New approach to 1-(phenylethynyl)germatranes and 1-(phenylethynyl)-3,7,10-trimethylgermatrane. Reactions of 1-(phenylethynyl)germatrane with N-bromosuccinimide and bromine

Article abstract of DOI:10.1016/S0022-328X(01)00708-2

Reaction of N(CH₂CHRO)₃GeBr (2a, b) with LiCCPh affords N(CH₂CHRO)₃GeCCPh (1a, b) (a, R=H; b, R=Me). Compound (1b) was also obtained by treatment of Cl₃GeCCPh (3) with N(CH₂CHMeOSnEt₃)₃ (4). (1a) reacts with N-bromosuccinimide to yield N(CH₂CH₂O)₃GeC(Br)₂C(O)Ph (5). Cis-N(CH₂CH₂O)₃GeC(Br)=C(Br)Ph (6) is formed by the reaction of 1a with Br₂ in equivalent amounts. All compounds were characterized by ¹H- and ¹³C-NMR spectroscopy and mass spectrometry. Single crystal structures of 1a and 6 were determined by X-ray diffraction studies.

Full text of DOI:10.1016/S0022-328X(01)00708-2

Journal of Organometallic Chemistry 627 (2001) 1–5
www.elsevier.nl/locate/jorganchem
Preliminary Communication
New approach to 1-(phenylethynyl)germatranes and
1-(phenylethynyl)-3,7,10-trimethylgermatrane. Reactions of
1-(phenylethynyl)germatrane with N-bromosuccinimide and
bromine
Sergey S. Karlov a, Pavel L. Shutov c, Andrei V. Churakov b, Jo¨rg Lorberth c,*1,
Galina S. Zaitseva a,*2
a Chemistry Department, Moscow State Uni6ersity, B-234 Vorobe’yu Gori, 119899 Moscow, Russia
b Institute of General and Inorganic Chemistry, Russian Academy of Science, Leninskii Pr. 31, 117907 Moscow, Russia
c Fachbereich Chemie, Philipps-Uni6ersita¨t Marburg, Hans-Meerwein-Strasse, D-35032 Marburg/Lahn, Germany
Received 9 November 2000; accepted 16 January 2001
Abstract
Reaction of N(CH2CHRO)3GeBr (2a, b) with LiCꢀCPh affords N(CH2CHRO)3GeCꢀCPh (1a, b) (a, R=H; b, R=Me).
Compound (1b) was also obtained by treatment of Cl3GeCꢀCPh (3) with N(CH2CHMeOSnEt3)3 (4). (1a) reacts with N-bromo-
succinimide to yield N(CH2CH2O)3GeC(Br)2C(O)Ph (5). Cis-N(CH2CH2O)3GeC(Br)ꢁC(Br)Ph (6) is formed by the reaction of 1a
1
with Br2 in equivalent amounts. All compounds were characterized by H- and 13C-NMR spectroscopy and mass spectrometry.
Single crystal structures of 1a and 6 were determined by X-ray diffraction studies. © 2001 Elsevier Science B.V. All rights
reserved.
Keywords: Germatrane; Crystal structure; Alkyne; Bromination
for synthesis of 1-(phenylethynyl)germatranes, N(CH2-
CHRO)3GeCꢀCPh (1a, R=H; 1b, R=Me). We fo-
1. Introduction
cussed our attention on the chemical transformations of
some germatranes as reactive precursors for new types
of germatranes. Viewing the synthetic usability of 1 for
functionalized germatranes, we have investigated reac-
tions of germatrane N(CH2CH2O)3GeCꢀCPh (1a) with
N-bromosuccinimide (NBS) and bromine.
Recently we have reported an efficient approach for
the synthesis of various functionally substituted germa-
tranes by transesterification reaction between tri-
halogermanes and organotin derivatives of tris-
(2-hydroxyalkyl)amines
[1,2]:
1-(Phenylethynyl)-
germatrane (1a) was obtained via this method [3]. More
recently we have developed an alternative simple and
effective method for the preparation of germatranes
using reactions of easily available N(CH2CHRO)3GeX
(X=Br, OSiMe3, OTf) with lithium reagents [4]. In this
article we describe our studies of the same procedure
2. Results and discussion
Reactions of THF solutions of LiCꢀCPh with a
suspension of 1-bromogermatranes (2a,b) [5] in toluene
for 48 h at room temperature afford, after work-up,
germatranes 1a and 1b (1a: R=H, 1b: R=Me) in
yields 70 and 65%, respectively, as shown in Eq. (1).
1 *Corresponding author. Tel./fax: +49-64212825642; e-mail: lor-
berth@chemie.uni-marburg.de
2 *Corresponding author. e-mail: zait@org.chem.msu.su
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00708-2

2
S.S. Karlo6 et al. / Journal of Organometallic Chemistry 627 (2001) 1–5
The structure of 5 is consistent with a carbonyl
stretching vibration at 1661 cm−1 in the IR spectrum
and with an intensive peak of [C6H5CꢀO]+ at m/z 105
in the mass spectrum.
(1)
When the reaction of 1a with NBS was carried out in
water, ketone 5, accompanied by dibromoacetophenone
and 1-hydroxygermatrane (Eq. (4)) as a result of GeꢂC
1
bond cleavage, has been obtained H-NMR monitoring
showed full conversion of ketone 5 to hydrolysis prod-
ucts (3 months, H2O/CDCl3).
NMR control shows the absence of degradation prod-
ucts of the ‘atrane’ fragment.
Compound 1b was synthesized also using the ‘organ-
otin route’ for the formation of the atrane framework
(Eq. (2)).
(4)
Our results contrast with data for reactions of NBS
with acetylenes containing only organic substituents.
For instance, diphenylacetylene reacts with NBS/
DMSO with the formation of dibenzyl in high yield.
Under the same conditions unsymmetrically substituted
acetylene, e.g. methylphenylacetylene, gives a mixture
of three products with the predominance of a-diketone
[7].
(2)
Two types of reactions of 1-(phenylethynyl)ger-
matrane 1a have been examined: the first is the reaction
of 1a with N-bromosuccinimide (NBS), another reac-
tion is the addition of bromine.
Earlier we reported a reaction of 1-vinylsilatrane with
NBS/H2O to form a bromohydrin, N(CH2CHRO)3-
SiCH(Br)CH2OH with subsequent transformation of
NMR control showed the absence of a corresponding
a-diketone and 1,2-dibromoethylene (6) in the reaction
products (3). We were able to obtain 6 by treatment of
1a with bromine (Eq. (5)). The Z-isomer was obtained
exclusively and no traces of the E-isomer could be
detected (NMR spectra) in the reaction mixture and the
cis-structure of 6 was determinated by X-ray diffraction
studies.
the latter into
a
silatranylacetaldehyde, N(CH2-
CHRO)3SiCH2CHO [6]. Here we have studied the reac-
tion with NBS for the functionalization of 1a.
Treatment of 1a with NBS in DMSO provided, after
aqueous work-up, germatranyldibromoacetophenone 5
with yield 68% (Eq. (3)).
(3)
(5)
The result of reaction (5) is a rare example of the
formation of a Z-isomer in the electrophilic bromina-
tion of alkynes [10].
Mechanism of the bromination reaction with alkynes
was discussed [7–10]. At the moment we are unable to
explain significant differences in the reaction pathways
of organic and organometallic substituted ethynyls, but
may be caused by specific stereoelectronic properties of
the germatranyl group. Further studies to investigate
the mechanism are in progress.
1b, 5 and 6 were characterized by elemental analysis,
1H- and 13C-NMR spectroscopy and mass
spectrometry.
Structures of 1a and 6 were confirmed by a single
crystal X-ray analysis.
Fig. 1. Molecular structure of 1a. Hydrogen atoms are omitted for
,
clarity. Selected bond lengths (A) and angles (°): GeꢂN 2.178(6),
GeꢂC(1) 1.920(8), GeꢂO(1) 1.768(5), GeꢂO(2) 1.793(4), C(1)ꢂC(2)
1.19(1), C(1)ꢂGeꢂN 179.4(3), C(2)ꢂC(1)ꢂGe 179.5(7), C(1)ꢂC(2)ꢂC(3)
179.8(7).
The main geometrical parameters of 1a (Fig. 1) are
close to those previously reported for the same

S.S. Karlo6 et al. / Journal of Organometallic Chemistry 627 (2001) 1–5
3
molecule in the structure of its chloroform solvate (7)
[3]. The structure of 7 was measured at 150 K and
the atrane moiety in 7 did not display any kind of
disorder. In contrast, Ca atoms of the atrane skeleton
in molecule 1a are disordered over two positions re-
lated to each other by a mirror plane.
The molecular structure of 6 is shown in Fig. 2.
The coordination polyhedron of the germanium atom
in 6 is typical for germatrane derivatives [1,2a–c,3]
and represents a distorted trigonal bipyramid with N
and C atoms in the apical positions and the three
oxygen atoms in equatorial positions. The germanium
,
atom is displaced by 0.20 A from a plane defined by
three oxygen atoms. The bond angle at the NꢂGeꢂC
fragment is almost linear (178.0(7)°) and the NꢂGe
,
distance (2.23(1) A) is within the normal range for
germatranes containing a NꢂGeꢂC moiety (2.16–2.32
,
A) [3,11].
Fig. 2. Molecular structure of 6. Hydrogen atoms are omitted for
All five-membered rings GeꢂOꢂCH2ꢂCH2ꢂN of the
atrane skeleton in structure 6 are disordered over two
positions with approximately equal occupancies and
adopt an envelope conformation. Atoms C(21),
C(211), C(22), C(221), C(23) and C(231) (all in b-po-
sition to the nitrogen atom) occupy ‘flap’ sites while
the Ca atoms sit on the base envelope planes (Cb-en-
velope). It should be noted that germatranes without
Cb-substituents usually possess Ca-envelope conforma-
tion. The Cb-envelope conformation was previously
reported for structures of 3,7,10-methyl substituted
germatranes only [2c].
,
clarity. Selected bond lengths (A) and angles (°): Ge(1)ꢂN(1) 2.23(1),
Ge(1)ꢂC(1) 1.98(2), Ge(1)ꢂO(1) 1.78(1), Ge(1)ꢂO(2) 1.75(1),
Ge(1)ꢂO(3) 1.75(1), C(1)ꢂC(2) 1.30(2), C(1)ꢂGe(1)ꢂN(1) 178.0(7).
3.2. Reactions of 1-bromogermatranes 2a, b with
LiCꢀCPh
3.2.1. Synthesis of
1-(phenylethynyl)-3,7,10-trimethylgermatrane 1b
A 1M solution of LiCꢀCPh in THF (2.14 ml, 2.14
mmol) was added to a suspension of 2b (0.73 g, 2.14
mmol) in toluene (30 ml) at room temperature (r.t.).
The reaction mixture was stirred for 24 h at r.t., then
2/3 of the volatiles were evaporated in vacuo. A pre-
cipitate was filtered off and volatiles were removed in
vacuo. To the residue pentane (20 ml) was added and
the mixture stored at −30°C for 20 h. A white solid
was filtered off and dried in vacuo (1 Torr) for 3 h.
After sublimation (100°C/0.05 Torr) 0.54 g, (70%) of
3. Experimental
3.1. General comments
1b was obtained. 1H-NMR (C6D6):
l 0.80–3.9
All solvents were dried by standard methods and
distilled before use. Solutions of LiCꢀCPh in THF
were commercially obtained. Reactions with lithium
reagents were carried out under argon atmosphere us-
ing standard Schlenk techniques. 2a, 2b [5], 3 [12] and
4 [1] were prepared according to the literature. NMR
spectra were recorded at 25°C on Bruker AC 300 and
Varian VXR 400 spectrometers, CDCl3 and C6D6
were used as solvents and for internal deuterium lock.
(ABXM3 system of NCH2CHMeO group protons),
6.7–7.0, 7.3–7.5 (2m, C6H5, 5H); 13C-NMR (C6D6):
20.60, 20.71, 21.13, 23.22 (CH3); 58.97, 62.13, 62.45,
63.36, 63.82, 64.46, 65.90, 66.28 (NCH2, OCH); 90.12,
90.13 (GeCꢀ); 98.72, 98.75 (Cꢀ); 124.40, 124.41,
132.44, 132.45 (aromatic C; 4 signals at 127–128 ppm
are crossed with signals of C6D6); two diastereomers.
EI MS m/e (rel. int.): [M+] 363 (1.74); [M+
ꢂCH3CHO] 319 (12.74); [M+ꢂ2 CH3CHO] 275 (4.0);
[M+ꢂPhCꢀC] 262 (1.08); [M+ꢂPhCꢀCꢂCH3CHOꢂ
CH2CH(CH3)O] 160 (100). Anal. Found: C, 56.78; H,
6.63; Ge, 20.50. Calc. for C17H23GeNO3 (361.96): C,
56.41; H, 6.40; Ge, 20.05%.
Chemical shifts in the H- and 13C-NMR spectra are
1
given in ppm relative to internal TMS. Elemental
analyses were carried out by the Microanalytical Lab-
oratory of the Chemistry Department of the Moscow
State University. Mass spectra (EI-MS) were recorded
on a VARIAN CH-7a device using electron impact
ionisation at 70 eV; all assignments were made with
reference to the most abundant isotopes.
3.2.1.1. 1-(Phenylethynyl)germatrane 1a. Synthesis of
1a was analogous to that of 1b (Section 3.2.1) except
that 1-bromogermatrane 2a was used instead of 2b.

4
S.S. Karlo6 et al. / Journal of Organometallic Chemistry 627 (2001) 1–5
Yield 65%. 1H- and 13C-NMR data in CDCl3 are
consistent with those already published [3].
3.5. Reaction of 1a with bromine. Synthesis of
cis-1,2-dibromo-2-phenyl-1-germatranylethene 6
A solution of bromine (0.10 g, 0.63 mmol) in CCl4
was added to a solution of 1a (0.2 g, 0.63 mmol) in
CHCl3 (10 ml). The reaction mixture was stirred for 4 h
at r.t. and solvents were removed in vacuo. Hexane (5
ml) was added to the residue. A white solid was filtered
off and recrystallized from toluene to give 0.17 g (55%)
of 6, m.p. 191–192°C. IR (nujol): w 1560–1580 cm−1
3.3. Synthesis of 1-(phenylethynyl)germatrane 1b by
reaction of 3 with 4
A solution of Cl3GeCꢀCPh 3 (4.2 g, 15 mmol) in 20
ml of CHCl3 was added dropwise to a solution of
N(CH2CHMeOSnEt3)3 4 (12.89 g, 16 mmol) in 10 ml of
CHCl3. The reaction mixture was stirred for 4 h at r.t.,
then hexane (10 ml) was added and the precipitate was
filtered off, washed with cold hexane (5×10 ml) and
dried in vacuo (2 Torr) for 2 h. Yield: 5.1 g (94%).
1
(CꢁC). H-NMR (CDCl3): l 2.72 (t, NCH2, 6H); 3.55
(t, OCH2, 6H); 7.2–7.3, 7.4–7.5 (2m, C6H5, 5H); 13C-
NMR (CDCl3): l 52.45 (NCH2); 56.94 (OCH2); 134.59
(PhCꢁ); 126.40 (GeCꢁ); 127.17, 128.22, 129.14, 142.89
(aromatic C). EI MS m/e (rel. int.): [M+] 479 (0.2);
[M+ꢂBr] 400 (30); [AꢁM+ꢂCBrCBrC6H5] 220 (100);
[AꢂCH2O] 190 (36); [Aꢂ2CH2O] 160 (37); [C8H5Br] 180
(49); [AꢂCH2OꢂCH2CH2O] 146 (87); [Aꢂ3CH2O] 130
(14). Anal. Found: C, 35.33; H, 3.42; N, 2.72. Calc. for
C14H17Br2GeNO3 (479.69): C, 35.05; H, 3.57; N, 2.92%.
3.4. Reactions of 1a with NBS
3.4.1. Reaction of 1a with NBS (1:2) in DMSO.
Synthesis of
2,2-dibromo-2-germatranyl-1-phenyl-1-ethanone 5
NBS (0.28 g, 1.57 mmol) was added to a solution of
1a (0.25 g, 0.78 mmol) in DMSO (5 ml). The reaction
mixture was stirred for 24 h at r.t. and water (50 ml)
was added. The reaction mixture was extracted with
CHCl3 (20 ml), the extract was washed with water
(3×15 ml) and dried (MgSO4). CHCl3 was removed in
vacuo. The residue was recrystallized from chloroform/
hexane, dried in vacuo to give 0.26 g (68%) of 5 as a
colourless solid, m.p. 155–156°C. IR (nujol): w 1661
3.6. X-ray crystallographic study of 1a and 6
Crystal data for 1a: C14H17NO3Ge, M=319.88, or-
,
thorhombic, a=14.597(9), b=9.823(5), c=9.643(7) A,
3
,
V=1383(2) A , space group Pnma, Z=4, Dcalc=1.537
g cm−3, F(000)=656, v(Mo–Ka)=2.219 mm−1, col-
orless block with dimensions ca. 0.4×0.2×0.1 mm. A
total of 3547 reflections (1291 unique) were measured
on an Enraf-Nonius CAD4 diffractometer (graphite
1
cm−1 (CꢁO). H-NMR (CDCl3): l 2.89 (t, NCH2, 6H);
3.89 (t, OCH2, 6H); 7.33–7.47, 8.34–8.38 (2m, C6H5,
5H); 13C-NMR (CDCl3): l 40.97 (CBr2); 53.20 (NCH2);
57.51 (OCH2); 127.64, 131.24, 132.62, 132.79 (aromatic
C); 190.10 (CꢁO). EI MS m/e (rel. int.): [M+] 495 (11);
[AꢁM+ꢂCBr2COC6H5] 220 (100); [Aꢂ2CH2O] 160 (14);
[Aꢂ3CH2O] 130 (14); [C6H5CO] 105 (38). Anal. Found:
C, 33.78; H, 3.23; Ge, 14.30. Calc. for
C14H17Br2GeNO4 (495.69): C, 33.92; H, 3.46; Ge,
14.64%.
,
monochromatized Mo–Ka radiation, u=0.71073 A) at
r.t. Data were collected in the range 2.53BqB24.98
(−35h517, −115k52, −115l58) using ꢀ–
scan mode. The structure was solved by direct methods
[13] and refined by full-matrix least-squares on F2 [14]
with anisotropic thermal parameters for all non-hydro-
gen atoms. All H atoms were placed in calculated
positions and refined using a riding model. The atrane
skeleton was found to be disordered over two positions
with equal occupancies. Final residuals were R1=
0.0508, wR2=0.1062 for 761 reflections with I\2|(I)
3.4.2. Reaction of 1a with NBS (1:2) in water.
NBS (0.49g, 2.8 mmol) was added to a suspension of
1a (0.45 g, 1.4 mmol) in water (10 ml). The reaction
mixture was stirred for 48 h at r.t., then water was
removed in vacuo. 1H-NMR spectra of the residue
(0.92 g) showed the presence of 5 and Br2CHCOPh
and 112 parameters. Goodness-of-fit=0.965, maximum
−3
,
Dz=0.632 e×A
.
Crystal data for 6: C14H17NO3GeBr2, M=479.69,
monoclinic, a=9.288(2), b=10.256(2), c=17.061(7)
3
,
,
A, i=97.66(3)°, V=1611(1) A , space group P21/n,
Z=4, Dcalc=1.978 g cm−3, F(000)=936, v(Mo–
Ka)=6.873 mm−1, colorless block with dimensions ca.
0.3×0.1×0.05 mm. A total of 2188 reflections (1964
unique) were measured on an Enraf-Nonius CAD4
diffractometer (graphite monochromatized Mo–Ka ra-
1
(9:1) and succinimide (l 2.4 ppm). H- and 13C-NMR
data of Br2CHCOPh in CDCl3 are consistent with
those already published [8].
A solution of 5 in CDCl3 (not dried prior to use) was
1
stored in a NMR tube for 3 months. H-, 13C-NMR
,
data showed complete hydrolysis of germatrane 5 re-
diation, u=0.71073 A) at r.t. Data were collected in
sulting in the formation of Br2CHCOPh and
the range 1.30BqB21.97 (−95h59, 05k510,
05l517) using ꢀ–scan mode. The structure was
solved by direct methods [13] and refined by full-matrix
least-squares on F2 [14] with anisotropic thermal
1
N(CH2CH2O)3GeOH; H-, 13C-NMR data of the latter
in CDCl3 are consistent with those already published
[1].

S.S. Karlo6 et al. / Journal of Organometallic Chemistry 627 (2001) 1–5
5
Churakov, J.A.K.Howard, E.V. Avtomonov, J. Lorberth,
Chem. Ber, 130 (1997) 739, and references cited therein.
[2] (a) G.S. Zaitseva, S.S. Karlov, E.S. Alekseyeva, L.A. Aslanov,
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tomonov, A.V. Churakov, J.A.K. Howard, J. Lorberth, Z.
Naturforsch. 53b (1998) 1247. (c) G.S. Zaitseva, S.S. Karlov,
G.V. Pen’kovoy, A.V. Churakov, J.A.K. Howard, B.A.
Siggelkow, E.V. Avtomonov, J. Lorberth, Z. Anorg. Allg.
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parameters for all non-hydrogen atoms except disor-
dered carbon atoms. All H atoms were placed in calcu-
lated positions and refined using a riding model. The
atrane skeleton was found to be disordered over two
positions with equal occupancies. Final residuals were
R1=0.0723, wR2=0.1447 for 994 reflections with I\
2|(I) and 188 parameters. Goodness-of-fit=0.989,
−3
,
maximum Dz=0.717 e×A
.
4. Supplementary material
Crystallographic data (excluding structure factors) for
the structures reported here have been deposited with the
Cambridge Crystallographic Data Centre CCDC nos.
147346 (1a) and 140561 (6). Copies of this information
may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (Fax:
+44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk or
www: http://www.ccdc.cam.ac.uk).
[8] H. Masuda, K. Takase, M. Nishio, A. Hasegawa, Y.
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Alekseev, T.K. Gar, N.Yu. Khromova, I.R. Segel’man, Zh.
Strukt. Khim. 23 (1982) 101.
Acknowledgements
We thank Dr A.V. Yatsenko for the X-ray crystal
structure determination of 6. This work was supported
by the Fonds der Deutschen Chemischen Industrie (VCI)
for J.L. as well as by the Russian Foundation for Basic
Research under Grants No. 98-03-32988a for S.S.K.,
P.L.Sh. and G.S.Z. and No. 98-03-33142 for A.V.C.
[12] I.V. Efimova, B.E. Kalganov, M.A. Kazankova, I.F. Lut-
senko, Zh. Obshch. Khim. 54 (1984) 459.
[13] G.M. Sheldrick, Acta Crystallogr. A46 (1990) 467.
[14] G.M. Sheldrick, SHELXL-93. Program for the Refinement of
Crystal Structures, University of Go¨ttingen, Go¨ttingen, Ger-
many, 1993.
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