434 Organometallics, Vol. 15, No. 1, 1996
Sharma et al.
spectra were recorded on a Hewlett Packard 5890/5971 GC/
mass spectrometer; elemental analyses were performed by
Galbraith Laboratories, and all data are recorded in Table 1.
Syn th esis of Me3CSiMe2GeMe2P h . A 250 mL three-
necked flask equipped with magnetic stirring bar and an
addition funnel was charged with t-BuSiMe2Cl (3.08 g, 20.4
mmol) in 30 mL of THF. The solution was cooled to -25 °C.
In a separate 100 mL Schlenk flask PhMe2GeLi was prepared
from PhMe2GeCl (4.4 g, 20.4 mmol) and lithium metal (0.56
g) in 70 mL of THF. The green solution of PhMe2GeLi was
transferred via a cannula to the addition funnel and added
dropwise to the cooled solution of t-BuSiMe2Cl. Upon complete
addition, the reaction mixture was stirred at low temperature
for 30 min, and then the solution was permitted to warm to
room temperature and stirred for an additional 15 h. The
solvent was removed on a rotary evaporator, 150 mL of hexane
was added, and the resultant slurry was stirred for 15 min.
The solution was filtered, hexane was removed on a rotary
evaporator, and the residue was distilled at 148-150 °C at 20
mmHg to yield 4.3 g, 14.6 mmol (71%), of Me3CSiMe2GeMe2-
Ph as a colorless liquid.
hexane was distilled off at 70 mmHg and the residue was
distilled at 68 °C/20 mmHg to yield 1.8 g (7.74 mmol, 51%) of
Me3CSiMe2GeMe3.
Syn th esis of Me3CSiMe2Sn Me3. Into a 250 mL three-
necked-flask was placed 3.02 g (20.0 mmol) of t-BuSiMe2Cl in
30 mL of THF. To this solution was added slowly a solution
of Me3SnLi (prepared from 4.0 g (20.0 mmol) of Me3SnCl and
1 g of lithium in 60 mL of THF) at -78 °C. The reaction
mixture was stirred at low temperature for 1 h and then
permitted to warm to room temperature and stirred for 16 h.
THF was removed on a rotary evaporator, and 200 mL of
hexane was added and stirred for 15 min. LiCl was removed
by filtration, and hexane was removed at 60 mmHg. The
residue was distilled at 86-88 °C/20 mmHg (lit.21 72-73.5 °C/
11 mmHg) to yield 2.4 g (8.6 mmol, 43%) of Me3CSiMe2SnMe3
as a colorless liquid.
Syn th esis of Me3CSiMe2GeMe2Sn Me3. A flame-dried
250 mL three-necked-flask equipped with stirring bar and
addition funnel was charged with 12.5 g (49.4 mmol) of Me3-
CSiMe2GeMe2Cl in 100 mL of THF. To this solution was
added dropwise a solution of Me3SnLi (prepared from 9.84 g
(49.4 mmol) of Me3SnCl and 1.0 g of finely divided lithium
metal in 100 mL of THF) at -78 °C. The addition was
conducted over a period of 1 h. After complete addition of Me3-
SnLi the reaction mixture was stirred at low temperature for
45 min and then stirred for 16 h at room temperature. THF
was removed on a rotary evaporator, and the residue was
extracted with 200 mL of hexane and filtered to remove LiCl.
Hexane was removed and the residue was distilled through a
small vigroux column at 96 °C/2 mmHg to yield 8.54 g (22.4
mmol, 45%) of Me3CSiMe2GeMe2SnMe3 as a colorless liquid.
Alter n a tive Meth od for th e Syn th esis of Me3CSiMe2-
GeMe2Sn Me3. Rea ction of Me3CSiMe2GeMe2H w ith Me3-
Sn NEt2. A flame-dried 100 mL Schlenk flask equipped with
a reflux condenser and a magnetic stirring bar was charged
with 0.6 g (2.71 mmol) of Me3CSiMe2GeMe2H and 0.64 g (2.71
mmol) of Me3SnNEt2 in 15 mL of benzene. The reaction
mixture was heated at reflux, and the formation of Et2NH in
the reaction was checked by IR spectroscopy. After 1 h
evaporation of the solvent yielded 0.35 g (0.92 mmol, 34%) of
crude Me3CSiMe2GeMe2SnMe3.
Syn th esis of Me3CSiMe2GeMe2Sn P h 3. A 100 mL three-
necked flask equipped with magnetic stirring bar and an
addition funnel was charged with 1.0 g (3.95 mmol) of Me3-
CSiMe2GeMe2Cl in 20 mL of THF. To this solution at 0 °C
was added a dark gray solution of Ph3SnLi (prepared from 1.52
g (3.95 mmol) of Ph3SnCl and 0.11 g of Li metal in 30 mL of
THF). Upon complete addition, the mixture was stirred at 0
°C for 30 min, and then the solution was allowed to warm to
room temperature and further stirred for 20 h. The solvent
was removed on a rotary evaporator, and the residue was
extracted with 50 mL of hexane and filtered. Removal of
hexane yielded 1.42 g (2.50 mmol, 63%) of Me3CSiMe2GeMe2-
SnPh3 as a white crystalline solid. It was purified by sublima-
tion at 70-75 °C/0.04 mmHg, mp 53 °C.
P h otolysis of Me3CSiMe2GeMe2Sn Me3. A quartz tube
was charged with 0.1 g (0.26 mmol) of Me3CSiMe2GeMe2SnMe3
in 10 mL of degassed benzene. The solution was irradiated
with a 450-W medium-pressure Hg lamp at a distance of 6
cm. The progress of the reaction was periodically monitored
by GC/mass spectroscopy. Photolysis after 14 h showed
formation of traces of Me3CSiMe2GeMe2H and Me3SnSnMe3,
and the color of the solution changed to orange. After 38 h of
photolysis, the color of the solution changed to orange-yellow
and the solution became slightly turbid. The GC/mass spectra
Syn th esis of Me3CSiMe2GeMe2Cl. In a 250 mL Schlenk
flask at room temperature hydrogen chloride was bubbled
slowly into a 50 mL benzene solution of Me3CSiMe2GeMe2Ph
(4.0 g, 13.5 mmol) and 100 mg of AlCl3. The reaction flask
became slightly warm, and the progress of chlorination was
1
followed by GC and H NMR spectroscopy. After 20 min, when
the chlorination was complete, 5 mL of acetone was added to
deactivate the catalyst. The solution was filtered and solvents
were distilled at 50 mmHg. Finally, distillation at 118-119
°C at 61 mmHg yielded Me3CSiMe2GeMe2Cl, 2.4 g (9.48 mmol,
70%).
Syn th esis of (Me3CSiMe2GeMe2)2. A flame-dried 250 mL
Schlenk flask was charged with 3.93 g (15.5 mmol) of Me3-
CSiMe2GeMe2Cl and 0.1 g of finely cut lithium metal in 60
mL of THF. The reaction mixture was vigorously stirred at
room temperature. After 30 min the mixture became a gray
slurry, and monitoring of the reaction via GC/mass spectrom-
etry indicated that the coupled product was being formed.
Continued stirring for 2 h resulted in the complete disappear-
ance of the starting material and formation of the desired
product, together with 5% of a material whose mass spectral
properties indicated it was Me3CSiMe2GeMe2SiMe2CMe3. Ex-
cess lithium was removed by filtration, the solvent was
removed in vacuo, and the residue was extracted with 150 mL
of hexane. Subsequent to filtration of this solution, and
removal of the solvent, the residue was distilled at 88-99 °C/
0.05 mmHg to yield 1.55 g (3.56 mmol, 46%) of (Me3CSiMe2-
GeMe2)2.
Syn th esis of Me3CSiMe2GeMe2H. To a slurry of 0.15 g
(3.95 mmol) of lithium aluminium hydride in 10 mL of THF
was added slowly via a syringe 1.0 g (3.95 mmol) of Me3CSiMe2-
GeMe2Cl in 20 mL of THF at 0 °C. The reaction mixture was
stirred at 0 °C for 1 h and then at room temperature for 30
min. The solution was filtered and quenched with 50 mL of
cold water containing a few drops of HCl. The organic layer
was extracted twice with hexane and washed with water and
dried over MgSO4. After the organic layer was filtered, and
the solvent removed, distillation at 82 °C/61 mmHg yielded
0.32 g (1.46 mmol, 37%) of Me3CSiMe2GeMe2H.
Syn th esis of Me3CSiMe2GeMe3. A flame-dried three-
necked flask equipped with stirring bar and dropping funnel
was charged with 2.29 g (15.2 mmol) of t-BuMe2SiCl in 20 mL
of THF and cooled to -78 °C. To this cooled solution was
added a solution of Me3GeLi (prepared from 3.0 g, 15.2 mmol,
of Me3GeBr and 0.45 g of lithium metal in a mixture of HMPA
(6 mL) and THF (15 mL)). The addition was conducted over
a period of 45 min. The mixture was stirred at low temper-
ature for 1 h and then further stirred for 16 h at room
temperature. The reaction was quenched with cold water and
extracted with hexane. The organic layer was repeatedly
washed with water and dried over MgSO4. After filtration,
(21) Chenard, B. L.; VanZyl, C. M. J . Org. Chem. 1986, 51, 3561.
(22) (a) Egorov, M. P.; Gal’minas, A. M.; Basovo, A. A.; Nefedov, O.
M. Dokl. Akad. Nauk. 1993, 329, 594. (b) Egorov, M. P.; Nefedov, O.
M.; Lin, T.-S.; Gaspar, P. P. Organometallics 1995, 14, 1539. (c) Walsh,
R.; Becerra, R.; Boganov, S.; Egorov, M. P.; Nefedov, O. M. Presented
at the 28th Organosilicon Symposium; Gainesville, FL, 1995; abstract
A19.
Sharma, Hemant K.
