Reaction of zirconocene-carboryne with alkenes: Synthesis and structure of zirconacyclopentanes with a carborane auxiliary

Article abstract of DOI:10.1021/om300202p

Reaction of zirconocene-carboryne in situ generated from Cp ₂Zr(μ-Cl)(μ-C₂B₁₀H₁₀) Li(OEt₂)₂ with various alkenes RCH=CH₂ in refluxing toluene gave the monoinsertion products 1,2-[Cp₂ZrCH(R) CH₂]-1,2-C₂B₁₀H₁₀ (R = aryl) or 1,2-[Cp₂ZrCH₂CH(R)]-1,2-C₂B₁₀H ₁₀ (R = alkyl) in good to high isolated yields with very high regioselectivity, depending on the polarity of the alkenes. This reaction offered an efficient route to zirconacyclopentanes with a carborane auxiliary, which can be viewed as a carborane version of zirconacyclopentanes. They are thermally very stable and chemically inert toward unsaturated organic molecules such as alkenes, alkynes, nitriles, CO, and CO₂. All complexes have been fully characterized by various spectroscopic techniques. Some have been further confirmed by single-crystal X-ray analyses.

Full text of DOI:10.1021/om300202p

Article
pubs.acs.org/Organometallics
Reaction of Zirconocene−Carboryne with Alkenes: Synthesis and
Structure of Zirconacyclopentanes with a Carborane Auxiliary
Shikuo Ren,† Zaozao Qiu,† and Zuowei Xie*,†,‡
†Department of Chemistry and Center of Novel Functional Molecules, The Chinese University of Hong Kong, Shatin, New
Territories, Hong Kong, China
‡State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, China
S
* Supporting Information
ABSTRACT: Reaction of zirconocene−carboryne in situ
generated from Cp2Zr(μ-Cl)(μ-C2B10H10)Li(OEt2)2 with vari-
ous alkenes RCHCH2 in refluxing toluene gave the
monoinsertion products 1,2-[Cp2ZrCH(R)CH2]-1,2-C2B10H10
(R = aryl) or 1,2-[Cp2ZrCH2CH(R)]-1,2-C2B10H10 (R = alkyl)
in good to high isolated yields with very high regioselectivity,
depending on the polarity of the alkenes. This reaction offered
an efficient route to zirconacyclopentanes with a carborane
auxiliary, which can be viewed as a carborane version of zirconacyclopentanes. They are thermally very stable and chemically inert
toward unsaturated organic molecules such as alkenes, alkynes, nitriles, CO, and CO2. All complexes have been fully
characterized by various spectroscopic techniques. Some have been further confirmed by single-crystal X-ray analyses.
INTRODUCTION
RESULTS AND DISCUSSION
Synthesis. Treatment of Cp2Zr(μ-Cl)(μ-C2B10H10)Li-
■
■
The reactivity patterns of carboryne (1,2-dehydro-o-carbor-
ane)1 can be modified and controlled by the formation of
metal−carboryne complexes whose chemical properties are
dominated by the nature of transition metals.2 For example, Ni-
(OEt2)2 (1)8a with 1.2−2 equiv of terminal alkenes RCH
CH2 in refluxing toluene gave 1,2-[Cp2ZrCH(R)CH2]-1,2-
C2B10H10 (3; R = aryl) or 1,2-[Cp2ZrCH2CH(R)]-1,2-
C2B10H10 (4; R = alkyl) in 59−91% isolated yields (Scheme
1). No double-insertion products were observed. An excess
amount of alkenes was used to ensure the full consumption of
1, facilitating the isolation of the products. Both solvents and
temperatures were crucial to this reaction. Complexes 3 or 4
were not observed if donor solvents such as Et2O and THF
were used instead of toluene, suggesting that the coordination
of alkene to the Zr atom was essential for the subsequent
insertion. High temperature was required, as it not only can
promote the dissociation of LiCl from 1 forming the
zirconocene−carboryne intermediate but may also facilitate
the coupling reaction between carboryne and the coordinated
alkene via the intermediates A/B (Scheme 1). However,
disubstituted alkenes such as α-methylstyrene and cyclohexene
did not react with 1 even after prolonged heating in toluene
probably due to steric reasons.
3
carboryne complex (η2-C2B10H10)Ni(PPh3)2 can undergo
coupling reaction with alkenes to generate alkenylcarboranes,4
two-component [2+2+2] cycloaddition with 2 equiv of alkynes
to afford benzocarboranes,5 and three-component [2+2+2]
cyclotrimerization with activated alkene and alkyne to give
dihydrobenzocarboranes.6 The reaction of carboryne with
alkynes can also proceed in a catalytic manner using Ni species
as catalyst.7 In contrast, the zirconium−carboryne, in situ
generated from Cp2Zr(μ-Cl)(μ-C2B10H10)Li(OEt2)2 (1), reacts
with polar unsaturated organic substrates such as isonitrile,
nitrile, and azide to give monoinsertion products8 and with
alkynes to give the corresponding zirconacyclopentenes,9 which
is a very useful intermediate for the synthesis of a variety of
benzocarboranes.10 We have very recently communicated that
transmetalation of zirconacyclopentanes with a carborane
auxiliary to nickel allows the insertion of alkyne into the
resultant Ni−C bond, leading to the formation of a series of
dihydrobenzocarboranes.11 In this connection, we explored the
generality of the reaction of 1 with various kinds of alkenes.
The results show that the prepared zirconacyclopentanes with a
carborane auxiliary are thermally very stable and chemically
inert. In sharp contrast, zirconacyclopentanes without a
carborane unit are very unstable and reactive and can undergo
ring-contraction to give alkene−zirconocene complexes or
ligand exchange with alkynes to afford the corresponding
zirconacyclopentenes and zirconacyclopentadienes.12 These
findings are reported in this article.
As shown in Table 1, a variety of styrenes inserted effectively
into the Zr−C(cage) bond of the Zr-carboryne intermediate to
form zirconacyclopentanes 3 in 67−91% isolated yields (entries
1−12). It was noted that a small amount of another
regioisomer, 1-CH3CH(R)-1,2-C2B10H11 (R = aryl), was
observed by GC-MS analyses of the quenched reaction mixture.
However, no pure 1,2-[Cp2ZrCH2CH(R)]-1,2-C2B10H10 (R =
aryl) was isolated. The results showed that the electronic nature
Received: March 15, 2012
Published: June 6, 2012
© 2012 American Chemical Society
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10). TMSCHCH2 also generated the monoinsertion product
3m in good yield (78%, entry 13). The reaction of CH2CH2
and Ph2PCHCH2 resulted in much lower yields (45−59%,
entries 14 and 15) probably due to the low concentration of
ethylene in solution or the large steric effect of the Ph2P unit.
Scheme 1. Reaction of 1 with Alkenes
n
On the other hand, BuCHCH2 and Ph2PCH2CHCH2
afforded another kind of regioisomeric insertion products, 4q
and 4r, in 88% and 59% yield, respectively (entries 17 and 18),
and no other regioisomer was observed by GC-MS analyses of
the quenched reaction mixture. These data suggest that the
regioselectivity of the reactions is mainly controlled by the
polarity of the alkenes.13 In general, the electron-donating
substituents on vinyl carbon give complexes 4 via intermediate
B, whereas the electron-withdrawing substituents offer
complexes 3 via intermediate A (Scheme 1).
To investigate the relative reactivity between alkene and
alkyne, PhCCCH2CHCH2 was treated with 1 to afford a
mixture of alkyne insertion product 1,2-[Cp2ZrC(Ph)
C(CH2CHCH2)]-1,2-C2B10H10 (5) and alkene insertion
product 1,2-[Cp2ZrCH2CH(CH2CCPh)]-1,2-C2B10H10 (6)
in a ratio of 65 to 35 based on the GC-MS analyses of the
hydrolysis products (Scheme 2).
Scheme 2. Reaction of 1 with Eneyne
Table 1. Reaction of 1 with Alkenes
Complexes 3−6 are very soluble in donor solvents, but are
insoluble in hexane. Complexes 3b−g,i,j,l,m,o and 4q,r are also
soluble in hot aromatic solvents, whereas 3a,k,n and 5/6 are
only barely soluble. They are stable in air for a few minutes in
the solid state, while their solutions are moisture-sensitive.
They are chemically inert toward alkenes, alkynes, nitriles, CO,
and CO2. In sharp contrast, zirconacyclopentanes without a
carborane unit are reactive and can undergo ring-contraction in
the presence of phosphine ligands to give alkene−zirconocene
complexes, ligand exchange with alkynes to afford the
of the substituents on the phenyl ring had little effect on the
reaction yields, and on the other hand, the bulkiness of
substituents on the phenyl ring influenced largely the insertion
of alkenes. For example, 2-trifluoromethylstyrene did not react
with 1, whereas 3- and 4-trifluoromethylstyrene reacted well to
give 3i and 3j in 91% and 73% yield, respectively (entries 8−
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corresponding zirconacyclopentenes and zirconacyclopenta-
dienes, and insertion reaction with CO, cyanides, azides, or
diazomethanes.14
Å clearly suggest their single-bond characters. The C(1)−C(2)
distance of ca. 1.69 Å is a typical value found in o-carboranes.18
The Zr−C(1) distances (2.389(3)−2.502(4) Å) are very close
to the corresponding values observed in zirconocene−
carboranyl complexes.19 The Zr−C(4) distances fall in the
range 2.268(8)−2.401(2) Å, which are comparable to the
corresponding values of 2.289(4)/2.307(4) Å in rac-[1,2-
ethylene-1,1′-bis(η5-tetrahydroindenyl)]Zr(C4H8),15 2.302(2)/
2.307(2) Å in (η5-menthyl-C5H4)2Zr(C4H8),20 and 2.275 (2)/
2.286(2) Å in Cp2Zr[1,4-(2,3-C3H6)C4H8].21 On the other
hand, the sum of five interior angles on the five-membered
zirconacyclopentane ring falls in the range 527.6−529.4°
(Table 2), suggestive of a nonplanar geometry, which is
different from those of zirconacyclopentenes incorporating a
carboranyl unit.9
Complexes 3−6 were fully characterized by various
spectroscopic techniques and elemental analyses. Two distinct
cage carbons were found at ∼92 and ∼90 ppm, respectively, in
the 13C NMR spectra. The unique Cp carbons at ∼115 and
∼116 ppm and protons at 5 to 6 ppm as two singlets were also
observed. For complexes 3a−n, the protons on the
zirconacyclopentane rings were observed as an AMX pattern
in the range 2 to 4 ppm in their 1H NMR spectra. For 3o, two
triplets at 0.82 and 2.76 ppm corresponding to the α- and β-H,
respectively, were observed, which compares to those of 0.91
ppm (α-H) and 1.70 ppm (β-H) in Cp2Zr(1,4-C4H8),15 0.39/
1.34 ppm (α-H) and 1.83/1.95 ppm (β-H) in rac-[1,2-
ethylene-1,1′-bis(η5-tetrahydroindenyl)]Zr(1,4-C4H8),15 1.25
ppm (α-H) and 3.25 ppm (β-H) in Cp2Zr[CH2CH2(1,2-
C6H4)],16 and 0.81/1.39 ppm (α-H) and 2.11/2.27 ppm (β-H)
in Cp2Zr[1,4-CH2CH2CH2CH(2-C5H4N)].17 On the other
hand, the two α-H and one β-H were observed at −0.43/0.16,
CONCLUSION
■
We have developed an efficient and practical method for the
preparation of a new class of zirconacyclopentanes incorporat-
ing a carboranyl unit from the reaction of zirconocene−
carboryne precursor 1 with terminal alkenes. High regiose-
lectivity is observed for different alkenes depending upon the
polarity of the CC double bond. In general, aryl substituents
go to the α position (3 in Scheme 1), whereas the alkyl
substituents prefer the β position (4 in Scheme 1). These
carborane-functionalized zirconacycles are very thermally stable
and chemically inert, which is significantly different from those
without a carboranyl moiety.12 However, after transmetalation
to nickel, they become useful intermediates for the synthesis of
functional carboranes, as evidenced by our preliminary
results.11
1
2.12/2.41, and 3.03/3.12 ppm, respectively, in the H NMR
spectrum of 4q/4r, which are very similar to that of 0.25, 2.15,
and 3.50 ppm in Cp2Zr[CH2CH(Me)(1,2-C6H4)].16 The
characteristic α- and β-carbons of zirconacyclopentane rings
were observed at about 40 and 60 ppm in their 13C NMR
spectra, respectively. The 11B NMR spectra of 3−6 exhibited
different patterns spanning the range 0 to −12 ppm.
Structure. Molecular structures of 3a,e,l,m,n,o, 4q, and 4r
were further confirmed by single-crystal X-ray analyses, and
their representative structures are shown in Figures 1−6,
EXPERIMENTAL SECTION
■
General Procedures. All reactions were performed under an
atmosphere of dry nitrogen with the rigid exclusion of air and moisture
using standard Schlenk or cannula techniques, or in a glovebox.9a 1H
NMR spectra were recorded on either a Bruker DPX 300 spectrometer
at 300 MHz or a Bruker DPX 400 spectrometer at 400 MHz. 13C{1H}
NMR spectra were recorded on either a Bruker DPX 300 spectrometer
at 75 MHz or a Bruker DPX 400 spectrometer at 100 MHz. 11B{1H}
NMR spectra were recorded on either a Bruker DPX 300 spectrometer
at 96 MHz or a Varian Inova 400 spectrometer at 128 MHz. 31P NMR
spectra were recorded on a Bruker DPX 300 spectrometer at 121
MHz. All chemical shifts were reported in δ units with references to
the residual solvent resonances of the deuterated solvents for proton
and carbon chemical shifts, to external BF3·OEt2 (0.00 ppm) for boron
chemical shifts, and to external 85% H3PO4 (0.00 ppm) for
phosphorus chemical shifts. Infrared spectra were obtained from KBr
pellets prepared in the glovebox on a Perkin-Elmer 1600 Fourier
transform spectrometer. Mass spectra were obtained on a Thermo
Finnigan MAT 95 XL spectrometer. Elemental analyses were
performed by the Shanghai Institute of Organic Chemistry, the
Chinese Academy of Sciences, China. All organic solvents were freshly
distilled from sodium benzophenone ketyl immediately prior to use.
Cp2Zr(μ-Cl)(μ-C2B10H10)Li(OEt2)2 (1) was prepared according to
the reported procedure.8a Complexes 3a and 4q were communicated
earlier.11 Other chemicals were purchased from either Sigma-Aldrich
or Acros Chemical Co. and used as received unless otherwise specified.
Preparation of 1,2-[Cp2ZrCH(4-Me-C6H4)CH2]-1,2-C2B10H10
(3b). To a toluene solution (20 mL) of Cp2Zr(μ-Cl)(μ-C2B10H10)-
Li(OEt2)2 (1; 554 mg, 1.0 mmol) was added 4-methylstyrene (2b; 236
mg, 2.0 mmol), and the reaction mixture was heated to reflux for 48 h.
After removal of the precipitate (LiCl) by filtration, the clear solution
was concentrated to about 5 mL, from which 3b was isolated as red
crystals after the solution stood at room temperature overnight (359
Figure 1. Molecular structure of 1,2-[Cp2ZrCH(2-Cl-C6H4)CH2]-1,2-
C2B10H10 (3e).
respectively. Selected bond distances and angles are summar-
ized in Table 2. Except for 3n (Figure 4), in which an additional
coordination bond between the Zr and P atoms with a Zr−P
distance of 2.670(1) Å is observed, all other complexes adopt a
distorted-tetrahedral coordination environment. As shown in
Table 2, the Zr−C(1) distance of 2.502(4) Å in 3n is much
longer than those (2.389(3)−2.434(2) Å) observed in its
analogues, whereas the C(3)−C(4) distance of 1.323(6) Å in
3n is significantly shorter than the corresponding values
(1.493(8)−1.552(3) Å) found in its analogues. Such differences
should result from the additional coordination of the P to the
Zr atom. The C(3)−C(4) and C(2)−C(3) distances of ca. 1.51
1
mg, 75%). H NMR (400 MHz, benzene-d6): δ 6.83 (d, J = 7.2 Hz,
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Table 2. Selected Bond Lengths (Å) and Angles (deg)
b
b
compd
3a
3e
3l
3m
3n
3o
4q
4r
a
av Zr−Cent
2.216
2.212
2.209
2.228
2.220
2.212
2.222
2.217
av Zr−C (C5 ring)
Zr−C(1)
Zr−C(4)
C(1)−C(2)
C(2)−C(3)
2.516(2)
2.434(2)
2.352(2)
1.700(3)
1.520(3)
1.520(3)
128.0
2.513(3)
2.398(3)
2.375(3)
1.690(5)
1.523(5)
1.547(5)
128.2
2.503(5)
2.399(4)
2.367(5)
1.683(6)
1.531(7)
1.532(7)
128.7
2.524(2)
2.406(2)
2.308(2)
1.691(3)
1.534(3)
1.552(3)
128.4
2.501(5)
2.502(4)
2.357(4)
1.687(5)
1.521(6)
1.323(6)
127.4
2.506(3)
2.401(2)
2.401(2)
1.689(3)
1.534(4)
1.541(4)
128.4
2.498(10)
2.391(7)
2.268(8)
1.679(10)
1.539(11)
1.493(8)
130.0
2.513(3)
2.389(3)
2.294(3)
1.700(3)
1.546(3)
1.540(4)
130.3
C(3)−C(4)
Cent−Zr−Cent
C(1)−Zr−C(4)
Zr−C(1)−C(2)
C(3)−C(4)−Zr
C(1)−C(2)−C(3)
C(2)−C(3)−C(4)
74.2(1)
111.2(1)
117.4(2)
114.7(2)
78.8(1)
108.3(2)
109.5(3)
115.7(3)
115.7(3)
77.3(2)
109.4(3)
111.6(3)
115.3(4)
114.0(4)
78.3(1)
108.4(1)
111.8(1)
114.9(2)
114.5(2)
69.2(1)
112.6(2)
130.0(3)
112.9(3)
115.0(4)
77.7(1)
109.3(1)
113.8(2)
114.6(2)
114.0(2)
76.8(3)
76.4(1)
111.0(4)
119.3(6)
114.1(6)
115.5(7)
110.5(1)
115.6(2)
113.8(2)
111.7(2)
112.7(2)
a
b
Cent = the centroid of Cp ring. Average values of two independent molecules in the unit cell.
Figure 2. Molecular structure of 1,2-[Cp2ZrCH(4-F-C6H4)CH2]-1,2-
C2B10H10 (3l).
Figure 4. Molecular structure of 1,2-[Cp2ZrCH(PPh2)CH2]-1,2-
C2B10H10 (3n).
2H), 5.82 (d, J = 7.2 Hz, 2H) (aromatic H), 5.78 (s, 5H), 5.01 (s, 5H)
(C5H5), 3.32 (m, 1H, CH), 3.15 (m, 1H, CHH), 2.95 (dd, J = 6.0, 13.6
Hz, 1H, CHH), 2.10 (s, 3H, CH3). 13C{1H} NMR (100 MHz,
benzene-d6): δ 138.2, 132.2, 132.0, 119.1 (aromatic C), 115.3, 114.1
(C5H5), 94.3, 90.4 (cage C), 66.5 (CH), 41.9 (CH2), 20.6 (CH3).
Figure 3. Molecular structure of 1,2-[Cp2ZrCH(TMS)CH2]-1,2-
C2B10H10 (3m).
Figure 5. Molecular structure of 1,2-[Cp2ZrCH2CH2]-1,2-C2B10H10
(3o).
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12.2 Hz, 1H, CH), 3.01 (m, 1H, CHH), 2.74 (dd, J = 6.0 and 14.2 Hz,
1H, CHH). 13C{1H} NMR (100 MHz, benzene-d6): δ 145.8, 136.7,
131.9, 121.9, 120.0, 118.3 (aromatic C), 116.1, 115.1 (C5H5), 92.2,
87.9 (cage C), 63.6 (CH), 41.8 (CH2). 11B{1H} NMR (96 MHz,
benzene-d6): δ −0.3 (1B), −5.0 (3B), −7.0 (3B), −10.2 (3B). IR
(KBr, cm−1): ν 2568 (BH). Anal. Calcd for C20H27B10ClZr (3f): C,
47.83; H, 5.42. Found: C, 48.07; H, 5.68.
Preparation of 1,2-[Cp2ZrCH(4-Cl-C6H4)CH2]-1,2-C2B10H10
(3g). This complex was prepared as purple crystals from 1 (554 mg,
1.0 mmol) and 4-chlorostyrene (2g; 277 mg, 2.0 mmol) using the
same procedures reported for 3b: yield 430 mg (86%). 1H NMR (400
MHz, benzene-d6): δ 6.99 (d, J = 8.4 Hz, 2H), 5.78 (d, J = 8.4 Hz, 2H)
(aromatic H), 5.74 (s, 5H), 5.16 (s, 5H) (C5H5), 3.58 (dd, J = 6.4,
12.8 Hz, 1H, CH), 3.01 (m, 1H, CHH), 2.72 (dd, J = 6.4, 14.4 Hz, 1H,
CHH). 13C{1H} NMR (100 MHz, benzene-d6): δ 142.9, 129.8, 127.4,
123.4 (aromatic C), 116.6, 115.5 (C5H5), 91.2, 86.6 (cage C), 62.6
(CH), 42.4 (CH2). 11B{1H} NMR (96 MHz, benzene-d6): δ 0.27 (1B),
−5.0 (2B), −6.6 (3B), −10.3 (4B). IR (KBr, cm−1): ν 2574 (BH).
Anal. Calcd for C20H27B10ClZr (3g): C, 47.83; H, 5.42. Found: C,
48.23; H, 5.11.
Figure 6. Molecular structure of 1,2-[Cp2ZrCH2CH(CH2PPh2)]-1,2-
C2B10H10 (4r).
Preparation of 1,2-[Cp2ZrCH(3-CF3-C6H4)CH2]-1,2-C2B10H10
(3i). This complex was prepared as a pale white solid from 1 (554
mg, 1.0 mmol) and 3-trifluoromethylstyrene (2i; 344 mg, 2.0 mmol)
11B{1H} NMR (96 MHz, benzene-d6): δ 0.66 (1B), −4.0 (1B), −5.6
(5B), −8.7 (3B). IR (KBr, cm−1): ν 2567 (BH). Anal. Calcd for
C21H30B10Zr (3b): C, 52.35; H, 6.28. Found: C, 52.53; H, 6.44.
Preparation of 1,2-[Cp2ZrCH(4-MeO-C6H4)CH2]-1,2-C2B10H10
(3c). This complex was prepared as a purple solid from 1 (554 mg, 1.0
mmol) and 4-methoxystyrene (2c; 270 mg, 2.0 mmol) using the same
procedures reported for 3b: yield 387 mg (78%). 1H NMR (400 MHz,
pyridine-d5): δ 7.09 (d, J = 8.4 Hz, 2H, aromatic H), 6.54 (m, 7H,
aromatic H and C5H5), 5.64 (s, 5H, C5H5), 3.71 (s, 3H, OCH3), 3.55
(m, 2H, CH and CHH), 3.09 (dd, J = 5.6, 13.2 Hz, 1H, CHH).
13C{1H} NMR (100 MHz, pyridine-d5): δ 156.2, 131.8, 119.8, 116.8,
1
using the same procedures reported for 3b: yield 490 mg (91%). H
NMR (400 MHz, benzene-d6): δ 6.89 (m, 2H), 6.25 (s, 1H), 6.24(d, J
= 8.8 Hz, 1H) (aromatic H), 5.79 (s, 5H), 5.16 (s, 5H) (C5H5), 3.67
(dd, J = 6.0, 12.6 Hz, 1H, CH), 3.13 (m, 1H, CHH), 2.73 (dd, J = 6.0,
14.2 Hz, 1H, CHH). 13C{1H} NMR (75 MHz, benzene-d6): δ 146.0,
130.4, 129.3, 126.1, 118.2 (aromatic C), 116.8, 115.9 (C5H5), 90.8,
86.0 (cage C), 61.9 (CH), 42.2 (CH2). 11B{1H} NMR (96 MHz,
benzene-d6): δ 0.7 (1B), −2.0 (1B), −4.8 (2B), −6.4 (3B), −8.7 (1B),
−10.1 (2B). IR (KBr, cm−1): ν 2566 (BH). Anal. Calcd for
C24.5H31B10F3Zr (3i + 0.5 toluene): C, 50.58; H, 5.37. Found: C,
50.52; H, 5.43.
112.2 (aromatic C), 114.9, 113.8 (C5H5), 95.3, 91.1 (cage C), 66.0
(CH), 54.7 (OCH3), 41.3 (CH2). 11B{1H} NMR (96 MHz, pyridine-
d5): δ −1.2 (1B), −5.3 (1B), −6.2 (2B), −7.2 (2B), −9.9 (4B). IR
(KBr, cm−1): ν 2562 (BH). Anal. Calcd for C21H30B10OZr (3c): C,
50.67; H, 6.07. Found: C, 50.39; H, 6.01.
Preparation of 1,2-[Cp2ZrCH(4-CF3-C6H4)CH2]-1,2-C2B10H10
(3j). This complex was prepared as a pale white solid from 1 (554
mg, 1.0 mmol) and 4-trifluoromethylstyrene (2j; 344 mg, 2.0 mmol)
1
using the same procedures reported for 3b: yield 391 mg (73%). H
Preparation of 1,2-[Cp2ZrCH(4-tBuO-C6H4)CH2]-1,2-C2B10H10
(3d). This complex was prepared as red crystals from 1 (554 mg, 1.0
mmol) and 4-tert-butoxystyrene (2d; 352 mg, 2.0 mmol) using the
same procedures reported for 3b: yield 362 mg (67%). 1H NMR (400
MHz, benzene-d6): δ 6.80 (d, J = 8.4 Hz, 2H, aromatic H), 5.73 (m,
7H, aromatic H and C5H5), 4.99 (s, 5H, C5H5), 3.28 (dd, J = 6.4, 12.0
Hz, 1H, CH), 3.07 (m, 1H, CHH), 2.93 (dd, J = 6.4, 14.0 Hz, 1H,
CHH), 1.24 (s, 9H, C(CH3)3). 13C{1H} NMR (100 MHz, benzene-
d6): δ 150.8, 134.9, 128.3, 126.0, 124.6, 118.9 (aromatic C), 114.3,
113.1 (C5H5), 93.0, 89.1 (cage C), 77.2 (OC(CH3)3), 64.8 (CH), 41.1
(CH2), 27.9 (OC(CH3)3). 11B{1H} NMR (96 MHz, benzene-d6): δ
0.2 (1B), −4.2 (2B), −5.0 (1B), −6.2 (2B), −9.3 (4B). IR (KBr,
cm−1): ν 2571 (BH). Anal. Calcd for C24H36B10OZr (3d): C, 53.39; H,
6.72. Found: C, 53.51; H, 6.65.
NMR (400 MHz, benzene-d6): δ 7.26 (d, J = 8.0 Hz, 2H), 5.93 (d, J =
8.0 Hz, 2H) (aromatic H), 5.75 (s, 5H), 5.15 (s, 5H) (C5H5), 3.76
(dd, J = 5.6, 12.4 Hz, 1H, CH), 3.11 (m, 1H, CHH), 2.71 (dd, J = 5.6,
14.0 Hz, 1H, CHH). 13C{1H} NMR (100 MHz, benzene-d6): δ 149.3,
129.3, 126.4, 122.3 (aromatic C), 116.9, 116.0 (C5H5), 90.6, 85.8 (cage
C), 62.2 (CH), 42.1 (CH2). 11B{1H} NMR (96 MHz, benzene-d6): δ
0.6 (1B), −4.7 (3B), −6.4 (3B), −8.8 (1B), −10.1 (2B). IR (KBr,
cm−1): ν 2573 (BH). Anal. Calcd for C21H27B10F3Zr (3j): C, 47.08; H,
5.08. Found: C, 46.72; H, 4.94.
Preparation of 1,2-[Cp2ZrCH(4-Br-C6H4)CH2]-1,2-C2B10H10
(3k). This complex was prepared as purple crystals from 1 (554 mg,
1.0 mmol) and 4-bromostyrene (2k; 366 mg, 2.0 mmol) using the
same procedures reported for 3b: yield 364 mg (82%). 1H NMR (400
MHz, pyridine-d5): δ 7.47 (d, J = 8.4 Hz, 2H), 6.66 (d, J = 8.4 Hz, 2H)
(aromatic H), 6.71 (s, 5H), 6.00 (s, 5H) (C5H5), 4.10 (dd, J = 6.0,
12.6 Hz, 1H, CH), 3.68 (m, 1H, CHH), 2.96 (dd, J = 6.0, 14.2 Hz, 1H,
CHH). 13C{1H} NMR (100 MHz, pyridine-d5): δ 143.1, 132.4, 123.6,
114.4 (aromatic C), 116.8, 115.9 (C5H5), 91.6, 86.9 (cage C), 62.2
(CH), 41.7 (CH2). 11B{1H} NMR (96 MHz, pyridine-d5): δ −0.6
(2B), −2.5 (1B), −5.5 (4B), −9.2 (3B). IR (KBr, cm−1): ν 2571 (BH).
Anal. Calcd for C20H27B10BrZr (3k): C, 43.94; H, 4.98. Found: C,
44.20; H, 5.10.
Preparation of 1,2-[Cp2ZrCH(4-F-C6H4)CH2]-1,2-C2B10H10 (3l).
This complex was prepared as purple crystals from 1 (554 mg, 1.0
mmol) and 4-fluorostyrene (2l; 244 mg, 2.0 mmol) using the same
procedures reported for 3b: yield 393 mg (81%). 1H NMR (400 MHz,
benzene-d6): δ 6.69 (t, J = 8.4 Hz, 2H), 5.81 (dd, J = 5.2, 8.4 Hz, 2H)
(aromatic H), 5.75 (s, 5H), 5.17 (s, 5H) (C5H5), 3.60 (dd, J = 6.4,
12.6 Hz, 1H, CH), 3.04 (m, 1H, CHH), 2.76 (dd, J = 6.4, 14.2 Hz, 1H,
CHH). 13C{1H} NMR (75 MHz, benzene-d6): δ 140.3, 123.5 (J = 6.8
Hz), 116.4, 115.5 (aromatic C), 116.5, 115.5 (C5H5), 86.7 (cage C),
62.5 (CH), 42.8 (CH2). 11B{1H} NMR (128 MHz, benzene-d6): δ 0.4
Preparation of 1,2-[Cp2ZrCH(2-Cl-C6H4)CH2]-1,2-C2B10H10
(3e). This complex was prepared as purple crystals from 1 (554 mg,
1.0 mmol) and 2-chlorostyrene (2e; 277 mg, 2.0 mmol) using the
same procedures reported for 3b: yield 378 mg (75%). 1H NMR (400
MHz, benzene-d6): δ 7.05 (d, J = 8.0 Hz, 1H), 6.95 (m, 2H), 6.54 (m,
1H) (aromatic H), 5.99 (s, 5H), 5.53 (s, 5H) (C5H5), 3.83 (m, 1H,
CH), 3.02 (dd, J = 9.4, 15.0 Hz, 1H, CHH), 2.84 (dd, J = 7.6, 15.0 Hz,
1H, CHH). 13C{1H} NMR (75 MHz, benzene-d6): δ 149.2, 129.9,
129.1, 127.3, 126.0, 123.2 (aromatic C), 117.6, 116.7 (C5H5), 88.8,
84.5 (cage C), 58.0 (CH), 44.4 (CH2). 11B{1H} NMR (96 MHz,
benzene-d6): δ 0.45 (1B), −5.4 (2B), −6.4 (3B), −7.8 (2B), −9.6
(2B). IR (KBr, cm−1): ν 2566 (BH). Anal. Calcd for C21.75H29B10ClZr
(3e + 0.25 toluene): C, 49.74; H, 5.57. Found: C, 49.85; H, 5.64.
Preparation of 1,2-[Cp2ZrCH(3-Cl-C6H4)CH2]-1,2-C2B10H10
(3f). This complex was prepared as purple crystals from 1 (554 mg,
1.0 mmol) and 3-chlorostyrene (2f; 277 mg, 2.0 mmol) using the same
procedures reported for 3b: yield 440 mg (84%). 1H NMR (400 MHz,
benzene-d6): δ 6.71 (m, 2H), 5.95 (s, 1H), 5.86 (d, J = 7.6 Hz, 1H)
(aromatic H), 5.78 (s, 5H), 5.12 (s, 5H) (C5H5), 3.42 (dd, J = 6.0,
4439
dx.doi.org/10.1021/om300202p | Organometallics 2012, 31, 4435−4441

Organometallics
Article
(1B), −5.0 (3B), −6.4 (3B), −9.1 (1B), −10.3 (2B). IR (KBr, cm−1):
ν 2569 (BH). Anal. Calcd for C20H27B10FZr (3l): C, 49.45; H, 5.60.
Found: C, 49.73; H, 5.56.
pyridine-d5): δ −0.9 (1B), −3.3 (1B), −5.0 (1B), −7.4 (2B), −9.7
(2B), −11.0 (2B), −13.4 (1B). IR (KBr, cm−1): ν 2557 (BH). Anal.
Calcd for C23H30B10Zr (5/6): C, 54.62; H, 5.98. Found: C, 54.62; H,
5.97.
Preparation of 1,2-[Cp2ZrCH(TMS)CH2]-1,2-C2B10H10 (3m).
This complex was prepared as light brown crystals from 1 (554 mg,
1.0 mmol) and TMSCHCH2 (2m; 200 mg, 2.0 mmol) using the
same procedures reported for 3b: yield 364 mg (78%). 1H NMR (300
MHz, benzene-d6): δ 5.83 (s, 5H), 5.81 (s, 5H) (C5H5), 3.30 (dd, J =
5.1, 13.2 Hz, 1H, CH), 3.00 (m, 1H, CHH), 2.62 (dd, J = 5.1, 14.7 Hz,
1H, CHH), −0.36 (s, 9H, Si(CH3)3). 13C{1H} NMR (75 MHz,
benzene-d6): δ 116.0, 115.3 (C5H5), 89.7, 88.4 (cage C), 64.7 (CH),
42.9 (CH2), 0.28 (TMS). 11B{1H} NMR (96 MHz, benzene-d6): δ
−0.0 (1B), −5.6 (4B), −7.8 (2B), −9.6 (1B), −11.4 (2B). IR (KBr,
cm−1): ν 2561 (BH). Anal. Calcd for C17H32B10SiZr (3m): C, 44.02;
H, 6.95. Found: C, 43.82; H, 6.85.
Preparation of 1-[PhCHC(CH2CHCH2)]-1,2-C2B10H11 (7)
and 1-[CH3CH(CH2CCPh)]-1,2-C2B10H11 (8). A solution of the
above mixture (5 + 6) obtained from the reaction of 1 (277 mg, 1.00
mmol) with PhCCCH2CHCH2 (85 mg, 1.20 mmol) was treated
with 1 M HCl aqueous solution (10 mL). The organic layer was
separated, and the aqueous solution was extracted twice with diethyl
ether (10 mL × 2). The organic phases were combined, washed with
saturated brine aqueous solution (20 mL), and dried over anhydrous
Na2SO4. After removal of the solvent under reduced pressure, the
residue was subjected to flash column chromatography on silica gel
using hexane as eluent to give 7 as a white solid (79 mg, 55%) and 8 as
1
a colorless oil (35 mg, 24%). For 7: H NMR (400 MHz, CDCl3): δ
Preparation of 1,2-[Cp2ZrCH(PPh2)CH2]-1,2-C2B10H10 (3n).
This complex was prepared as black crystals from 1 (554 mg, 1.0
mmol) and diphenylvinylphosphine (2n; 424 mg, 2.0 mmol) using the
same procedures reported for 3b: yield 405 mg (59%). 1H NMR (300
MHz, pyridine-d5): δ 7.92 (m, 4H), 7.40 (m, 6H) (aromatic H), 6.03
(s, 5H), 5.82 (s, 5H) (C5H5), 3.90 (m, 1H, CH), 2.64 (m, 1H, CHH),
2.18 (m, 1H, CHH). 13C{1H} NMR (75 MHz, pyridine-d5): δ 137.1
(d, J = 7.7 Hz), 133.3 (d, J = 10.0 Hz), 131.7 (d, J = 13.1 Hz), 130.3
(d, J = 22.5 Hz), 129.2 (d, J = 9.2 Hz), 129.1 (d, J = 9.5 Hz) (aromatic
C), 107.9, 107.4 (C5H5), 101.0 (d, J = 9.9 Hz), 95.2 (d, J = 23.0 Hz)
(cage C), 41.7 (CH2), 23.3 (d, J = 34.8 Hz, CH). 11B{1H} NMR (96
MHz, pyridine-d5): δ −1.7 (1B), −5.8 (4B), −7.3 (2B), −9.4 (2B),
−11.3 (1B). IR (KBr, cm−1): ν 2561 (BH). Anal. Calcd for
C26H33B10PZr (3n): C, 54.23; H, 5.78. Found: C, 53.87; H, 5.92.
Preparation of 1,2-[Cp2ZrCH2CH2]-1,2-C2B10H10 (3o). This
complex was prepared as light brown crystals from 1 (554 mg, 1.0
mmol) and excess ethylene (1 atom) (2o) using the same procedures
reported for 3b, but the reaction mixture was stirred for 3 d at room
7.32 (m, 3H), 7.27 (m, 2H) (aromatic H), 7.04 (s, 1H, CCHPh),
5.89 (m, 1H, CHCH2), 5.24 (dd, J = 1.3 and 10.3 Hz, 1H, CH
CHH), 5.16 (dd, J = 1.3 and 17.2 Hz, 1H, CHCHH), 3.92 (brs, 1H,
cage H), 3.11 (m, 2H, CH2). 13C{1H} NMR (100 MHz, CDCl3): δ
136.4, 135.2, 135.0, 131.2, 128.5, 128.3, 117.9 (aromatic and olefinic
C), 79.1, 59.2 (cage C), 35.3 (CH2). 11B{1H} NMR (96 MHz,
CDCl3): δ −4.0 (1B), −5.4 (1B), −10.4 (2B), −11.6 (2B), −12.9
(2B), −14.4 (2B). HRMS: m/z calcd for C13H22B810B2+ (7) 286.2719,
found 286.2713. For 8: 1H NMR (400 MHz, CDCl3): δ 7.38 (m, 2H),
7.31 (m, 3H) (aromatic H), 3.94 (brs, 1H, cage H), 2.75 (dd, J = 5.2
and 16.4 Hz, 1H, CHH), 2.66 (m, 1H, CH), 2.52 (dd, J = 7.2 and 16.4
Hz, 1H, CHH), 1.33 (d, J = 6.8 Hz, 3H, CH3). 13C{1H} NMR (100
MHz, CDCl3): δ 131.5, 128.4, 128.3, 122.8 (aromatic C), 85.8, 83.8
(CC), 79.3, 60.0 (cage C), 38.8 (CH), 27.1 (CH2), 20.3 (CH3).
11B{1H} NMR (96 MHz, CDCl3): δ −4.0 (1B), −5.8 (1B), −10.4
+
(2B), −12.5 (2B), −14.4 (4B). HRMS: m/z calcd for C13H22B810B2
(8) 286.2719, found 286.2712.
1
X-ray Structure Determination. All single crystals were
immersed in Paraton-N oil and sealed under nitrogen in thin-walled
glass capillaries. Data were collected at 293 K on a Bruker SMART
1000 CCD diffractometer using Mo Kα radiation. An empirical
absorption correction was applied using the SADABS program.22 All
structures were solved by direct methods and subsequent Fourier
difference techniques and refined anisotropically for all non-hydrogen
atoms by full-matrix least-squares on F2 using the SHELXTL program
package.23 Structures of 3e and 3n showed one-quarter and one
toluene of solvation, respectively. All hydrogen atoms were geometri-
cally fixed using the riding model. Crystal data and details of data
collection and structure refinements are given in the Supporting
Information.
temperature: yield 176 mg (45%). H NMR (400 MHz, benzene-d6):
δ 5.72 (s, 10H, C5H5), 2.76 (t, J = 7.2 Hz, 2H, CH2), 0.82 (t, J = 7.2
Hz, 2H, CH2). 13C{1H} NMR (100 MHz, benzene-d6): δ 115.5
(C5H5), 90.2, 88.1 (cage C), 44.6, 41.1 (CH2). 11B{1H} NMR (96
MHz, benzene-d6): δ 0.4 (1B), −5.6 (4B), −7.2 (1B), −8.8 (4B). IR
(KBr, cm−1): ν 2561 (BH). Anal. Calcd for C14H24B10Zr (3o): C,
42.93; H, 6.18. Found: C, 42.86; H, 6.17.
Preparation of 1,2-[Cp2ZrCH2CH(CH2PPh2)]-1,2-C2B10H10 (4r).
This complex was prepared as colorless crystals from 1 (554 mg, 1.0
mmol) and allyldiphenylphosphine (2r; 271 mg, 1.2 mmol) using the
same procedures reported for 3b: yield 350 mg (59%). 1H NMR (400
MHz, benzene-d6): δ 7.61 (m, 2H), 7.40 (m, 2H), 7.15 (m, 3H), 7.07
(m, 3H) (aromatic H), 5.76 (s, 5H), 5.60 (s, 5H) (C5H5), 3.10 (m,
1H, CH), 2.76 (m, 1H, CHHP), 2.38 (t, J = 12.8 Hz, 1H, CHH), 2.07
(m, 1H, CHHP), 0.16 (m, 1H, CHH). 13C{1H} NMR (100 MHz,
benzene-d6): δ 140.8 (d, J = 13.3 Hz), 138.3 (d, J = 16.2 Hz), 134.4 (d,
J = 20.5 Hz), 132.0 (d, J = 17.0 Hz), 129.8, 129.0 (d, J = 7.4 Hz), 128.7
(d, J = 5.3 Hz), 128.2 (aromatic C), 115.7, 115.4 (C5H5), 93.5 (d, J =
8.2 Hz), 90.8 (cage C), 56.1 (d, J = 7.1 Hz, CH2), 47.9 (d, J = 14.7 Hz,
CH2P), 43.1 (d, J = 10.3 Hz, CH). 11B{1H} NMR (128 MHz,
benzene-d6): δ −0.1 (1B), −5.5 (3B), −7.9 (3B), −11.9 (3B). IR
(KBr, cm−1): ν 2560 (BH). Anal. Calcd for C27H35B10PZr (4r): C,
54.89; H, 5.98. Found: C, 54.80; H, 6.37.
ASSOCIATED CONTENT
* Supporting Information
■
S
Crystal data and summary of data collection and refinement as
well as crystallographic data in CIF format for 3a, 3e, 3l, 3m,
3n, 3o, 4q, and 4r. This material is available free of charge via
the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: zxie@cuhk.edu.hk. Fax: +852 26035057.
■
Preparation of 1,2-[Cp2ZrC(Ph)C(CH2CHCH2)]-1,2-
C2B10H10 (5) and 1,2-[Cp2ZrCH2CH(CH2CCPh)]-1,2-C2B10H10
(6). Complexes 5 and 6 were prepared as a yellow solid mixture
(65/35) from 1 (554 mg, 1.00 mmol) and PhCCCH2CHCH2
(170 mg, 1.20 mmol) using the same procedures reported for 3b: yield
415 mg (82%). They were inseparable by recrystallization. The molar
Notes
The authors declare no competing financial interest.
1
ratio of 5/6 was determined by GC-MS analyses after hydrolysis. H
ACKNOWLEDGMENTS
■
NMR (300 MHz, pyridine-d5): δ 7.38 (m), 7.31 (m), 7.10 (t, J = 7.5
Hz), 6.97 (d, J = 7.5 Hz) (aromatic H), 6.61 (s, C5H5), 5.95 (m), 5.80
(m), 5.21 (m), 4.96 (m) (CCH), 3.17 (d, J = 3.4 Hz, CH2), 2.85 (d,
J = 6.0 Hz, CH2). 13C{1H} NMR (75 MHz, pyridine-d5): δ 196.9,
143.7, 139.2, 135.7, 128.7, 128.4, 128.2, 128.0,127.9, 126.1, 124.1
(aromatic C), 117.0, 114.6 (C5H5), 91.3, 87.9 (cage C), 65.1,
61.1(CH), 41.7, 38.1, 34.9, 14.8 (CH2). 11B{1H} NMR (96 MHz,
The work described in this paper was jointly supported by
grants from the Research Grants Council of the Hong Kong
Special Administration Region (Project No. 404609), Direct
Grant (No. 2060432) of The Chinese University of Hong
Kong, National Basic Research Program of China (973
Program; Project No. 2012CB821600), and State Key
4440
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(17) Thomas, D.; Baumann, W.; Spannenberg, A.; Kempe, R.;
Rosenthal, U. Organometallics 1998, 17, 2096−2102.
Laboratory of Elemento-Organic Chemistry, Nankai University
(Project No. 0314).
(18) (a) Xie, Z. Acc. Chem. Res. 2003, 36, 1−9. (b) Xie, Z. Coord.
Chem. Rev. 2002, 231, 23−46. (c) Hosmane, N. S.; Maguire, J. A. In
Comprehensive Organometallic Chemistry III; Crabtree, R. H.; Mingos,
D. M. P., Eds.; Elsevier: Oxford, 2007; Vol. 3, pp 175−264. (d) Saxena,
A. K.; Hosmane, N. S. Chem. Rev. 1993, 93, 1081−1124. (e) Oliva, J.
REFERENCES
■
(1) (a) Gingrich, H. L.; Ghosh, T.; Huang, Q.; Jones, M., Jr. J. Am.
Chem. Soc. 1990, 112, 4082−4083. (b) Ghosh, T.; Gingrich, H. L.;
Kam, C. K.; Mobraaten, E. C. M.; Jones, M., Jr. J. Am. Chem. Soc. 1991,
113, 1313−1318. (c) Huang, Q.; Gingrich, H. L.; Jones, M., Jr. Inorg.
Chem. 1991, 30, 3254−3257. (d) Cunningham, R. T.; Bian, N.; Jones,
M., Jr. Inorg. Chem. 1994, 33, 4811−4812. (e) Ho, D. M.;
Cunningham, R. J.; Brewer, J. A.; Bian, N.; Jones, M., Jr. Inorg.
Chem. 1995, 34, 5274−5278. (f) Barnett-Thamattoor, L.; Zheng, G.;
Ho, D. M.; Jones, M., Jr.; Jackson, J. E. Inorg. Chem. 1996, 35, 7311−
7315. (g) Jeon, J.; Kitamura, T.; Yoo, B.-W.; Kang, S. O.; Ko, J. Chem.
Commun. 2001, 2110−2111. (h) Lee, T.; Jeon, J.; Song, K. H.; Jung, I.;
Baik, C.; Park, K.-M.; Lee, S. S.; Kang, S. O.; Ko, J. Dalton Trans. 2004,
933−937. (i) Wang, S. R.; Qiu, Z.; Xie, Z. J. Am. Chem. Soc. 2010, 132,
9988−9989. (j) Wang, S. R.; Qiu, Z.; Xie, Z. J. Am. Chem. Soc. 2011,
133, 5760−5763. (k) Wang, S. R.; Xie, Z. Tetrahedron 2012, 68,
5269−5278. (l) Wang, S. R.; Xie, Z. Organometallics 2012, 31, 3316−
3323.
M.; Allan, N. L.; Schleyer, P. V. R.; Vinas, C.; Teixidor, F. J. Am. Chem.
̃
Soc. 2005, 127, 13538−13547.
(19) (a) Kang, S. O.; Ko, J. Adv. Organomet. Chem. 2001, 47, 61−99.
(b) Deng, L.; Xie, Z. Organometallics 2007, 26, 1832−1845. (c) Deng,
L.; Xie, Z. Coord. Chem. Rev. 2007, 251, 2452−2476. (d) Xie, Z. Coord.
Chem. Rev. 2006, 250, 259−272. (e) Wang, H.; Li, H.-W.; Xie, Z.
Organometallics 2003, 22, 4522−4531. (f) Zi, G.; Li, H.-W.; Xie, Z.
Organometallics 2002, 21, 1136−1145. (g) Wang, S.; Li, H.-W.; Xie, Z.
Organometallics 2004, 23, 2469−2478.
(20) Klahn, M.; Baumann, W.; Arndt, P.; Burlakov, V. V.; Schareina,
T.; Spannenberg, A.; Rosenthal, U. Organometallics 2009, 28, 915−
918.
(21) Taber, D. F.; Louey, J. P.; Wang, Y.; Nugent, W. A.; Dixon, D.
A.; Harlow, R. L. J. Am. Chem. Soc. 1994, 116, 9457−9463.
(22) Sheldrick, G. M. SADABS: Program for Empirical Absorption
(2) For reviews, see: (a) Qiu, Z.; Ren, S.; Xie, Z. Acc. Chem. Res.
2011, 44, 299−309. (b) Qiu, Z.; Xie, Z. Sci. China Ser. B: Chem. 2009,
52, 1544−1558.
(3) (a) Sayler, A. A.; Beall, H.; Sieckhaus, J. F. J. Am. Chem. Soc. 1973,
95, 5790−5792. (b) Qiu, Z.; Deng, L.; Chan, H.-S.; Xie, Z.
Organometallics 2010, 29, 4541−4547.
(4) Qiu, Z.; Xie, Z. Angew. Chem., Int. Ed. 2008, 47, 6572−6575.
(5) Deng, L.; Chan, H.-S.; Xie, Z. J. Am. Chem. Soc. 2006, 128, 7728−
7729.
Correction of Area Detector Data; University of Gottingen: Germany,
̈
1996.
(23) Sheldrick, G. M. SHELXTL 5.10 for Windows NT: Structure
Determination Software Programs; Bruker Analytical X-ray Systems,
Inc.: Madison, WI, USA, 1997.
(6) Qiu, Z.; Xie, Z. J. Am. Chem. Soc. 2009, 131, 2084−2085.
(7) (a) Qiu, Z.; Wang, S. R.; Xie, Z. Angew. Chem., Int. Ed. 2010, 49,
4649−4652. (b) Qiu, Z.; Xie, Z. J. Am. Chem. Soc. 2010, 132, 16085−
16093.
(8) (a) Deng, L.; Chan, H.-S.; Xie, Z. J. Am. Chem. Soc. 2005, 127,
13774−13775. (b) Ren, S.; Deng, L.; Chan, H.-S.; Xie, Z.
Organometallics 2009, 28, 5749−5756.
(9) (a) Ren, S.; Chan, H.-S.; Xie, Z. Organometallics 2009, 28, 4106−
4114. (b) Ren, S.; Chan, H.-S.; Xie, Z. J. Am. Chem. Soc. 2009, 131,
3862−3863.
(10) Ren, S.; Qiu, Z.; Xie, Z. J. Am. Chem. Soc. 2012, 134, 3242−
3254.
(11) Ren, S.; Qiu, Z.; Xie, Z. Angew. Chem., Int. Ed. 2012, 51, 1010−
1013.
(12) (a) Titanium and Zirconium in Organic Synthesis; Marek, I., Ed.;
Wiley-VCH: Weinhein, Germany, 2002. (b) Negishi, E.; Takahashi, T.
Acc. Chem. Res. 1994, 27, 124−130. (c) Negishi, E. Dalton Trans. 2005,
827−848.
(13) Bennett, M. A.; Macgregor, S. A.; Wenger, E. Helv. Chim. Acta
2001, 84, 3084−3104.
(14) (a) Rousset, C. J.; Swanson, D. R.; Lamaty, F.; Negishi, E.
Tetrahedron Lett. 1989, 30, 5105−5108. (b) Swanson, D. R.; Rousset,
C. J.; Negishi, E. J. Org. Chem. 1989, 54, 3521−3523. (c) Negishi, E.;
Choueiry, D.; Nguyen, T. B.; Swanson, D. R. J. Am. Chem. Soc. 1994,
116, 9751−9752. (d) Knight, K. S.; Wang, D.; Waymouth, R. M.;
Ziller, J. J. Am. Chem. Soc. 1994, 116, 1845−1854. (e) Xi, Z.; Hara, R.;
Takahashi, T. J. Org. Chem. 1995, 60, 4444−4448. (f) Probert, G. D.;
Whitby, R. J. Tetrahedron Lett. 1995, 36, 4113−4116. (g) Luker, T.;
Whitby, R. J.; Webster, M. J. Organomet. Chem. 1995, 492, 53−57.
(h) Takahashi, T.; Xi, Z.; Yamazaki, A.; Liu, Y.; Nakajima, K.; Kotora,
M. J. Am. Chem. Soc. 1998, 120, 1672−1680. (i) Liu, Y.; Xi, C.; Hara,
R.; Nakajima, K.; Yamazaki, A.; Kotora, M.; Takahashi, T. J. Org. Chem.
2000, 65, 6951−6957. (j) Sun, H.; Burlakov, V. V.; Spannenberg, A.;
Baumann, W.; Arndt, P.; Rosenthal, U. Organometallics 2001, 20,
5472−5477. (k) Bradley, C. A.; Keresztes, I.; Lobkovsky, E.; Young, V.
G.; Chirik, P. J. J. Am. Chem. Soc. 2004, 126, 16937−16950.
(15) Mansel, S.; Thomas, D.; Lefeber, C.; Heller, D.; Kempe, R.;
Baumann, W.; Rosenthal, U. Organometallics 1997, 16, 2886−2890.
(16) Erker, G.; Kropp, K. J. Am. Chem. Soc. 1979, 101, 3659−3660.
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