N,N-Bis[ethoxy(methyl)silylmethyl]methylamines MeN[CH2SiMem(OEt)3-m]2 (m = 0 - 2). Synthesis and reactions with phenol

Article abstract of DOI:10.1023/A:1012387018984

Previously unknown N,N-bis[ethoxy(methyl)silylmethyl]amines MeN[CH₂SiMe_m(OEt)_3-m]2 (m = 0-2) were synthesized. According to UV spectral data, only MeN[CH₂SiMe₂(OEt)]₂ form hydrogen bond with phenol in a heptane solution. The amines with m = 0 and 1 fail to forms hydrogen bond with phenol [under the same conditions, N-(triethoxysilylmethyl)dimethylamine Me₂NCH₂Si(OEt)₃ forms a strong hydrogen bond with phenol]. All the amines (m = 0 - 2) enter transetherification with phenol to give compounds of the general formula MeN[CH₂SiMe_m(OPh)_n(OEt)_3-m-n]₂ (m = 0 - 2, n = 1 - 3). Refluxing of N,N-bis[ethoxy(methyl) silylmethyl]amines with excess phenol results in cleavage of the Si-C bond by phenol, providing phenoxysilanes Me_mSi(OPh)_4-m (m = 0 - 2) and trimethylamine.

Full text of DOI:10.1023/A:1012387018984

Russian Journal of General Chemistry, Vol. 71, No. 2, 2001, pp. 201 205. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 2, 2001,
pp. 226 231.
Original Russian Text Copyright
2001 by Lazareva, Brodskaya.
N,N-Bis[ethoxy(methyl)silylmethyl]methylamines
MeN[CH2SiMem(OEt)3 m]2 (m = 0 2).
Synthesis and Reactions with Phenol
N. F. Lazareva and E. I. Brodskaya
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received August 18, 1999
Abstract Previously unknown N,N-bis[ethoxy(methyl)silylmethyl]amines MeN[CH2SiMem(OEt)3 m]2 (m =
0 2) were synthesized. According to UV spectral data, only MeN[CH2SiMe2(OEt)]2 form hydrogen bond with
phenol in a heptane solution. The amines with m = 0 and 1 fail to forms hydrogen bond with phenol [under the
same conditions, N-(triethoxysilylmethyl)dimethylamine Me2NCH2Si(OEt)3 forms a strong hydrogen bond
with phenol]. All the amines (m = 0 2) enter transetherification with phenol to give compounds of the general
formula MeN[CH2SiMem(OPh)n(OEt)3
] (m = 0 2, n = 1 3). Refluxing of N,N-bis[ethoxy(methyl)
m
n 2
silylmethyl]amines with excess phenol results in cleavage of the Si C bond by phenol, providing phenoxy-
silanes MemSi(OPh)4 (m = 0 2) and trimethylamine.
m
The electron-donor ability of the piperidine nitro-
gen atom in organosilicone amines (CH2)5*NCH2
To assess the effect of CH2SiMem(OEt)3 groups
on nitrogen basicity, we synthesized previomusly un-
SiMen(OEt)3 (n = 2, 3) is reduced by n, inter-
known
N,N-bis[ethoxy(methyl)silylmethyl]methyl-
n
action in the N CH2 Si fragment [1, 2]. However, in
amines MeN[CH2MemSi(OEt)3 m]2 by scheme (1):
the RmN(CH2SiMe3)3
series, no such effect with
m
increasing number of CH2SiMe3 groups at the nitro-
gen atom was observed: The ionization potential of
the lone electron pair of the nitrogen atom (7.93, 7.82,
and 7.66 at m = 2, 1, and 0, respectively [3]) decrease
as the electron-donor ability of the latter increases
with the increasing number of donor substituents.
Compounds containing several CH2SiMem(OAlk)3
groups at the nitrogen atom have not been studiemd
from this viewpoint.
ClCH2SiMem(OEt)3
+ MeNH2
m
MeN[CH2SiMem(OEt)3
]
+ MeNH2 HCl, (1)
m 2
m = 0 (I), 1 (II), 2 (III).
The physicochemical characteristics of these com-
pounds are listed in Table 1. Their structure was
1
proved by H NMR and IR spectral data (Tables 2
and 3).
Table 1. Physicochemical characteristics of amines MeN[CH2SiMem(OEt)3 m]2 (m = 0 2) and their reaction products
with phenol MeN[CH2SiMem(OPh)n(OEt)3
] (m = 0 2, n = 1 3)
m
n 2
Found, %
Calculated, %
Comp.
no.
Yield,
%
bp,
(p, mm)
C
m
n
n2D0
Formula
C
H
N
Si
C
H
N
Si
I
II
0
1
2
0
0
0
1
2
0
0
0
1
2
3
2
1
55
43
52
40
35
38
41
35
124 125 (1) 1.4174 46.65 9.63 3.69 13.75 C15H37NO6Si2 46.96 9.72 3.65 14.64
105 106 (1) 1.4098 48.01 9.98 4.35 16.92 C13H33NO4Si2 48.25 10.28 4.32 17.36
III
IV
V
VI
VII
VIII
220 224
1.4054 50.28 11.65 4.98 20.98 C11H29NO2Si2 50.13 11.09 5.32 21.32
200 202 (1) 1.4998 57.78 7.98 3.13 11.70 C23H37NO6Si2 57.58 7.77 2.92 11.71
240 242 (1) 1.5225 64.92 6.91 2.75 9.58 C31H37NO6Si2 64.66 6.47 2.43 9.76
295 297 (1) 1.5638 70.15 5.98 2.05 8.38 C39H37NO6Si2 69.72 5.55 2.08 8.36
238 240 (1) 1.5448 67.81 6.93 2.61 11.12 C29H33NO4Si2 67.53 6.45 2.72 10.89
180 183 (2) 1.5145 63.93 8.58 4.01 15.95 C19H29NO2Si2 63.46 8.13 3.89 15.62
1070-3632/01/7102-0201$25.00 2001 MAIK Nauka/Interperiodica

202
LAZAREVA, BRODSKAYA
1
Table 2. Group frequencies (cm ) in the IR spectra of amines MeN[CH2SiMem(OPh)n(OEt)3
compounds MemSi(OPh)n (IX XI)
n]2 (I VIII) and model
m
Comp.
no.
m
n
CH3N
SiOCAlk
SiOCPh
C6H5
CH2Si; CH3Si
I
II
0
1
2
0
0
0
1
2
1
2
3
0
0
0
1
2
3
2
1
3
2
1
2745, 2755 815, 955, 1070, 1100
2745, 2760 795, 955, 1070, 1100
2740, 2755 795, 955, 1070, 1100
750
750, 845, 1255
750, 845, 1250
III
IV
V
VI
VII
VIII
IX
X
2760
2760
2760
800, 950, 1080, 1100 950, 1240 690, 760, 1495, 1600, 3035, 3055 755
805, 950, 1080, 1100 950, 1240 690, 760, 1495, 1600, 3035, 3055 755
950, 1220 690, 760, 1500, 1600, 3035, 3060 760
2740, 2755
2760
915, 1250 695, 750, 1490, 1595, 3035, 3055 755, 800, 1270
925, 1240 695, 750, 1490, 1600, 3035, 3055 750, 798, 1270
950, 1240 690, 755, 1490, 1595, 3040, 3055 800, 1280
925, 1240 690, 755, 1490, 1595, 3040, 3060 805, 1270
915, 1250 695, 755, 1490, 1595, 3035, 3055 755, 845, 1270
XI
Table 3. 1H NMR spectra ( , ppm) of amines MeN[CH2SiMem(OPh)n(OEt)3
MemSi(OPh)n (IX XI)a
n]2 (I VIII) and model compounds
m
Comp. no.
CH3N
NCH2Si
OCH2CH3
OC6H5
CH3Si
I
II
2.30 s
2.31 s
2.26 s
2.43 s
2.43 s
2.44 s
2.38 s
2.36 s
2.00 s
2.01 s
1.96 s
2.27 s
2.37 s
2.36 s
2.01 s
2.18 s
1.20 t, 3.83 q
1.20 t, 3.80 q
1.17 t, 3.68 q
1.25 t, 3.94 q
1.20 t, 3.90 q
0.18 s
0.14 s
III
IV
V
VI
VII
VIII
IX
X
7.04 m, 7.23 m
6.96 m, 7.21 m
6.94 m, 7.15 m
6.97 m, 7.13 m
6.98 m, 7.22 m
6.83 m, 7.19 m
6.98 m, 7.24 m
7.02 m, 7.16 m
0.39 s
0.38 s
0.25 s
0.37 s
0.48 s
XI
a
Solvent CDCl , internal standard TMS (for I and IV VI) and cyclohexane (for II, III, VII, and VIII).
3
Compounds I III react with phenol in a heptane
solution at room temperature. By vacuum distillation
we also isolated viscous yellowish specifically smell-
ing products IV VIII.
IV VIII, there are bands of stretching and bending
vibrations characteristic of a monosubstituted benzene
1
ring, as well as a strong broad band at 1240 cm
[ (CAr O)] [5].
1
The H NMR spectra of IV VIII compared with
MeN[CH2SiMem(OEt)3
]
+ nPhOH
m 2
those of parent I III show new signals at 6.8
7.2 ppm, characteristic of benzene ring protons
(Table 3). The signals of ethoxy groups are preserved
MeN[CH2SiMem(OPh)n(OEt)3
n]2 + nEtOH, (2)
m
m = 0, n = 1 (IV); m = 0, n = 2 (V); m = 0, n = 3 (VI);
m = 1, n = 2 (VII); m = 2, n = 1 (VIII).
1
only in the H NMR spectra of IV and V.
Compounds I III have a weak UV absorption
maximum below 210 nm, like trialkylamines [6]. The
Their physicochemical characteristics and elemen-
tal analyses are listed in Table 1. The IR spectra of
compounds IV VIII contain CH3N stretching absorp-
tion bands [4] (Table 2). The CAlk O Si absorption
bands [5] are present in the spectra of IV, V and
absent in the spectra of VI VIII. In the spectra of
UV spectra of IV VIII show two maxima at 260 280
*
and 211 nm, assignable to
benzene ring (Table 4). The
transitions in the
values in the
and
1
2
UV spectra of the isolated products only slightly
differ from those for model compounds MemSi
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 2 2001

N,N-BIS[ETHOXY(METHYL)SILYLMETHYL]METHYLAMINES
203
1
(OPh)4
(IX XI) (m = 1 3). The intensities of the
bands in the spectra of IV VIII grow
Table 4. UV spectra [ , nm ( , l mol 1 cm )] of amines
m
and
MeN[CH2SiMem(OPh)n(OEt)3 (IV VIII) and
]
1
2
m n 2
regularly with increasing number of phenoxy groups.
Thus, the IR, H NMR, and UV data give conclusive
model compounds MemSi(OPh)n (IX XI)
1
evidence showing that N,N-bis[ethoxy(methyl)silyl-
Comp.
( )
( )
2
1
1
2
methyl]methylamines
MeN[CH2SiMem(OEt)3
]
no.
IV
V
m 2
enter transetherification with phenol.
265 (1900), 268 (1900), 271 (2800), 211 (9300)
278 (2500)
265 (4500), 268 (4000), 271 (6000), 211 (20900)
278 (5100)
265 (7300), 268 (6700), 271 (9100), 211 (30500)
278 (8000)
We discovered the transetherification of I III with
phenol when studied their basicity by UV spectro-
scopy in a heptane solution. Compounds containing
heteroatoms with lone electron pairs (N, O, S, etc.)
enter with phenol hydrogen bonding which have been
fairly well studied by IR (in CCl4) and UV (in hydro-
carbon solvents) spectroscopy [7 11]. Earlier by the
latter method we determined the electron-donor ability
of the nitrogen atom in compounds like (CH2)5NCH2
VI
VII 265 (4350), 268 (4400), 271 (6400), 211 (24500)
278 (4650)
VIII 265 (2500), 268 (2600), 271 (3400), 211 (16300)
278 (3100)
SiMen(OEt)3 (n = 2, 3) [1, 2], which formed hydro-
gen bond with phenol but did not react with it. The
UV spectrum of a solution of phenol and excess com-
IX
X
XI
267 (1200), 271 (1590), 277 (1270) 211 (8400)
262 (1650), 268 (2250), 275 (1650) 211 (14800)
261 (2250), 267 (3050), 274 (2550) 211 (25300)
n
pound III (m = 2) in heptane shows a bathochromi-
*
cally shifted
band of phenol, implying hydro-
gen bonding with nitrogen (Fig. 1, spectrum 2). For
III this shift ( ) is larger than for Me2NCH2SiMe2
not react with phenol under the same conditions. This
fact suggsts that autocatalysis is not a single driving
force of the reaction in question. The unusual facility
of trasetherification of N,N-bis[ethoxy(methyl)silyl-
methyl]methylamines with phenol can be explained
1
(OEt) (540 and 450 cm , respectively). However,
*
already after 10 min the
bands of free and H-
bonded phenol get weaker. On mixing of phenol solu-
tions with excess compounds I, II no H-bonded com-
plex is observed at all: The long-wave band at 260
290 nm gets half that of the free phenol band and
shifts hypsochromically, after which it no longer
changes (Fig. 1, spectrum 3). It should be noted that
under the same conditions dimethyl(triethoxysilyl-
in terms of electronic effects of CH2SiMem(OEt)3
m
groups on the basicity of the nitrogen atom. The elec-
tron-donor ability of N-[ethoxy(methyl)silylmethyl]-
dimethylamines Me2NCH2SiMem(OEt)3
in solu-
m
tions is determined by a combination of two effects:
The +I effect increases the electron density on the
methyl)amine Me2NCH2Si(OEt)3 forms a stable
1
H-bonded complex with ohenol (
490 cm ), and
, nm
its UV spectrum is invariable even after 3 h. As
follows from our results, compounds I III rapidly
react with phenol at room temperature in heptane.
Therefore, their basicity cannot be estimated by UV
spectroscopy {unlike ethoxypiperidinomethylsilanes
260
270
280
290
D
0.8
0.6
0.4
0.2
0
1
C5H10NCH2SiMen(OEt)3
[1, 2] and triethoxydi-
n
methylaminomethylsilane Me2NCH2Si(OEt)3}.
Transetherification of silanes containing a SiOC
group with alcohols and phenols is one of the most
thoroughly studied reactions of organosilicon com-
pounds (see [12] and references therein). The reaction
is usually performed with heating in the presence of
catalysts. The transetherification of N,N-bis[ethoxy-
(methyl)silylmethyl]amines I III with phenol occurs
already at room temperature, and it may be driven by
autocatalysis. However, ethoxy(dialkylaminomethyl-
2
3
38
37
36
35
3
1
10 , cm
Fig. 1. UV spectra of heptane solutions of (1) phenol,
(2) phenol with MeN[CH SiMe (OEt)] (c 3.2
silanes R2NCH2SiMen(OEt)3
(R2 = Me2, C5H10;
2
2
2
b
n = 0 2) whose nitrogen atom nis also very basic (and,
10 M), and (3) phenol with MeN[CH Si(OEt) ] (c
2
2
3 2
b
2
consequently, they are also able to autocatalysis) do
2.0 10 M).
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 2 2001

204
LAZAREVA, BRODSKAYA
OH
N
MeN[CH2SiMem(OEt)3
]
m 2
620
XVIII
XVI
PhOH
MeN[CH2SiMem(OPh)3 m 2
]
580
PhOH
(3)
MenSi(OPh)4 m + Me3N,
XIX
540
500
III
XV
m = 0 2.
XIV
XX
XXI
XVII
Heterolytic Si C bond cleavage is commonly
encountered in the silicon chemistry [15 25]. Lewis
acids catalyze the Si C bond cleavage with various
electrophiles (see [15] and references therein). Bases,
too, catalyze Si C bond cleavage [20 23]. The Si C
bond cleavage in tetralkylsilanes occurs under rigid
conditions under the action of concentrated sulfuric
acid [24]. However, this reaction is much facilitated
by functional substitution in the alkyl group [25]. As
shown above, the partial positive charge on the silicon
atom in the compounds in study is increased com-
pared with Me2NCH2SiMem(OEt)3 m. The Si C bond
cleavage, being SN2 substitution at silicon [25, 26], is
facilitated by increased positive charge on the latter.
Moreover, the Si O bond formation is favored thermo-
dynamically, since Si O is a stronger bond than Si C
(Edis 530 and 360 kJ/mol, respectively [27]).
460
XIII
XII
2.4 2.0 1.6 1.2 0.8 0.4
0
*
1
*
Fig. 2.
for the (CH ) SiX groups in MeN[CH SiMe (OEt)]
2
(cm ) vs. Taft inductive
constants
OH
N
2 m
3
2
2
(III), (CH ) NCH Si(OEt) (XII), (CH ) NCH MeSi
2 5
2
3
2 5
2
(OEt)
(XIII),
(CH ) N(CH ) Si(OEt)
(XIV),
2
2 5
2 3
3
(CH ) N(CH ) MeSi(OEt) (XV), (CH ) NCH MeSi
2 5
2 3
2
2 5
2
(OCH CH ) NMe
(XVI),
(XVII),
(CH ) N(CH ) MeSi
2
2 2
2 5 2 3
(OCH CH ) NMe
(CH ) NCH Si(OCH
2 5 2 2
2
2 2
CH ) N
(XVIII),
(CH ) N(CH ) Si(OCH CH ) N
2 3
2 5 2 3 2 2 3
(XIX), Me NCH Si(OEt) (XX), and Me NCH SiMe
2
2
3
2
2
2
*
(OEt) (XXI). The
constants were taken from [10].
nitrogen atom, while the n, *-conjugation effect acts
in the opposite direction [10]. Compounds R2NCH2
EXPERIMENTAL
SiMem(OEt)3 m, where the latter effect is operative,
*
The IR spectra were obtained on a Specord IR-75
instrument in thin films. The UV spectra of heptane
solutions of the compounds in study and their com-
plexes with phenol were obtained on a Specord UV-
Vis spectrophotometer at 200 450 nm. The concentra-
do not fit the linear dependence
= f(
)
CH2SiX3
[12]. Unlike Me2NCH2SiMe2(OEt) (XXI), the
value for compound III does not deviate from the
*
= f( CH SiX ) dependence (Fig. 2). This fact
2
3
suggests prevailing indictive effect of the two
CH2SiX3 groups on the nitrogen atom (apparently, the
4
1
tion of phenol was 4.5 10 M. The H NMR spectra
were recorded on a JEOL Q-90 spectrometer. Heptane
and phenol were purified by standard procedures [5].
*
n, effect in I III is almost inoperative). As a result,
the partial positive charge on the silicon atom in these
compounds increases. Apparently, this favors faster
transetherification of I III with phenol, as compared
with Me2NCH2SiMem(OEt)3 m, since here it occurs
as SN2 substitution at silicon [13, 14].
Compounds I III. A mixture of 0.2 mol of
ClCH2SiMem(OEt)3
(m = 0 2) and 0.5 mol of
m
methylamine was kept in a sealed ampule for 48 h.
The ampule was then unsealed, excess methylamine
was evaporated, and the precipitate was filtered off
and washed with dry ether. The ether solution was
combined with the filtrate and distilled.
For better yields of IV VIII, a mixture of I III
with excess phenol was heated under reflux (without
solvent). The products that were isolated contained
Compounds IV VIII. Compound I III, 0.01 mol,
was mixed with 10 ml of dry heptane and equimolar
amount of phenol, and the mixture was kept at room
temperature for 48 h. The ethanol that formed and
heptane were removed by distillation, and the residue
was distilled in a vacuum to isolate compounds IV
VIII. Further are given I III:phenol ratio (product
no.): 1:2 (IV); 1:4 (V); 1:6 (VI); 1:4 (VII); and
1:2 (VIII).
1
no N CH3 and N CH2 Si groups (by H NMR and
1
IR spectroscopy). The H NMR, IR, and UV spectra
of the reaction products of compounds II, III with
phenol coincide with the spectra of compounds X, XI,
1
while the H NMR spectrum of the reaction product
of compound I concides with that of tetraphenoxy-
silane.
The resulting data suggest that the reaction initially
involves substitution of ethoxy groups by phenoxy to
afford compounds VI VIII, followed by cleavage of
the Si C bond in the latter by phenol [scheme (3)].
Si C bond cleavage. Compound I III, 0.01 mol,
was heated with excess phenol (silane:phenol
ratio 1:9 (I), 1:7 (II), and 1:5 (III)] in a flask
equipped with a reflux condenser attached to a trap
Triethylamine was isolated as hydrochloride.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 2 2001

N,N-BIS[ETHOXY(METHYL)SILYLMETHYL]METHYLAMINES
205
containing a benzene solution of hydrogen chloride.
Heating was continued for 1.5 h until triethylamine no
longer evolved (the presence of trimethylamine in
the vapor was determined using a wet universal in-
dicator paper placed at the top of the reflux condenser).
The residue was distilled in a vacuum to isolate the
following products (yield, %): (PhO)4Si (89) for com-
pound I; MeSi(OPh)3 (92) for compound II; and
Me2Si(OPh)2 (85) for compound III. Their melting
points and n2D0 values were consistent with those
reported in [28]. Trimethylamine hydrochloride was
isolated from benzene, mp 276 277 C.
12. Voronkov, M.G., Mileshkevich, V.P., and Yuzhelev-
skii, Yu.A., Siloksanovaya svyaz’ (Siloxane Bond),
Novosibirsk: Nauka, 1976.
13. Sommer, L.H., Stereochemistry, Mechanism, and
Silicon, New York: McGraw-Hill, 1965.
14. Sommer, L.H. and Fujimoto, H., J. Am. Chem. Soc.,
1969, vol. 91, no. 25, pp. 7040 7045.
15. Parnes, L.N. and Bolestova, G.I., Synthesis, 1984,
no. 12, pp. 991 1086.
16. Voronkov, M.G., Chernov, N.F., and Perlova, E.M.,
J. Organomet. Chem., 1988, vol. 341, nos. 1 3,
pp. 225 229.
REFERENCES
17. Valk, J.-M., Boersma, J., and Koten, G. van,
J. Organomet. Chem., 1994, vol. 483, no. 1 2,
pp. 213 216.
1. Brodskaya, E.I., Voronkov, M.G., Belyaeva, V.V.,
Baryshok, V.P., and Lazareva, N.F., Zh. Obshch.
Khim., 1993, vol. 63, no. 10, pp. 2252 2256.
2. Brodskaya, E.I., Belyaeva, V.V., Lazareva, N.F., and
Voronkov, M.G., Zh. Obshch. Khim., 1999, vol. 69,
no. 3, pp. 403 406.
3. Bock, H., Kaim, W., Kira, M., Osawa, H., and Sa-
kurai, H., J. Organomet. Chem., 1979, vol. 164, no. 1,
pp. 295 304.
4. Nakanishi, K., Infrared Absorption Spectroscopy.
Practical, San Francisco: Holden-Day, 1962.
5. Gordon, A.J. and Ford, R.A., The Chemist’s Com-
panion, New York: Wiley, 1972.
6. Stern, E.S. and Timmons, C.J., Gillam and Stern’s
Introduction to Electronic Absorption Spectroscopy
in Organic Chemistry, London: Edward Arnold, 1970.
7. Murthy, A.S.N. and Rao, C.N.R., Appl. Spectrosc.
Rev., 1968, vol. 2, no. 1, pp. 69 191.
8. Pimentel, G.C. and McClellan, A.L., Annu. Rev. Phys.
Chem., 1971, vol. 22, pp. 347 385.
9. Arnett, E.M. and Mitchell, E.J., J. Am. Chem. Soc.,
1974, vol. 96, no. 12, pp. 3875 3891.
10. Voronkov, M.G., Brodskaya, E.I., Belyaeva, V.V.,
Baryshok, V.P., Sorokin, M.S., and Yarosh, O.G.,
Dokl. Akad. Nauk SSSR, 1982, vol. 267, no. 3,
pp. 654 659.
11. Shah, S.B. and Murthy, A.S.N., Indian J. Chem., Sect.
A, 1976, vol. 14, pp. 104 106.
18. Lazarev, I.M., Dolgushin, G.V., Feshin, V.P., and Vo-
ronkov, M.G., Mendeleev Commun., 1996, no. 4,
pp. 150 151.
19. Gibert, S. and Schubert, U., J. Organomet. Chem.,
1993, vol. 444, no. 1 2, pp. C12 C14.
20. Eaborn, C., Eidenschink, R., Harris, S.I., and Wal-
ton, D.R.M., J. Organomet. Chem., 1977, vol. 124,
no. 2, pp. S27 S29.
21. Chakrabrorty, K. and Reddy, G.V., Chem. Commun.,
1989, no. 4, pp. 251 253.
22. Chan, T.H., Low, P.W.K., and Li, M.P., Tetrahedron
Lett., 1976, no. 31, pp. 2667 2670.
23. Stanczyk, W. and Choinowski, J., J. Organomet.
Chem., 1976, vol. 117, no. 2, pp. 219 229.
24. Reavill, R.E., J. Chem. Soc., 1964, no. 1, pp. 519 520.
25. Fleming, I. and Snowden, R.R., Chem. Commun.,
1976, no. 5, pp. 182 183.
26. Eaborn, C., J. Chem. Soc., 1956, no. 12, pp. 4858 4864.
27. Comprehensive Organic Chemistry, Barton, D. and
Ollis, W.D., Eds., Oxford: Pergamon, 1979, vol. 3.
Translated under the title Obshchaya organicheskaya
khimiya, Moscow: Khimiya, 1984, vol. 6.
28. Bazant, V., Chvalovsky, V., and Rathousky J., Organo-
silicon Compounds, Prague: Czechoslovak. Akad. Sci.,
1965, vol. 2 (1).
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 2 2001