Direct synthesis of organotrichlorogermanes by the reaction of elemental germanium, hydrogen chloride, and alkene

Article abstract of DOI:10.1021/om034202q

The reaction of elemental germanium, hydrogen chloride, and ethylene with copper(I) chloride catalyst gave ethyltrichlorogermane with a 66% selectivity, tetrachlorogermane also being formed. The addition of tetrachlorogermane to the reaction system increased the formation rate of ethyltrichlorogermane. The reaction of germanium, tetrachlorogermane, and butadiene resulted in the formation of 1,1-dichlorogermacyclopent-3-ene. These results indicate the intermediacy of dichlorogermylene, which is formed by the reaction of elemental germanium with tetrachlorogermane. In place of ethylene, allyl chloride was fed with hydrogen chloride. Allyltrichlorogermane was obtained with a 92% selectivity together with a small amount of tetrachlorogermane. It is highly plausible that the formation of allyltrichlorogermane is caused by the insertion of dichlorogermylene intermediate to the carbon - chlorine bond of allyl chloride.

Full text of DOI:10.1021/om034202q

Organometallics 2004, 23, 595-599
595
Dir ect Syn th esis of Or ga n otr ich lor oger m a n es by th e
Rea ction of Elem en ta l Ger m a n iu m , Hyd r ogen Ch lor id e,
a n d Alk en e
Masaki Okamoto*
Department of Applied Chemistry, Tokyo Institute of Technology,
Ookayama, Meguro-ku, Tokyo 152-8552, J apan
Takehiko Chikamori, Takuya Asano, and Eiichi Suzuki*
Department of Chemistry and Materials Science, Tokyo Institute of Technology,
Ookayama, Meguro-ku, Tokyo 152-8550, J apan
Received September 26, 2003
The reaction of elemental germanium, hydrogen chloride, and ethylene with copper(I)
chloride catalyst gave ethyltrichlorogermane with a 66% selectivity, tetrachlorogermane also
being formed. The addition of tetrachlorogermane to the reaction system increased the
formation rate of ethyltrichlorogermane. The reaction of germanium, tetrachlorogermane,
and butadiene resulted in the formation of 1,1-dichlorogermacyclopent-3-ene. These results
indicate the intermediacy of dichlorogermylene, which is formed by the reaction of elemental
germanium with tetrachlorogermane. In place of ethylene, allyl chloride was fed with
hydrogen chloride. Allyltrichlorogermane was obtained with a 92% selectivity together with
a small amount of tetrachlorogermane. It is highly plausible that the formation of
allyltrichlorogermane is caused by the insertion of dichlorogermylene intermediate to the
carbon-chlorine bond of allyl chloride.
In tr od u ction
Hydrogen chloride also reacts with elemental germa-
nium to form trichlorogermane and tetrachlorogermane
with a copper catalyst,4,6 even with no catalyst.7
In this work, a new method of direct synthesis of
organogermane was developed and the reaction mech-
anism was examined. Here, we have found that alkyl-
trichlorogermane was synthesized by the reaction of
elemental germanium and hydrogen chloride in the
presence of alkene.
Elemental germanium reacts with methyl chloride
with use of a copper catalyst to form methylchloroger-
manes.1,2 This is called “direct synthesis” since organ-
ogermanes are synthesized directly from elemental
germanium. The reactions of germanium with various
alkyl and aryl halides have also been reported for the
direct synthesis of alkylhalogermanes and arylhaloger-
manes, respectively.2-5 Only organic halides are reactive
to directly synthesize organogermanes. In refs 2-5
copper and silver have been used as the catalysts, and
these metals have formed the germanium-metal inter-
metallic compounds, in which germanium atom reacts
with organic halides.
Resu lts a n d Discu ssion
Rea ction of Elem en ta l Ger m a n iu m , Hyd r ogen
Ch lor id e, a n d Eth ylen e. When the mixture of ger-
manium and 20 wt % of copper(I) chloride was pre-
treated at 450 °C for 1 h in a helium stream, 4% of ger-
manium charged reacted with copper(I) chloride to form
tetrachlorogermane. After the pretreatment, the reac-
tion of elemental germanium, hydrogen chloride, and
ethylene was carried out at 450 °C. Ethyltrichloroger-
mane was formed together with tetrachlorogermane.
The changes of formation rates of ethyltrichlorogermane
and tetrachlorogermane with time are shown in Figure
1. Both the rates increased with reaction time to the
maxima around 1 h, and then gradually decreased. The
overall selectivity and yield of ethyltrichlorogermane for
7 h were 61% and 15%, respectively, the germanium
* Address correspondence to these authors. M.O.: phone +81-3-
5734-2625, fax +81-3-5734-2878, e-mail mokamoto@apc.titech.ac.jp.
E.S.: phone +81-3-5734-2118, fax +81-3-5734-2878, e-mail esuzuki@
o.cc.titech.ac.jp.
(1) (a) Belij, A. P.; Gorbunov, A. I.; Golubtsov, S. A.; Feldshein, N.
S. J . Organomet. Chem. 1969, 17, 485. (b) Chong, T.; Skaates, J . M. J .
Catal. 1973, 28, 20. (c) Lee, M. E.; Bobbitt, K. L.; Lei, D.; Gasper, P.
P. Synth. React. Met.-Org. Chem. 1990, 20, 77.
(2) (a) Rochow, E. G. J . Am. Chem. Soc. 1947, 69, 1729. (b)
Moedritzer, K. J . Organomet. Chem. 1966, 6, 282. (c) Zueva, G. Ya.;
Luk’yankina, N. V.; Ponomarenko, V. A. Bull. Acad. Sci. USSR, Div.
Chem. Sci. 1967, 186. (d) Gorbunov, A. I.; Belyi, A. P.; Rybakov, N. N.
Russ. J . Phys. Chem. 1978, 52, 1054. (e) Gar T. K.; Mironov, V. F.
Metalloorg. Khim. 1993, 6, 285 and references therein.
(3) (a) Rochow, E. G. J . Am. Chem. Soc. 1950, 72, 198. Rochow, E.
G. J . Am. Chem. Soc. 1950, 72, 198. (b) Rochow, E. G.; Didtschenko,
R.; West, R. C., J r. J . Am. Chem. Soc. 1951, 73, 5486. (c) Zueva, G.
Ya.; Luk’yankina, N. V.; Kechina, A. G.; Ponomarenko, V. A. Bull.
Acad. Sci. USSR, Div. Chem. Sci. 1966, 10, 1780. (d) Okamoto, M.;
Asano, T.; Suzuki, E. Catal. Lett. 2002, 78, 33.
(6) Petrov, A. D.; Mironov, V. F.; Dzhurinskaya, N. G. Dokl. Akad.
Nuak SSSR 1959, 128, 302.
(4) Petrov, A. D.; Mironov, V. F.; Golgy, I. E. Bull. Akad. Sci. USSR,
Div. Chem. Sci. 1956, 1169.
(5) Zueva, G. Ya.; Khaustova, T. I.; Serezhkina, N. V.; Ponomarenko,
V. A. Izv. Akad. Nauk SSSR, Ser. Khim. 1979, 2792.
(7) (a) Rochow, E. G.; Abel, E. W. In The Chemistry of Germanium,
Tin and Lead; Pergamon: Oxford, UK, 1973. (b) Dennis, L. M.;
Orndorff, W. R.; Tabern, D. L. J . Phys. Chem. 1926, 30, 1049. (c)
Delwaulle M. L.; Francois, F. Compt. Rend. 1949, 228, 1007.
10.1021/om034202q CCC: $27.50 © 2004 American Chemical Society
Publication on Web 01/07/2004

596 Organometallics, Vol. 23, No. 3, 2004
Okamoto et al.
F igu r e 3. Effect of the catalyst amount on the germanium
conversion (square), the selectivity (circle), and the yield
(triangle) of ethyltrichlorogermane. The pretreatment was
carried out at 450 °C for 1 h. The amount of germanium
charged in the reactor was 2.76 mmol. The reaction
temperature was 450 °C. The flow rates of hydrogen
chloride and ethylene were 5 and 10 mmol h-1, respectively.
F igu r e 1. Time courses of the germanium conversion
(circle) and the formation rates of ethyltrichlorogermane
(triangle) and tetrachlorogermane (square) in the reaction
of germanium, hydrogen chloride, and ethylene. The pre-
treatment was carried out at 450 °C for 1 h. The reaction
temperature was 450 °C. The amount of germanium
charged in the reactor was 2.76 mmol. The catalyst amount
was 20 wt %. The flow rates of hydrogen chloride and
ethylene were 5 and 10 mmol h-1, respectively.
F igu r e 4. Effect of the ratio of ethylene to hydrogen
chloride on the germanium conversion (square), the selec-
tivity (circle), and the yield (triangle) of ethyltrichloroger-
mane. The pretreatment was carried out at 450 °C for 1 h.
The amount of germanium charged in the reactor was 2.76
mmol. The catalyst amount was 20 wt %. The reaction
temperature was 450 °C. The total flow rate of hydrogen
F igu r e 2. Effect of reaction temperature on the germa-
nium conversion (square), the selectivity (circle), and the
yield (triangle) of ethyltrichlorogermane. The pretreatment
was carried out at 450 °C for 1 h. The amount of germa-
nium charged in the reactor was 2.76 mmol. The catalyst
amount was 20 wt %. The flow rates of hydrogen chloride
and ethylene were 5 and 10 mmol h-1, respectively.
chloride and ethylene was kept at 15 mmol h-1
.
yltrichlorogermane for the 7-h reaction. Both the selec-
tivity and the conversion increased with reaction
temperature.
conversion for 7 h being 24%. No formation of ethyl
chloride was observed, indicating that this reaction is
not a general direct synthesis from germanium and
ethyl chloride. The reaction shown in this work is a new
method of direct synthesis of organogermanes.
On the other hand, in the absence of ethylene only
tetrachlorogermane was formed, the germanium con-
version for 7 h being 23%. No formation of trichloro-
germane was observed. In some reports,4,6,7 trichloro-
germane, not tetrachlorogermane, has been reported as
a main product for the reaction of germanium and
hydrogen chloride. Thus, under our reaction conditions,
the germanium-hydrogen bond in trichlorogermane
was completely converted to the germanium-chlorine
bond by an attack of hydrogen chloride.
The amount of copper(I) chloride catalyst was varied.
As shown in Figure 3, even without the catalyst, the
reaction proceeded and ethyltrichlorogermane was formed
with a 74% selectivity. With use of 5 wt % of copper(I)
chloride, the selectivity for ethyltrichlorogermane de-
creased, while the germanium conversion did not change.
When the catalyst amount was further increased, the
selectivity slightly decreased and the conversion in-
creased.
The ratio of ethylene to hydrogen chloride greatly
affected the reaction results as shown in Figure 4. At a
ratio of 0.5, the selectivity for ethyltrichlorogermane was
very low, 19%, while above 2, it was constant at 61%.
The germanium conversion slightly declined at a higher
ratio.
The effect of reaction temperature on the product
distribution was examined. Figure 2 shows the germa-
nium conversion, the selectivity, and the yield of eth-

Direct Synthesis of Organotrichlorogermane
Organometallics, Vol. 23, No. 3, 2004 597
It is well-known8 that silicon, a congener of germa-
nium, also reacts with methyl chloride to afford di-
methyldichlorosilane, which is a raw material of sili-
cones. We have elucidated the reaction mechanism in-
volving a surface silylene intermediate (:SiCu2) on the
silicon surface as shown in eq 1.9 When the reaction of
elemental silicon with methyl chloride was carried out
in the presence of butadiene as a silylene-trapping rea-
gent, silacyclopent-3-enes were formed as the products
trapped by butadiene, together with methylchloro-
silanes.
F igu r e 5. Effect of the tetrachlorogermane addition to
the noncatalyzed Ge-HCl-C2H4 reaction system on the
effluent rates of ethyltrichlorogermane (triangle) and tet-
rachlorogermane (square). The pretreatment was carried
out at 450 °C for 1 h. The reaction temperature was 450
°C. The amount of germanium charged in the reactor was
2.76 mmol. No catalyst was used. The flow rates of
Furthermore, the intermediacy of surface silylene in
the reaction of silicon with hydrogen chloride has also
been revealed.10 The reaction of silicon with hydrogen
chloride gave di-, tri-, and tetrachlorosilanes,11 while the
reaction in the presence of alkene resulted in the
formation of alkyldichlorosilane together with chlorosi-
lanes.10 The alkyldichlorosilane formation also indicates
that surface silylene is the reaction intermediate. The
key step of the organosilane formation is the reaction
of alkene with the silylene as shown in eq 2.
hydrogen chloride and ethylene were 5 and 10 mmol h-1
respectively. The flow rate of tetrachlorogermane added
was 0.32 mmol h-1
,
.
trichlorogermane, and trimethylchlorogermane were
91%, 6%, and 3%, respectively. No detection of germa-
cyclopent-3-enes was observed, indicating that the
intermediate in the direct synthesis of methylchlorog-
ermanes is not surface germylene (:GeCu2). This strongly
suggests that surface germylene is not the intermediate
of the ethyltrichlorogermane formation in the reaction
of germanium, hydrogen chloride, and ethylene either.
It has been reported that tetrachlorogermane reacts
with elemental germanium without a catalyst to form
dichlorogermylene, which is easily trapped by butadi-
ene12 and chlorobenzene13 to give 1,1-dichlorogermacy-
clopent-3-ene and phenyltrichlorogermane, respectively.
It is highly plausible that dichlorogermylene is produced
by the reaction of elemental germanium and tetrachlo-
rogermane thus formed by the Ge-HCl reaction (eq 3)
and that the dichlorogermylene formed is the interme-
diate in the ethyltrichlorogermane formation (eq 4). It
has been reported that the 1,1-dichlorogermacyclo-
propane intermediate is formed by the reaction of
dichlorogermylene with ethylene.14
Trapping an intermediate of the methylchloroger-
mane synthesis from elemental germanium was at-
tempted with butadiene. The mixture of methyl chloride
and 1,3-butadiene (CH3Cl/C4H6 was changed between
2 and 20) was fed at 400-500 °C to the reactor, in which
the mixture of germanium (2.76 mmol) and copper(I)
chloride (10 wt %) was charged. The reaction products
were methylchlorogermanes and dimers of butadiene.
The selectivities for dimethyldichlorogermane, methyl-
(8) (a) Rochow, E. G. J . Am. Chem. Soc. 1945, 67, 963. (b) Voorhoeve,
R. J . H. In Organohalosilanes: Precursors to Silicones; Elsevier:
Amsterdam, The Netherlands, 1967, and references therein. (c) Clarke,
M. P. J . Organomet. Chem. 1989, 376, 165 and references therein. (d)
Lewis, K. M.; McLeod, D.; Kanner, B.; Falconer, J . L.; Frank, T. C. In
Catalyzed Direct Reactions of Silicon; Lewis, K. M., Rethwisch, D. G.,
Eds.; Elsevier: Amsterdam, The Netherlands, 1993; pp 333-440 and
references therein.
(9) Okamoto, M.; Onodera, S.; Okano, T.; Suzuki, E.; Ono, Y. J .
Organomet. Chem. 1997, 531, 67.
(10) (a) Okamoto, M.; Onodera, S.; Yamamoto, Y.; Suzuki, E.; Ono,
Y. Chem. Commun. 1998, 1275. (b) Okamoto, M.; Onodera, S.;
Yamamoto, Y.; Suzuki, E.; Ono, Y. J . Chem. Soc., Dalton Trans. 2001,
1, 71.
To examine the intermediacy of dichlorogermylene,
tetrachlorogermane was added to the feed during the
reaction of germanium, hydrogen chloride, and ethylene.
The result with no catalyst is shown in Figure 5. The
reaction started with flowing the mixture of hydrogen
(11) (a) Shiihara, I.; Iyoda, J . Bull. Chem. Soc. J pn. 1959, 32, 636.
(b) Kanner, B.; Lewis, K. M. In Catalyzed Direct Reactions of Silicon;
Lewis, K. M., Rethwisch, D. G., Eds.; Elsevier: Amsterdam, The
Netherlands, 1993; pp 1-66 and references therein. (c) Breneman, W.
C. In Catalyzed Direct Reactions of Silicon; Lewis, K. M., Rethwisch,
D. G., Eds.; Elsevier: Amsterdam, The Netherlands, 1993; pp 441-
457.
(12) Berliner, E. M.; Gar, T. K.; Mironov, V. F. J . Gen. Chem. USSR
1972, 42, 1165.
(13) Okamoto, M.; Asano, T.; Suzuki, E. Organometallics 2001, 20,
5583.
(14) (a) Nefedov, O. M.; Kolesnikov, S. P.; Sheichenko, V. I. Angew.
Chem., Int. Ed. Engl. 1964, 3, 508. (b) Nefedov, O. M.; Kolesnikov, S.
P. Polym. Sci. USSR 1965, 7, 2038.

598 Organometallics, Vol. 23, No. 3, 2004
Okamoto et al.
hydrogen chloride and ethylene. The rate of ethyl-
trichlorogermane increased just after the addition;
however, the difference between the rates before and
after the addition was smaller than the 2-fold rate of
consuming tetrachlorogermane. Perhaps a part of tet-
rachlorogermane converted reacts with metallic copper
to form an intermetallic compound of germanium and
copper together with chlorine. Actually, chlorine was
formed, and a decrease of the volume of the germanium-
catalyst mixture due to the consumption of elemental
germanium was not observed. The increase of the
ethyltrichlorogermane rate just after the addition of
tetrachlorogermane was smaller than that with no
catalyst. This suggests that copper inhibits the forma-
tion of dichlorogermylene from germanium and tetra-
chlorogermane. Thus, tetrachlorogermane reacts with
germanium on the surface of elemental germanium, not
on the surface of the copper-germanium intermetallic
compound where chlorogermanes are formed rapidly by
the reaction of germanium with hydrogen chloride.
Further to prove the intermediacy of dichloroger-
mylene, the reaction of germanium and tetrachloroger-
mane was carried out in the presence of 1,3-butadiene
as a germylene-trapping reagent. 1,1-Dichlorogeramcyclo-
pent-3-ene was formed as the butadiene-trapped product
(eq 6). This result is in agreement with the report of
F igu r e 6. Effect of the tetrachlorogermane addition to the
catalyzed Ge-HCl-C2H4 reaction system on the effluent
rates of ethyltrichlorogermane (triangle) and tetrachlorog-
ermane (square). The pretreatment was carried out at 450
°C for 1 h. The reaction temperature was 450 °C. The
amount of germanium charged in the reactor was 2.76
mmol. The catalyst amount was 20 wt %. The flow rates of
hydrogen chloride and ethylene were 5 and 10 mmol h-1
respectively. The flow rate of tetrachlorogermane added
was 0.32 mmol h-1
,
.
the synthesis of 1,1-dimethylgermacyclopent-3-ene by
methylation of 1,1-dichlorogermacyclopent-3-ene pro-
duced from dichlorogermylene and butadiene.12 Figure
7 shows the time courses of effluent rates of tetrachlo-
rogermane and 1,1-dichlorogermacyclopent-3-ene. The
formation rate of the trapped product was equal to the
2-fold conversion rate of tetrachlorogermane, also indi-
cating the intermediacy of dichlorogermylene.
Laukmanis and Feltyn have studied the kinetics
using dichlorogermylene as an intermediate in the
reaction of germanium and hydrogen chloride with no
catalyst (eq 7).15 It is plausible that dichlorogermylene
also originates from germanium and hydrogen chloride
without use of copper(I) chloride as well as from
germanium and tetrachlorogermane and that the reac-
tions of hydrogen chloride and ethylene with the formed
dichlorogermylene lead to the tetrachlorogermane (eq
8) and ethyltrichlorogermane (eq 4), respectively.
F igu r e 7. Changes in the formation rates of 1,1-dichlo-
rogermacyclopent-3-ene (triangle) and tetrachlorogermane
(square) with time in the noncatalyzed Ge-GeCl4-C4H6
reaction. The pretreatment was carried out at 450 °C for 1
h. The reaction temperature was 450 °C. The amount of
germanium charged in the reactor was 2.76 mmol. No
catalyst was used. The flow rates of tetrachlorogermane,
butadiene, and helium were 0.32, 5, and 10 mmol h-1
respectively.
,
chloride and ethylene, and at 3.1 h, 0.32 mmol h-1 of
tetrachlorogermane was added to the flow. J ust after
adding tetrachlorogermane, the effluent rate of ethyl-
trichlorogermane rapidly increased. When the tetra-
chlorogermane flow was stopped at 4.1 h, the amount
of ethyltrichlorogermane formed decreased. The change
of the ethyltrichlorogermane rates before and after the
addition of tetrachlorogermane was twice as much as
the conversion rate of tetrachlorogermane. This strongly
indicates that the reaction shown in eq 5 occurs.
Rea ction of Elem en ta l Ger m a n iu m , Hyd r ogen
Ch lor id e, a n d Allyl Ch lor id e. The direct synthesis
of allylchlorogermanes by the reaction of elemental
germanium and allyl chloride has been reported.4,5 The
products were allyltrichlorogermane and diallyldichlo-
rogermane, whose selectivities were 60% and 40%,
respectively.5 Allyl chloride can easily react with dichlo-
rogermylene to afford allyltrichlorogermane.16 It was
expected that allyltrichlorogermane could be selectively
Figure 6 shows the effect of the tetrachlorogermane
addition in the reaction with the catalyst. At 3.1 h,
tetrachlorogermane was fed to the reactor together with
(15) Laukmanis, L. A.; Feltyn, I. A. Inorg. Mater. 1968, 4, 1275.

Direct Synthesis of Organotrichlorogermane
Organometallics, Vol. 23, No. 3, 2004 599
method of direct synthesis of organogermane. The reac-
tion intermediate is dichlorogermylene, which reacts
with ethylene to form the germanium-carbon bond. The
intermediate is formed by the reaction of elemental ger-
manium and tetrachlorogermane and by the reaction
of germanium with hydrogen chloride in the absence of
the catalyst. The copper catalyst enhances only the for-
mation of tetrachlorogermane from germanium and
hydrogen chloride and inhibits the formation of dichlo-
rogermylene by the reaction of germanium and tetra-
chlorogermane.
When the reaction of germanium with allyl chloride
in the presence of hydrogen chloride was carried out,
allyltrichlorogermane was obtained with a 92% selectiv-
ity and a 72% yield. The dichlorogermylene intermediate
inserts to the carbon-chlorine bond of allyl chloride to
form allyltrichlorogermane.
F igu r e 8. Time courses of the germanium conversion
(circle) and the formation rates of allyltrichlorogermane
(triangle) and tetrachlorogermane (square) in the reaction
of germanium, hydrogen chloride, and allyl chloride. The
pretreatment was carried out at 450 °C for 1 h. The
reaction temperature was 260 °C. The amount of germa-
nium charged in the reactor was 2.76 mmol. The catalyst
amount was 10 wt %. The flow rates of hydrogen chloride
and allyl chloride were 10 and 5 mmol h-1, respectively.
Exp er im en ta l Section
Rea ction P r oced u r e. Elemental germanium grains (purity
99.99%, impurity: Ca 0.001, Fe 0.001, Mg 0.001 wt %) were
sieved between 45 and 63 µm and washed by 46% hydrofluoric
acid for 2 h with stirring to remove oxide overlayers. Copper-
(I) chloride was used as a catalyst because it can readily react
with elemental germanium to form germanium-copper alloys
which are reactive sites for the direct synthesis. The germa-
nium grains (2.76 mmol, 200 mg) and copper(I) chloride grains
(45-63 µm, Cu/(Ge + CuCl) ) 0-20 wt %) were mixed vigor-
ously and charged in a fixed-bed flow reactor (quartz, i.d. 10
mm). The mixture was pretreated at 450 °C for 1 h in a 20
mL min-1 stream of helium, before the mixture of hydrogen
chloride (5 mmol h-1) and ethylene (10 mmol h-1) was fed to
the reactor at 450 °C. The reaction products were identified
by GC-MS, and the formation rates of the products were ana-
lyzed by gas chromatography. The selectivity, the yield, and
the germanium conversion are defined by the following equa-
tions.
obtained by the reaction of germanium, hydrogen chlo-
ride, and allyl chloride.
When 10 mmol h-1 of hydrogen chloride and 5 mmol
h-1 of allyl chloride were fed to the reactor at 260 °C,
allyltrichlorogermane was formed with a high selectiv-
ity. Figure 8 shows the time course of the reaction. The
formation rate of allyltrichlorogermane was almost 10
times larger than that of tetrachlorogermane at 1 h, and
the germanium conversion reached 78% at 7 h. The
overall selectivity for allyltrichlorogermane for 7 h was
92%, its yield being 72%. In the absence of hydrogen
chloride, diallyldichlorogermane and allyltrichloroger-
mane were formed with 70% and 30% selectivities,
respectively, the germanium conversion being 83%.
Adding hydrogen chloride to the reaction of germanium
and allyl chloride enhanced the selectivity for allyl-
trichlorogermane.
selectivity (%) )
amount of the product (mmol)
× 100
sum of amounts of Ge-containing products (mmol)
yield (%) )
amount of the product (mmol)
Diallyldichlorogermane was mainly formed in the
absence of hydrogen chloride. The fact that the diorga-
nodichlorogermane was a main product is the same as
that in the direct synthesis of methylchlorogermanes.
This indicates that copper catalyzes the reaction of
germanium and allyl chloride to form diallyldichloro-
germane mainly. On the other hand, no formation of
diallyldichlorogermane was observed in the presence of
hydrogen chloride. This strongly suggests that allyl-
trichlorogermane is not formed by the catalysis of
copper. Therefore, it is concluded that allyltrichloro-
germane is formed by the insertion of dichlorogermylene
to the carbon-chlorine bond in allyl chloride (eq 9).
×
amount of the Ge charged in the reactor (2.76 mmol)
100
Ge conversion (%) )
sum of amounts of Ge-containing products (mmol)
×
amount of the Ge charged in the reactor (2.76 mmol)
100
P r od u cts. (a) Ethyltrichlorogermane: 1H NMR (300 MHz,
CDCl3) δ 1.36 (3H, t, J ) 7.8 Hz, CH2CH3), 2.06 (2H, q, J )
7.8 Hz, CH2CH3); 13C NMR (300 MHz, CDCl3) δ 7.26, 26.05;
GC-MS m/e (rel intensity) [M - C2H5]+ and/or [M - Cl]+ 167(4),
168(8), 169(11), 170(18), 171(20), 172(25), 173(17), 174(16),
175(9), 176(7), 177(6), 178(6), 179(8), 180(5), 181(6), 182(2),
183(2), [C2H5]+ 29(100). (b) 1,1-Dichlorogermacyclopent-3-
ene: 1H NMR (300 MHz, CDCl3) δ 2.16 (4H, broad s, CHCH2),
6.17 (2H, br s, CHCH2); 13C NMR (300 MHz, CDCl3) δ 25.00,
128.77; GC-MS m/e (rel intensity) M+ 194(0.6), 195(0.7),
196(1.2), 197(1.1), 198(1.7), 199(0.8), 200(0.9), [C4H6]+ 54(100).
(c) Allyltrichlorogermane: 1H NMR (300 MHz, CDCl3) δ 2.88
(2H, d), 5.35 (1H, m), 5.36 (1H, m), 5.85 (1H, m); 13C NMR
(300 MHz, CDCl3) δ 37.26, 121.79, 126.04; GC-MS m/e (rel
intensity) M+ 216(2), 217(1), 218(4), 219(3), 220(6), 221(2),
222(4), 224(2), [C3H5]+ 41(100).
Con clu sion
Ethyltrichlorogermane was directly obtained with a
66% selectivity by the reaction of elemental germanium,
hydrogen chloride, and ethylene. This reaction is a new
(16) Chernyshev, E. A.; Komalenkova, N. G.; Yakovleva, G. N.;
Bykovchenko, V. G.; Khromykh, N. N.; Bochkarev, V. N. Russ. J . Gen.
Chem. 1997, 67, 894.
OM034202Q