhSiFClOC(O)CCl3
PhSiFClOC(O)CF3
EXPERIMENTAL
Phenyl(fluoro)dichlorosilane PhSiFCl2 (I). Alumiꢀ
num chloride (1.2 g) was added to a mixture of 30 mL
(0.2251 mol) of PhSiF3 and 36.23 mL (0.2251 mol) of
PhSiCl3. The mixture was heated under reflux for 6 h.
Then the mixture was distilled at 100–120 mmHg to
remove the catalyst and fractionated in vacuum (100–
120 mmHg) using a 20ꢀcm column packed with
Rashig rings. The initially collected fraction (103–
PhSiFClOC(O)CCH3=CH2
(E
)ꢀPhSiFClOC(O)CH=CHCH3 –38.9 –129.83 294.9
(
E)ꢀPhSiFClOC(O)CH=CHPh –38.7 –129.75 294.5
PhSiFCl(OMe)
PhSiFCl(OEt)
PhSiFCl(OBu)ꢀ
PhSiFCl(OOct)
–41.4 –125.33 297.2
–43.4 –123.56 297.4
–43.5 –123.83 297.6
–43.5 –123.67 297.6
–50.5 –120.04 288.4
–26.1 –122.26 289.9
–51.3 –120.32 288.2
–50.1 –120.39 288.4
–48.6 –121.00 293.0
–48.6 –121.11 291.4
–48.5 –120.84 296.7
–51.6 –130.53 254.4
t
109 C at 120 mmHg) was distilled repeatedly to give
°
PhSiFCl(OSiMe3)
9.44 g (86%) (21.5% toward the initial reactants) of
PhSiFCl2 (96% purity according to GLC and 19F
NMR).
PhSiFCl(NHSiMe3)
PhSiFCl(OSiMe2OSiMe3)
PhSiFCl(OSiMe2H)
(PhSiFCl)2O *
PhSiFCl2: n2D5 1.4847, bp 164–166
19F NMR (
, ppm): –113.16.
29Si NMR (
, ppm): –18.8 (d, JSi–F = 326.5 Hz).
MS (m/z (I
rel, %)): [M]+• 194 (100), [M–Cl]+ 159
°
C (cf. [10]).
PhSiFClOSiF2Ph
δ
PhSiFClOSiCl2Ph
PhSiFOSiMe3(NHSiMe3)
δ
Note: Carbon tetrachloride is used as a solvent, concentration 20 vol %,
20 C. * For the second fluorine atom in the molecule,
121.03 ppm.
°
δ
F
=
(83), [M–F]+ 159 (4), [Ph]+ 77 (100).
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222
BASENKO et al.
Reactions with other alcohols were carried out in
REFERENCES
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°
C was distilled off, the residue was
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289.9 Hz), 6.9 (–SiMe3).
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DOKLADY CHEMISTRY Vol. 439
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2011