Cyclo and spirozirconation: Synthesis of new phospholane-boranes and polyphosphine-boranes

Article abstract of DOI:10.1016/S0040-4020(99)00780-2

The diallylic phosphine-borane Ph(BH₃)P(allyl)₂ 6, reacts with the zirconocene 'Cp₂Zr' and gives the bicyclocomplex intermediate 7, characterized by ¹H and ³¹P NMR. The electrophilic addition of H⁺, Br₂, PhPCl₂(BH₃), Ph₂PCl(BH₃) leads to the corresponding stabilized phospholanes 8, 9, 11 and bicyclophospholane 10, whereas Ph₂P(BH₃)Li on 9 gives the boro(phospholane-diphosphine) 12. Under the same conditions, the tetraallylsilane (or germane) 13a-b leads to the spirometallacyclopentane 14a-b intermediates. After reaction with Br₂, Ph₂PLi(BH₃) and PhPCl₂(BH₃), the racemic spirannic tetraphosphines 16a-b and the protected spirannic diphosphine 17b are obtained with a remarkable selectivity. Decomplexation reaction by Et₂NH gives corresponding free phosphines 3'-17'.

Full text of DOI:10.1016/S0040-4020(99)00780-2

TETRAHEDRON
Pergamon
Tetrahedron 56 (2000) 121–127
Cyclo and Spirozirconation: Synthesis of New
Phospholane-Boranes and Polyphosphine-Boranes
*
Gabriel Oba, Sovannary Phok, Georges Manuel and Max Koenig
´ ´
´
´
Laboratoire d’Heterochimie Fondamentale et Appliquee—UPRESA CNRS no. 5069 Universite Paul-Sabatier,
31062 Toulouse Cedex, France
Received 3 March 1999; accepted 12 July 1999
Abstract—The diallylic phosphine-borane Ph(BH3)P(allyl)2 6, reacts with the zirconocene ‘Cp2Zr’ and gives the bicyclocomplex inter-
1
mediate 7, characterized by H and 31P NMR. The electrophilic addition of Hϩ, Br2, PhPCl2(BH3), Ph2PCl(BH3) leads to the corresponding
stabilized phospholanes 8, 9, 11 and bicyclophospholane 10, whereas Ph2P(BH3)Li on 9 gives the boro(phospholane–diphosphine) 12. Under
the same conditions, the tetraallylsilane (or germane) 13a–b leads to the spirometallacyclopentane 14a–b intermediates. After reaction with
Br2, Ph2PLi(BH3) and PhPCl2(BH3), the racemic spirannic tetraphosphines 16a–b and the protected spirannic diphosphine 17b are obtained
with a remarkable selectivity. Decomplexation reaction by Et2NH gives corresponding free phosphines 30 –170. ᭧ 1999 Published by Elsevier
Science Ltd. All rights reserved.
Introduction
but after the purification of 30b by chromatography on silica
column, we observed the formation of the corresponding
phosphine oxide. In order to avoid this oxidation, we
protected the phosphines with BH3 and isolated the
diphosphine-boranes 5a–b.
The cyclozirconation reaction, initiated independently by
Nugent1 and Negishi2 is one of recent powerful carbo-
metallation methods.3 Heterodiynes and dienes containing
oxygen,4 boron,5 nitrogen,6 silicon7 have been reacted on a
zirconium dicyclopentadienyl dichloride complex in the
presence of n-butyllithium. We recently published cyclo-
zirconation reactions in heteroelementary series (Si, Ge,
P,…).8 As the cyclozirconation with diallyl phosphine
oxide failed, we used diallylphosphine bearing a sterically
bulky substituent as the protective group. In order to prevent
the phosphorus–zirconium interaction,9 we present a new
approach involving the cyclozirconation of protected allyl-
phosphines by borane (BH3). Furthermore, with the purpose
of obtaining polyphosphines, we will use phosphine-
boranes acting as an electrophile on zirconocene complex
intermediates.
10
In these cases, the cyclometallation was highly selective and
the addition of various electrophiles on the intermediates
2a–b led to the trans isomer only.
In order to prepare new functional phospholanes,11 we
extended the cyclozirconation reaction to diallyl phos-
phine-borane 6 (Scheme 2). As for diallyl silane or germane,
the reaction was carried out from Ϫ78ЊC to room tempera-
ture. The zirconocene adduct intermediate 7 was detected by
1
31P and H NMR on the crude mixture: three isomers were
observed at d 31Pˆ16 (60%); 24 (25%); 28 (15%). The
acidic hydrolysis of 7 gave the corresponding borane
complex 8 as a mixture of three isomers (Table 1). The
trans configuration of the major isomer (85%) and the cis
configuration of the minor isomers are determined from
13C NMR. The bromination of 7 at low temperature leads
to the dibromophospholane 9. As before, we detected the
presence of three isomers in the same proportions (Table 1).
Notice that the iodination reaction does not lead to the
expected C-diiodo isolog of 9. Competitive reactions may
occur giving iodo-substituted borane-phospholane12 or iodo
phosphonium salts. Such reactions may explain the
observed low yields.
Results and Discussion
We have already synthesized phosphines 30a–b or diphos-
phines 5a–b by cyclozirconation of diallyl silanes (or
germanes) 1a–b.8 The addition of non-protected dichloro-
phosphine on the intermediates 2a–b led to the bicyclo
derivative 30a–b (Scheme 1). The reaction is quantitative,
Keywords: zirconocene; heteroallyl derivatives; cyclo(spiro)zirconation;
phospholane-borane; diphosphine-borane; triphosphine-borane; tetraphos-
phine-borane.
* Corresponding author. Tel.: ϩ5-61-55-62-98; fax: ϩ5-61-55-82-45;
e-mail: koenig@iris.ups-tlse.fr
The bicyclo-diphospholane 10 was obtained in two steps
from 7 under treatment, at room temperature, with PhPCl2
followed by the protecting boration reaction. As shown by
0040–4020/00/$ - see front matter ᭧ 1999 Published by Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(99)00780-2

122
G. Oba et al. / Tetrahedron 56 (2000) 121–127
Scheme 1.
13C NMR, three isomers (trans and cis) were characterized
in the isolated product (Table 1).
14a–b, gave the tetrabromospirosilane 15a and germane
15b after hydrolysis.14 Such tetrafunctional spiro-
compounds, isolated as only one trans/trans isomer are
convenient starting materials to prepare the corresponding
protected tetraphosphines 16a–b (Scheme 4).
The successive treatment of the intermediate complex 7 by
Ph2PCl and BH3SMe2 gave the phosphino-phospholane
diborane 11 even if an excess of the chlorophosphine was
used. After purification, two isomers were characterized.
The diphosphino-phospholane triborane 12 was obtained
by addition of lithium phosphide on the dibromo-phospho-
lane 9 (Scheme 3). Three isomers were identified by
31P NMR (Table 1). The major isomer (70%) was in trans
configuration.
Moreover, the electrophilic attack of dichlorophosphine on
14b, followed by the protection of the two phosphorus
atoms by BH3, led to two isomers of the germaspirane 17b.
Selectivity and stereochemistry
We extended this approach to synthesize new polyphos-
phines13 (Scheme 4). The first step was the spirozirconation
of tetraallylsilane (13a) or germane (13b) using the same
method as before. The spiro intermediates 14a–b, stable at
room temperature, were characterized by 1H NMR. The
bromination at low temperature of the intermediates
The stereochemistry and the selectivity of the reactivity of
zirconocene towards di- and tetraallylic heteroderivatives are
directly dependent on the nature of the substituents linked to
the different heteroatoms (P, Si, Ge). Thus, the approach of
‘Cp2Zr’ to the unsaturated moities, and consequently the
geometry of the intermediates, would be controlled by the
Scheme 2.

G. Oba et al. / Tetrahedron 56 (2000) 121–127
123
Table 1. Selectivity of cyclo and spirozirconation reaction and 31P NMR parameters of phosphine–boranes
Compounds
Diastereoisomers
Theoretic
Configuration.
%
d
31P PhP–BH3
d
31P Ph2P–BH3
Observed
5a
5b
8
2
2
3
1
1
3
trans
trans
trans
cis
cis
trans
cis
cis
trans
cis
100
100
85
10
5
15
15
20
27
13
5
Ϫ9
15
48
9
3
5
3
3
85
10
5
10
43a
36a
21a
70a
30a
70
cis
11
12
4
3
2
3
trans
trans
trans
cis
21
15
22
25
21.9
15
16
15
15
15
20
10
100
100
50a
50a
cis
16a
16b
17b
4
4
4
1
1
2
trans/trans
trans/trans
trans/trans
35
a % deduced from 13C NMR.
In the case of diallyldiphenyl silane and germane 1, it
appeared (Table 1) that the cyclozirconation was stereo-
selective, as only trans isomers 3–5 were synthesized,
while for the unsymmetrical diallylic phosphine-borane 6,
the cyclozirconation was not selective. The isolated
products 8–12 were a mixture of trans/cis isomers, where
the trans isomers are predominant.
Scheme 3.
The spirozirconation14 involved the symmetrical tetraallylic
derivatives 13. The reactivity of the zirconocene led to a
spirannic skeleton bearing four asymmetric carbons (stereo-
genic centers). In this case, the highly selective synthesis led
to only one trans/trans isomer. We have checked by
13C NMR on the crude product, the absence of any possible
other stereoisomers. Moreover, the X-ray structural
determination of 15a14c revealed the presence of this
trans/trans isomer in a racemic form (RRRR/SSSS) and
not in a meso form (RRSS). Consequently, the spirannic
symmetry or the dissymmetry of the allylic starting
material.
In our studies, all cyclozirconation reactions were carried
out on symmetrical derivatives of silicon and germanium
1a–b and unsymmetrical phosphorus compound 6. The
spirozirconation was performed on symmetrical starting
materials 13a–b.
Scheme 4.

124
G. Oba et al. / Tetrahedron 56 (2000) 121–127
31
Table 2. Selectivity and P NMR parameters of free phosphines n0 obtained from corresponding phosphine–boranes n
Compounds
Diastereoisomers
Theoretic
Configuration
%
d
31P PhP
d
31P Ph2P
Observed
30a
30b
50a
50b
80
3
3
2
2
3
1
1
1
1
3
trans
trans
trans
trans
trans
cis
cis
trans
cis
100
100
100
100
85
10
5
55
25
Ϫ1.0
Ϫ2.6
Ϫ19.2
Ϫ19.0
Ϫ24.0
Ϫ18.4
Ϫ14.0
21.8
21.4
21.1
100a
120
5
3
3
3
cis
trans
cis
20
70
20
cis
10
160a
160b
170b
1
1
4
1
1
2
trans/trans
trans/trans
trans/trans
100
100
50
Ϫ18.6
Ϫ18.7
Ϫ3.0
Ϫ3.1
50
tetraphosphine-boranes 16a–b would be obtained in race-
mic trans/trans form.
of the cyclo and spirozirconations depend more on the
relative size of the substituents than on the nature of the
heteroelement.
All the phospholanes and phosphines were isolated in stable
borane protected forms. The decomplexation reactions were
carried out using an excess of diethylamine15 (5–10 equiv.)
in toluene (or THF) at 34–38ЊC and monitored by 31P NMR.
The half-time reactions varied from 3 h (for 100 in THF,
38ЊC, 10 equiv. Et2NH) to 13 h (for 170b, in toluene/THF,
So, it appears that the protection of unsaturated phosphines
by BH3 which permitted the cyclozirconation reactions,
could be extended, in the near future, to other cyclometal-
lation reactions with various transition metals.
34ЊC, 10 equiv.): 24 kcal molϪ1 ϽDGءϽ25 kcal molϪ1
.
The deboration reactions give free phospholanes and free
phosphines with sharpened NMR 31P signals (Table 2).
Experimental
General procedure
In the case of the bicyclo-diphospholane 10, deprotection
energies of the two phosphorus were different and allowed
observation of the monoborane intermediate leading to three
detectable isomers of the free diphospholane 100 (Scheme 5).
In the same experimental conditions, the two steps of the
decomplexation of the spirannic diphospholane 17b!170b
were not observed.
All manipulations, except chromatography on silica gel, were
carried out under an argon atmosphere. Tetrahydrofuran,
diethylether and hexane were distilled from sodium/benzo-
phenone solution and stored under argon. All NMR spectra
were recorded at 25ЊC on Bruker AC 80 and 250 MHz in
1
CDCl3. The H and 13C chemical shifts are referenced rela-
tive to TMS while 31P NMR shifts are referenced to H3PO4
(85%). Coupling constants are given in Hertz. Mass spectra
were obtained on a Ribermag R1010 under electron impact
(EI) or chemical ionization (DCI conditions) with CH4 or
NH3. Low-resolution mass spectra were determined by GC/
MS using Hewlett–Packard 5890 series II gas chromato-
graph equipped with a HP/MS 5989A mass selective detec-
tor. Melting points were determined in evacuated capillaries
with a Buchi–Tottoli apparatus. IR spectra were recorded on
Perkin Elmer 1600 Series FTIR.
Conclusion
The cyclozirconation of diallyl phosphine-borane consti-
tutes a new way to synthesize functionalized phospholanes,
phosphino-phospholanes and bicyclo-diphospholanes.
Moreover, the remarkable selectivity of the spirocyclization
of tetraallylsilane (or germane) leading to a functionalized
spirannic skeleton allows synthesis of chiral (racemic) di-
and tetraphosphines. Our results indicate that the selectivity
Scheme 5.

G. Oba et al. / Tetrahedron 56 (2000) 121–127
125
Compound 7
(0.2 mol, 0.25 mL) at room temperature. After 12 h, the
solvent was removed in vacuo and the product was extracted
from the residue with CH2Cl2. Removal of solvent followed
by chromatography on silica gel (hexane/CH2Cl2:30/70)
afforded 10 (36%) as white powder. m.p.: 182–185ЊC 31P
To a solution of dichlorozirconocene (Cp2ZrCl2) (0.63 g,
2.2 mmol) in 10 mL of THF at Ϫ78ЊC was added n-BuLi
1.6 M (2.8 mL, 4.4 mmol). After stirring (1 h), the diallyl
phosphine-borane 6 (0.4 g, 2.0 mmol) in 5 mL THF was
added at Ϫ78ЊC. The solution was stirred for 12 h at room
temperature. The intermediate 7 was detected by 31P and 1H
NMR: three isomers were observed at d 31Pˆ16 (60%); 24
(25%) and 28 (15%).1H NMR (80 MHz, CDCl3) dˆ0:5–2:3
(13H, CH2P, CH, CH2Zr, BH3), 5.9 (s, 10H, Cp), 7.5–7.9
(5H, H arom.)
1
NMR (81 MHz, CDCl3) dˆ47:9 (m). H NMR (250 MHz,
CDCl3) dˆ0:5–2:5 (m, 16H, CH2P, CH, BH3), 7.5–7.8 (m,
10H, Ph), 13C NMR (62.89 MHz, CDCl3). Isomer I (trans):
1
3
dˆ30:75 (dd, JC–Pˆ34.5 Hz, JC–Pˆ11 Hz, CH2P), 50.82
2
(d, JC–Pˆ3.2 Hz, CH). Isomer II (cis): dˆ31:22 (dd,
3
2JC–Pˆ36 Hz, JC–Pˆ9 Hz, CH2P), 52.6 (s, CH). Isomer
1
3
III (cis): 30.11 (dd, JC–Pˆ36 Hz, JC–Pˆ12 Hz, CH2P),
49.08 (s, CH). MS (DCI/NH3): m/zˆ344 (M, NH4)ϩ
(100%), 313 (MH–BH3)ϩ, 299 (M–2BH3)ϩ. Anal. Calc.
for C18H26P2B2: C, 66.33; H, 8.00; found: C, 65.48; H, 8.2%.
Compound 8
The solution of 7 (2 mmol) was quenched (room tempera-
ture) by HCl (0.1 M) (0.2 mL) in 20 mL of water. After
stirring (15 min), the product was extracted with ether
(3×15 mL) and dried (MgSO4). Removal of solvents
followed by purification with Chromatotron (hexane/
CH2Cl2:80/20) gave 8 (58%) as yellow liquid. 31P NMR
(81 MHz, CDCl3) dˆϩ13 (5%), ϩ20 (85%), ϩ27 (10%).
1H NMR (80 MHz, CDCl3) dˆ1–2:7 (m, 15H, CH2P, CH,
CH3, BH3), 7.2–7.9 (m, 5H, Ph). 13C NMR (62, 89 MHz,
Compound 11
To a solution of 7 (2 mmol) in 10 mL of THF, was added
Ph2PCl (0.53 g, 2.42 mmol) at room temperature. The
mixture was stirred for 1 h 30 min, then BH3.SMe2 was
added (2.42 mmol, 0.18 mL) at room temperature. After
12 h, the mixture was hydrolysed with 0.33 mL of HCl
(0.1 M) in 20 mL of water. The product was extracted
with ether and dried with MgSO4.
3
CDCl3). Isomer I (trans): dˆ18:84 (d, JC–Pˆ24 Hz, CH3),
1
18.85 (s. CH3), 35.1 (d, CH2P, JC–Pˆ37.4 Hz), 35.6 (d,
2
1JC–Pˆ36.5 Hz, CH2P), 41.9 (d, JC–Pˆ2.8 Hz, CH), 43.1
Removal of solvent followed by chromatography on silica
gel (hexane/CH3Cl:70/30) afforded 11 (38%) as white
powder. m.p: 50–52ЊC 31P NMR (81 MHz, CDCl3)
(s, CH). Isomer II (cis): dˆ16:1 (s, CH3), 32.7 (s,
1JC–Pˆ36.3 Hz, CH2P), 39.6 (s, CH). Isomer III (cis):
1
1
dˆ16:0 (s, CH3), 33.9 (d, JC–Pˆ35.8 Hz, CH2P), 38.3 (d,
dˆ21:4 (m, P–Ph), 14.7 (m, P-Ph2). H NMR (80 MHz,
2JC–Pˆ2.3 Hz, CH). MS (EI): m=zˆ192 (M–BH3)ϩ (100%).
Anal. Calc. for C12H20PB: C, 69.97, H, 9.70; found: C,
69.92; H, 9.49 %.
CDCl3) dˆ1:01–2:8 (m, 17H, CH2P, CH, BH3), 7.2–7.5
(m, 15H, Ph). 13C NMR (50.3 MHz, CDCl3). Isomer I:
3
1
dˆ18:6 (d, JC–Pˆ13 Hz, CH3,), 30.3 (dd, JC–Pˆ36 Hz,
3JC–Pˆ10.5 Hz, CH2PPh2), 33.6 (d, 1JC–Pˆ36 Hz,
1
Compound 9
CH2PPh), 35.2 (d, JC–Pˆ36 Hz, CH2PPh), 41.9 (dd,
2
2JC–Pˆ2 Hz, JC–Pˆ13 Hz, CH), 43.9 (s,CH). Isomer II:
To a solution of 7 (2 mmol) in 10 mL of THF, was added a
solution of bromine (0.75 g, 4.7 mmol) in carbon tetra-
chloride (15 mL) at Ϫ78ЊC. The reaction was quenched
(room temperature) with saturated aqueous NH4Cl
(20 mL), extracted with ether (3×15 mL) and dried
(MgSO4). Removal of solvents followed by chromato-
graphy (hexane/CH2Cl2:95/5) afforded 9 (25%) as white
powder. m.p: 108–110ЊC 31P NMR (81 MHz, CDCl3)
dˆ15:4 (s, CH3), 30.2 (1JC–Pˆ36 Hz, CH2PPh2), 33.4 (d,
1JC–Pˆ36 Hz, CH2PPh), 34.9 (d, JC–Pˆ36 Hz, CH2PPh),
1
2
40.1 (d, JC–Pˆ11 Hz, CH), 40.7 (s, CH) MS (EI):
m/zˆ389 (M–CH3)ϩ (100%), 299 (M–Ph–2BH3)ϩ.
Compound 12
To a solution of Ph3P (1.15 g, 4.4 mmol) in 20 mL of THF,
was added BH3.SMe2 (2.2 mL, 4.4 mmol) and stirred 12 h at
room temperature. Then, lithium (0.3 g, 44 mmol) was
added in the reactor. After stirring (1 h 30 min), excess
lithium was removed, and t-BuCl (0.48 mL, 4.4 mmol)
was introduced. After cooling at Ϫ78ЊC, 9 (0.53 g,
1.46 mmol) in 4 mL of THF was added. The mixture was
stirred for 15 h. Removal of solvent followed by chromato-
graphy on silica gel (hexane/CH2Cl2:40/60) afforded 12
(30%) as colorless oil. 31P NMR (81 MHz, CDCl3)
dˆ(three isomers) 21.9, 22.0, 25 (m, P–Ph), 14.9 (m,
1
dˆϪ9 (m), ϩ5 (m), ϩ15.4 (m) (three isomers). H NMR
(80 MHz, CDCl3) dˆ0:8–3:41 (m, 9H, CH2P, CH, BH3),
3.42–3.68 (m, 4H, CH2Br), 7.5–7.9 (m, 5H, Ph).
13C NMR (62.89 MHz, CDCl3). Isomer I (trans): dˆ26:7
1
1
(d, JC–Pˆ41.4 Hz, CH2P), 26.3 (d, JC–Pˆ42.1 Hz,
3
CH2P), 34.3 (d, JC–Pˆ12.4 Hz, CH2Br), 35.2 (d,
3JC–Pˆ12.2 Hz, CH2Br), 43.6 (s, CH), 43.8 (d,
2JC–Pˆ1.7 Hz, CH). Isomer II (cis): dˆ26:1 (d, CH2P,
1JC–Pˆ33.6 Hz), 34.9 (d, CH2Br, JC–Pˆ12.5 Hz), 43.3 (d,
3
2JC–Pˆ3 Hz, CH). Isomer III (cis): dˆ25:4 (d, CH2P,
1JC–Pˆ33.9 Hz), 34.9 (d, CH2Br, JC–Pˆ11.2 Hz), 43.9
3
1
P–Ph2). H NMR (80 MHz, CDCl3) dˆ0:5–2:8 (m, 19H,
(s, CH) MS (DCI/NH3): m/zˆ351 (M–BH3)ϩ,
CH, CH2P, BH3), 7.2–7.8 (m, 25H, CH arom.). 13C NMR
(62.89 MHz, CDCl3), trans isomer: dˆ30:7 (dd,
1JC–Pˆ35 Hz, 3JC–Pˆ12 Hz, CH2PPh2), 30.8 (dd,
271(M–BH3–Br).
Compound 10
1JC–Pˆ35 Hz,
1JC–Pˆ17 Hz, CH2PPh2), 33.6 (d,
1JC–Pˆ37 Hz, CH2PPh), 33.7 (d, JC–Pˆ37 Hz, CH2PPh),
1
2
2
To a solution of 7 (2 mmol) in 10 mL of THF, was added
PhPCl2 (0.43 g, 0.33 mL) at room temperature. The mixture
was stirred for 4 h 30 min, then BH3.SMe2 was added
42.3 (d, JC–Pˆ3 Hz, CH). 43.1 (d, JC–Pˆ10 Hz, CH),
128.4–132.8 (CH arom.). MS (EI): m=zˆ511 (M–Ph–
BH3)ϩ, 389 (M-PPh2–2BH3)ϩ.

126
G. Oba et al. / Tetrahedron 56 (2000) 121–127
Compound 14a
21 mmol), the mixture was stirred for 1 h 30 min, then
excess lithium was removed, and t-BuCl (0.3 mL,
2.7 mmol) was introduced. After cooling at Ϫ78ЊC, 15b
(0.32 g, 0.75 mmol) in 4 mL of THF was added. The
mixture was stirred for 15 h. Removal of solvent followed
by chromatography on silica gel (hexane/CH2Cl2:40/60)
afforded 16b (23%) as white powder. m.p: 102–105ЊC.
31P NMR (81 MHz, CDCl3) dˆ15 (m). 1H NMR
(250 MHz, CDCl3) dˆ0:3–2:3 (32H, CH2Ge, CH2P, CH,
BH3), 7.2–7.7 (40H, PH). 13C NMR (62.9 MHz, CDCl3)
To a solution of dichlorozirconocene (Cp2ZrCl2) (2.6 g,
8.76 mmol) in 30 mL of THF at Ϫ78ЊC was added n-BuLi
1.6 M (10.9 mL, 17.52 mmol). The resulting mixture was
stirred for 1 h at Ϫ78ЊC. To this new solution was added
the tetraallyl silane 13a (4.17 mmol) in 5 mL THF at
Ϫ78ЊC. The solution was stirred for 12 h at room tempera-
ture. The intermediate 14a was identified by H NMR. H
NMR (80 MHz, CDCl3) dˆ0:6–2:3 (m, 20H, CH2Si,CH,
CH2Zr), 6.1 (s, 20H, Cp).
1
1
1
dˆ19:5 (s, CH2Ge), 32.3 (d, JC–Pˆ35.3 Hz, CH2P), 42.4
2
(d, JC–Pˆ11.5 Hz, CH), 128–132 CH arom.). MS (DCI/
Compound 14b
NH3): m=zˆ1051 (M, NH4)ϩ (72Ge), 1020(M–BH3)ϩ
(72Ge).
To a solution of dichlorozirconocene (Cp2ZrCl2) (2.7 g,
9.3 mmol) in 30 mL of THF at Ϫ78ЊC was added n-BuLi
1.6 (11.6 mL, 18.6 mmol). The resulting mixture was stirred
for 1 h at Ϫ78ЊC. To this new solution was added the tetra-
allyl silane germane 13b (4.17 mmol) in 5 mL THF at
Ϫ78ЊC. The solution was stirred for 12 h at room tem-
Compound 17b
To a solution of 14b (2.1 mmol) in 25 mL of THF, was
added PhPCl2 (1.2 mL, 4.2 mmol) at room temperature.
The mixture was stirred for 3 h 30 min, then BH3.SMe2
was added (8.4 mmol, 4.2 mL) at room temperature. After
12 h, the solvent was removed in vacuo and the product was
extracted from the residue with CH2Cl2. Removal of solvent
followed by chromatography on silica gel (hexane/CH2Cl2;
50/50) afforded 17b (37%) as white powder. m.p.:
218–219ЊC. 31P NMR (81 MHz, CDCl3) dˆϩ34:9 (m).
1H NMR (250 MHz, CDCl3) dˆ0–2:5 (m, 26H, CH2Ge,
1
perature. The intermediate 14b was detected by H NMR.
1H NMR (80 MHz, CDCl3) dˆ0:6–2:3 (m, 20H, CH2Ge,
CH, CH2Zr), 6.1 (s, 20H, Cp).
Compounds 15a–b14
To a solution of 14a–b (4.2 mmol) in 25 mL of THF, was
added a solution of bromine (2.82 g, 20.85 mmol) for 15a or
(3.4 g, 21.2 mmol) for 15b in CCl4 (20 mL) at Ϫ78ЊC. The
reaction was quenched (room temperature) with H2SO4 10%
(30 mL), extracted with ether (3×20 mL) and dried
(MgSO4). Removal of solvent followed by precipitation in
pentane and ether afforded 15a (43%, m.p.: 146ЊC) and 15b
CH2P, CH, BH3), 7.3–7.7 (m, 10H, Ph). 13C NMR
3
(62.89 MHz, CDCl3). Isomer I: dˆ19:8 (d, JC–P
ˆ
3
10.8 Hz, CH2Ge), 20.0 (d, JC–Pˆ10.3 Hz, CH2Ge), 32.5
1
1
(d, JC–Pˆ38 Hz, CH2P), 33.3 (d, JC–Pˆ40 Hz, CH2P),
2
50.3 (s, CH), 51.9 (d, JC–Pˆ4.3 Hz, CH). Isomer II:
3
3
dˆ20:1 (d, CH2Ge, JC–Pˆ8.6 Hz), 20.4 (d, JC–Pˆ8.8 Hz,
1
1
1
(48%, m.p.: 150ЊC) as white powder. H NMR (80 MHz,
CH2Ge), 32.8 (d, JC–Pˆ34.2 Hz, CH22P), 33.3 (d, JC–P
ˆ
CDCl3) dˆ0:5–2:2 (m, 12H, CH2M, CH), 3.4–3.6 (m, 8H,
34 Hz, CH2P), 50.3 (s, CH), 51.9 (d, JC–Pˆ4.3 Hz, CH).
MS (DCI/NH3): m=zˆ500 (M, NH4)ϩ, 468 (M-BH3)ϩ, 454
(M–2BH3)ϩ. Anal. Calc. for C24H36B2GeP2: C, 59.97; H,
7.49; found: C, 59.63; H, 7.55%.
CH).
Compound 16a
To a solution of Ph3P (0.53 g, 2.02 mmol) in 10 mL of THF,
was added BH3.SMe2 (1.02 mL, 2.02 mmol). The mixture
was stirred for 12 h at room temperature. Then, lithium
(0.14 g, 20.2 mmol) was added in the reactor. After stirring
(1 h 30 min), the excess of lithium was removed, and t-BuCl
(0.22 mL, 2.02 mmol) was introduced. After cooling at
Ϫ78ЊC, 15a (0.24 g, 0.24 mmol) in 4 mL of THF was
added. The mixture was stirred for 15h. Removal of solvent
followed by chromatography (hexane/CH2Cl2:30/70)
afforded 16a (26%) as white powder. m.p: 160–161ЊC.
31P NMR (81 MHz, CDCl3) dˆ14:7 (m). 1H NMR
(250 MHz, CDCl3) dˆ0–2:4 (m, 32H, CH2Si, CH, CH2P,
BH3), 7.2–7.8 (m, 40H, CH arom.). 13C NMR (62.89 MHz,
References
1. Nugent, W. A.; Taber, D. F. J. Am. Chem. Soc. 1989, 111, 6435.
2. (a) Negishi, E.; Holmes, S. J.; Tour, J. M.; Miller, J. A. J. Am.
Chem. Soc. 1985, 107, 2568. (b) Negishi, E.; Cederbaum, F. E.;
Takahashi, T. Tetrahedron Lett. 1986, 27, 2829. (c) Negishi, E.;
Zhang, Y.; Cederbaum, F. E.; Webb, M. B. J. Org. Chem. 1986, 51,
4080. (d) Negishi, E.; Swanson, D. R.; Cederbaum, F. E.;
Takahashi, T. Tetrahedron Lett. 1987, 28, 917. (e) Negishi, E.;
Takahashi, T. Synthesis 1988, 1. (f) Negishi, E.; Holmes, S. J.;
Tour, J. M.; Miller, J. A.; Cederbaum, F. E.; Swanson, D. R.;
Takahashi, T. J. Am. Chem. Soc. 1989, 111, 3336. (g) Negishi,
E.; Miller, S. R. J. Org. Chem. 1989, 54, 6014. (h) Negishi, E. In
Comprehensive Organic Synthesis; Trost, B. M.; Fleming, I.;
Paquette L. A. Eds. Pergamon Press, 1991, vol. 5, 1163.
1
CDCl3) dˆ19.9 (s, CH2Si), 32.3 (d, JC–Pˆ35 Hz,
2
CH2P), 41.9 (d, JC–Pˆ12 Hz, CH). MS (DCI/NH3):
m=zˆ1006 (M,NH4)ϩ, 975 (MH–BH3). Anal. Calc. for
C60H72SiP4B4: C,72.93; H, 7.29; found: C, 70.93; H,
7.38%.
3. (a) Gordon, G. J.; Whitby, R. J. J. Chem. Soc., Chem. Commun.
1997, 1045. (b) Barluenga, J.; Sanz, R.; Fananas, F. J. J. Org.
Chem. 1997, 62, 5953. (c) Mori, M.; Kuroda, S.; Zhang, C. S.;
Sato, Y. J. Org. Chem. 1997, 62, 3263.
Compound 16b
4. (a) Nugent, W. A.; Thorn, D. L.; Harlow, R. L. J. Am. Chem.
Soc. 1987, 109, 2788. (b) Rousset, C. J.; Swanson, D. R.; Lamaty,
F.; Negishi, E. Tetrahedron Lett. 1989, 30, 5105. (c) Bird, A. J.;
Taylor, R. J. K.; Wei, X. Synlett. 1995, 1237.
A solution of Ph3P (0.7 g, 2.7 mmol) in 10 mL of THF was
treated with BH3.SMe2 (1.4 mL, 2.7 mmol) and stirred for
12 h at room temperature. After addition of lithium (0.15 g,

G. Oba et al. / Tetrahedron 56 (2000) 121–127
127
¨
5. (a) Metzler, N.; Noth, H.; Thomann, M. Organometallics 1993,
Z. Naturforsch., B: Chem. Sci. 1995, 50, 239. (f) Breen, T. L.;
Stephan, D. W. J. Am. Chem. Soc. 1995, 117, 11914. (g) Zablocka,
M.; Miquel, Y.; Igau, A.; Majoral, J. P.; Skowronska, A. Chem.
Commun. 1998, 1177.
¨
12, 2423. (b) Desurmont, G.; Klein, R.; Uhlenbrock, S.; Laloe, E.;
Deloux, L.; Giolando, D. M.; Kim, Y. W.; Pereira, S.; Srebnik, M.
Organometallics 1996, 15, 3323.
6. (a) Fagan, P. J.; Nugent, W. A. J. Am. Chem. Soc. 1988, 110,
2310. (b) Jensen, M.; Livinghouse, T. J. Am. Chem. Soc. 1989, 111,
4495. (c) Mori, M.; Saitoh, F.; Uesaka, N.; Okamura, K.; Date, T. J.
J. Org. Chem. 1994, 59, 4993. (d) Mori, M.; Uesaka, N.; Saitoh, F.;
Shibasaki, M. J. Org. Chem. 1994, 5643. (e) Kemp, M. I.; Whitby,
R. J.; Coote, S. J. Synlett 1994, 451. (f) Takahashi, T.; Kondakov,
D. Y.; Suzuki, N. Organometallics 1994, 13, 3411. (g) Negishi, E.;
Maye, J. P.; Choueiry, D. Tetrahedron 1995, 51, 4447. (h)
Barluenga, J.; Sanz, R.; Fananas, F. J. J. Chem. Soc., Chem.
Commun. 1995, 1009.
7. (a) Takahashi, T.; Swanson, D. R.; Negishi, E. Chem. Lett.
1987, 623. (b) Tour, J. M.; Wu, R.; Schumm, J. S. J. Am. Chem.
Soc. 1990, 112, 5662. (c) Horn, T. D.; Baumgarten, M.; Gerghel,
L.; Enkelmann, V.; Mu¨llen, K. Tetrahedron Lett. 1993, 34, 5889.
8. (a) Mirza-Aghayan, M.; Boukherroub, R.; Etemad-Moghadam,
G.; Manuel, G.; Koenig, M. Tetrahedron Lett. 1996, 37, 3109. (b)
Mirza-Aghayan, M.; Boukherroub, R.; Oba, G.; Manuel, G.;
Koenig, M. J. Organomet. Chem. 1998, 564, 61.
10. (a) Gourdel, B.; Pelon, P.; Toupet, L.; Le Corre, M. Tetra-
´
hedron Lett. 1994, 35, 1197. (b) Brodie, N.; Juge, S. Inorg. Chem.
1998, 37, 2438 and references cited therein. (c) Lipshutz, B. H.;
Buzard, D. J.; Yun, C. S. Tetrahedron Lett. 1999, 40, 201.
11. (a) Fell, B.; Barhmann, H. Synthesis 1974, 119. (b) Morimoto,
T.; Ando, N.; Achiwa, K. Synlett. 1996, 1211. (c) Guillen, F.;
Moinet, C.; Fiaud, J. C. Bull. Soc. Chim. Fr. 1997, 371. (d)
Holz, J.; Quirmbach, M.; Schmidt, U.; Heller, D.; Stu¨rmer, R.;
¨
Borner, A. J. Org. Chem. 1998, 63, 8031.
12. (a) Smith, G. L.; Kelly, H. C. Inorg. Chem. 1969, 8, 2000.
(b) Myers, W. H.; Ryschkewitsch, G. E. Phosphorus 1975, 5, 97.
(c) Imamoto, T.; Hikosaka, T. J. Org. Chem. 1994, 56, 6753.
13. (a) Ellermann, J.; Dorn, K. Chem. Ber. 1966, 653. (b) Antberg,
M.; Pregel, C.; Dahlenburg, L. Inorg. Chem. 1984, 23, 4170.
(c) Schmidbaur, H.; Stu¨tzer, A.; Herdtweck, E. Chem. Ber. 1991,
124, 1095. (d) Seitz, Th.; Huttner, G.; Bu¨chner, M. Z. Naturforsch.,
B: Chem. Sci. 1994, 49, 1813.
´
14. (a) Dejean, V.; Manuel, G. XIth Symposium International de
9. (a) Hey, E.; Lappert, M. F.; Atwood, J. L., Bott, S. G. J. Chem.
Soc., Chem. Commun. 1987, 597. (b) Binger, P.; Biedenbach, B.;
Kru¨ger, C.; Regitz, M. Angew. Chem. Int. Ed. Engl. 1987, 764. (c)
Zablocka, M.; Boutonnet, F.; Igau, A.; Dahan, F.; Majoral, J. P.;
Pietrusiewicz, K. M. Angew. Chem. Int. Ed. Engl. 1993, 32, 1735.
(d) Le Floch, P.; Kolb, A.; Mathey, F. J. Chem. Soc., Chem.
Commun. 1994, 2065. (e) Hey-Hawkins, E.; Kurtz, S.; Baum, G.
´
la Chimie des Organosilicies, Montpellier, 1996. (b) Oba, G.;
´
´ ´
Moreira, G.; Dejean, V.; Manuel, G.; Koenig, M. Societe
´
Franc¸aise de Chimie, Pau, 1998. (c) Dejean,V.; Gornitzka, H.;
Oba, G.; Koenig, K.; Manuel, G., to be submitted.
15. Brisset, H.; Gourdel, Y.; Pellon, P.; Le Corre, M. Tetrahedron
Lett. 1993, 34, 4523.