Synthesis and characterization of new lithiated organogermanium compounds

Article abstract of DOI:10.1021/om960299n

New (8-methoxy-1-naphthyl)arylgermanes 1a-c are synthesized. The crystal structure of 1b (aryl = mesityl), determined by X-ray diffraction, shows that an intramolecular interaction occurs between the oxygen and germanium atoms, the Ge- - -O distance being 2.75 ?. The corresponding (diarylgermyl)lithiums R₂HGeLi are prepared in high yield by hydrogermolysis of tert-butyllithium in THF and are susprisingly stable. Their characterization by ¹H, ¹³C, and ⁷Li NMR spectroscopy is reported. Dimetalation of the initial arylgermanes depends upon steric hindrance around the germanium atom and the nature of the organolithium compound RLi. The reaction of 1a or 1c with n-BuLi followed by MeI affords the expected dialkylation product, whereas 1b gives the unexpected iodide 5b due to steric hindrance around the germanium atom.

Full text of DOI:10.1021/om960299n

4488
Organometallics 1996, 15, 4488-4492
Syn th esis a n d Ch a r a cter iza tion of New Lith ia ted
Or ga n oger m a n iu m Com p ou n d s
A. Castel, P. Rivie`re,* F. Cosledan, J . Satge´, M. Onyszchuk,† and A. M. Lebuis†
Laboratoire “He´te´rochimie Fondamentale et Applique´e”, UPRES(A) No. 5069, Universite´ Paul
Sabatier, 118 Route de Narbonne, 31062 Toulouse Ce´dex, France
Received April 18, 1996X
New (8-methoxy-1-naphthyl)arylgermanes 1a -c are synthesized. The crystal structure
of 1b (aryl ) mesityl), determined by X-ray diffraction, shows that an intramolecular
interaction occurs between the oxygen and germanium atoms, the Ge- - -O distance being
2.75 Å. The corresponding (diarylgermyl)lithiums R2HGeLi are prepared in high yield by
hydrogermolysis of tert-butyllithium in THF and are susprisingly stable. Their characteriza-
tion by 1H, 13C, and 7Li NMR spectroscopy is reported. Dimetalation of the initial
arylgermanes depends upon steric hindrance around the germanium atom and the nature
of the organolithium compound RLi. The reaction of 1a or 1c with n-BuLi followed by MeI
affords the expected dialkylation product, whereas 1b gives the unexpected iodide 5b due
to steric hindrance around the germanium atom.
In tr od u ction
In our studies of organogermyllithium compounds R2-
HGeLi1a we have described the first compounds of this
type1b and we have shown that they can be stabilized
by steric effects. More recently, the (triorganogermyl)-
lithiums (Me3Si)3GeLi‚2THF2a and Mes3GeLi‚2THF,2b
as well as a germacyclopentadienide anion,3a have been
isolated, suggesting the possibility of stabilization by
steric crowding or by an electronic effect. In this paper,
we consider the possibility of stabilization of (organ-
ogermyl)lithiums by intramolecular complexation. To
this end, we have used chelating substituents having
methoxy groups such as 2-methoxyphenyl and 1,8-
methoxynaphthyl, because methoxy groups are well-
known to undergo intramolecular coordination in orga-
nolithium systems.
F igu r e 1. ORTEP drawing of 1b with ellipsoids drawn at
50% probability.
Resu lts a n d Discu ssion
The starting diorganogermanes were prepared by an
organomagnesium route or directly by the reaction of
the corresponding organolithiums. Their reduction by
LiAlH4 gave the expected diorganogermanes 1 (eqs 1
and 2).
The new compounds are stable in air at room tem-
perature, but certain ones such as 1a should be stored
in the dark. In chlorinated solvents, the corresponding
chlorohydrogen derivatives, Ar2GeHCl, are formed rap-
idly.
The results of an X-ray crystal structure determina-
tion of compound 1b are shown in Figure 14 Tables 1
and 2. Regarding crystal packing, there is no evidence
of an intermolecular interaction between the methoxy
oxygen atom of one molecule and the germanium atom
of a neighboring molecule. A simple stacking of aro-
matic rings is observed. The Ge-O distance of 2.75 Å
is longer than that of the Ge-O covalent bond (1.95 Å)5
but appreciably less than the van der Waals radii sum
(3.40 Å). This suggests a weak coordinative interaction
between germanium and methoxy-oxygen atoms. In-
terestingly, a study of the structures of pentavalent
germanium compounds6 showed that Ge-O bond dis-
tances between 3.23 and 2.51 Å indicate weak interac-
tions, whereas distances between 2.17 and 2.08 Å
† Present address: Department of Chemistry, McGill University, 801
Sherbrooke St., West, Montreal, PQ, H3A 2K6, Canada.
X Abstract published in Advance ACS Abstracts, August 15, 1996.
(1) (a) Castel, A.; Rivie`re, P.; Satge´, J . J . Organomet. Chem. 1993,
462, 97. (b) Castel, A.; Rivie`re, P.; Satge´, J ., Ko, Y. H. Organometallics
1990, 9, 205.
(2) (a) Brook, A. G.; Abdesaken, F.; Soˆllradl, H. J . Organomet. Chem.
1986, 299, 9. (b) Castel, A.; Rivie`re, P.; Satge´, J .; Ko, Y. H.; Desor, D.
J . Organomet. Chem. 1990, 397, 7.
(3) (a) Hong, J . H.; Boudjouk, P. Bull. Soc. Chim. Fr. 1995, 132,
495. (b) Freeman, W. P.; Tilley, T. D.; Arnold, F. P.; Rheingold, A. L.;
Gantzel, P. K. Angew. Chem., Int. Ed. Engl. 1995, 34, 1887.
(4) J ohnson, C. K. ORTEP-A Fortran Thermal Ellipsoid Plot Pro-
gram; Technical Report ORNL-5138; Oak Ridge, TN, 1976.
(5) Rivie`re, P.; Rivie`re-Baudet M.; Satge´, J . Comprehensive Orga-
nometallic Chemistry; Pergamon Press: Oxford, U.K., 1982; Vol. 2,
Chapter 10.
S0276-7333(96)00299-3 CCC: $12.00 © 1996 American Chemical Society

Lithiated Organogermanium Compounds
Organometallics, Vol. 15, No. 21, 1996 4489
Ta ble 1. Cr ysta llogr a p h ic Da ta
Ta ble 2. Selected Bon d Len gth s (Å) a n d Bon d
An gles (d eg) in Com p ou n d 1ba
chem formula
fw
C20H22GeO
350.98
Ge(1)-O(1)
Ge(1)-HA
Ge(1)-HB
Ge(1)-C(1)
2.746(5)
1.47(5)
1.54(6)
1.966(6)
Ge(1)-C(11)
O(1)-C(8)
O(1)-C(20)
1.954(7)
1.354(11)
1.420(11)
cryst system
space group
Z
orthorhombic
Pbca
8
F(000)
a (Å)
b (Å)
1449.90
11.3208(13)
38.846(7)
8.1331(11)
3576.7(9)
1.304
C(1)-Ge(1)-C(11)
C(1)-Ge(1)-HA
C(1)-Ge(1)-HB
C(11)-Ge(1)-HA
105.6(3)
C(11)-Ge(1)-HB
HA-Ge(1)-HB
O(1)-Ge(1)-C(11)
110.5(21)
104.0(3)
175.20(23)
113.3(17)
110.9(21)
112.0(17)
c (Å)
V(Å3)
d (g cm-3
)
a
Standard uncertainties are in parentheses.
diffractometer
AFC6S
λ (Å) (graphite monochromator)
data collcn (deg in 2θ)
hkl range
1.54056
4-120
-12/12, -43/43, 0/9
0.50 × 0.40 × 0.02
20
ψ scans
22.8
0.802-0.998
0.011(3)
0.059
0.056
2.73
9745
2667
1801
228
44
atoms (mesityl, phenyl, and naphthyl) are near those
of the methoxynaphthyl group; they can be unambigu-
ously assigned by HMBC (1H/13C-3J ) and COSY (1H/
1H) correlations (Figure 2).2 Chemical shift variations
of ipso aromatic carbon atoms (cf. Table 3) toward low
field suggest a localization of negative charge on the
germanium atom.1b,8 At the methoxy group, shifts to
cryst size (mm)
collcn temp (°C)
abs corr
µ (cm-1
)
transm range
secondary extinctn
Ra
1
lower field are also observed, in the H NMR as in the
13C NMR spectra. The same phenomenon has already
been reported for the reaction of 1-methoxynaphthalene
with n-BuLi, and this has been attributed to an oxygen-
lithium complexation.9 In our case, strengthening of the
oxygen-germanium interaction in (organogermyl)lithi-
ums appears less probable because the germanium atom
already has a negative charge due to the presence of
the lithium. Therefore, we suggest an intramolecular
OCH3/Li interaction in a structure of the following type:
a
Rw
Sa
no. of reflcns measd
no. of unique reflcns (Rint
no. used in LS (I > 3σ(I))
no. of variables
)
no. of atoms
last ∆F map (e/Å3)
-0.33 to 0.33
a
2
R ) ∑||Fo| - |Fc||/∑|Fo|; Rw ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2; S )
[∑w(|Fo| - |Fc|)2/(N - V)]1/2
.
indicate strong interactions. The germanium atom
retains its tetrahedral geometry though slightly de-
formed (cf. Table 2) as has already been observed in
silicon analogs,7 and the two hydrogen atoms occupy
equatorial positions.
7
1
Our Li NMR spectra of (organohydrogermyl)lithiums
In the H NMR spectra, complexation is indicated by
were measured in THF relative to an external reference
consisting of 1 M LiCl in D2O (cf. Table 4). In a
comparison of the δ(7Li) signal of our germyllithiums
with those of n-BuLi and t-BuLi,10ab it appears that
germyllithiums exhibit a lower ionic character than
t-BuLi but a higher ionic character than n-BuLi. Thus,
as Lambert et al.10c have previously observed, the
ionicities of our germyllithiums are about midrange on
the scale for lithium-carbon systems.
a change in the chemical shift displacement, ∆δ ) -0.22
ppm, of the δ(OMe) signal relative to the starting
1-methoxynaphthalene. Such a shift is not observed in
1d for which a Ge‚‚‚O interaction appears difficult or
impossible.
These organogermanes easily undergo metalation on
reaction with t-BuLi giving (organohydrogermyl)lithi-
ums in high yield (eq 3).
The UV spectrum of the (arylgermyl)lithium 2a ,
compared to that of the starting compound 1a , exhibits
a new absorption band (λmax ) 348 nm) in a wavelength
range similar to those observed in the case of (trimeth-
ylgermyl)alkali metals. This absorption can be consid-
ered as characteristic of a transition from the nonbond-
ing orbital of the germyl anions (HOMO) to the more
accessible LUMO in the conjugated (arylgermyl)lithium
compound.11
Compound 1c gives only a moderate (∼50%) yield of
lithiation product with t-BuLi. The presence of two
methoxynaphthyl groups probably decreases the reac-
tivity of the Ge-H bond due to steric hindrance. The
(organogermyl)lithiums 2a ,c,d are very stable at ambi-
ent temperature; 2b should be prepared and stored at
low temperature.
The proton NMR spectra show high-field chemical
shift displacements characteristic of δ(GeH).1b In the
13C NMR spectra, displacements of ipso aromatic carbon
All new (organogermyl)lithiums were characterized
mainly by alkylation with MeI which proved to be the
best trapping agent.
(8) (a) Batchelor, R. J .; Birchall, T. J . Am. Chem. Soc. 1983, 105,
3848. (b) Mochida, K.; Matsushige, N.; Hamashima, M. Bull. Chem.
Soc. J pn. 1985, 58, 1443. (c) Bravo-Zhivotovskii, D. A.; Kalikhman, I.
D.; Pigarev, S. D.; Vyazankina, O. A.; Vyazankin, N. S. Zh. Obshch.
Khim. 1987, 57, 239; J . Gen. Chem. USSR (Engl. Transl.) 1987, 57,
210.
(9) Graybill, B. M.; Shirley, D. A. J . Org. Chem. 1966, 31, 1221.
(10) (a) Scherr, P. A.; Hogan, R. J .; Oliver, J . P. J . Am. Chem. Soc.
1974, 96, 6055. (b) Brevard, C.; Granger, P. Handbook of High
Resolution Multinuclear NMR; Wiley Interscience: New York, 1981;
p 84. (c) Lambert, J . B.; Urdaneta-Pe´rez, M. J . Am. Chem. Soc. 1978,
100, 157.
(6) Mozzchukhin, A. O.; Macharashvili, A. A.; Shklover, V. E.;
Struchkov, Yu. T.; Shipov, A. G.; Sergeev, V. N.; Artamkin, S. A.;
Pestunovich, S. V.; Baukov, Yu. I. J . Organomet. Chem. 1991, 408,
305.
(7) (a) Chuit, C.; Corriu, R. J . P.; Reye, C.; Young, J . C. Chem. Rev.
1993, 93, 1371. (b) Auner, N.; Probst, R.; Hahn, F.; Herdtweck, R. J .
J . Organomet. Chem. 1993, 459, 25.
(11) Mochida, K.; Kugita, T.; Nakadaira, Y. Polyhedron 1990, 9,
2263.

4490 Organometallics, Vol. 15, No. 21, 1996
Castel et al.
Ta ble 4. 7Li NMR Da ta (δ; in THF -d 8) for
(Dia r ylger m yl)lith iu m s
1b
2b
2c
2d
0.67 (s)
0.86 (s)
0.98 (s)
0.81 (s)
GeK2.8b More recently, the preparation of Et2GeLi2 by
a very difficult route has been described.12 Also, transi-
tory germyl anions [Me4C4Ge]-‚2M+ have been charac-
terized by a silylation reaction.3a,b The reaction of 2
equiv of n-BuLi with 1a followed by alkylation with MeI
gave the expected dimethyl derivative 4a almost quan-
titatively (eq 4).
Dialkylation using MeI1b,13 or disilylation using Me3-
SiCl,3a,b through direct nucleophilic substitution, is
thought to involve the transient formation of a germa-
nium-centered dianion. However, the reaction mecha-
nism might be more complex than expected, as we
observed that steric hindrance around the germanium
atom in 1b induces a different pathway which results
in the formation of the unexpected iodide 5b (eq 5). In
this case, a radical mechanism (eq 6) is proposed, as it
was recently shown that a reaction mixture of RI/RLi
can generate radical species R• by SET.14
In contrast, regardless of the organolithium used,
n-BuLi or t-BuLi, 1d gives only partial dialkylation
(eq 7).
1
F igu r e 2. (a) 2D H,1H COSY homonuclear shift correla-
1
tion using 45° read pulse of 1b. (b) 2D H/13C correlation
of 1b via heteronuclear zero and double-quantum coherence
optimized on long coupling with a low-pass, J -filter to
suppress one-bond correlations and no decoupling during
acquisition.
The dimethyl derivatives 4a ,d have also been syn-
thesized (eqs 8 and 9).
Ta ble 3. Va r ia tion of δ (p p m ) of th e
(Dia r ylger m yl)lith u m s Com p a r ed to Sta r tin g
Com p ou n d s
NMR 1H (THF-d8)
NMR 13C (THF-d8)
∆δ(OCH3) ∆δ(GeH) ∆δ(OCH3) ∆δ(C1′) ∆δ(C1)
2a /1a
2b/1b
2c/1c
2d /1d
-0.19
-0.22
-0.08
-0.01
-0.25
-0.36
-0.23
-0.61
+0.52
+0.40
+1.18
-0.18
+23.53 +28.68
+25.09 +27.16
+26.83
+25.47
These results show that the presence of methoxyphe-
nyl and methoxynaphthyl groups stabilizes (organohy-
We tried to prepare (organogermyl)dilithiums by the
same method. At present, little is known about ger-
myldilithiums. The formation of (diphenylgermyl)-
dilithium has been noted, without comment, in the
reaction of lithium with diphenylgermane in HMPA
using a method analogous to that described for Ph2-
(12) Bravo-Zhivotovskii, D. A.; Pigarev, S. D.; Vyazankina, O. A.;
Vyazankin, N. S. J . Gen. Chem. USSR (Engl. Transl.) 1987, 57, 2644.
(13) Ando, W.; Wakahara, T.; Akasaka, T. Organometallics 1994,
13, 4683.
(14) Holm, T. J . Organomet. Chem. 1996, 506, 37.

Lithiated Organogermanium Compounds
Organometallics, Vol. 15, No. 21, 1996 4491
) 0.059, Rw ) 0.056, and S ) 2.73. Calculations were done
with NRCVAX,16 and scattering factors are from usual sources.17
Atomic coordinates, bond lengths and angles, and thermal
parameters have been deposited with the Cambridge Crystal-
lographic Data Centre, University Chemical Laboratory, Lens-
field Road, Cambridge, U.K. CB2/EW.
drogermyl)lithiums. By contrast, dimetalations are
more difficult since they depend upon the substituent
on germanium and on the organolithium used. At
present, we are trying to stabilizes (organogermyl)-
dilithiums with strongly complexing bidentates with the
object of determining their true structures.
Syn th esis of Bis(8-m eth oxyn a p h th yl)ger m a n e, 1c. A
solution of 35.4 mmol of (8-methoxynaphthyl)lithium in 100
mL of THF was added dropwise to a solution at -78 °C of 3.8
g (17.7 mmol) of GeCl4 freshly distilled in 25 mL of THF. The
mixture was warmed to room temperature and stirred over-
night. The mixture was reduced with LiAlH4 as described
above. The residue so obtained was analyzed by 1H NMR and
showed the formation of three compounds. Several treatments
with a mixture of methanol/ether allowed isolation of pure 1c
Exp er im en ta l Section
All of the reactions were performed under a dry argon
atmosphere using standard Schlenk techniques. The com-
pounds were characterized by the usual analytical tech-
niques: 1H NMR, AC 80 Bruker; 13C NMR, AC 200 and ARX
7
400 Bruker; Li NMR, AC 200 Bruker (external reference: 1
M LiCl in D2O); IR, Perkin-Elmer 1600 FT; mass spectra,
Ribermag R 10 10 (DCI, CH4) and HP 5989 A (CG/MS); UV,
Hewlett Packard 8452 A diode array spectrophotometer (solu-
tions in THF). Elemental analyses were done by the Centre
de Microanalyse de l’Ecole Nationale Supe´rieure de Chimie
de Toulouse.
1
as white crystals: 2.29 g (33%); mp 131 °C; H NMR (CDCl3)
δ 3.68 (s, 6H, OCH3), 5.81 (s, 2H, GeH2), 6.81 (dd, J ) 6.2 Hz,
J ) 2.5 Hz, 2H, C10H6), 7.24-7.46 (m, 6H, C10H6), 7.59 (dd, J
) 6.8 Hz, J ) 1.6 Hz, 2H, C10H6), 7.81 (dd, J ) 7.8 Hz, J ) 1.6
Hz, 2H, C10H6); 13C NMR (50.32 MHz, CDCl3, {1H}) δ 54.31
(OCH3), 104.68, 121.21, 125.63, 126.19, 128.76, 129.61, 133.30,
134.94, 135.41, 156.52 (C10H6); IR (Nujol) 2077.2, 2028.8 (GeH);
MS (EI, 70 eV) m/z 390 ((M+), 18%); 389 ((M - H), 22%), 374
((M - H - CH3), 8%), 233 ((M - C11H9O), 14%). Anal. Calcd
for C22H20GeO2: C, 67.93; H, 5.18. Found: C, 67.76; H, 5.24.
Syn th esis of (8-m eth oxy-1-n a p h th yl)p h en ylger m a n e,
1a . A solution of 17.9 mmol of (8-methoxynaphthyl)lithium15
in 50 mL of THF was added dropwise at 20 °C to a suspension
of 18.8 mmol of MgBr2 in 20 mL of THF. The mixture was
refluxed 2 h and then added to a solution of PhGeCl3 (5.58 g,
17.9 mmol) in 14 mL of THF. The mixture was stirred at room
temperature overnight and then reduced by LiAlH4 (1.71 g,
44.9 mmol) in 30 mL of ether. After 1 h at 40 °C, hydrolysis,
extraction, drying with Na2SO4, and concentration, the residue
was distilled resulting in 1a (4.08 g, 74%): Bp 120 °C/0.05
mmHg; mp 34 °C; 1H NMR (CDCl3) δ 3.74 (s, 3H, OCH3), 5.46
(s, 2H, GeH2), 6.80 (dd, J ) 6.2 Hz, J ) 2.5 Hz, 1H, C10H6),
7.24-7.59 (m, 8H, C6H5, C10H6), 7.72 (dd, J ) 6.9 Hz, J ) 1.6
Hz, 1H, C10H6), 7.85 (dd, J ) 7.9 Hz, J ) 1.6 Hz, 1H, C10H6);
13C NMR (50.32 MHz, CDCl3, {1H}) δ 53.78 (OCH3), 128.22,
128.47, 134.74, 137.72 (C6H5), 104.84, 121.38, 126.01, 126.23,
129.41, 129.45, 129.68, 135.10, 136.36, 155.98 (C10H6); IR (neat)
2014.9, 2061.4 (GeH); MS (EI, 70eV) m/z 310 ((M+), 63%), 309
((M - H), 82%), ((M - H - CH3), 43%), 233 ((M - Ph), 23%).
Anal. Calcd for C17H16GeO: C, 66.10; H, 5.22. Found: C,
66.35; H, 4.89.
Syn th esis of Bis(2-m eth oxyp h en yl)ger m a n e, 1d .
A
solution of 100 mmol of (2-methoxyphenyl)magnesium (pre-
pared from 5 g (206 mmol) of Mg and 18.94 g (100 mmol) of
1-bromoanisole) was added dropwise to a solution of GeCl4
(10.82 g, 50 mmol) in 200 mL of ether. The mixture was
stirred overnight and then hydrolyzed (6 N HCl), extracted,
dried, and concentrated. The residue was dissolved into 40
mL of THF and reduced with LiAlH4 as above. After concen-
tration, the reaction mixture was crystallized by adding 30
mL of pentane. Pure white crystals of 1d were obtained after
a second recrystallization from pentane: 4.88 g (34%); mp 85-
86 °C; 1H NMR (CDCl3) δ 3.78 (s, 3H, OCH3), 5.01 (s, 2H,
GeH2), 6.91 and 7.34 (m, 4H, C6H4); 13C NMR (50.32 MHz,
CDCl3, {1H}) δ 55.51 (OCH3), 109.84, 121.01, 122.90, 136.96,
163.20 (C6H4;. IR (Nujol) 2077 (GeH); MS (EI, 70 eV) m/z 290
((M+), 31%); 182 ((M - H - (MeOC6H4), 32%). Anal. Calcd
for C14H16GeO2: C, 58.20; H, 5.58. Found: C, 57.94; H, 5.46.
Syn th esis of Mesityl(8-m eth oxyn a p h th yl)ger m a n e, 1b.
A solution of 22.8 mmol of (8-methoxynaphthyl)lithium15 in
50 mL of THF was added dropwise at -78 °C to a solution of
6.79 g (22.79 mmol) of MesGeCl3 in 50 mL of THF. The
mixture was warmed to room temperature and stirred at 20
°C overnight. It was then reduced with LiAlH4 as described
above. The residue so obtained was recrystallized from
methanol leading to pure white crystals of 1b: 5.27 g (66%);
mp 83 °C; 1H NMR (CDCl3) δ 2.32 (s, 3H, p-CH3), 2.35 (s, 6H,
o-CH3), 3.89 (s, 3H, OCH3) 5.46 (s, 2H, GeH2), 6.85 (dd, J )
5.9 Hz, J ) 2.7 Hz, 1H, C10H6), 6.91 (s, 2H, C6H2), 7.20-7.44
(m, 4H, C10H6), 7.82 (dd, J ) 6.8 Hz, J ) 2.5 Hz, 1H, C10H6);
13C NMR (50.32 MHz, CDCl3, {1H}) δ 21.28 (p-CH3), 23.87 (o-
CH3), 128.26, 129.94, 138.54, 144.24 (C6H2), 104.90, 121.37,
125.85, 126.27, 129.22, 129.56, 132.67, 134.17, 135.17, 156.52
(C10H6); IR (Nujol) 2125.6, 2076.9 (GeH); MS (EI, 70 eV) m/z
352 ((M+), 81%), 351 ((M - H), 76%), 233 ((M - C9H11), 29%),
336 ((M - H - CH3), 38%). Anal. Calcd for C20H22GeO: C,
68.44; H, 6.31. Found: C, 68.46; H, 6.30.
Cr ysta l a n d Exp er im en ta l Da ta for 1b. Crystallo-
graphic information is given in Table 1. An ORTEP4 diagram
of 1b is shown in Figure 1. Selected bond lengths and angles
are in Table 2. The structure was solved by the Patterson
heavy atom method; the first difference map afforded positions
for all atoms except hydrogen. Hydrogen atoms on Ge and in
methyl groups were located in difference maps, the remainder
were introduced in calculated positions, all C-H distances
were normalized to 0.95 Å, and thermal parameters were
refined anisotripically. Refinement was on |F| with weights
based on counting statistics. Final agreement factors were R
Rea ction of 1a -d w ith t-Bu Li. Gen er a l P r oced u r e. A
solution of 1.4 mmol of t-BuLi (1.7 M in pentane) was added
to a solution of the organogermane (1 mmol) in 4 mL of THF
(1a , 20 °C; 1b-d , -40 °C). The mixture was stirred for 40
min at the indicated temperature. Analysis by 1H, 13C, and
7Li NMR showed that the corresponding (organogermyl)-
lithiums were formed in high yield.
2a (red solution) (90%): 1H NMR (400.13 MHz, THF-d8) δ
3.41 (s, 3H, OCH3), 5.11 (s, 1H, GeH), 6.48 (d, J ) 7.5 Hz, 1H,
H7 naphthyl), 6.78 (t, J ) 7.1 Hz, 1H, H4 phenyl), 6.87 (dd, J
) 7.1 Hz, J ) 6.8 Hz, 2H, H3 phenyl), 6.96 (dd, J ) 7.6 Hz, J
) 6.8 Hz, 1H, H3 naphthyl), 7.05 (dd, J ) 7.5 Hz, J ) 7.9 Hz,
1H, H6 naphthyl), 7.15 (d, J ) 7.9 Hz, 1H, H5 naphthyl), 7.28
(d, J ) 7.6 Hz, 1H, H4 naphthyl), 7.50 (d, J ) 6.8 Hz, 2H, H2
phenyl), 7.97 (d, J ) 6.6 Hz, 1H, H2 naphthyl); 13C NMR
(100.62 MHz, THF-d8, {1H}) δ 54.90 (OCH3), 123.77 (C4),
126.65 (C3), 137.43 (C2), 161.71 (C1) (C6H5), 104.05 (C7), 121.87
(C5), 124.50 (C4), 124.72 (C6 and C3), 133.42 (C9), 136.38 (C10),
7
136.62 (C2), 158.76 (C1), 160.15 (C8) (C10H6); Li NMR (77.77
MHz, THF-d8) δ 0.67 (s).
2b (red solution) (90%): 1H NMR (200.13 MHz, THF-d8) δ
2.13 (s, 3H, p-CH3), 2.36 (s, 3H, o-CH3), 3.57 (s, 3H, OCH3),
5.07 (s, 1H, GeH), 6.54 (d, J ) 8 Hz, 1H, C10H6), 6.59 (s, 2H,
C6H2), 6.77-7.24 (m, 4H, C10H6), 7.57 (d, J ) 7 Hz, 1H, C10H6);
13C NMR (50.32 MHz, THF-d8, {1H}) δ 21.53 (p-CH3), 26.70
(o-CH3), 54.86 (OCH3), 127.05, 132.40, 144.55, 155.57 (C6H2),
(16) Gabe, E. J .; Le Page, Y.; Charland, J . P.; Lee, F. I.; White, P.
S. J . Appl. Crystallogr., 1989, 22, 384.
(17) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, England, 1974; Vol. IV.
(15) Shirley, D. A.; Cheng, C. F. J . Organomet. Chem. 1969, 20, 251.

4492 Organometallics, Vol. 15, No. 21, 1996
Castel et al.
103.83, 121.59, 123.58, 124.25, 125.66, 133.00, 133.74, 136.32,
158.73, 160.20 (C10H6); Li NMR (77.77 MHz, THF-d8) δ 0.86
hydrolysis, extraction and concentration, analysis of the
residue by H NMR confirmed the formation of 4a (86%) and
7
1
(s) ppm.
3a (16%).
2c (red solution) (55%): 1H NMR (200.13 MHz, THF-d8) δ
3.50 (s, 6H, OCH3), 5.58 (s, 1H, GeH), 6.61 (d, J ) 7.3 Hz, 2H,
P r ep a r a tion of 4a . A solution of 8.7 mmol of t-BuLi (1.7
M in pentane) was added to 3a (2 g, 6.2 mmol) in 10 mL of
THF at -40 °C. The mixture was stirred at -40 °C for 40
min and treated with an excess of MeI (see above). Analysis
of the residue by 1H NMR showed the presence of 4a (96%).
4a was then distilled: Bp 68 °C/0.003 mmHg; 1H NMR (CDCl3)
δ 0.76 (s, 6H, CH3), 3.61 (s, 3H, OCH3), 6.74 (dd, J ) 6.3 Hz,
J ) 2.5 Hz, 1H, C10H6), 7.24-7.51 (m, 8H, C6H5, C10H6), 7.62
(dd, J ) 6.9 Hz, J ) 1.7 Hz, 1H, C10H6), 7.81 (dd, J ) 7.8 Hz,
J ) 1.8 Hz, 1H, C10H6); 13C NMR (50.32 MHz, CDCl3, {1H}) δ
0.58 (CH3), 53.88 (OCH3), 127.77, 127.84, 133.30, 144.27
(C6H5), 104.27, 121.36, 125.68, 125.82, 129.21, 134.36, 134.55,
135.30, 156.00 (C10H6); MS (EI, 70eV) m/z ) 338 ((M+), 12%),
323 ((M - CH3), 85%), 308 ((M - 2 CH3), 48%), 261 ((M -
C
10H6), 6.95 (d of d, J ) 7.8 Hz, J ) 7.1 Hz, 2H, C10H6), 7.12
(d of d, J ) 7.6 Hz, J ) 8 Hz, 2H, C10H6), 7.24-7.43 (m, 4H,
10H6), 7.92 (d, J ) 6.7 Hz, 2H, C10H6); 13C NMR (50.32 MHz,
C
THF-d8, {1H}) δ 55.59 (OCH3), 105.00, 122.20, 123.99, 126.01,
133.52, 135.13, 136.30, 160.40, 160.76 (C10H6); 7Li NMR (77.77
MHz, THF-d8) δ 0.98 (s) ppm.
2d (yellow solution) (90%): 1H NMR (200.13 MHz, THF-
d8) δ 3.88 (s, 3H, OCH3), 4.60 (s, 1H, GeH), 6.80-8.00 (m, 6H,
C6H4); 13C NMR (50.32 MHz, THF-d8, {1H}) δ 55.33 (OCH3),
109.08, 120.67, 125.59, 139.78, 146.82, 164.26 (C6H4).
Rea ction of 2a -d w ith MeI. An excess of MeI (100%) was
added to a solution of (organohydrogermyl)lithium at the
temperature used for their preparation (2a , 20 °C; 2b-2d -40
°C). The mixture was allowed to warm to ambient tempera-
ture for 1 h. After hydrolysis, extraction, and concentration,
the residue yielded the following.
C6H5), 12%), 293 ((M - 3CH3), 31%). Anal. Calcd for C19H20
GeO: C, 67.72; H, 5.98. Found: C, 68.23; H, 6.38.
-
Rea ction of 1b w ith 2 n -Bu Li. A solution of 1.7 mmol of
n-BuLi (1.6 M in hexane) was added to 1b in 2 mL of ether at
-20 °C. After 8 min at this temperature, an excess of MeI
was added. The mixture was allowed to warm to ambient
temperature during 1 h and then concentrated. The residue
was treated with 10 mL of CH2Cl2. After decantation from
LiI, the solution was evaporated leading to a white powder
identified as 5b: 0.11 g (28%); mp 155-165 °C; 1H NMR
(CDCl3) δ 1.54 (s, 3H, CH3), 2.25 (s, 9H, p-CH3 and o-CH3),
3.38 (s, 3H, OCH3), 6.75 (dd, J ) 1.8 Hz, J ) 6.9 Hz, 1H,
C10H6), 6.76 (s, 2H, C6H2), 7.24-7.66 (m, 3H, C10H6), 7.87 (dd,
J ) 1.4 Hz, J ) 8.2 Hz, 1H, C10H6), 8.18 (dd, J ) 1.4 Hz, J )
6.9 Hz, 1H, C10H6); 13C NMR (50.32 MHz, CDCl3, {1H}) δ 16.35
(CH3), 21.02 (p-CH3), 23.80 (o-CH3), 54.07 (OCH3), 129.35,
134.87, 138.88, 141.08 (C6H2), 104.33, 121.79, 125.69, 127.04,
129.49, 134.17, 136.36, 137.68, 154.21 (C10H6); MS (DCI, CH4)
m/z ) 493 ((MH)+, 2%), 477 ((M - CH4), 3%), 461 ((M - CH3-
3a (51%): viscous oil which slowly precipitated white
crystals at 20 °C; mp 51-53 °C; 1H NMR (CDCl3) δ 0.79 (d, J
) 3.1 Hz, 3H, GeCH3), 3.67 (s, 3H, OCH3), 5.42 (q, J ) 3.1 Hz,
1H, GeH), 6.77 (dd, J ) 6.1 Hz, J ) 2.2 Hz, 1H, C10H6), 7.24-
7.52 (m, 8H, C6H5, C10H6), 7.68 (dd, J ) 6.9 Hz, J ) 1.5 Hz,
1H, C10H6), 7.83 (dd, J ) 7.9 Hz, J ) 1.6 Hz, 1H, C10H6); 13C
NMR (50.32 MHz, CDCl3, {1H}) δ -2.21 (CH3Ge), 54.07
(OCH3), 127.98, 128.12, 133.98, 141.02 (C6H5), 104.49, 121.31,
125.77, 126.01, 129.36, 131.01, 132.49, 135.13, 135.55, 155.96
(C10H6); IR (pure) 2043.9, 1991.4 (GeH); MS (EI, 70 eV) m/z )
324 ((M+), 26%), 309 ((M - CH3), 100%), 231 ((M - CH3
-
C6H6), 40%), 200 ((M - CH3 - C6H6 - OCH3, 11%). Anal.
Calcd for C18H18GeO: C, 66.94; H, 5.62. Found: C, 66.70; H,
5.68.
3b (47%): viscous oil; bp 80 °C/0.01 mmHg (with partial
1
decomposition); H NMR (CDCl3) δ 0.76 (d, J ) 3.4 Hz, 3H,
OH), 2%), 365 ((M - HI), 100%). Anal. Calcd for C21H23
GeIO: C, 51.38; H, 4.72. Found: C, 50.82; H, 4.80.
-
GeCH3), 2.29 (s, 9H, o-CH3 and p-CH3), 3.67 (s, 3H, OCH3),
5.66 (q, J ) 3.4 Hz, 1H, GeH), 6.78 (dd, J ) 6.1 Hz, J ) 2.7
Hz, 1H, C10H6), 6.84 (s, 2H, C6H2), 7.24-7.53 (m, 3H, C10H6),
7.61 (dd, J ) 6.9 Hz, J ) 1.6 Hz, 1H, C10H6), 7.78 (dd, J ) 7.9
Hz, J ) 1.7 Hz, 1H, C10H6); 13C NMR (50.32 MHz, CDCl3, {1H})
δ -0.43 (GeCH3), 21.14 (p-CH3), 24.32 (o-CH3), 54.22 (OCH3),
128.45, 134.55, 137.87, 143.41 (C6H2), 104.57, 121.32, 125.69,
126.11, 128.98, 131.12, 133.56, 135.24, 135.95, 156.51 (C10H6);
IR (pure) 2062.0, 1980.5 (GeH); MS (EI, 70 eV) m/z 366 ((M+),
6%), 351 ((M - CH3), 100%), 336 ((M - 2CH3), 29%), 247 ((M
- C9H11), 26%), 232 ((M - CH3 - C9H11), 38%).
Rea ction of 3b w ith MeI. The mixture of 3b (0.064 g (0.13
mmol), 5 mL of MeI, and a catalytic quantity of AIBN (2,2′-
azobis(2-methylpropionitrile)) was heated at 80 °C for 48 h.
After concentration under vacuum, the analysis of the trans-
parent residue showed the formation of 5b (50%) with decom-
position.
Rea ction of 1d w ith 2 n -Bu Li. A solution of 1.8 mmol of
n-BuLi (1.6 M in hexane) was added to a solution of 1d (0.22
g, 0.75 mmol) in 2 mL of ether at -40 °C. After 1 h, an excess
of MeI was added and the mixture was treated using the same
conditions as those described above. Analysis of the residue
3c formed as a white powder. 1H NMR analysis showed
the presence of 3c (70%). Further recrystallizations did not
allow us to isolate pure 3c. 1H NMR (CDCl3): δ 0.80 (d, J )
2.8 Hz, 3H, GeCH3), 3.58 (s, 6H, OCH3), 5.76 (q, J ) 2.8 Hz,
1H, GeH), 6.76 (dd, J ) 2.4 Hz, J ) 6.3 Hz, 2H, C10H6), 7.24-
7.51 (m, 6H, C10H6), 7.62 (dd, J ) 1.5 Hz, J ) 6.8 Hz, 2H,
1
by H NMR showed the formation of 3d (51%) and 4d (49%).
Rea ction of 1d w ith 2 t-Bu Li. The same reaction was
realized with t-BuLi and led, after treatment with MeI, to a
mixture of 3d (41%) and 4d (59%).
10H6), 7.78 (dd, J ) 1.5 Hz, J ) 7.8 Hz, 2H, C10H6). 13C NMR
P r ep a r a tion of 4d . A solution of 1d (0.54 g, 2 mmol) in 5
mL of CCl4 with a catalytic quantity of AIBN was warmed at
reflux for 1 h. After concentration, a white powder identified
as (MeOC6H4)2GeCl2 (0.54 g, 75%) was obtained. This com-
pound was alkylated by MeMgI (20 mmol). After hydrolysis,
extraction, and concentration, 0.20 g (32%) of 4d was ob-
C
(50.32 MHz, CDCl3, {1H}): δ 0.88 (GeCH3), 54.11 (OCH3),
104.30, 121.21, 125.47, 125.99, 128.52, 134.75, 135.05, 136.47,
156.29 (C10H6). IR (Nujol): 2071.5, 2009.5 (GeH). MS (GC-
MS, EI, 30 eV): m/z 404 ((M+), 6%), 389 ((M - CH3), 100%),
374 ((M - 2CH3), 33%).
1
tained: Mp 68-72 °C; H NMR (CDCl3) δ 0.65 (s, 6H, CH3),
3d (64%) was obtained after crystallization from pentane:
Mp 45-46 °C; 1H NMR (CDCl3) δ 0.78 (d, J ) 3 Hz, 3H, CH3),
3.81 (s, 3H, OCH3), 5.17 (q, J ) 3 Hz, 1H, GeH), 6.84-7.44
(m, 4H, C6H4); 13C NMR (50.32 MHz, CDCl3, {1H}) δ -4.27
(CH3), 55.40 (OCH3), 109.94, 120.85, 126.04, 130.58, 136.08,
163.32 (C6H4); IR (Nujol) 2073 (GeH); MS (EI, 70 eV) m/z )
304 ((M+), 10%), 289 ((M - CH3), 30%). Anal. Calcd for
3.75 (s, 3H, OCH3), 6.79-7.31 (m, 4H, C6H4); 13C NMR (50.32
MHz, CDCl3, {1H}) δ -1.66 (CH3), 55.22 (OCH3), 109.75,
120.60, 128.46, 130.13, 135.25, 163.41 (C6H4); MS (EI, 70 eV)
m/z 318 ((M+), 8%), 303 ((M - CH3), 100%). Anal. Calcd for
C16H20GeO2: C, 60.64; H, 6.36. Found: C, 59.99; H, 6.26.
C
15H18GeO2: C, 59.43; H, 5.99. Found: C, 58.63; H, 6.14.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, atom coordinates, thermal parameters, and bond dis-
tances and angles and ORTEP diagrams (11 pages). Ordering
information is given on any current masthead page.
Rea ction of 1a w ith 2 n -Bu Li. A solution of 2.5 mmol of
n-BuLi (1.6 M in hexane) was added to a solution of 1a (0.25
g, 0.8 mmol) in 1 mL of ether at -40 °C. The mixture was
stirring at -40 °C for 1 h, and an excess of MeI (0.2 mL) was
then added. The mixture was allowed to warm for 2 h. After
OM960299N