Synthesis of 1-organyl-1-(trimethylsiloxy)-2-(dimethylamino)ethenes and new hypervalent silicon compounds based thereon

Article abstract of DOI:10.1134/S107042801610002X

1-Organyl-1-(trimethylsiloxy)-2-(dimethylamino)ethenes were synthesized for the first time, and their reactions with trichloro(methyl)silane and trifluoro(phenyl)silane afforded silicon bis-chelates, methylbis-[2-(dimethylamino)-1-(organyl)ethenolato-N,O]

Full text of DOI:10.1134/S107042801610002X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2016, Vol. 52, No. 10, pp. 1385–1389. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © B.A. Gostevskii, A.I. Albanov, A.V. Vashchenko, V.I. Smirnov, 2016, published in Zhurnal Organicheskoi Khimii, 2016, Vol. 52,
No. 10, pp. 1397–1401.
Synthesis of 1-Organyl-1-(trimethylsiloxy)-
2-(dimethylamino)ethenes and New Hypervalent Silicon
Compounds Based Thereon
B. A. Gostevskii,* A. I. Albanov, A. V. Vashchenko, and V. I. Smirnov
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
*e-mail: gost_bgu@irioch.irk.ru
Received April 22, 2016
Abstract—1-Organyl-1-(trimethylsiloxy)-2-(dimethylamino)ethenes were synthesized for the first time, and
their reactions with trichloro(methyl)silane and trifluoro(phenyl)silane afforded silicon bis-chelates, methylbis-
[2-(dimethylamino)-1-(organyl)ethenolato-N,O]siliconium chlorides and bis[1-(dimethylamino)-3,3-dimethyl-
but-1-en-2-olato-N,O]fluoro(phenyl)silicon(IV), respectively.
DOI: 10.1134/S107042801610002X
As shown previously, N,N-dimethyl carbohydra-
zonic acid trimethylsilyl esters are convenient inter-
mediate products for the synthesis of hypervalent
silicon compounds [1–3] that are capable of under-
going various intramolecular transformations [4–7]. In
continuation of studies in this line, we have developed
a procedure for the synthesis of 1-organyl-1-(tri-
methylsiloxy)-2-(dimethylamino)ethenes and exam-
ined their reaction with polyhalosilanes with the goal
of obtaining hypervalent silicon compounds.
which showed in the 29Si NMR spectra a signal at
δSi –60 ppm typical of five-coordinate silicon [8].
According to the X-ray diffraction data for a single
crystal of 5 (Fig. 1), the silicon atom therein has
a slightly distorted trigonal–bipyramidal configuration
with trans arranged nitrogen atoms of the donor di-
methylamino groups and a Si–Cl distance of 10.705 Å
(cf. 2.019 Å for a covalent Si–Cl bond).
Replacement of the chlorine atom in 5 and 6 by
more silicophilic fluorine atom was expected to
hamper ionization and favor formation of neutral six-
coordinate silicon compounds. In order to verify this
assumption enamine 3 was subjected to transsilylation
Dimethylaminomethyl ketones 1 and 2 were
synthesized by reaction of the corresponding α-bromo
ketones with dimethylamine in diethyl ether. The
silylation of 1 and 2 with trimethylsilyl trifluoro-
methanesulfonate in the presence of triethylamine
smoothly afforded enamines 3 and 4 (Scheme 1). The
use of chloro- or bromo(trimethyl)silane for this
purpose was unsuccessful even under harsh conditions
(100°C, 20 h). By transsilylation [4] of 3 and 4 with
trichloro(methyl)silane we obtained silicon bis-
chelates, siliconium chlorides 5 and 6 (Scheme 2)
1
with trifluoro(phenyl)silane. H NMR monitoring
showed that this reaction was slower, and it required
more severe conditions. The reason is that the Si–F
bond has higher energy than Si–Cl; therefore, the
transsilylation stage is more difficult and is probably
reversible. Nevertheless, the reaction led to the forma-
tion of nonionic fluorosilicon bis-chelate 7 in 30%
yield (Scheme 3).
Scheme 1.
O
O
OSiMe3
NMe2
2Me2NH
Et3N–Me3SiOSO2CF3
Br
NMe2
–Me2NH·HBr
–Et3N·CF3SO3H
R
R
R
1, 2
3, 4
1, 3, R = t-Bu; 2, 4, R = Ph.
1385

GOSTEVSKII et al.
1386
Scheme 2.
R
R
O
O
OSiMe3
NMe2
CHCl3
2
+
MeSiCl3
Cl–
Si
Me
–2Me3SiCl
R
N
N
Me
Me
Me
Me
3, 4
5, 6
5, R = t-Bu; 6, R = Ph.
Scheme 3.
t-Bu
Bu-t
O
O
Si
Ph
OSiMe3
NMe2
CHCl3
+ PhSiF3
2
–2Me3SiF
t-Bu
N
N
F
Me
Me
Me
Me
3
7
29
spectrometers at 400.13, 100.61, 161.98, and
In the Si NMR spectrum of 7, the silicon nucleus
resonated at δSi –138.6 ppm, in keeping with its six-
coordinate state [9]. The structure of 7 was also con-
firmed by X-ray analysis (Fig. 2); the coordination
entity is a regular octahedron with trans arrangement
of the nitrogen atoms.
1
40.56 MHz, respectively. The H, 13C, and 29Si
chemical shifts were measured relative to tetramethyl-
15
silane, and the N chemical shifts, relative to nitro-
methane. The elemental analyses were obtained on
a Thermo Scientific Flash 2000 automated CHNS
analyzer; the silicon content was determined by the dry
combustion method.
We have found that the synthesis of 7 through
sodium enolate 8 derived from dimethylamino ketone
1 is more efficient since sodium fluoride formed in this
reaction is almost insoluble in most organic solvents.
Enolate 8 was synthesized by metalation of 1 with
sodium bis(trimethylsilyl)amide in THF, and it reacted
with trifluoro(phenyl)silane in THF at room tempera-
ture (20 h) to produce compound 7 in quantitative
yield (Scheme 4).
Dimethylaminomethyl ketones 1 and 2 (general
procedure). A 100-mL glass ampule was charged with
0.025 mol of the corresponding bromomethyl ketone
and 50 mL of anhydrous diethyl ether. The mixture
was degassed and frozen with liquid nitrogen,
0.050 mol of anhydrous dimethylamine was condensed
thereinto, and the ampule was sealed. The ampule was
allowed to warm up to room temperature with inter-
mittent shaking and kept for 24 h at room temperature.
The precipitate was filtered off, the filtrate was
evaporated under reduced pressure, and the residue
was purified by vacuum distillation.
Scheme 4.
O
2
+
2(Me3Si)2NNa
NMe2
t-Bu
1
1-(Dimethylamino)-3,3-dimethylbutan-2-one (1).
ONa
THF
PhSiF3
2
7
Yield 2.88 g (80%, 0.020 mol), colorless liquid, bp 72–
NMe2
–2HN(SiMe3)2
–2NaF
74°C (28 mm), nD20 = 1.4296. H NMR spectrum
1
t-Bu
8
(CDCl3), δ, ppm: 1.16 s (9H, t-Bu), 2.29 s (6H, NMe2),
3.33 s (2H, CH2). 13C NMR spectrum (CDCl3), δC,
ppm: 26.40 [C(CH3)3], 43.44 [C(CH3)3], 45.63
(NCH3), 63.28 (CH2), 152.86 (C=O). Found, %:
C 67.21; H 12.03; N 9.54. C8H17NO. Calculated, %:
C 67.09; H 11.96; N 9.78.
Thus, we have synthesized for the first time
1-organyl-1-(trimethylsiloxy)-2-(dimethylamino)-
ethenes and demonstrated the possibility of using them
as precursors to new hypervalent silicon compounds
which still attract persistent interest [10–12].
2-(Dimethylamino)-1-phenylethan-1-one (2).
Yield 5.31 g (90%, 0.023 mol), colorless liquid,
EXPERIMENTAL
bp 57°C (0.08 mm), nD20 = 1.5085. H NMR spectrum
1
The H, 13C, 29Si, and 15N NMR spectra were
recorded on Bruker DPX-400 and Bruker AV-400
(CDCl3), δ, ppm: 2.38 s (6H, NMe2), 3.76 s (2H, CH2),
7.43–7.47 m (2H, m-H), 7.54–7.58 m (1H, p-H), 7.98–
1
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 10 2016

SYNTHESIS OF 1-ORGANYL-1-(TRIMETHYLSILOXY)-2-(DIMETHYLAMINO)ETHENES
1387
Cl00
13
C9
8.00 m (2H, o-H). C NMR spectrum, δC, ppm: 45.88
(NCH3), 65.66 (CH2), 128.10 (Cm), 128.55 (Co),
133.18 (Cp), 135.99 (Ci), 196.86 (C=O). Found, %:
C 73.67; H 8.11; N 8.43. C10H13NO. Calculated, %:
C 73.59; H 8.03; N 8.58.
C17
C7
N1
C5
C8
C4
C15
C11
O-Trimethylsilyl derivatives 3 and 4 (general
procedure). Trimethylsilyl trifluoromethanesulfonate
was added dropwise with stirring in a stream of argon
to a solution of equimolar amounts of triethylamine
and amino ketone 1 or 2 in anhydrous diethyl ether.
The mixture was refluxed for 3 h, the solution was
separated by decanting and evaporated under reduced
pressure, and the residue was distilled in a vacuum.
C16
O0AA
C3
C6
Si1
O2
C1
C2
N2
C14
C12
C13
C10
N,N,3,3-Tetramethyl-2-[(trimethylsilyl)oxy]but-
1-en-1-amine (3) was synthesized from 2.25 g
(0.016 mol) of 1 and 3.73 g (0.017 mol) of
CF3SO3SiMe3 using 1.70 g (0.017 mol) of Et3N. Yield
3.00 g (91%, 0.015 mol), colorless liquid, bp 70–72°C
(15 mm), nD20 = 1.4314. 1H NMR spectrum (CDCl3), δ,
ppm: 0.18 s (9H, Me3Si), 1.00 s (9H, t-Bu), 2.24 s (6H,
NMe2), 4.78 s (1H, CH=). 13C NMR spectrum
(CDCl3), δC, ppm: 0.55 (SiMe3), 28.15 [C(CH3)3],
34.88 [C(CH3)3], 45.31 (NCH3), 119.24 (=CH), 152.59
(=CO). 29Si NMR spectrum (CDCl3): δSi 15.2 ppm.
15N NMR spectrum (CDCl3): δN –355.1 ppm. Found,
%: C 61.45; H 11.84; N 6.91; Si 13.25. C11H25NOSi.
Calculated, %: C 61.33; H 11.70; N 6.50; Si 13.04.
Fig. 1. Structure of the molecule of bis[1-(dimethylamino)-
3,3-dimethylbut-1-en-2-olato-N,O]methylsiliconium chloride
(5) according to the X-ray diffraction data. Hydrogen atoms
are not shown; non-hydrogen atoms are shown as thermal
vibration ellipsoids with a probability of 50%.
C1
C15
C20
C19
C0AA
C3
C21
C16
C14
O1
C1AA
C18
C12
C17
N,N-Dimethyl-2-phenyl-2-[(trimethylsilyl)oxy]-
ethen-1-amine (4) was synthesized from 1.40 g
(0.009 mol) of 2 and 2 g (0.009 mol) of CF3SO3SiMe3
using 0.91 g (0.009 mol) of Et3N. Yield 1.50 g (75%,
0.006 mol), colorless liquid, bp 65°C (0.08 mm), nD20 =
N1
C2
Si1
C13
N8
O0AA
F1
1
1.5089. H NMR spectrum (CDCl3), δ, ppm: 0.18 s
C22
(9H, SiMe3), 2.65 s (6H, NMe2), 5.72 s (1H, =CH),
7.08–7.11 m (1H, p-H), 7.20–7.24 m (2H, m-H), 7.36–
7.38 m (2H, o-H). 13C NMR spectrum (CDCl3), δC,
ppm: 0.53 (SiMe3), 43.66 (NCH3), 123.70 (Co), 124.71
(HC=), 125.64 (Cp), 127.98 (Cm), 134.58 (PhC=),
139. 16 (Ci). 29Si NMR spectrum (CDCl3):
δSi 19. 6 ppm. 15N NMR spectrum (CDCl3):
δN –342.4 ppm. Found, %: C 66.85; H 8.73; N 6.31;
Si 11.82. C13H21NOSi. Calculated, %: C 66.33; H 8.99;
N 5.95; Si 11.93.
C10
C9
C4
C5
C7
C6
Fig. 2. Structure of the molecule of bis[1-(dimethylamino)-
3,3-dimethylbut-1-en-2-olato-N,O]fluoro(phenyl)silicon(IV)
(7) according to the X-ray diffraction data. Hydrogen atoms
are not shown; non-hydrogen atoms are shown as thermal
vibration ellipsoids with a probability of 50%.
Compounds 5 and 6 (general procedure).
A Schlenk flask was evacuated, 5 mL of chloroform
and trichloro(methyl)silane were condensed thereinto
through a glass adapter equipped with a rubber tube,
and enamine 3 or 4 was then added in one portion from
a preliminarily evacuated ampule. The mixture was
stirred under the conditions indicated below, and the
product was isolated by evaporation under reduced
pressure, followed by recrystallization of the residue
from hexane. Compounds 5 and 6 were formed
quantitatively, but the preparative yields were fairly
low due to their very high solubility even in hexane.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 10 2016

GOSTEVSKII et al.
1388
3
2
Bis[1-(dimethylamino)-3,3-dimethylbut-1-en-
(Co, JCF = 7.3 Hz), 146.58 d (Ci, JCF = 48.3 Hz).
29Si NMR spectrum (CDCl3): δSi –138.6 ppm. 15N NMR
spectrum (CDCl3): δN –334.5 ppm. Found, %: C 64.79;
H 9.01; N 6.71; Si 6.69. C22H37FN2O2Si. Calculated,
%: C 64.66; H 9.13; N 6.86; Si 6.87.
2-olato-N,O]methylsiliconium chloride (5) was
synthesized from 1.87 g (8.68 mmol) of 3 and 0.65 g
(4.35 mmol) of MeSiCl3; the reaction mixture was
heated for 40 h at 90°C. Yield 0.79 g (50%,
1
2.19 mmol), white powder, mp 166–169°C. H NMR
Single crystals of 5 and 7 for X-ray analysis were
obtained by crystallization from diethyl ether and
hexane, respectively. The X-ray diffraction data were
acquired at 100.0 K on a Bruker D8 Venture
diffractometer equipped with a Photon 100 detector
(MoKα radiation, λ 0.71073 Å; ω–2θ scanning,
2 Θmax = 52.76°). The data were processed using
Bruker SAINT software. Absorption by the crystal was
taken into account by analysis of equivalent reflection
intensities. The structures were solved by the direct
method using SHELXS [13] and were refined by the
least-squares method using SHELXL [13].
spectrum (CDCl3), δ, ppm: 0.33 s (3H, MeSi), 1.21 s
(18H, t-Bu), 2.91 s and 2.94 s (12H, NMe2), 5.86 s
(2H, HC=). 13C NMR spectrum (CDCl3), δC, ppm:
–9.98 (H3CSi), 26.56 [(H3C)3C], 33.51 (CMe3), 46.43,
49.29 (NCH3), 114.34 (=CHN), 159.98 (OC=).
29Si NMR spectrum (CDCl3): δSi –61.1 ppm. 15N NMR
spectrum (CDCl3): δN –331.9 ppm. Found, %: C 56.31;
H 9.84; N 7.33; Si 7.84. C17H35ClN2O2Si. Calculated,
%: C 56.25; H 9.72; N 7.72; Si 7.74.
Bis[2-(dimethylamino)-1-(phenyl)ethenolato-
N,O]methylsiliconium chloride (6) was synthesized
from 0.97 g (4.12 mmol) of 4 and 0.28 g (1.88 mmol)
of MeSiCl3; the reaction mixture was stirred for 14 h at
25°C. Yield 0.24 g (31%, 0.59 mmol), white powder,
Compound 5. C17H34N2O2SiCl, M 363.01; mono-
clinic crystal system, space group Cc; unit cell param-
eters: a = 13.5869(5), b = 13.5818(5), c = 11.7494(4) Å;
β = 104.3070(10)°; V = 2099.14(13) Å3; Z = 4;
μ(MoKα) = 0.25 mm–1; dcalc = 1.149 g/cm3. Total of
22019 reflection intensities were measured, including
4078 independent reflections (Rint = 0.027) which were
used in the structure solution and refinement. Final
divergence factor R = 0.071. Interatomic distances:
Si–N1 2.017, Si–N2 1.992, Si–O2 1.670, Si–O0AA 1.673,
Si–C15 1.858 Å; bond angles: O0AASiN1 85.17,
1
mp 172–174°C. H NMR spectrum (CDCl3), δ, ppm:
0.50 s (3H, SiCH3), 3.18 s (12H, NMe2), 6.98 s (2H,
HC=), 7.41–7.43 m (6H, m-H, p-H), 7.62–7.64 m (4H,
o-H). 13C NMR spectrum (CDCl3), δC, ppm: –9.11
(SiCH3), 46.85 and 49.43 (NCH3), 116.23 (HC=),
124.87 and 128.87 (Co, Cm), 129.39 (Ci), 130.28 (Cp),
148.83 (PhC=). 29Si NMR spectrum (CDCl3):
δSi –60.6 ppm. Found, %: C 62.71; H 6.66; N 6.74;
Si 7.05. C21H27ClN2O2Si. Calculated, %: C 62.59;
H 6.75; N 6.95; Si 6.97.
O
0AASiN2 85.25, O2SiC15 109.98, O0AASiO2 137.99,
N1SiN2 156.20°. The complete set of X-ray diffraction
data for compound 5 was deposited to the Cambridge
Crystallographic Data Centre (CCDC entry
no. 1471762).
Bis[1-(dimethylamino)-3,3-dimethylbut-1-en-
2-olato-N,O]fluoro(phenyl)silicon(IV) (7). A Schlenk
flask was evacuated and charged with 1.29 g
(9.00 mmol) of 1, 1.65 g (9.00 mmol) of NaN(SiMe3)2,
and 10 mL of THF, and the mixture was stirred for 2 h
at 25°C. Volatile compounds were removed under
reduced pressure to leave 1.50 g of sodium salt 8 as
a yellowish powder. Tetrahydrofuran, 10 mL, and tri-
fluoro(phenyl)silane, 0.74 g (4.54 mmol), were con-
densed into the flask, and the mixture was stirred for
20 h at 25°C. The mixture was filtered and evaporated
under reduced pressure. The crude product, 1.86 g
(100%) was purified by recrystallization from hexane
where it is soluble very readily. Yield of 7 0.70 g
(37%, 1.71 mmol), colorless crystals, mp 81°C.
Compound 7. C22H37N2O2SiF, M 406.61; triclinic
crystal system, space group P-1; unit cell parameters:
a = 8.5268(9), b = 10.5515(11), c = 13.7342(9) Å; α =
77.703(4), β = 73.365(4), γ = 83.992(5)°; V =
1155.53(19) Å3; Z = 2; μ(MoKα) = 0.13 mm–1; dcalc
=
1.169 g/cm3. Total of 24946 reflection intensities were
measured, including 4431 independent reflections
(Rint = 0.022) which were used in the structure solution
and refinement. Final divergence factor R = 0.029.
Interatomic distances: Si–N8 2.068, Si–N1 2.046,
Si–O1 1.768, Si–O0AA 1.780, Si–F 1.664 Å; bond
angles: O1SiN1 86.36, O0AASiN1 86.48, O1SiN8 91.33,
1H NMR spectrum (CDCl3), δ, ppm: 1.08 s (18H,
4
O
0AASiN8 85.43, N1SiF 89.54, N8SiF 92.20, O1SiF
t-Bu), 2.33 s [12H, N(CH3)2], 4.68 s (2H, HC=, JHF
=
174.38, O0AASiF 88.18°. The complete set of X-ray
diffraction data for compound 7 was deposited to the
Cambridge Crystallographic Data Centre (CCDC entry
no. 1473286).
1.8 Hz), 7.17–7.22 m (3H, m-H, p-H), 7.83–7.86 m
(2H, o-H). 13C NMR spectrum (CDCl3), δC, ppm:
27.85 [(H3C)3C], 33.82 [C(CH3)3], 50.14 [N(CH3)2],
109.50 (=CHN), 126.68 (Cm), 126.91 (Cp), 137.88 d
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 10 2016

SYNTHESIS OF 1-ORGANYL-1-(TRIMETHYLSILOXY)-2-(DIMETHYLAMINO)ETHENES
1389
7. Chernyshev, K.A., Gostevskii, B.A., Albanov, A.I., and
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Siberian Branch, Russian Academy of Sciences.
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Silbert, G., Stalke, D., Kocher, N., Kalikhman, I., and
Kost, D., Chem. Commun., 2004, p. 1644.
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