Synthesis of tri-and tetraalkynylgermanes

Article abstract of DOI:10.1007/s11172-006-0434-5

A straightforward synthesis of tetra-and trialkynylgermanes by reactions of compounds containing Ge-N or Ge-Cl bonds with alk-1-ynes was proposed. Reactions of appropriate amino-or halogermanes with alk-1-ynes were effective only in the presence of an equivalent amount of zinc dihalide.

Full text of DOI:10.1007/s11172-006-0434-5

Russian Chemical Bulletin, International Edition, Vol. 55, No. 8, pp. 1430—1432, August, 2006
1430
Synthesis of triꢀ and tetraalkynylgermanes
A. A. Andreev,ꢀ V. V. Konshin, N. A. Vinokurov, and N. V. Komarov
Kuban State University,
149 ul. Stavropol´skaya, 350040 Krasnodar, Russian Federation.
Fax: +7 (861 2) 69 9570. Eꢀmail: silan@chem.kubsu.ru
A straightforward synthesis of tetraꢀ and trialkynylgermanes by reactions of compounds
containing Ge—N or Ge—Cl bonds with alkꢀ1ꢀynes was proposed. Reactions of appropriate
aminoꢀ or halogermanes with alkꢀ1ꢀynes were effective only in the presence of an equivalent
amount of zinc dihalide.
Key words: alkꢀ1ꢀynes, zinc dihalides, alkynylgermanes, aminogermanes, organogermanium
compounds, germanium tetrachloride, chlorogermanes.
Acetylene derivatives of germanium, in which the
Ge atom is bound to spꢀhybridized C atoms, are well
known and are conventionally synthesized by reactions of
alkali metal or magnesium alkynides with halogermanes.1,2
However, direct replacement of the acid H atom in
alkꢀ1ꢀynes by germanium has been reported for only a few
cases,3,4 in contrast to similar reactions of alkꢀ1ꢀynes with
compounds containing Sn—Cl,5 Sn—O,6 Sn—N,7 and
Pb—O bonds.8 Earlier,9 we have shown that dialkylaminoꢀ
silanes react with alkꢀ1ꢀynes in the presence of zinc
dihalides to give silylalkynes in high yields.
Here we found that reactions of tetrakis(dialkylꢀ
amino)germanes 1 and tris(dialkylamino)phenylgermanes
2 with alkꢀ1ꢀynes 3 in dioxane or THF at 70—100 °C in
the presence of zinc dihalides afford alkynylgermanes in
high yields (Scheme 1; Tables 1, 2).
kis(dialkylamino)germanes 1, respectively. In the absence
of zinc dihalides, the reaction did not occur even at elꢀ
evated temperatures. This distinguishes triꢀ and tetraꢀ
aminogermanes from trialkyl(amino)germanes, which
react with alkꢀ1ꢀynes at 150—180 °C for a long time.3,4
The starting trisꢀ and tetrakis(dialkylamino)germanes
are easily accessible via reactions of secondary amines
with appropriate halogermanes.14 When used in excess,
these amines serve as a reaction medium and provide
virtually quantitative yields of aminogermanes 1 and 2.
We also found that germanium tetrachloride and
trichloro(phenyl)germane in the presence of zinc dihalides
react with alkꢀ1ꢀynes differently from what has been reꢀ
ported earlier.15 The presence of zinc dihalide increases
the alkynylation degree and allows one to obtain tetraꢀ
alkynylgermanes from germanium tetrachloride and
trialkynyl(phenyl)germane from trichloro(phenyl)gerꢀ
mane (Scheme 2).
Scheme 1
Scheme 2
n = 0; NR22 = NEt2 (1a), N(CH2)5 (1b);
R
3 = Bu (3a, 4a), Me3Si (3b, 4b), Ph (3c, 4c), CH2OAc (3d, 4d),
C6H13 (3e, 4e), 4ꢀBrC6H4 (3f, 4f); 1ꢀC10H7 (3g, 4g);
n = 0; R2 = Me3Si (3b, 4b), Ph (3c, 4c), CH2OAc (3d, 4d);
n = 1; R1 = Ph; R2 = Bu (3a, 5a), Me3Si (3b, 5b), Ph (3c, 5c)
n = 1; R1 = Ph; NR22 = NEt2 (2a), N(CH2)5 (2b);
R
3 = Bu (3a, 5a), Me3Si (3b, 5b), Ph (3c, 5c);
The yields of tetraalkynylgermanes 4 and trialꢀ
kynyl(phenyl)germanes 5 were up to 85 and 75%, respecꢀ
tively. We found this method to be inapplicable to
trialkylchlorogermanes and dialkyl(dichloro)germanes:
they did not react with alkꢀ1ꢀynes in the presence of
Hal = Cl, Br
With an excess of the acetylene component, three or
four amino groups were exhaustively replaced in the reacꢀ
tions with tris(dialkylamino)phenylgermanes 2 or tetraꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1377—1379, August, 2006.
1066ꢀ5285/06/5508ꢀ1430 © 2006 Springer Science+Business Media, Inc.

Germylation of alkꢀ1ꢀynes
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 8, August, 2006
1431
Table 1. Yields and physicochemical characteristics of tetraꢀ and trialkynylgermanes 4a—g and 5a—c
20
20
Comꢀ
pound
Yield (%)
(method)
M.p./°C
nD
d4
Found
Calculated
IR,
Reference
(%)
ν(C≡C)/cm–1
C
H
Ge
4a
4b
4c
4d
4e
4f
78 (А)
85 (C)
86 (C)
81(C)
79 (А)
81 (А)
80 (А)
83 (B)
87 (C)
85 (C)
—
160
1.4909
—
0.9970
—
72.37
72.60
51.82
52.06
80.37
80.59
48.86
49.12
75.24
75.46
48.25
48.49
84.88
85.12
75.01
75.24
56.96
57.15
79.30
79.53
8.98
9.14
7.61
7.86
4.01
4.23
3.92
4.12
10.08
10.30
1.84
2.03
3.90
4.12
8.19
8.42
7.04
7.31
4.22
4.45
17.83
18.28
15.29
15.73
14.78
15.22
14.45
14.84
13.83
14.25
8.69
2185
2180
2180
2195
2185
2190
2190
2185
2180
2180
—
10
11
—
—
12
—
—
—
13
187—188
57
—
—
—
—
—
1.4840
—
0.9745
—
255—266
—
9.16
4g
5a
5b
5c
1.6357
1.5198
—
1.0017
0.9961
—
10.29
10.72
18.41
18.95
16.06
16.45
15.67
16.02
—
121
108—109
—
—
equimolar amounts of ZnCl2 and triethylamine. This fact
casts doubt on the possible formation of intermediate zinc
alkynides in the reactions under study, although this asꢀ
sumption has been made earlier.16,17 Apparently, the
germylation of an alkyne follows an analogous electroꢀ
philic mechanism proposed earlier for direct silylation of
alkꢀ1ꢀynes and confirmed experimentally.9 In this case,
coordination of zinc dihalide to aminogermane through
its N atom makes the Ge atom more electrophilic and
simultaneously forms an effective leaving group. The forꢀ
mation of a similar germylating system from a tertiary
amine and germanium halides is also possible in the reacꢀ
tions shown in Scheme 2. In this case, zinc dihalide seems
to bind the chloride anion and shift the reaction equilibꢀ
rium to the right (Scheme 3).
solids that are stable up to their melting points. They can
find use in the synthesis of scarcely accessible organoꢀ
germanium compounds and polymeric materials.
Experimental
IR spectra were recorded on an InfraꢀLUM FTꢀ02 specꢀ
trometer in the 4500—350 cm–1 range (experimental error
+0.5 cm–1). 1H NMR spectra were recorded on a Tesla BS 587
instrument (80 MHz) in CDCl3 with HMDS as the internal
standard.
Table 2. Effect of the germylation conditions on the yields of
alkynylgermanes 4 and 5
Comꢀ
pound
Germylation conditions
Yield
(%)
Method of
τ*/h
Solvent
Scheme 3
the synthesis
4b
4c
4d
5b
5c
A
C
A
C
A
C
B
C
B
C
4
3
4
3
3.5
2
4
2.5
4
3.5
THF
Dioxane
THF
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
THF
81
85
80
86
75
81
79
87
78
85
The reactions outlined in Schemes 1 and 2 can be
used to obtain not easily accessible triꢀ and tetraalꢀ
kynylgermanes. The method we propose has undoubted
advantages over conventional ones involving metallated
terminal alkynes. It is essential that our method is appliꢀ
cable to functionalized acetylene derivatives. The resultꢀ
ing alkynylgermanes are undistillable oils or crystalline
Dioxane
* The reaction duration.

1432
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 8, August, 2006
Andreev et al.
Table 3. 1H NMR data (80 MHz, CDCl3) for selected alkynylgermanes 4 and 5
Comꢀ
pound
δ
C≡CCH2
Other signals
Ge(C≡CBu)4 (4а)
2.27 (m, 8 H)
4.75 (s, 8 Н)
2.21 (t, 8 Н)
2.24 (m, 6 Н)
—
1.51 (m, 16 Н, CH2CH2Me); 0.92 (m, 12 Н, Me)
2.12 (s, 12 Н, COMe)
1.23 (m, 32 Н, CH2); 0.85 (m, 12 Н, Me)
7.31 (m, 5 Н, Ph); 1.48 (m, 12 Н, CH2CH2Me); 0.90 (m, 9 Н, Me)
7.34 (m, 5 Н, Ph); 1.14 (s, 27 Н, Me)
Ge(C≡CCH2OCOMe)4 (4d)
Ge(C≡CC6H13)4 (4е)
PhGe(C≡CBu)3 (5a)
PhGe(C≡CSiMe3)3 (5b)
The starting reagents and solvents were thoroughly purified
before use. Commercial zinc dihalides were additionally deꢀ
hydrated by melting (ZnCl2) or heating in vacuo (ZnBr2).
Tetrakis(phenylethynyl)germane (4c). Procedure A. A mixꢀ
ture of anhydrous ZnCl2 (10.6 g, 77.6 mmol) and dioxane
(150 mL) was heated to 85—90 °C. Phenylacetylene (7.92 g,
77.6 mmol) and tetrakis(diethylamino)germane (1a) (7 g,
19.4 mmol) were added. The reaction mixture was kept at 100 °C
for 4 h and treated with 5% HCl. The product was extracted with
chloroform and the extract was dried with CaCl2. Removal of
the solvent resulted in prompt crystallization of the residue. The
crystals were washed with methanol and recrystallized from benꢀ
zene—light petroleum, m.p. 188—189 °C (cf. Ref. 11: m.p.
188—189 °C). IR (CCl4), ν/cm–1: 2190 (C≡C).
Phenyltris(trimethylsilylethynyl)germane (5b). Procedure B.
A mixture of anhydrous ZnCl2 (10.6 g, 77.6 mmol) and dioxane
(150 mL) was heated to 85—90 °C. Trimethylsilylacetylene
(7.92 g, 77.6 mmol) and tris(diethylamino)phenylgermane (2a)
(7 g, 19.4 mmol) were added. The reaction mixture was kept at
100 °C for 4 h and treated with 5% HCl. The product was
extracted with chloroform and the extract was dried with CaCl2
and concentrated. The residue crystallized slowly; m.p. 121 °C
(from hexane). IR (CCl4), ν/cm–1: 2180 (C≡C).
Tetrakis(3ꢀacetoxypropynꢀ1ꢀyl)germane (4d). Procedure C.
A mixture of anhydrous ZnCl2 (16.32 g, 0.120 mol) and dioxane
(150 mL) was heated to 85—90 °C. Triethylamine (12.2 g,
0.121 mol) and propargyl acetate (11.76 g, 0.120 mol) were
added. After 10 min, GeCl4 (6 g, 0.028 mol) was added. The
reaction mixture was kept at 100 °C for 4 h and treated with
5% HCl. The product was extracted with chloroform and the
extract was dried with CaCl2 and concentrated. The resulting oil
was purified by column chromatography on Merck 250 silica gel
with chloroform as the eluent to give a light yellow oil that
crystallized slowly, m.p. 57 °C (from hexane). IR (CCl4),
ν/cm–1: 2195 (C≡C); 1750 (C=O).
References
1. L. K. Luneva, Usp. Khim., 1967, 36, 1140 [Russ. Chem. Rev.,
1967, 36 (Engl. Transl.)].
2. W. E. Davidson and M. C. Henry, Chem. Rev., 1967, 67, 73.
3. J. Satge, M. Lesbre, and M. Baudet, C. R. Acad. Sci., 1964,
259, 4733.
4. V. F. Mironov, E. S. Sobolev, and L. M. Antipin, Zh. Obshch.
Khim., 1967, 37, 1707 [J. Gen. Chem. USSR, 1967, 37 (Engl.
Transl.)].
5. N. V. Komarov and A. A. Andreev, Dokl. Akad. Nauk SSSR,
1981, 261, 103 [Dokl. Chem., 1981 (Engl. Transl.)].
6. M. F. Shostakovskii, N. V. Komarov, I. S. Guseva, and
V. K. Misyunas, Dokl. Akad. Nauk SSSR, 1965, 163, 390
[Dokl. Chem., 1965 (Engl. Transl.)].
7. K. Jones and M. F. Lappert, Proc. Chem. Soc., 1964, 22.
8
. M. F. Shostakovskii, N. V. Komarov, and T. I. Ermolova,
Dokl. Akad. Nauk SSSR, 1967, 175, 1079 [Dokl. Chem., 1967
(Engl. Transl.)].
9. A. A. Andreev, V. V. Konshin, N. V. Komarov, M. Rubin,
C. Brouwer, and V. Gevorgyan, Org. Lett., 2004, 6, 421.
10. N. V. Komarov and O. G. Yarosh, Zh. Obshch. Khim.,
1967, 37, 264 [J. Gen. Chem. USSR, 1967, 37 (Engl.
Transl.)].W
11. K. H. Birr and D. Z. Kräft, Z. Anorg. Allg. Chem., 1961,
311, 235.
12. H. Hartmann and M. K. El A´ssar, Naturwissenschaften,
1965, 52, 304.
13. H. Hartmann, H. Wagner, B. Karbstein, M. K. El A´ssar,
and W. Reiss, Naturwissenschaften, 1964, 51, 215.
14. H. H. Anderson, J. Am. Chem. Soc., 1952, 74, 1421.
15. I. V. Efimova, B. E. Kalganov, M. A. Kazankova, and I. F.
Lutsenko, Zh. Obshch. Khim., 1983, 54, 459 [J. Gen. Chem.
USSR, 1983, 54 (Engl. Transl.)].
16. N. Anand and E. M. Carreira, J. Am. Chem. Soc., 2001,
123, 9687.
17. D. E. Frantz, R. Fässler, and E. M. Carreira, J. Am. Chem.
Soc., 2000, 122, 1806.
All other products were obtained according to one or two
procedures A, B, or C described above (see Tables 1, 2). The
physicochemical properties and spectroscopic characteristics of
the products are given in Tables 1 and 3.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. r_yug_a
06ꢀ03ꢀ96667).
Received December 22, 2005;
in revised form June 7, 2006