Preparation of germatranyl triflates: Reactions of germatranes N(CH2CHRO)3X (X=Br, OTf, OSiMe3; R=H, Me) with lithium reagents

Article abstract of DOI:10.1016/S0022-328X(99)00739-1

New germatranes N(CH₂CHRO)₃GeOTf (4a, R=H; 4b, R=Me) were prepared in quantitative yield by treatment of N(CH₂CHRO)₃GeOSiMe₃ (2a and 2b), with Me₃SiOTf. The reactions of germatranes N(CH₂CHRO)₃GeX [3a, X=Br, R=H; 4a, X=OSO₂CF₃, R=H; 4b, X=OSO₂CF₃, R=Me; 2a, X=OSiMe₃, R=H; 2b, X=OSiMe₃, R=Me] with LiY reagents were studied. A series of germatranes N(CH₂CHRO)₃GeY [5a, R=H, Y=Ind (indenyl); 5b, R=Me, Y=Ind; 6a, R=H, Y=N(SiMe₃)₂; 6b, R=Me, Y=N(SiMe₃)₂; 7a, R=H, Y=Cp (cyclopentadienyl); 7b, R=Me, Y=Cp; 8a, R=H, Y=Flu (fluorenyl); 9a, R=H, Y=t-Bu] were obtained by nucleophilic substitution with the corresponding LiY reagent. Reactions of N(CH₂CHMeO)₃GeOSiMe₃ (2b) and N(CH₂CH₂O)₃GeBr (3a) with excess n-BuLi and of N(CH₂CH₂O)₃GeOSiMe₃ (2a) with excess LiNMe₂ led to the formation of n-Bu₄Ge and (Me₂N)₄Ge. The structures of new germatranes 4a, 4b, 6b and 7b were confirmed by NMR spectroscopy, mass spectrometry and elemental analyses.

Full text of DOI:10.1016/S0022-328X(99)00739-1

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 598 (2000) 387–394
Preparation of germatranyl triflates: reactions of germatranes
N(CH2CHRO)3X (X=Br, OTf, OSiMe3; R=H, Me) with lithium
reagents
Sergey S. Karlov a, Pavel L. Shutov a, Novruz G. Akhmedov a, Markus A. Seip b,
Jo¨rg Lorberth* b,1, Galina S. Zaitseva* a,2
a Chemistry Department, Moscow State Uni6ersity, B-234 Vorob’e6y Gory, 119899 Moscow, Russia
b Fachbereich Chemie, Philipps-Uni6ersita¨t Marburg, Hans-Meerwein-Strasse, D-35032 Marburg/Lahn, Germany
Received 17 September 1999; accepted 24 November 1999
Abstract
New germatranes N(CH2CHRO)3GeOTf (4a, R=H; 4b, R=Me) were prepared in quantitative yield by treatment of
N(CH2CHRO)3GeOSiMe3 (2a and 2b), with Me3SiOTf. The reactions of germatranes N(CH2CHRO)3GeX [3a, X=Br, R=H;
4a, X=OSO2CF3, R=H; 4b, X=OSO2CF3, R=Me; 2a, X=OSiMe3, R=H; 2b, X=OSiMe3, R=Me] with LiY reagents
were studied. A series of germatranes N(CH2CHRO)3GeY [5a, R=H, Y=Ind (indenyl); 5b, R=Me, Y=Ind; 6a, R=H,
Y=N(SiMe3)2; 6b, R=Me, Y=N(SiMe3)2; 7a, R=H, Y=Cp (cyclopentadienyl); 7b, R=Me, Y=Cp; 8a, R=H, Y=Flu
(fluorenyl); 9a, R=H, Y=t-Bu] were obtained by nucleophilic substitution with the corresponding LiY reagent. Reactions of
N(CH2CHMeO)3GeOSiMe3 (2b) and N(CH2CH2O)3GeBr (3a) with excess n-BuLi and of N(CH2CH2O)3GeOSiMe3 (2a) with
excess LiNMe2 led to the formation of n-Bu4Ge and (Me2N)4Ge. The structures of new germatranes 4a, 4b, 6b and 7b were
confirmed by NMR spectroscopy, mass spectrometry and elemental analyses. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Germatranes; Lithium reagents
1. Introduction
Most of the previous extensive work on metallatranes
has been focused on the synthesis, physico-chemical
properties and RSA studies of these compounds in
order to confirm the supposed intramolecular M’N
coordination. Much less attention has been directed
toward chemical transformations of these compounds.
We are interested in the chemistry of metallatranes
(M=Si, Ge) that contain the substituent Z with differ-
ent steric and electronic properties, including studying
the influence of the ‘atrane’ moiety on the stability, the
reactivity and the ability to undergo chemical transfor-
mations [5a–d].
Atranes of type (A) are cyclic esters containing a
hypervalent atom M with a transannular interaction
between M and the bridgehead nitrogen atom [1,2]. The
nature of substituent Z affects the properties of atranes,
such as biological activities [3a,b] and the strength of
the transannular M’N bonding [4].
We have focused our attention on germatranes with
germanium–carbon bonds containing
a functional
group neighbouring the germanium atom (M=Ge,
Z=allyl [6a], phenylacetylenyl [6b], fluorenyl [6b,c,d],
benzyl [6e], alkoxycarbonylmethyl [4]). These com-
pounds have been found to be reactive precursors for
new types of germatranes. For example, we have
1 *Corresponding author. Tel./fax: +49-6421-282-5642; e-mail:
lorberth@chemie.uni-marburg.de
2 *Corresponding author.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00739-1

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S.S. Karlo6 et al. / Journal of Organometallic Chemistry 598 (2000) 387–394
2. Results and discussion
described two kinds of reactions proceeding with a
retention of both the ‘atrane’ skeleton and the GeꢀC
bond: cyclopropanation of allylgermatranes with
CH2N2/Pd(OAc)2 [6a], and stannylation of 1-fluorenyl-
germatranes [6c,d]. A series of the above-mentioned
germatranes [4,6a–e] was synthesized by a transmetal-
lation reaction of trihalogenogermanes with stannyl
esters of trialkanolamines. This organotin route to
germatranes achieved excellent results and can be
carried out using easily accessible trihalogenoger-
manes.
The starting materials, 1-trimethylsiloxygermatranes
(2a and 2b) [7,8], were prepared by a silylation reaction
of the monohydrates of 1-hydroxygermatranes (1) [1]
(here and for other compounds: a, R=H, b, R=Me)
with (Me3Si)2NH (Eqs. (1) and (2))).
GeO2+N(CH2CHROH)3/H2O“
N(CH2CHRO)3GeOH · H2O
(1)
(2)
1a,b
1a,b
(Me3Si)2NH ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢁ
Here we report our studies with functionalized
germatranes starting from the most simple and avail-
able germatranes — 1-hydroxygermatranes (1a and 1b)
[1].
−1/2(Me Si) O, −NH , −H O
3
2
3
2
N(CH2CHRO)3GeOSiMe3 2a,b
Compound 2a was used for the preparation of 1-bro-
mogermatrane (3a) [5a,8] (Eq. (3))
2a
Me3SiBrꢀꢀꢀꢀꢀꢀꢀꢁN(CH2CH2O)3GeBr
(3)
−(Me Si) O
2
3a
3
The new 1-trifluoromethanesulfonatogermatranes
(germatranyltriflates) (4a and 4b) were obtained almost
quantitatively by substitution of the OSiMe3 group with
the OSO2CF3(OTf) group from the reaction of (2a and
2b) with Me3SiOTf (Eq.(4)).
(4)
The synthetic potential of N(CH2CHRO)3GeX (X=
Br, OTf, OSiMe3) as precursors for functionally substi-
tuted germatranes was investigated in many reactions
with lithium reagents.
Triisopropanolamine derivatives (R=Me) were syn-
thesized in order to clarify the possible influence of
steric crowding on the reaction pathways.
2.1. Reactions of 1-bromogermatrane 3a with lithium
reagents
We demonstrate that these germatranes can be
transformed via 1-trimethylsiloxygermatranes (2a and
2b) to new germatranes N(CH2CHRO)3GeOSO2CF3
(4a, R=H) and (4b, R=Me). Germatranes 2–4 bear-
ing a highly electronegative apical substituent X react
with LiY reagents to yield the corresponding germa-
tranes 5–8. NMR data of the compounds 4a, 4b, 6b
and 7b are reported. To the best of our knowledge,
there have been no reports in the literature on the
reaction of germatranes with lithium reagents [1,2].
Interestingly, the ‘atrane’ framework in 2–4 was found
to be stable under reaction conditions with LiY when
Y=Flu, Ind, Cp, and N(SiMe3)2. Treatment of 2b and
3a with n-BuLi as well as 2a with LiNMe2 gave the
reaction products with the destruction of the ‘atrane’
fragment.
Halogenides of Ge(IV) are widely used as key
reagents in the synthesis of functionalized germanes [9].
Exchange reactions between halogenogermanes and
functionally substituted organotin compounds are a
convenient approach for the synthesis of various func-
tional germanes [9,10]. The question of whether 1-bro-
mogermatrane (3a) was suitable as a starting material
for an analogous route was explored by reacting it with
different organotin reagents. We have recently shown
that this method is applicable for the preparation of a
variety of 1-organoxygermatranes by replacement of
bromine in 3a in a reaction with organoxytrialkylstan-
nanes [5a]. However, our attempted reactions of germa-
trane 3a with organotin ketoenol derivatives failed [11].
These results contrasted those obtained for tetracoordi-
nated halogenogermanes in analogous reactions [10]. In

S.S. Karlo6 et al. / Journal of Organometallic Chemistry 598 (2000) 387–394
389
our present work from 3a and Et3SnN(SiMe3)2 we
obtained only an impure product in low yield.
The GeꢀO bonds remain unchanged in the case of the
reaction of 3a with LiN(SiMe3)2 (Eq. (7)). Compound
6a was obtained in moderate yield when a solution of 3a
in THF was treated with equimolar amounts of
LiN(SiMe3)2; the product was isolated as an analytically
pure sample and identified by comparison with an
authentic sample prepared earlier in our group by
reaction of 1a with [(Me3Si)2N]2Sn [15].
Therefore, we investigated another approach to func-
tionalized germatranes: reactions of germatrane 3a with
stronger nucleophilic reagents, e.g. with lithium
reagents. The results of this reaction essentially depend
on the nature of the lithium reagents; treatment of a
suspension of 3a in THF with an excess of n-butyl-
lithium in n-hexane at room temperature for 4 h pro-
vides, after work-up, tetra-n-butylgermane in 61% yield.
Therefore, n-butyllithium, acts as a strong, non-selective
nucleophilic reagent, alkylates GeꢀBr bonds and cleaves
GeꢀO bonds of the germatrane fragment (Eq. (5)).
(7)
3a4ꢀnꢀ-ꢀBuꢀLꢁin-Bu4Ge (61%)
(5)
Conversion of 3a into n-Bu4Ge takes place even in the
presence of only one equivalent of n-BuLi.
Reaction (7) contrasts a known reaction of four-coor-
dinate alkoxy and aryl germanium derivatives with
MN(SiMe3)2 (M=Na, Li), where GeꢀO bonds are
cleaved to form GeꢀN(SiMe3)2 bonds [16].
Treatment of germatrane 3a with fluorenyllithium or
9-Me3Ge-fluorenyllithium in THF at room temperature
for 12 h results, after standard work-up, in the forma-
tion of a mixture of the starting material and uniden-
tified products. In the case of CpLi, a reaction takes
place; however, 1-(5-cyclopentadienyl)germatrane (7a)
was only obtained in relatively low yield (29%).
Our results contrast with those obtained for a recent
study of the silicon analogue of 3a (1-halosilatranes)
with n-BuLi, where substitution, involving cleavage of
the equatorial SiꢀO bond rather than of the SiꢀHal
linkage, takes place. The lower reactivity of the SiꢀCl
bond of halogenosilatranes in this case was interpreted
as a consequence of the unusual molecular geometry of
the ‘atrane’ framework [12a,b]. The X-ray crystal struc-
ture analysis of the 1-bromogermatrane (3a) [13] shows,
that the GeꢀBr bond is considerably longer than a SiꢀCl
,
,
bond (2.36 A instead of 2.15 A [14]). The GeꢀBr bond
elongation in the structure of N(CH2CH2O)3GeBr is
correlated to the enhanced reactivity of the GeꢀBr bond
toward n-BuLi. In germatranes the germanium atom
possibly becomes hexacoordinated and nucleophilic
substitution of bromine may occur via the intermediate
B:
2.2. Reactions of germatranyltriflates 4a and 4b with
lithium reagents
Group 14 triflates are highly reactive reagents and
have been widely used for metallation and catalysis
[17a,b]. In this respect, germatranyltriflates 4 are
analogous (or even more reactive) to 1-bromogerma-
trane (3a) in their reactions with lithium reagents. Treat-
ment of triflates 4a and 4b (as a suspension in xylene)
with solutions of LiN(SiMe3)2 in THF–hexane led to
the formation of the corresponding 1-aminogermatranes
6a and 6b in good yields (Eq. (8)). A white solid 6b,
which was obtained after standard procedure as a
mixture of two diastereomers, was further purified by
sublimation.
In contrast to n-butyllithium, indenyllithium gave
with stoichiometric amounts of 3a 1-(1-in-
denyl)germatrane (5a) in 56% yield. NMR control
showed the absence of degradation products of the
‘atrane’ fragment (Eq. (6)).
(8)
(6)
Note the substantial difference in reactivity between
1-bromogermatrane 3a and germatranyltriflates 4a and

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S.S. Karlo6 et al. / Journal of Organometallic Chemistry 598 (2000) 387–394
4b toward LiN(SiMe3)2. It appears that the nature of
the leaving group is not of great importance since the
yields of 6a from reactions (7) and (8) are comparable.
Likewise, the OTf group in compounds 4a and 4b
can be easily replaced by a cyclopentadienyl group
resulting in the formation of germatranes 7a and 7b in
good yield (Eq. (9)):
produces the aminogermatrane 6a in good yield (Eq.
(11)):
LiN(SiMe )
3 2
2a ꢀꢀꢀꢀꢀꢀꢁ 6a (71%)
(11)
−LiOSiMe
3
This method is applicable for the synthesis of 1-indenyl-
3,7,10-trimethylgermatrane 5b and 1-(9-fluorenyl)-
germatrane 8a (Eqs. (12) and (13)):
(9)
(12)
(13)
Compound 7a is a known compound and was made
earlier by reacting Cl3GeCp with N(CH2CH2OSnEt3)3
[18]. Although this organotin route to give 7a has been
reported in 98% yield, our approach (reaction (9)) in
the case of this germatrane is preferable because of the
readily available starting reagents. Purification of the
reaction product from 4b with CpLi, obtained in a 70%
yield as a mixture of two diastereomers, gave almost
solely the symmetric diastereomer of 7b (NMR data).
The second (unsymmetric) diastereomer does not sub-
lime under these conditions.
However, extension of this method for synthesizing
1-(9-fluorenyl)germatrane (8a) was unsuccessful; all our
attempts to react 4a with fluorenyllithium failed. After
standard work-up we obtained a complex mixture of
products, all of which contained the starting material
4a.
Cleavage of the endocyclic GeꢀO bonds of the
‘atrane’ skeleton is the predominant reaction when 2a
was treated with an excess of LiNMe2 (Eq. (14)) and
t-BuLi (see Section 4).
2.3. Reactions of 1-trimethylsiloxygermatranes 2a and
2b with lithium reagents
(14)
We have recently shown that 1-trimethylsiloxyger-
matranes 2a and 2b can serve as excellent starting
materials for the preparation of a variety of 1-
halogenogermatranes [5a,8] (Eq. (10)):
With one equivalent of t-BuLi and 2a we could
obtain 1-t-butylgermatrane (9a) in satisfactory yield
(Eq. (15)):
E-Hal
N(CH2CHRO)3GeOSiMe3−ꢀꢀMꢀeꢀSꢀiꢀOꢁEN(CH2CHRO)3-
3
GeHal
(15)
R=H, Me; E-Hal: HF, SOCl2, Me3SiBr, Me3SiI (10)
Other results concerning the reactivity of 1-trimethyl-
siloxygermatranes have not been reported. Previously it
has been described that the reaction of phenyllithium
with Me3GeOSiMe3 quantitatively affords Me3GePh
(as a product of nucleophilic attack at the electrophilic
germanium atom) [19].
Reaction (16) shows that methyl groups in positions 3,
7 and 10 of the ‘atrane’ fragment do not prevent the
cleavage of the equatorial GeꢀO bonds with n-BuLi.
No reactions were detected from 2a and CpLi or
Me4CpLi.
Treatment of 2a with one equivalent of LiN(SiMe3)2
in hexane–THF, analogous to reactions (7) and (8),

S.S. Karlo6 et al. / Journal of Organometallic Chemistry 598 (2000) 387–394
391
lar Ge’N bond of germatranes takes place with the
lithium reagents.
The reactions occur without degradation of the cyclic
skeleton of the molecule. We have developed a simple
and effective method of preparation under very mild
conditions from 1-cyclopentadienyl-, 1-indenyl-, 1-(9-
fluorenyl)- and 1-[bis(trimethylsilyl)amino]germatranes,
N(CH2CHRO)3GeY, using reactions of lithium
reagents with N(CH2CHRO)3GeX (X=Br, OTf,
OSiMe3; R=H, Me) as easily available starting materi-
als. We are attempting to further extend the scope of
this method to functionally substituted germatranes.
(16)
All compounds were characterized by H-, 13C- (ex-
cluding 4a and 4b) and 19F- (for 4a and 4b) NMR
spectroscopy; new compounds 4a, 4b, 6b and 7b were
also characterized by elemental analyses and mass
spectrometry.
1
1H- and 13C-NMR spectra were in accordance with
1
the suggested structures. In the H-NMR spectrum of
4. Experimental
4a, signals of the methylene protons of the germatrane
skeleton appear as a set of two pseudo-triplets, forming
an AA%XX% spin system (J=5.6 Hz). This pattern is a
general feature of the ‘atrane’ framework for a variety
of germatranes [1,4,6]. 3,7,10-Trimethylsubstituted
metallatranes 4b, 6b and 7b are mixtures of two
diastereomers which differ in the orientation of the
methyl groups relative to the GeꢀN-axis (Structures C
and D).
4.1. General comments
The synthesis of 4a, 4b and reactions with lithium
reagents were carried out under an argon atmosphere
using standard Schlenk techniques. All solvents (hex-
ane, tetrahydrofuran (THF) and xylene) were dried by
standard methods and distilled before use. Solutions of
n-butyllithium in hexane were commercially obtained
and analysed regularly by the Gilman double-titration
method [21]. Commercially available Me3SiBr,
Me3SiOSO2CF3 and (Me3Si)2NH (Aldrich) were used
without further purification. Organoelement com-
pounds used in this study were prepared according to
the literature method indicated: N(CH2CH2O)3-
GeOH·H2O [7], N(CH2CH2O)3GeOSiMe3 [7], N(CH2-
CHMeO)3GeOSiMe3 [8], 9-trimethylgermyl-fluorene
[22], 1-trimethylsilylindene [23], N(CH2CH2O)3GeBr
[5a]. NMR spectra were recorded at 25°C in CDCl3,
C6D6 and CD5CD3 with internal deuterium lock, on
Bruker AMX 400 and Varian VXR 400 spectrometers.
Proton signals of the OCH(CH3)CH2N groups of the
‘atrane’ framework appear in the H-NMR spectra as
1
1
Chemical shifts in the H- and 13C-NMR spectra are
given in ppm relative to internal TMS; in 19F-NMR
experiments CFCl3 was used as an external standard.
Assignment of the 13C-NMR data were supported by
APT experiments. Elemental analyses were carried out
by the Microanalytical Laboratory of the Chemistry
Department of the Moscow State University and by
that of the Fachbereich Chemie of the Philipps-Univer-
sity Marburg (Heraeus-Rapid-Analyser). Mass spectra
(EI-MS, 70 eV) were recorded on a Varian CH-7a
device; all assignments were made with reference to the
most abundant isotopes.
complex multiplets (ABMX3 spin system). This pattern
is also a general feature of the 3,7,10-trimethylsubsti-
tuted ‘atrane’ framework. In this case the composition
of mixtures can be examined by 13C-NMR spectroscopy
as described earlier for other 1-substituted germatranes
[1,4,6]. In the 19F-NMR spectrum of 4a the signal of
the fluorine atoms of the CF3 groups appears at l= −
79.34 ppm; in the 19F NMR spectrum of 4b two signals
of the CF3 group appear for two diastereomers at
−78.81 and −79.18 ppm [20]. 5b is a mixture of four
diastereomers according to the 13C-NMR spectrum.
4.2. (1-Germatranyl)triflate, N(CH2CH2O)3GeOTf (4a)
3. Conclusions
To a solution of 2a (0.85 g, 2.8 mmol) in xylene (10
ml) Me3SiOTf was added (1 ml, 1.23 g, 5.5 mmol). The
mixture was stirred at r.t. for 12 h; after removal of all
volatiles in vacuo 1.03 g (100%) pure 4a was left as a
In summary, we conclude that in our studies substi-
tutive cleavage of equatorial GeꢀO bonds as well as a
cleavage of the apical bond opposite to the transannu-
1
white solid, m.p. \250°C. H-NMR (CDCl3): l 3.10

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S.S. Karlo6 et al. / Journal of Organometallic Chemistry 598 (2000) 387–394
(t, 6H, NCH2), 4.06 (t, 6H, OCH2). 19F NMR (CDCl3):
l −79.34. EI MS m/e (rel. int.): [M+−CH2O] 339
(20); [M+−2CH2O] 309 (24); [M+−CF3SO3] 220 (47);
100 (45); 86 (77); CF3, 69 (100). Anal. Calc. for
C7H12F3GeNO6S: C, 22.86; H, 3.29; N, 3.81. Found: C,
22.60; H, 3.30; N, 3.61%.
(Me3Si)2NH (0.17 g, 1 mmol) in THF (10 ml) and
n-butyllithium (0.6 ml, 1 mmol) as a 1.66 M solution in
hexane, was added to a suspension of 3a (0.30 g, 1
mmol) in THF (10 ml) at r.t. The reaction mixture was
stirred for 24 h at r.t., then two thirds of the volatiles
were evaporated in vacuo. A white precipitate was
filtered off and volatiles were removed in vacuo. The
residue was recrystallized from hexane–xylene, washed
with hexane (2×5 ml). After drying in vacuo 6a (0.25
g, 65%) was obtained as a white solid, m.p. 161–162°C
(Ref. [15]: 161–163°C).
4.3. [1-(3,7,10-Trimethylgermatranyl)]triflate,
N(CH2CHMeO)3GeOTf (4b)
The procedure is analogous to that in Section 4.2.
The reaction of 2b (1.0 g, 2.9 mmol) in xylene (10 ml)
with Me3SiOTf (1 ml, 1.23 g, 5.5 mmol) gave 1.19 g
1
4.6.2. Reaction of (1-germatranyl)triflate 4a with
LiN(SiMe3)2
The synthesis of 6a was analogous to that of 6a in
Section 4.6.1, except that a suspension of 4a in xylene
was used instead of a suspension of 4a in THF. 6a was
obtained in 76% yield.
(100%) of 4b as a white solid, m.p. \250°C. H-NMR
(CDCl3): l 1.30–4.30 (ABXM3 system of NCH2CH-
MeO group protons). 19F-NMR (CDCl3): l −78.81,
−79.18; two diastereomers, 4b-C and 4b-D. EI MS m/e
(rel. int.): [M+−CH3CHO] 367 (20); [M+−
2CH3CHO] 323 (24); [M+−CF3SO3] 262 (47); 128 (47);
100 (100); CF3, 69 (61). Anal. Calc. for C10H18F3-
GeNO6S: C, 29.30; H, 4.43; Ge, 17.71. Found: C, 29.13;
H, 4.53; Ge, 17.90%.
4.6.3. Reaction of 1-trimethylsiloxygermatrane 2a
with LiN(SiMe3)2
The synthesis of 6a was analogous to that of 6a in
Section 4.6.1 except that a suspension of 2a in toluene
was used instead of a suspension of 4a in THF. 6a was
obtained in 71% yield.
4.4. 1-(1-Indenyl)germatrane, N(CH2CH2O)3GeC9H7
(5a)
A solution of IndLi, prepared from indene (0.10 g,
0.84 mmol) and n-BuLi (0.49 ml, 0.84 mmol) as a 1.72
M solution in hexane, was added to a solution of 3a
(0.25 g, 0.84 mmol) in THF (10 ml) at room tempera-
ture (r.t.). The reaction mixture was stirred for 12 h at
r.t.; a precipitate was separated and volatiles were
evaporated in vacuo. The residue was recrystallized
twice from chloroform–hexane to give 0.16 g (56%
yield) of 5a as a white solid. 1H- and 13C-NMR data are
consistent with those already published [24].
4.7. Reaction of 3a with Et3SnN(SiMe3)2
A
mixture of 3a (0.5 g, 1.7 mmol) and
Et3SnN(SiMe3)2 (1.23 g, 3.4 mmol) was heated at 100°C
for 1 h. A mixture of Et3SnBr and Et3SnN(SiMe3)2 was
separated by vacuum distillation, b.p. 60–80°C (1 Torr)
(1H-NMR data). 1H and 13C spectra of the residue
showed the presence of 3a and of product 6a.
4.5. 1-(1-Indenyl)-3,7,10-trimethylgermatrane,
N(CH2CHMeO)3GeC9H7 (5b)
4.8. 1-[Bis(trimethylsilyl)amino]-3,7,10-
trimethylgermatrane, N(CH2CHMeO)3Ge N(SiMe3)2
(6b)
A solution of IndLi, prepared from indene (0.15 g,
1.26 mmol) in THF (10 ml) and n-BuLi (0.72 ml, 1.26
mmol) as a 1.75 M solution in hexane, was added to a
solution of 2b (0.44, 1.26 mmol) in benzene (10 ml) at
r.t. The reaction mixture was stirred for 12 h at r.t., a
precipitate was separated and volatiles were evaporated
in vacuo, the residue was recrystallized twice from
chloroform–hexane to give 0.22 g (46% yield) of 5b as
Synthesis of 6b was analogous to that of 6a (Section
4.6.2.) except that triflate 4b was used instead of 4a.
Colourless crystalline 6b was obtained on sublimation
at 80°C (2 Torr) with 68% yield, m.p. 149–151°C.
1H-NMR (CDCl3): l 1.30–4.30 (ABXM3 system of
NCH2CHMeO
group
protons);
0.48
(minor
1
a white solid (four diastereomers); H- and 13C-NMR
diastereomer, 6b-C), 0.49 (major diastereomer, 6b-D)
(2s, 9H, SiMe3). 13C-NMR (CDCl3): l 2.92 (SiMe3),
20.56, 20.71, 21.04, 23.18 (CH3); 59.24, 62.09, 62.45,
62.95, 63.86, 64.18, 65.69, 66.11 (NCH2, OCH). Two
diastereomers. EI MS m/e (rel. int.): [M+−Me] 407
(100); [M+−N(SiMe3)2] 262 (4). Anal. Calc. for
C15H36GeN2O3Si2 (421.22): C, 42.77; H, 8.61; Ge,
17.23. Found: C, 42.38; H, 8.43; Ge, 17.60%.
data are consistent with those already published [24].
4.6. 1-[Bis(trimethylsilyl)amino]germatrane,
N(CH2CH O)3GeN(SiMe3)2 (6a)
2
4.6.1. Reaction of 1-bromogermatrane 3a with
LiN(SiMe3)2
A
solution of LiN(SiMe3)2, prepared from

S.S. Karlo6 et al. / Journal of Organometallic Chemistry 598 (2000) 387–394
393
4.9. 1-(5-Cyclopentadienyl)germatrane (7a)
2a was used instead of 3a. 8a was obtained in 71%
1
yield; m.p. 240–241°C (Ref. [6b]: m.p. 240–242°C). H-
4.9.1. Reaction of (1-germatranyl)triflate 4a with
cyclopentadienyllithium
and 13C-NMR data are consistent with those already
published [6b].
A solution of cyclopentadienyllithium, prepared from
cyclopentadiene (0.06 g, 0.95 mmol) in THF (10 ml)
and n-butyllithium (0.6 ml, 0.95 mmol) as a 1.66 M
solution in hexane, was added to a suspension of 4a
(0.35 g, 0.95 mmol) in xylene (10 ml). Using a proce-
dure analogous to that of 6a (Section 4.6.1), product 7a
(0.18 g, yield 65%) was obtained as a white solid, m.p.
127–129°C (dec.) (Ref. [18]: 128–129°C (dec.)). 1H-
NMR data are consistent with those already published
[18].
4.12. Reactions of N(CH2CHRO)3GeX with n-BuLi
4.12.1. Reaction of 1-bromogermatrane (3a) with
n-BuLi
n-Butyllithium (2.0 ml, 3 mmol) as a 1.66 M solution
in hexane was added to a suspension of 3a (0.21 g, 0.7
mmol) in THF (10 ml). The mixture was stirred at r.t.
for 4 h; after evaporation of volatiles (one third of the
reaction mixture) under vacuo a precipitate was filtered
off. Evaporation of the solvents from the filtrate under
vacuo gave tetra-n-butylgermane (0.13 g) as a colour-
less liquid in 61% yield, n2D0 1.4567 (Ref. [25]: n2D0
1.4571). 13C-NMR data are consistent with those
already published [26].
4.9.2. Reaction of 1-bromogermatrane 3a with
cyclopentadienyllithium
A solution of cyclopentadienyllithium, prepared from
cyclopentadiene (0.17 g, 2.6 mmol) in THF (10 ml) and
n-butyllithium (1.64 ml, 2.6 mmol) as a 15% solution in
hexane, was added to a suspension of 3a (0.78 g, 2.6
mol) in THF (10 ml). at r.t. The reaction mixture was
stirred for 24 h at r.t., then two thirds of the volatiles
were evaporated in vacuo. A white precipitate was
filtered off and the volatiles were removed in vacuo.
The residue was recrystallized from pentane–toluene,
washed with pentane (2×5 ml). After drying in vacuo
product 6a (0.29 g, 39%) was obtained as a white solid,
m.p. 127–129°C (dec.) (Ref. [18]: 128–129°C (dec.)).
1H-NMR data are consistent with those already pub-
lished [18].
4.12.2. Reaction of 1-trimethylsiloxy-3,7,10-
trimethylgermatrane (2b) with n-BuLi
The procedure is analogous to that given in Section
4.12.1. except that 2b was used instead 3a. Tetra-n-
butylgermane was obtained in 65% yield.
4.13. Reaction of 1-trimethylsiloxygermatrane (2a)
with LiNMe2
The procedure is analogous to that given in Section
4.12.1. except that 2a was used instead 3a and LiNMe2
was used instead n-BuLi. Tetrakis(dimethylamino)-
germane was obtained in 65% yield as a pure colorless
liquid, b.p. 49–50°C (3 Torr) (Ref. [27]: b.p. 82–83°C
4.10. 1-(5-Cyclopentadienyl)-3,7,10-trimethyl-
germatrane (7b)
1
(12 Torr)). H and 13C-NMR data are consistent with
those already published [28].
Synthesis of 7b was analogous to that of 7a (Section
4.9.) except that triflate 4b was used instead 4a. A white
solid 7b (1.1 g, yield 70%) was obtained as a mixture of
two diastereomers. Sublimation at 80°C (2 Torr) af-
forded 0.33 g (m.p. 117–118°C (dec.) of pure symmetric
diastereomer 7b-D. 1H-NMR (C6D6): l 1.01–3.47
(ABXM3 system of NCH2CHMeO group protons);
4.09 (m, 1H, CHGe), 6.86 (m, 4H, Cp). 13C-NMR
(C6D6): l 20.70 (CH3), 38.95 (CHGe), 59.27 (NCH2),
62.19 (OCH), 130.53 (CHꢂ); 133.96 (CHꢂ). EI MS m/e
(rel. int.): [M+] 326 (1); [M+−C5H5] 262 (100); [M+−
C5H5−2CH3CHO] 174 (20); [M+−C5H5−CH3-
CHO−CH2CH(CH3)O] 160 (21), [M+−C5H5−
2CH3CHO−CH2CH(CH3)O] 130 (8). Anal. Calc. for
C14H23GeNO3 (325.93): C, 51.59; H, 7.11; Ge, 22.27.
Found: C, 52.08; H, 7.43; Ge, 22.60%.
4.14. 1-tert-Butylgermatrane, N(CH2CH2O)3GetBu (9a)
tert-Butyllithium (2.20 ml, 3.2 mmol) as a 15% solu-
tion in pentane was added to a suspension of 2a (1.00 g,
3.2 mmol) in THF (10 ml) at r.t. The reaction mixture
was stirred for 24 h at r.t., then two thirds of the
volatiles were evaporated in vacuo. A white precipitate
was filtered off and all volatiles were removed in vacuo.
The residue was recrystallized from pentane–toluene
and washed with pentane (2×5 ml). After drying in
vacuo product 9a (0.38 g, 42%) was obtained as a white
1
solid. H-NMR data are consistent with those already
published [29]. 13C-NMR (CDCl3): l 28.81 (CH3), 30.88
(CHGe), 53.51 (NCH2), 58.12 (OCH2).
4.15. Reaction of 1-trimethylsiloxygermatrane (2a)
with excess t-BuLi
4.11. 1-(9-Fluorenyl)germatrane (8a)
Synthesis of 8a was analogous to that of 5a (Section
4.4) except that fluorene was used instead of indene and
tert-Butyllithium (11.00 ml, 16 mmol) as a 15% solu-
tion in pentane was added to a solution of 2a (1.00 g,

394
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was stirred for 24 h at r.t., then all volatiles were
evaporated in vacuo. The residue was extracted with
pentane (2×10 ml) and the solvents were removed in
vacuo. H-NMR analysis of the residue gave evidence
for a complex mixture of products.
1
4.16. Attempted syntheses of N(CH2CHRO)3GeY
Reactions of 2a with CpLi, of 3a with FluLi and
(9-Me3Ge)FluLi, and also of 4a with FluLi (1-
Me3Si)IndLi, were carried out under standard condi-
1
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Acknowledgements
A research grant for G.S.Z. from the DAAD and
support from the Fonds der Deutschen Chemischen
Industrie VCI for J.L. and M.A.S. as well as from the
Russian Foundation for Basic Research under Grant
no. 98-03-32988a for S.S.K. and P.L.Sh. are gratefully
acknowledged.
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