Ni-catalyzed double gemylation of alkynes and alkenes

Article abstract of DOI:10.1021/om020399v

The reaction of 1,2-bis(dimethylgermyl)carborane with Ni(PEt₃)₄ yielded the cyclic bis-(germyl)nickel complex 2. 2 was found to be a good catalyst for the double germylation reaction. Thus, the reaction of 1 with RC=CR′ in the presence of a catalytic amount of 2 yielded the six-membered digermyl ring compounds B₁₀H₁₀C₂(GeMe₂)₂(RC=CR ′) (R = R′ = Ph (3); R = Ph, R′ = H (4); R = R′ = Et (5); R = Ph, R′ = Me (6); R = R′ = Me (7); R = Ph, R′ = SiMe₃ (8); R = R′ = SiMe₃ (9); R = R′ = CO₂Me (10)). In contrast, the reaction of 1 with 1-hexyne under the same reaction conditions yielded the five-membered digermyl ring compound B₁₀H₁₀C₂(GeMe₂)₂(C=C(C ₄H₉)H) (11). The intermediate was also found to be a good reactant for the double germylation of some alkenes. Thus, the stoichiometric reaction of 2 with 4-vinylanisole and 1,1-diphenylethylene gave the five-membered digermylene compounds (14 and 15). However, the stoichiometric reaction of 2 with 2,3-dimethylbutadiene afforded a different type of five-membered digerma compound 17 via the 1,4-migration of the hydride. The crystal structures of 2, 6, 12, 14, and 17 are described.

Full text of DOI:10.1021/om020399v

3922
Organometallics 2002, 21, 3922-3929
Ni-Ca ta lyzed Dou ble Gem yla tion of Alk yn es a n d Alk en es
J unghyun Lee,† Taegweon Lee,† Shim Sung Lee,‡ Ki-Min Park,§
Sang Ook Kang,*,† and J aejung Ko*†
Department of Chemistry, Korea University, Chochiwon, Chungnam 339-700, Korea,
Department of Chemistry, Gyeongsang National University, Chinju 660-701, Korea and
Research Institute of Natural Sciences, Gyeongsang National University,
Chinju 660-701, Korea
Received May 20, 2002
The reaction of 1,2-bis(dimethylgermyl)carborane with Ni(PEt3)4 yielded the cyclic bis-
(germyl)nickel complex 2. 2 was found to be a good catalyst for the double germylation
reaction. Thus, the reaction of 1 with RCtCR′ in the presence of a catalytic amount of 2
yielded the six-membered digermyl ring compounds B10H10C2(GeMe2)2(RCdCR′) (R ) R′)
Ph (3); R ) Ph, R′ ) H (4); R ) R′ ) Et (5); R ) Ph, R′ ) Me (6); R ) R′ ) Me (7); R ) Ph,
R′ ) SiMe3 (8); R ) R′ ) SiMe3 (9); R ) R′ ) CO2Me (10)). In contrast, the reaction of 1 with
1-hexyne under the same reaction conditions yielded the five-membered digermyl ring
compound B10H10C2(GeMe2)2(CdC(C4H9)H) (11). The intermediate was also found to be a
good reactant for the double germylation of some alkenes. Thus, the stoichiometric reaction
of 2 with 4-vinylanisole and 1,1-diphenylethylene gave the five-membered digermylene
compounds (14 and 15). However, the stoichiometric reaction of 2 with 2,3-dimethylbutadiene
afforded a different type of five-membered digerma compound 17 via the 1,4-migration of
the hydride. The crystal structures of 2, 6, 12, 14, and 17 are described.
In tr od u ction
(chlorogermyl)platinum has been structurally charac-
terized by Tanaka and co-workers.5
Recently, we6 reported a variety of silylation reactions
of a bis(silyl)nickel complex containing an o-bis(dimeth-
ylsilyl)carboranyl unit (A). We were also successful in
preparing its congener, o-bis(dimethylgermyl)carborane
(1).7
Although the transition metal-catalyzed double silyl-
ation of unsaturated organic substrates has been well
documented for three decades,1 little is known about the
double germylation2 because the synthetic methods
available for organogermanium compounds are quite
limited compared with those for organosilicon com-
pounds. The double germylation reactions were mainly
carried out in the presence of [Pd(PPh3)4] as a catalyst.3
Recently, Mochida and co-workers reported on the
platinum-catalyzed bis-germylation of alkynes with
organodigermanes and cyclic oligogermanes.4 In the
catalytic cycle, the bis(germyl) complexes have been
implicated as important intermediates. However, there
are only a few precedents for such species and only bis-
The property of moderate reactivity makes 1 a good
choice for the double germylation reaction. Accordingly,
we have started an investigation of the synthesis of the
bis(germyl)nickel complex bearing a bulky o-carboranyl
unit. We found that the bis(germyl)nickel complex is the
most efficient and reactive catalyst for the double
germylation reaction. This study includes the first
crystal structure of a cyclic bis(germyl)nickel complex
and a variety of double germylation reactions with
alkynes and alkenes. Early results of this study have
already been communicated.8
† Department of Chemistry, Korea University.
‡ Department of Chemistry, Gyeongsang National University.
§ Research Institute of Natural Sciences, Gyeongsang National
University.
(1) (a) Beletskaya, I.; Moberg, C. Chem. Rev. 1999, 99, 3435. (b)
Sharma, H. K.; Pannel, K. H. Chem. Rev. 1995, 95, 1351. (c) Suginome,
M.; Ito, Y. Chem. Rev. 2000, 100, 3221. (d) Okinoshima, H.; Yamamoto,
K.; Kumada, M. J . Am. Chem. Soc. 1972, 94, 9263. (e) Tamao, K.;
Miyake, N.; Kiso, Y.; Kumada, M. J . Am. Chem. Soc. 1975, 97, 5603.
(2) (a) Komoriya, H.; Kako, M.; Nakadaira, Y.; Mochida, K.
Organometallics 1996, 15, 2014. (b) Barrau, J .; Rima, G.; Cassano, V.;
Satge´, J . Inorg. Chim. Acta 1992, 198, 461. (c) Barrau, J .; Rima, G.;
Cassano, V.; Satge´, J . Organometallics 1995, 14, 5700. (d) Hayashi,
T.; Yamashita, H.; Sakakura, T.; Uchimaru, Y.; Tanaka, M. Chem. Lett.
1991, 245. (e) Mochida, K.; Hodota, C.; Yamashita, H.; Tanaka, M.
Chem. Lett. 1992, 1635.
(3) (a) Komoriya, H.; Kako, M.; Nakadaira, Y.; Mochida, K. J .
Organomet. Chem. 2000, 611, 420. (b) Tsumuraya, T.; Ando, W.
Organometallics 1989, 8, 2286. (c) Tsumuraya, T.; Ando, W. Organo-
metallics 1990, 9, 869.
(4) Mochida, K.; Wada, T.; Suzuki, K.; Hatanaka, W.; Nishiyama,
Y.; Nanjo, M.; Sekine, A.; Ohashi, Y.; Sakamoto, M.; Yamamoto, A.
Bull. Chem. Soc. J pn. 2001, 74, 123.
(5) Yamashita, H.; Kobayashi, T.; Tanaka, M. Organometallics 1992,
11, 2330.
(6) (a) Kang, Y.; Lee, J .; Kong, Y. K.; Kang, S. O.; Ko, J . Chem.
Commun. 1998, 2343. (b) Kang, Y.; Lee, J .; Kong, Y. K.; Kang, S. O.;
Ko, J . Organometallics 2000, 19, 1772. (c) Kang, Y.; Kim. J .; Kong, Y.
K.; Lee, S. W.; Kang, S. O.; Ko, J . Organometallics 2000, 19, 5027. (d)
Kim. J .; Kang, Y.; Lee, J .; Kong, Y. K.; Gong, M. S.; Kang, S. O.; Ko,
J . Organometallics 2001, 20, 937.
(7) Lee, C.; Lee, J .; Lee, S. W.; Kang, S. O.; Ko, J . Inorg. Chem. 2002,
41, 3084.
10.1021/om020399v CCC: $22.00 © 2002 American Chemical Society
Publication on Web 08/22/2002

Ni-Catalyzed Double Gemylation of Alkynes and Alkenes
Organometallics, Vol. 21, No. 19, 2002 3923
1H and 31P NMR spectra and mass spectrum were
consistent with the structure determined by X-ray
crystallography. In particular, the 31P NMR signal was
shifted from -2.2 ppm in Ni(PEt3)3 to 6.18 ppm. The
mass spectrum of 2 showed a molecular ion at m/z 642.
The formation 2 may be interpreted in terms of the
insertion of nickel into one of the Ge-H bonds of 1 and
subsequent insertion of another Ge-H bond. The silicon
analogue has been reported to undergo a similar type
of dehydrogenation to give the bis-silyl metal complex.6b
For an alternate synthesis of complex 2, we have also
carried out the reaction of Ni(PEt3)4 with 3,4-carbora-
nylene-1,1,2,2-tetramethyl-1,2-digermacyclobutane,7 pre-
pared from the Wu¨rtz reaction of 1,2-bis(chlorogermyl)-
carborane and sodium in toluene, which was isolated
as orange crystals in 88% yield (eq 2). A similar cyclic
F igu r e 1. X-ray crystal structure of 2 with 50% probability
thermal ellipsoids depicted. Selected bond lengths [Å] and
angles [deg]: Ni-Ge(1) 2.3316(5), Ni-Ge(2) 2.3264(5),
Ni-P(1) 2.2146(10), Ni-P(2) 2.2230(10), Ge(1)-C(1) 2.028(3),
C(1)-C(2) 1.659(5), Ge(2)-C(2) 2.035(3), Ge(1)-Ni-Ge(2)
84.231(18), P(1)-Ni-P(2) 103.10(4), P(1)-Ni-Ge(2)
146.73(3), P(2)-Ni-Ge(2) 92.08(3), Ge(2)-C(1)-C(2)
110.4(2).
Resu lts a n d Discu ssion
bis(silyl)platinum complex has been reported.11 Such an
alkyne insertion by the reaction of digermylacyclohexa-
dienes with acetylenedicarboxylate in the presence of
[PdCl2(PPh3)2] was observed by Sakurai and co-work-
ers.12
Syn th esis of [o-(GeMe2)2C2B10H10]Ni(P Et3)2 Com -
p lex 2. The synthesis of 1,2-bis(dimethylgermyl)carbo-
rane (1) was prepared by the salt elimination reaction
of 1,2-Li2C2B10H10 and 2 equiv of Me2GeCl2, followed
by reduction with a mild reducing agent, NaB(CN)H3.7
Compound 1 is a crystalline solid that is relatively
stable in air and to brief heating to 108-110 °C.
Compound 1 is soluble in toluene and THF. In an
attempt to synthesize a stable bis(germyl)nickel com-
plex, we investigated the reaction of 1 with Ni(PEt3)4.
The addition of 1.1 equiv of o-bis(dimethylgermyl)-
carborane to Ni(PEt3)4 in pentane gave a red solution.
Standard workup and crystallization from toluene-
pentane gave [o-(GeMe2)2C2B10H10]Ni(PEt3)2 (2) as a
spectroscopically pure, red crystalline solid that is very
sensitive to air and water in 60% yield (eq 1). Compound
Nick el-Ca t a lyzed R ea ct ion w it h Alk yn es. As
expected, the nickel complex 2 was found to be an
efficient catalyst for the double germylation reaction
under mild conditions. Thus, the reaction of 1 (0.10 g,
0.29 mmol) with diphenylacetylene (0.06 g, 0.35 mmol)
in the presence of a catalytic amount of 2 (0.01 g, 0.016
mmol) was heated under the conditions specified in
Table 2. Subsequent recrystallization gave 5,6-carbo-
ranylene-1,1,4,4-tetramethyl-2,3-diphenyl-1,4-digerma-
cyclohex-2-ene (3) by insertion of the carbon-carbon
triple bond into a germanium-nickel bond of 2 (entry
1). In a similar fashion, the reaction of 2 with other
alkynes such as phenylacetylene, 3-hexyne, 1-phenyl-
1-propyne, 2-butyne, and 1-phenyl-2-(trimethylsilyl)-
acetylene under the same reaction conditions also
yielded the six-membered insertion products. Such
alkyne insertion reactions in Ge-M have been reported
for the palladium-catalyzed double germylation reac-
tions of 3,4-benzo-1,2-germacyclobut-3-ene,3a digermi-
ranes,3b and 1,2-dichloro-1,1,2,2-tetramethyldigermane.2c
Compounds 3-9 were identified on the basis of their
1H and 13C NMR spectra, mass spectra, and elemental
analyses. The 1H NMR spectrum of 6 showed the phenyl
and methyl resonances in the expected 5:3:6:6 ratio. In
the 13C NMR spectrum of 6, two resonances at 158.3
and 156.7 ppm could be assigned to the olefinic carbon
atoms. The mass spectrum of 6 showed a molecular ion
at m/z 464.
2 is soluble in toluene and THF. The structure of 2 was
unambiguously established by single-crystal X-ray analy-
sis and is shown in Figure 1. The crystallographic data
and processing parameters are given in Table 1. Com-
plex 2 has a distorted tetrahedral geometry with the
dihedral angle between Ge(1)-Ni-Ge(2) and P(1)-Ni-
P(2) being 84.60°. This unstable bis(germyl)nickel com-
plex is the first such compound as indicated by a search
of the Cambridge Crystallographic Database. The aver-
age Ni-Ge bond length [2.3290(5) Å] is slightly longer
than 2.248(1) Å found in CpNi(PPh3)GeCl3.9 The Ni-P
bond distance [2.2188(10) Å] is comparable to those
observed in other phosphine nickel compounds.10 The
To provide structural information for one of the newly
prepared compounds (3-9), a single-crystal X-ray dif-
fraction study of the 1-phenyl-1-propyne insertion prod-
uct 6 was undertaken. The molecular structure of 6 is
(10) Aresta, M.; Nobile, C. F.; Albano, V. G.; Forni, E.; Manassero,
M. J . Chem. Soc., Chem. Commun. 1975, 636.
(11) Kang, Y.; Kang, S. O.; Ko, J . Organometallics 2000, 19, 1217.
(12) Sakurai, H.; Kamiyama, Y.; Nakadaira, Y. J . Am. Chem. Soc.
1975, 97, 932.
(8) Lee, J .; Lee, C.; Lee, S. W.; Kang, S. O.; Ko, J . Chem. Commun.
2001, 1730.
(9) Glockling, F.; Mcgredor, A.; Schneider, M. L.; Shearer, H. M. M.
J . Inorg. Nucl. Chem. 1970, 32, 3101.

3924 Organometallics, Vol. 21, No. 19, 2002
Lee et al.
Ta ble 1. Nick el-Ca ta lyzed Rea ction s of Alk yn es w ith 1,2-Bis(d im eth ylger m yl)ca r bor a n e
shown in Figure 2. A summary of the cell constants and
data collection parameters is included in Table 1. The
X-ray crystal structure of 6 confirmed the presence of a
six-membered ring comprising a carboranylene, two
germanium atoms, and an unsaturated hydrocarbon
unit containing a CdC bond. The C7-C9 bond length
(1.332(3) Å) is comparable to that of 5,6-carboranylene-
1,1,4,4-tetramethyl-2,3-diphenyl-1,4-disilacyclohex-2-
ene (1.33(1) Å)11 and the tricyclic product (1.346(3) Å)
formed from the reaction between diphenylacetylene
and tetrakis(dimethylsilyl)benezene.13
identified as the alkyne cyclotrimerization product.
However, the reaction of the nickel intermediate 2 with
dimethyl acetylenecarboxylate at room temperature
yielded the six-membered-ring compound 10 in 58%
yield.
In contrast to the above reactions, the reaction of
o-bis(dimethylgermyl)carborane (1) with 1-hexyne in the
presence of a catalytic amount of 2 at room temperature
afforded the five-membered-ring compound 11 in 62%
yield (eq 3). All the spectral data of 11 were consistent
The nickel-catalyzed reaction with alkynes was quite
sensitive to the reaction conditions. When the reaction
of o-bis(dimethylgermyl)carborane 1 with dimethyl acet-
ylenecarboxylate in the presence of a catalytic amount
of 2 was carried out at 80 °C, the major product was
1
with the proposed formulation. A key feature in the H
(13) Uchimaru, Y.; Brandl, P.; Tanaka, M. J . Chem. Soc., Chem.
Commun. 1993, 744.
NMR spectrum includes a singlet at 6.24 ppm assigned

Ni-Catalyzed Double Gemylation of Alkynes and Alkenes
Organometallics, Vol. 21, No. 19, 2002 3925
Ta ble 2. Cr ysta l Da ta for 2, 6, 12, 14, a n d 17
2
6
12
14
17
empirical formula
mol wt
C
18H52B10P2Ge2Ni
C15H30B10Ge2
463.67
C
14H34B10Ge2
C
15H32B10Ge2O
C12H32B10Ge2
429.66
641.52
455.69
481.69
cryst syst
space group
a (Å)
b (Å)
c (Å)
monoclinic
P2(1)/ n
11.2880(10)
14.2049(3)
20.6930(4)
104.7760(10)
3208.52(10)
4
monoclinic
P2(1)/ c
8.481(3)
15.592(5)
17.342(6)
97.870(7)
2271.8(14)
4
monoclinic
P2(1)/n
orthorhombic
Pbca
16.6363(9)
15.3576(8)
18.9404(10)
monoclinic
P2(1)/ c
11.431(2)
13.249(3)
14.957 (3)
90.000(4)
2265.3(8)
4
1.336
928
2.650
13.1554(9)
12.6872(9)
13.2244(9)
103.915(2)
2142.4(3)
4
1.332
872
2.798
â (deg)
V (Å3)
4839.2(4)
8
1.322
1952
2.488
Z value
D(calcd) (g cm-3
F(000)
)
1.328
1324
2.550
1.356
936
2.644
abs coeff (mm-1
cryst size (mm3)
scan type
)
0.30 × 0.30 × 0.30
0.25 × 0.35 × 0.40
0.10 × 0.10 × 0.20
0.20 × 0.30 × 0.40
0.20 × 0.35 × 0.40
ω-2θ
ω-2θ
ω-2θ
ω-2θ
ω-2θ
2 θ range, deg
no. of reflns
1.88-24.10
5038
1.76-28.33
14270
2.05-28.34
14258
2.10-28.30
30403
1.59-28.33
13641
no. of obsd reflns
338
5521
5433
5992
5140
(I > 3.00σ (I))
R
0.0339
0.0809
1.059
0.0300
0.0796
1.002
0.0826
0.2289
1.111
0.0378
0.0781
0.951
0.0396
0.1071
1.021
Rw
goodness of fit
to the vinyl proton. The characteristic high-field 13C
NMR signal at 142.8 ppm provided evidence for the
tethered carbon atom of the two germanium moieties.
The formation of the digerma ring compound can be
related to the nickel-catalyzed double silylation. The
isolation of 11 is interesting because a 1,2-hydrogen
shift must be involved in its formation. A similar 1,2-
shift in the alkynes has been observed in the stoichio-
metric reaction of Me2Si(o-C2B10H10)SiMe2Pt(PPh3)2
with 1-hexyne11 and the reaction of chloro(triisopropyl-
phosphine)rhodium(I) with trimethylsilyl-substituted
alkynes.14
resonance at 140.6 ppm was present. In addition, three
peaks were observed at 30.7, 29.2, and 26.2 ppm due to
the symmetrically substituted methylene carbons. The
1H NMR data for 12 conform to the structure deter-
mined by the X-ray structural study. The structure of
12 is closely related to the double silylating adducts of
the 1,2-bis(dimethylsilyl)carborane.6b The ORTEP dia-
gram in Figure 3 shows the molecular structure of 12
and confirms the six-membered-ring geometry contain-
ing the two germanium atoms. The CdC bond length
of C(7)-C(8) is 1.331(12) Å, which is in good agreement
with the existing values in the literature for a wide
variety of CdC bonds. An interesting structural feature
of 12 is that the two planes consisting of Ge1, C1, C2,
Ge2 and Ge2, C7, C8, Ge1 are slightly bent (168.4°).
The treatment of 1 with ferrocenylacetylene in the
presence of a catalytic amount of 2 resulted in the
formation of the six-membered-ring compound contain-
ing a ferrocenyl unit 13 (eq 5). The structure of 13 was
When cyclooctyne was employed as an angle-strained
cycloalkyne in the nickel-catalyzed reaction of 1 at 80
°C, the six-membered-ring compound 12 was isolated
as colorless crystals in 82% yield (eq 4). The structure
1
of 12 is fully consistent with its H and 13C NMR spectra
together with the mass spectrometric analysis. In the
olefinic region of the 13C NMR spectrum of 12, one
determined on the basis of its spectral data as well as
1
elemental analysis. The H NMR spectrum of 13 exhib-
ited a single and broad proton signal assignable to a
coordinated cyclopentadienyl ligand. In addition, a
characteristic feature in the 1H NMR spectrum includes
a singlet at 6.70 ppm assigned to the olefinic proton.
F igu r e 2. X-ray crystal structure of 6 with 50% probability
thermal ellipsoids depicted. Selected bond lengths (Å) and
angles (deg): Ge(1)-C(1) 1.986(2), Ge(2)-C(2) 1.989(2),
C(1)-C(2) 1.671(3), Ge(1)-C(7) 1.950(2), Ge(2)-C(9)
1.947(2), C(7)-C(9) 1.332(3), C(9)-C(10) 1.501(3), C(1)-
Ge(1)-C(7) 111.61(10), Ge(1)-C(7)-C(9) 126.86(18), C(7)-
C(9)-Ge(2) 127.61(18), C(1)-C(2)-Ge(2) 120.43(14).
(14) (a) Schneider, D.; Werner, H. Angew. Chem., Int. Ed. Engl.
1991, 700. (b) Werner, H.; Baum, M.; Schneider, D.; Windmu¨ller, B.
Organometallics 1994, 13, 1089.

3926 Organometallics, Vol. 21, No. 19, 2002
Lee et al.
F igu r e 3. X-ray crystal structure of 12 with 50% prob-
ability thermal ellipsoids depicted. Selected bond lengths
(Å) and angles (deg): Ge(1)-C(1) 1.974(8), Ge(1)-C(8)
1.940(9), C(7)-C(8) 1.331(12), Ge(2)-C(7) 1.933(9),
Ge(2)-C(2) 2.013(8), C(1)-C(2) 1.692(11), C(1)-Ge(1)-C(8)
111.6(3), Ge(1)-C(8)-C(7) 127.4(6), C(8)-C(7)-Ge(2)
126.4(7), C(7)-Ge(2)-C(2) 112.6(4), Ge(2)-C(2)-C(1)
117.9(5).
F igu r e 4. X-ray crystal structure of 14 with 50% prob-
ability thermal ellipsoids depicted. Selected bond lengths
(Å) and angles (deg): Ge(1)-C(7) 1.967(3), Ge(2)-C(7)
1.954(3), Ge(2)-C(2) 1.997(3), C(1)-C(2) 1.679(3), C(1)-
Ge(1) 1.990(3), C(7)-C(8) 1.539(4), Ge(1)-C(7)-Ge(2)
110.04(14), C(7)-Ge(2)-C(2) 100.39(10), Ge(2)-C(2)-C(1)
112.92(16), C(2)-C(1)-Ge(1) 112.30(16).
Stoich iom etr ic Rea ction of 2 w ith Alk en es. The
digermanickela compound 2 is not effective in the
nickel-catalyzed double germylation reaction with alk-
enes. However, the stoichiometric reaction of 2 with
some alkenes and dienes afforded five-membered di-
germa ring compounds. Thus, the stoichiometric reac-
tion of 2 with 4-vinylanisole afforded 4,5-carboranyl-
1,1,3,3-tetramethyl-2-(4-methoxymethyl)-1,3-digerma-
cyclopentane (14), which contained a saturated side
chain in 55% yield (eq 6). A similar reaction of 2 with
membered ring comprised of a carboranylene, two
germanium atoms, and a saturated carbon atom. The
formation of 14 and 15 may involve the initial oxidative
addition reaction of an olefinic C-H bond to the nickel
center, followed by the shift of a phenyl group from the
nickel atom to one of the two germanium atoms. Such
a C-H activation has been observed in the Ni-catalyzed
double silylation.16
In contrast to the double germylation reaction of 2
with the above alkenes, when 1-octene was employed
in the reaction of 2 under the same reaction conditions,
the five-membered digerma compound 16 was isolated
in 45% yield (eq 7). A key feature in the 1H NMR
1,1-diphenylethylene also gave a five-membered diger-
mylene compound 15. The formulation of 14 and 15 was
confirmed by spectroscopic analysis. The two charac-
1
teristic doublets at 4.07 and 1.68 ppm in the H NMR
spectrum of 15 are assigned to the two methine protons.
A large coupling contant (J HH ) 13.50 Hz) indicates that
the two methine protons are in a trans configuration
due to the steric hindrance of the phenyl groups. A low-
frequency 13C NMR resonance at 23.1 ppm provided
evidence for the tethered carbon atom of the germanium
moieties. These values are comparable to those observed
for 4,5-carboranylene-1,1,3,3-tetramethyl-2-diphenyl-
methylene-1,3-disilacyclopentane6b and cis-4,5-benzo-
1,1,3-triethyl-2-methyl-1,3-disilacyclopent-4-ene.15 The
structure of 14 has been determined by X-ray crystal-
lography. The molecular structure of 14 is shown in
Figure 4. The molecule contains one C2Ge2C five-
spectrum of 16 includes a singlet at 6.72 ppm assigned
to the vinyl proton. A characteristic high-frequency 13
C
NMR resonance at 135.4 ppm provided evidence for a
tethered sp2 carbon atom between the two germanium
atoms, in addition to a low-frequency resonance at 152.5
ppm assigned to the terminal olefinic carbon. These
values are close to those of 4,5-carboranylene-1,1,3,3-
tetramethyl-2-(n-butylmethylene)-1,3-disilacyclopen-
tane.6b The formation of 16 is of interest because two
olefinic C-H bond activations must have occurred
during the course of the reaction. Such C-H activations
have been observed in the nickel-catalyzed double
silylation reaction with alkenes.17
(15) Ishikawa, M.; Naka, A.; Ohshita, J . Organometallics 1993, 12,
4987.
(16) Ishikawa, M.; Okazaki, S.; Naka, A.; Tachibana, A.; Kawauchi,
S.; Yamabe, T. Organometallics 1995, 14, 114.

Ni-Catalyzed Double Gemylation of Alkynes and Alkenes
Organometallics, Vol. 21, No. 19, 2002 3927
Sch em e 1
F igu r e 5. X-ray crystal structure of 17 with 50% prob-
ability thermal ellipsoids depicted. Selected bond lengths
(Å) and angles (deg): Ge(1)-C(7) 1.976(3), Ge(1)-C(1)
1.983(2), Ge(2)-C(7) 1.971(3), Ge(2)-C(2) 1.979(2),
C(1)-C(2) 1.669(4), C(8)-C(9) 1.330(4), Ge(1)-C(7)-Ge(2)
109.21(13), C(7)-Ge(1)-C(1) 102.34(11), Ge(1)-C(1)-C(2)
112.88(14), C(1)-C(2)-Ge(2) 113.11(14), C(2)-Ge(2)-C(7)
102.44(11), C(7)-C(8)-9(2) 122.9(3).
nickel fragment lead to compound 17. Such a 1,4-
migration has been observed in the thermal reaction of
o-bis(dimethylsilyl)benzene and isoprene.18 It is inter-
esting to note that the Ni-, Pd-, and Pt-mediated
cycloaddition reactions of disilabutenes to conjugated
dienes proceed via a 1,4-addition reaction.19
The stoichiometric reaction of 2 with 2,3-dimethyl-
butadiene afforded the five-membered digerma com-
pound. A similar reaction of 2 and isoprene also gave a
five-membered digerma compound 18 (eq 8).
In summary, we have prepared a cyclic bis(germyl)-
nickel complex 2. The complex 2 was found to be a good
catalyst for the double germylation reaction of a variety
of alkynes. Thus, the nickel-catalyzed reactions of 1,2-
bis(dimethylgermyl)carborane with alkynes such as
diphenylacetylene, phenylacetylene, 3-hexyne, 1-phenyl-
1-propyne, 2-butyne, 1-phenyl-2-(trimethylsilyl)acety-
lene, bis(trimethylsilyl)acetylene, dimethyl acetylene-
dicarboxylate, 1-hexyne, and cyclooctyne afforded six-
membered-ring compounds. The complex 2 is not effective
in the nickel-catalyzed double germylation reaction with
alkenes. However, the stoichiometric reaction of 2 with
some alkenes and dienes afforded five-membered-ring
compounds. Thus, the cyclic bis(germyl)nickel complex
as a catalyst or reactant has been further exploited in
a series of novel chemical transformations.
1
Compounds 17 and 18 were characterized by H and
13C NMR and elemental analyses. Three singlets (δ 1.63,
1
1.56, 1.48) in the H NMR spectrum and three singlets
(δ 21.5, 21.3, 20.9) in the 13C NMR spectrum of 17 could
be assigned to the methyl groups on the diene, which
indicated that the three methyl groups are not equiva-
lent. The 1H NMR spectrum of 17 shows a single
resonance at δ 2.46 assigned to the methine proton, as
well as two resonances due to the methyl protons on
germanium which show the presence of two nonequiva-
lent methyl protons. The 13C NMR spectrum of com-
pound 17 exhibits resonances for the olefinic carbons
at δ 124.1 and 122.3, a methine carbon at δ 30.1, and
the methyl carbons of germanium at δ 0.6 and -0.4.
These spectral features are wholly consistent with the
proposed structure of 17. Structural confirmation was
provided by an X-ray crystallographic analysis of 17.
The molecular structure of 17 is shown in Figure 5. The
X-ray crystal structure of 17 confirmed the presence of
a five-membered ring comprised of an o-carboranylene,
two germaniums, and a saturated hydrocarbon frag-
ment.
Exp er im en ta l Section
All experiments were performed under a nitrogen atmo-
sphere in a Vacuum Atmospheres drybox or by standard
Schlenk techniques. Toluene, THF, and benzene were distilled
from sodium benzophenone. n-Hexane and pentane were dried
and distilled from CaH2. The 1H and 13C, 31P NMR spectra
were recorded on a Varian Gemini 300 spectrometer operating
at 300.00, 75.44, and 121.44 MHz, respectively. Chemical shifts
were referenced relative to TMS. The IR spectra were recorded
on a Biorad FTS-165 spectrometer. Mass spectra were recorded
on a Shimadzu Model QP-1000 spectrophotometer and el-
emental analyses were performed with a Carlo Erba Instru-
ments CHNS-O EA 1108 analyzer.
o-Carborane was purchased from Callery Chemical Co.
and used without purification. The starting materials Ni-
(COD)2, PEt3, and GeMe2Cl2 were purchased from Strem
Chemicals. The alkynes were purchased from Aldrich. 1,2-Bis-
(chlorodimethylgermyl)carborane,7 Ni(PEt3)4,20 cyclooctyne,21
A reasonable mechanism for the formation of 17 and
18 (Scheme 1) involves the initial oxidative addition
reaction of an olefinic C-H bond to the nickel center
B, followed by the shift of a diene group from the nickel
atom to one of the two germanium atoms C. The 1,4-
migration of hydride D and reductive elimination of the
(18) Tanaka, M.; Uchimaru, Y.; Lautenschlager, H.-J . J . Organomet.
Chem. 1992, 428, 1.
(19) (a) Tsuji, Y.; Lago, R. M.; Tomohiro, S.; Tsuneishi, H. Organo-
metallics 1992, 11, 2253. (b) Obora, Y.; Tsuji, Y.; Kawamura, T.
Organometallics 1993, 12, 2853. (c) Tanaka, M.; Uchimaru, Y.;
Lautenschlager, H.-J . Organometallics 1991, 10, 16.
(17) Naka, A.; Okazaki, S.; Hayashi, M.; Ishikawa, M. J . Organomet.
Chem. 1995, 499, 35.

3928 Organometallics, Vol. 21, No. 19, 2002
Lee et al.
and ferrocenylacetylene22 were prepared according to the
known procedures.
156.7 (dCMe), 128.7, 127.2, 126.6 (Ph), 20.3 (CH3), -1.3 (Ge-
CH3), -1.6 (Ge-CH3). MS: m/z 464 [M+]. Anal. Calcd for
C
15H30B10Ge2: C, 38.85; H, 6.51. Found: C, 38.46; H, 6.36.
Syn th esis of o-Bis(d im eth ylger m yl)ca r bor a n e (1). To
a stirred THF solution (15 mL) of the 1,2-bis(chlorodimeth-
ylgermyl)carborane (0.10 g, 0.24 mmol) was added a solution
of sodium cyanoborohydride (0.15 g, 2.4 mmol) in THF (10 mL)
at -78 °C. The reaction mixture was warmed to room tem-
perature and stirred for 12 h. The solvent was evaporated and
the residue was extracted with n-hexane (20 mL). The extracts
were concentrated to 3 mL and cooled to -20 °C to give 0.076
g (92%) of a white crystalline solid. Mp: 185-188 °C. 1H NMR
(C6D6): δ 4.23 (sept, 2H, 3J HH ) 3.04 Hz, Ge-H), 0.13 (d, 12H,
3J HH ) 3.04 Hz, Ge-CH3). 13C{1H} NMR (C6D6): δ -1.5. MS:
m/z 349 [M+]. Anal. Calcd for C6H24B10Ge2: C, 20.61; H, 6.91.
Found: C, 20.24; H, 6.68.
(v) 7 fr om th e Rea ction w ith 2-Bu tyn e. Yield: 72%.
1
Mp: 114-118 °C. H NMR (CDCl3): δ 1.18 (s, 3H, dC-CH3),
1.16 (s, 3H, C-CH3), 0.51 (s, 3H, Ge-CH3), 0.49 (s, 3H, Ge-
CH3), 0.46 (s, 3H, Ge-CH3), 0.26 (s, 3H, Ge-CH3). 13C{1H}
NMR (CDCl3): δ 148.4 (CdC), 29.5 (CH3), 12.6 (CH3), -2.1
(Ge-CH3), -2.4 (Ge-H3), -3.4 (Ge-CH3), -6.8 (Ge-CH3).
MS: m/z 402 [M+]. Anal. Calcd for C10H28B10Ge2: C, 29.91; H,
7.03. Found: C, 29.58; H, 6.91.
(vi) 8 fr om th e Rea ction w ith 1-P h en yl-2-(tr im eth yl-
silyl)a cetylen e. Yield: 72%. Mp: 138-139 °C. 1H NMR
(CDCl3): δ 7.29-6.83 (m, 5H, Ph), 0.63 (s, 6H, Ge-CH3), 0.26
(s, 6H, Ge-CH3), -0.21 (s, 9H, Si-CH3). 13C{1H} NMR
(CDCl3): δ 152.6 (dCPh), 146.0 (dCSiMe3), 129.8, 128.6, 127.0,
126.3 (Ph), 2.2 (Ge-CH3), 1.9 (Ge-CH3), -0.9 (Si-CH3). MS:
m/z 522 [M+]. Anal. Calcd for C17H36B10Ge2Si: C, 39.13; H,
6.95. Found: C, 39.46; H, 7.04.
Syn th esis of [o-(GeMe2)2C2B10H10]Ni(P Et3)2 (2). Com-
pound 1 (0.14 g, 0.38 mmol) in 5 mL of pentane was added to
a stirred solution of Ni(PEt3)4 (0.19 g, 0.37 mmol) in 10 mL of
pentane at -15 °C. The solution was warmed to room tem-
perature and stirred for 2 h. The solution was then evaporated
in vacuo and the residue was extracted with toluene (8 mL).
The solution was then covered with a layer of pentane (10 mL)
at -5 °C. Red crystals of 2 were formed over a period of several
(vii) 9 fr om th e Rea ction w ith Bis(tr im eth ylsilyl)-
a cetylen e. A mixture of bis(trimethylsilyl)acetylene (0.12 mL,
0.50 mmol), 1 (0.10 g, 0.29 mmol), and 2 (0.01 g, 0.015 mmol)
in toluene (20 mL) was refluxed overnight. The solvent was
removed in vacuo, and the residue was chromatographed with
hexane as eluent (Rf ) 0.5). Recrystallization from hexane at
-10 °C afforded 5,6-carboranylene-1,1,4,4-tetramethyl-2,3-di-
(trimethylsilyl)-1,3-digermacyclohex-2-ene (9) in 62% yield.
1
days in 60% yield (0.14 g). H NMR (C6D6): δ 1.14 (dq, 12H,
J HP ) 7.42 Hz, J HH ) 5.48 Hz, PCH2), 0.86 (dt, 18H, J HP
)
7.04 Hz, J HH ) 5.48 Hz, CH3), 0.21 (s, 12H, GeCH3). 31P{1H}
NMR (C6D6): δ 6.18. MS (EI): m/z 642 [M+]. Anal. Calcd for
1
C
18H52B10NiP2Ge2: C, 33.66; H, 8.16. Found: C, 33.28; H, 7.92.
Mp: 106-108 °C. H NMR (CDCl3): δ 0.58 (s, 6H, Ge-CH3),
0.45 (s, 6H, Ge-CH3), 0.13 (s, 18H, Si-CH3). 13C{1H} NMR
(CDCl3): δ 144.3 (dCSiMe3), 1.1 (Ge-CH3), -0.2 (Ge-CH3),
Nick el Com p lex-Ca ta lyzed Rea ction of 1 w ith Va r iou s
Alk yn es. Gen er a l P r oced u r e. Compound 3-15 were pre-
pared by the reaction of 1 with the corresponding alkynes in
the presence of a catalytic amount of 2. In a typical prepara-
tion, a mixture of diphenylacetylene (0.06 g, 0.35 mmol), 1 (0.1
g, 0.29 mmol), and 2 (0.01 g, 0.016 mmol) in toluene (20 mL)
was stirred at room temperature for 1 h and then warmed to
80 °C for 8 h. The mixture was filtered through a short silica
gel column to remove the nickel species. The solvent was
removed in vacuo, and the residue was chromatographed with
benzene/hexane (1:4) as the eluent (Rf ) 0.6). Recrystallization
from hexane at -20 °C afforded 5,6-carboranylene-1,1,4,4-
tetramethyl-2,3-diphenyl-1,4-digermacyclo-hex-2-ene (0. 11 g,
75%).
(i) 3 fr om th e Rea ction w ith Dip h en yla cetylen e. Mp:
115-117 °C. 1H NMR (CDCl3): δ 7.09-6.72 (m, 10H, Ph), 0.42
(s, 12H, GeCH3). 13C{1H} NMR (CDCl3): δ 154.0 (GeCd),
142.0, 128.0, 127.6, 126.2 (Ph), -1.0 (Ge-CH3). MS: m/z 526
[M+]. Anal. Calcd for C20H32B10Ge2: C, 45.69; H, 6.13. Found:
C, 45.26; H, 6.02.
(ii) 4 fr om th e Rea ction w ith P h en yla cetylen e. Yield:
65%. Mp: 133-135 °C. 1H NMR (CDCl3): δ 7.32-7.04 (m, 5H,
Ph), 6.49 (s, 1H, dCH), 0.54 (s, 6H, GeCH3), 0.50 (s, 6H, Ge-
CH3). 13C{1H} NMR (CDCl3): δ 159.3 (dCPh), 145.0 (dCH),
130.3, 128.7, 127.6, 126.2 (Ph), 68.9, 67.0 (carborane carbons),
-0.1 (Ge-CH3), -0.6 (Ge-CH3). MS: m/z 450 [M+]. Anal. Calcd
for C14H28B10Ge2: C, 37.39; H, 6.27. Found: C, 37.02; H, 6.12.
(iii) 5 fr om th e Rea ction w ith 3-Hexyn e. Yield: 87%.
Mp: 120-124 °C. 1H NMR (CDCl3): δ 2.28 (q, 4H, J HH ) 7.50
Hz, CH2), 0.95 (t, 6H, J HH ) 7.50 Hz, CH3), 0.47 (s, 12H,
GeCH3). 13C{1H} NMR (CDCl3): δ 150.9 (CdC), 67.6 (carbo-
rane carbons), 25.3 (CH2), 14.8 (CH3), -0.2 (Ge-CH3). MS: m/z
430 [M+]. Anal. Calcd for C12H32B10Ge2: C, 33.54; H, 7.49.
Found: C, 33.86; H, 7.58.
-1.0 (Si-CH3). MS: m/z 518 [M+]. Anal. Calcd for C14H40B10
Ge2Si2: C, 32.46; H, 7.77. Found: C, 32.38; H, 7.58.
-
(viii) 10 fr om th e Rea ction w ith Dim eth yl Acetylen e-
d ica r boxyla te. A mixture of dimethyl acetylenedicarboxylate
(0.04 mL, 0.30 mmol) and 2 (0.10 g, 0.20 mmol) in toluene (15
mL) was stirred at room temperature for 6 h. The solvent was
removed in vacuo, and the residue was chromatographed with
ethyl acetate/hexane (1:10) as eluent (Rf ) 0.62). Recrystalli-
zation from hexane at -20 °C afforded 5,6-carboranylene-
1,1,4,4-tetramethyl-2,3-dicarbomethoxy-1,4-digermacyclohex-
2-ene (10) in 58% yield. Mp: 126-128 °C.1H NMR (CDCl3): δ
3.77 (s, 6H, CO2CH3), 0.62 (s, 12H, Ge-CH3). 13C{1H} NMR
(CDCl3): δ 168.0 (CO2CH3), 151.0 (CdC), 52.6 (OCH3), -0.5
(Ge-CH3). MS: m/z 490 [M+]. Anal. Calcd for C12H28B10O4-
Ge2: C, 29.43; H, 5.76. Found: C, 29.08; H, 5.58.
(ix) 11 fr om th e Rea ction w ith 1-Hexyn e. A mixture of
1-hexyne (0.04 mL, 0.30 mmol), 1 (0.08 g, 0.22 mmol), and 2
(0.01 g, 0.016 mmol) in toluene (20 mL) was stirred at room
temperature for 14 h. The solvent was removed in vacuo. Pure
11 was isolated by chromatographic workup (eluent ) hexane,
1
Rf ) 0.6, 62% yield). H NMR (CDCl3): δ 6.28 (s, 1H, dCH),
2.16 (t, 2H, J HH ) 8.8 Hz, dCCH2), 1.59-1.27 (m, 4H, -CH2-
), 0.90 (t, 3H, J HH ) 5.2 Hz, CH3), 0.48 (s, 6H, Ge-CH3), 0.43
(s, 6H, Ge-CH3). 13C{1H} NMR (CDCl3): δ 159.2 (dCH), 142.8
(GeCd), 41.0, 31.4, 22.6, 14.2 (Bu), -0.6 (GeCH3), -0.8
(GeCH3). MS: m/z 415 [M+ - CH3]. Anal. Calcd for C12H32B10
-
Ge
2: C, 33.54; H, 7.50. Found: C, 33.22; H, 7.38.
(x) 12 fr om th e Rea ction w ith Cyclooctyn e. To a stirred
solution of 2 (0.20 g, 0.30 mmol) in toluene (15 mL) was added
cyclooctyne (0.07 g, 0.6 mmol) at room temperature. The
solution was heated to 80 °C for 14 h and then evaporated in
vacuo, and the residue was chromatographed with benzene/
hexane (1:4) as eluent (Rf ) 0.8). Recrystallization from hexane
at -10 °C afforded 12 as colorless crystals in 82% yield. Mp:
168-169 °C.1H NMR (CDCl3): δ 2.38 (br, 4H, dCH2), 1.45 (br,
8H, -CH2), 0.45 (s, 12H, Ge-CH3). 13C{1H} NMR (CDCl3): δ
140.6 (dCCH2), 30.7, 29.2, 26.2 (CH2), -1.6 (Ge-CH3). MS:
m/z 456 [M+]. Anal. Calcd for C14H34B10Ge2: C, 36.89; H, 7.51.
Found: C, 36.66; H, 7.38.
(iv) 6 fr om th e Rea ction w ith 1-P h en yl-1-p r op yn e.
Yield: 85%. Mp: 142-144 °C. 1H NMR (CDCl3): δ 7.35-6.90
(m, 5H, Ph), 1.65 (s, 3H, C-CH3), 0.53 (s, 6H, Ge-CH3), 0.29
(s, 6H, Ge-CH3). 13C{1H} NMR (CDCl3): δ 158.3 (dCPh),
(20) Browning, J .; Cundy, C. S.; Green, M.; Stone, F. G. A. J . Chem.
Soc. A 1969, 20.
(21) Allinger, N. L.; Meyer, A. Y. Tetrahedron 1975, 31, 1807.
(22) Doisneau, G.; Balavoine, G.; Fillebeen-Khan, T. J . Organomet.
Chem. 1992, 425, 113.
(xi) 13 fr om th e Rea ction w ith F er r ocen yla cetylen e.
Yield: 78%. Mp: 135-137 °C. 1H NMR (CDCl3): δ 6.70 (s,

Ni-Catalyzed Double Gemylation of Alkynes and Alkenes
Organometallics, Vol. 21, No. 19, 2002 3929
1H, dCH), 4.28 (br, 4H, C5H4), 4.07 (s, 5H, C5H5), 0.65 (s, 6H,
Ge-CH3), 0.51 (s, 6H, Ge-CH3). 13C{1H} NMR (CDCl3): δ
142.4 (dCH), 134.4 (dCC), 69.8, 69.1, 67.0 (Cp), 1.2 (Ge-CH3),
430 [M+]. Anal. Calcd for C12H32B10Ge2: C, 33.58; H, 7.50.
Found: C, 33.26; H, 7.34.
(xv) 18 fr om th e Rea ction w ith Isop r en e. Yield: 48%.
Mp: 146-149 °C. 1H NMR (CDCl3): δ 4.95 (d, 1H, J HH ) 11.72
Hz, dCH), 1.97 (d, 1H, J HH ) 11.72 Hz, CH), 1.69 (s, 3H,
C-CH3), 1.54 (s, 3H, C-CH3), 0.48 (s, 6H, Ge-CH3), 0.41 (s,
6H, Ge-CH3). 13C{1H} NMR (CDCl3): δ 130.6, 119.0 (CdC),
26.3 (CH), 21.6 (CH3), 0.6 (GeCH3), -1.1 (GeCH3). MS: m/z
416 [M+]. Anal. Calcd for C11H30B10Ge2: C, 31.82; H, 7.28.
Found: C, 31.54; H, 7.14.
-0.5 (Ge-CH3). MS: m/z 558 [M+]. Anal. Calcd for C18H32B10
-
Ge2Fe: C, 38.77; H, 5.78. Found: C, 38.46; H, 5.62.
Rea ction of Nick el In ter m ed ia te 2 w ith Va r iou s Alk -
en es. Gen er a l P r oced u r e. Compounds 14-18 were prepared
by the reaction of 2 with the corresponding alkenes. In a
typical preparation, a mixture of 2 (0.1 g, 0.15 mmol) and
4-vinylanisole (0.02 mL, 0.16 mmol) in toluene (15 mL) was
heated to 80 °C and stirred for 14 h. The solvent was removed
in vacuo, and the residue was chromatographed with benzene/
hexane (1:4) as eluent. Recrystallization from hexane at -10
°C afforded 4,5-carboranylene-1,1,3,3-tetramethyl-2-(4-meth-
oxymethyl)-1,3-digermacyclopenane, 14, in 55% yield. Mp:
X-r a y Cr ysta llogr a p h y. Details of the crystal data and a
summary of the intensity data collection parameters for 2, 6,
12, 14, and 17 are given in Table 1. A reddish-orange crystal
of 2 with the dimensions of 0.30 × 0.30 × 0.30 mm3 was
selected for structural analysis. The intensity data for 2 were
collected with a Siemens SMART ccd area detector mounted
on a Siemens P4 diffractometer equipped with graphite-
monochromated Mo KR radiation (λ ) 0.71073 Å). The sample
was first cooled to 130 K. The intensities were measured as a
series of φ oscillation frames each of 0.4° for 30 s/frame. A
colorless crystal of 6 with the dimensions of 0.25 × 0.35 × 0.40
mm3 was mounted on the tip of a glass fiber. The cell
parameters were obtained by least-squares refinement from
25 reflections in the range 1.76° < 2θ < 28.33° measured with
graphite-monochromated Mo KR radiation on a Simens P4
diffractometer. The X-ray intensity data were collected by the
ω-2θ scan method for ranges -11 < h < 10, -20 < k <19,
and -11 < l < 23. The cell parameters of 12 were obtained by
least-squares refinement in the range 1.76° < 2θ < 28.33° on
a Simens P4 diffractometer. The X-ray intensity data were
collected by the ω-2θ scan method for the ranges -14 < h <
14, -17 < k <11, and -13 < l < 19. The structures were solved
by direct methods and refined by the full-matrix least-squares
method on F2. The hydrogen atom positions were initially
determined by geometry and refined by a riding model. Non-
hydrogen atoms were refined by using anisotropic displace-
ment parameters.
1
138-141 °C. H NMR (CDCl3): δ 7.05 (d, 2H, J HH ) 8.96 Hz,
Ph), 6.83 (d, 2H, J HH ) 8.96 Hz, Ph), 3.79 (s, 3H, OCH3), 2.80
(d, 2H, J HH ) 8.74 Hz, CH2), 1.34 (t, 1H, J HH ) 8.74 Hz, CH),
0.38 (s, 6H, Ge-CH3), 0.33 (s, 6H, Ge-CH3). 13C{1H} NMR
(CDCl3): δ 139.2, 134.1, 128.9, 114.1, 55.4 (OCH3), 31.5 (CH2),
21.29 (CH), -0.3 (Ge-CH3), -3.2 (Ge-CH3). MS: m/z 482 [M+].
Anal. Calcd for C15H32B10Ge2O: C, 37.40; H, 6.68. Found: C,
37.08; H, 6.52.
(xii) 15 fr om th e Rea ction w ith 1,1-Dip h en yleth ylen e.
Yield: 48%. Mp: 176-179 °C. 1H NMR (CDCl3): δ 7.35-7.18
(m, 10H, Ph), 4.07 (d, 1H, J HH ) 13.50 Hz, CHPh2), 1.68 (d,
1H, J HH ) 13.50 Hz, CHGe2), 0.26 (s, 6H, Ge-CH3), -0.05 (s,
6H, Ge-CH3). 13C{1H} NMR (CDCl3): δ 145.5, 129.1, 127.9,
127.7, 50.3 (CHPh2), 23.1 (CHGe2), -0.1 (Ge-CH3), -2.7 (Ge-
CH3). MS: m/z 528 [M+]. Anal. Calcd for C20H34B10Ge2: C,
45.51; H, 6.49. Found: C, 45.22; H, 6.32.
(xiii) 16 fr om th e Rea ction w ith 1-Octen e. A mixture of
2 (0.10 g, 0.15 mmol) and 1-octene (0.05 mL, 0.32 mmol) in
toluene (15 mL) was refluxed for 14 h. The solvent was
removed in vacuo, and the residue was chromatographed with
benzene/hexane (1:4) to give 16 as a colorless oil in 45% yield.
1H NMR (CDCl3): δ 6.72 (t, 1H, J HH ) 13.86 Hz, dCH), 2.17
(dt, 2H, J HH ) 13.86 Hz, J HH ) 5.02 Hz, CH2), 1.48-1.27 (m,
8H, CH2), 0.88 (t, 3H, J HH ) 4.62 Hz, CH3), 0.37 (s, 6H, Ge-
CH3), 0.28 (s, 6H, Ge-CH3). 13C{1H} NMR (CDCl3): δ 152.5,
135.4, 36.9, 30.1, 27.4, 27.2, 20.9, 12.5, -2.7 (GeCH3), -2.9
(GeCH3). MS: m/z 458 [M+]. Anal. Calcd for C14H36B10Ge2: C,
36.74; H, 7.92. Found: C, 36.46; H, 7.72.
Ack n ow led gm en t. The work was supported by a
grant from KOSEF (R01-2001-000053-0).
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data and structure refinement, atomic coordinates, bond
lengths and angles, anisotropic displacement parameters, and
hydrogen coordinates and isotropic displacement parameters
for 2, 6, 12, 14, and 17. This material is available free of charge
via the Internet at http://pubs.acs.org.
(xiv) 17 fr om th e Rea ction w ith 2,3-Dim eth yl-1,3-
1
bu ta d ien e. Yield: 62%. Mp: 161-163 °C. H NMR (CDCl3):
δ 2.46 (s, 1H, CH), 1.63 (s, 3H, dCH3), 1.56 (s, 3H, CCH3),
1.48 (s, 3H, CCH3), 0.50 (s, 6H, Ge-CH3), 0.47 (s, 6H, Ge-
CH3). 13C{1H} NMR (CDCl3): δ 124.1 (CdC), 122.3 (CdC), 30.1
(CH), 21.5, 21.3, 20.9 (C-CH3), 0.6, -0.4 (GeCH3). MS: m/z
OM020399V