MCM-41-supported bidentate phosphine palladium(0) complex: a highly active and recyclable catalyst for the Sonogashira reaction of aryl iodides

Article abstract of DOI:10.1016/j.tet.2007.03.111

The first MCM-41-supported bidentate phosphine palladium(0) complex has been prepared. This complex is a highly efficient catalyst for Sonogashira reaction and can be reused at least 10 times without any decrease in activity.

Full text of DOI:10.1016/j.tet.2007.03.111

Tetrahedron 63 (2007) 4642–4647
MCM-41-supported bidentate phosphine palladium(0)
complex: a highly active and recyclable catalyst
for the Sonogashira reaction of aryl iodides
*
Mingzhong Cai, Junchao Sha and Qiuhua Xu
Department of Chemistry, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
Received 18 September 2006; revised 17 March 2007; accepted 19 March 2007
Available online 21 March 2007
Abstract—The first MCM-41-supported bidentate phosphine palladium(0) complex has been prepared. This complex is a highly efficient
catalyst for Sonogashira reaction and can be reused at least 10 times without any decrease in activity.
Ó 2007 Elsevier Ltd. All rights reserved.
1. Introduction
candidate for a solid support for immobilization of homoge-
neous catalysts.4 MCM-41 has a regular pore diameter of ca.
5 nm and a specific surface area >700 m2 gꢀ1.5 Its large pore
size allows passage of large molecules such as organic reac-
tants and metal complexes through the pores to reach the
surface of the channel.6–8 It is generally believed that high
surface area of heterogeneous catalyst results in high cata-
lytic activity. Considering the fact that MCM-41 support
has an extremely high surface area and the catalytic palla-
dium species is anchored on the inner surface of the
mesopore of MCM-41 support, we expect that MCM-41-
supported palladium catalyst will exhibit high activity and
good reusability. To date, a few palladium complexes on
functionalized MCM-41 support have been prepared and
successfully used in organic reactions.9–13 However, to the
best of our knowledge, there has been no general study of
Sonogashira coupling reaction catalyzed by a MCM-41-
supported phosphine palladium complex described to date.
In this paper, we wish to report the synthesis of the first
MCM-41-supported bidentate phosphine palladium(0) com-
plex [abbreviated as MCM-41-2P-Pd(0)] and its catalytic
properties in the Sonogashira coupling reaction.
The Sonogashira reaction, the palladium-catalyzed cross-
coupling of terminal alkynes with aryl and vinyl halides, is
one of the most important, powerful, and versatile tools in
organic synthesis and has been widely applied to diverse
areas such as natural product synthesis and material sci-
ence.1 The reaction generally proceeds in the presence of
a homogeneous palladium catalyst, which makes the catalyst
recovery a tedious operation and might result in unaccept-
able palladium contamination of the product. From the
standpoint of green chemistry, the development of more en-
vironmentally benign conditions for the reaction, for example,
the use of a heterogeneous palladium catalyst would be de-
sirable.2 So far, cross-linked polystyrene or silica-supported
palladium catalysts have been used for Sonogashira reac-
tion.3 Unfortunately, they often result in lower catalytic
activity compared with their soluble counterparts. In addi-
tion, the activity of the recycled catalysts gradually de-
creases because the palladium species leaches from the
supporting polymer or silica gel. To overcome these limita-
tions, a novel methodology for creating insoluble and highly
active catalysts is needed. Our approach was guided by three
imperatives: the support should be easily accessible (1),
starting from readily available and cheap reagents (2). The
ligand anchored on the support should be air stable at
room temperature, which should allow its storage in normal
bottles with unlimited shelf life (3). Recent developments on
the mesoporous material MCM-41 provided a new possible
2. Results and discussion
Over the last few years, the N,N-bis(diphenylphosphinome-
thyl)amino-functionality has been used for the preparation
of dendrimer bound and supramolecular homogeneous cata-
lysts.14 Just recently insoluble versions of this chelating
phosphine ligand have been applied in Rh-catalyzed hydro-
formylation and Rh-catalyzed hydrogenation.15 The first
MCM-41-supported bidentate phosphine palladium(0)
complex [MCM-41-2P-Pd(0)] was conveniently synthesized
Keywords: Sonogashira reaction; Supported catalyst; Bidentate phosphine
palladium complex; MCM-41; Heterogeneous catalysis.
* Corresponding author. Tel./fax: +86 791 8120388; e-mail: mzcai@jxnu.
edu.cn
0040–4020/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2007.03.111

M. Cai et al. / Tetrahedron 63 (2007) 4642–4647
4643
from commercially available and cheap g-aminopropyltri-
ethoxysilane via immobilization on MCM-41, followed by
reacting with diphenylphosphinomethanol, which resulted
from adduct formation between diphenylphosphine and
paraformaldehyde, and palladium chloride and then the
reduction with hydrazine monohydrate (Scheme 1).
(100)
1
XRD patterns of the parent MCM-41 and the modified
materials MCM-41-2P and MCM-41-2P-Pd(0) are displayed
in Figure 1. Small angle X-ray powder diffraction of the
parent MCM-41 gave peaks corresponding to hexagonally
ordered mesoporous phases. For MCM-41-2P and MCM-
41-2P-Pd(0), the (100) reflection of the parent MCM-41
with decreased intensity was remained after functionaliz-
ation, while the (110) and (200) reflections became weak
and diffused, which could be due to contrast matching
between the silicate framework and organic moieties, which
are located inside the channels of MCM-41. These results
indicated that the basic structure of the parent MCM-41 was
not damaged in the whole process of catalyst preparation.
2
3
(110)
4
(200)
1
2
3
2
5
6
(degrees)
Figure 1. XRD profiles of the parent MCM-41 (1), MCM-41-2P (2), and
MCM-41-2P-Pd(0) (3).
Elemental analyses and X-ray photoelectron spectroscopy
(XPS) were used to characterize the MCM-41-supported
bidentate phosphine palladium(0) complex. The phosphine
and palladium content of the MCM-41-2P-Pd(0) was deter-
mined to be 1.15 and 0.52 mmol/g, respectively, and the
P:Pd mole ratio of this complex was 2.21. The XPS data
for MCM-41-2P, MCM-41-2P-Pd(II), MCM-41-2P-Pd(0),
and PdCl2 are listed in Table 1. It can be seen that the binding
energies of N1s, Si2p, and O1s of MCM-41-2P-Pd(II) are simi-
lar to those of MCM-41-2P, and the binding energy of Cl2p
of MCM-41-2P-Pd(II) is similar to that of PdCl2. However,
the difference of Pd3d5/2 binding energies between MCM-
41-2P-Pd(II) and PdCl2 is 1.2 eV. The difference of P2p bind-
ing energies between MCM-41-2P-Pd(II) and MCM-41-2P
is 0.5 eV. These results suggest that a coordination bond
between P and Pd is formed in the MCM-41-2P-Pd(II). The
binding energy (336.2 eV) of Pd3d5/2 of MCM-41-2P-Pd(0)
was lower than the binding energy (336.9 eV) of Pd3d5/2 of
MCM-41-2P-Pd(II). The Pd3d5/2 binding energy depends
strongly on the nature of the ligands. Consequently, it is im-
possible to identify the reduced complex as a zerovalent one
Table 1. XPS data for MCM-41-2P, MCM-41-2P-Pd(II), MCM-41-2P-
Pd(0) and PdCl2
a
Sample
Pd3d5/2 P2p
N1s
Si2p
O1s
Cl2p
MCM-41-2P-Pd(0) 336.2
MCM-41-2P-Pd(II) 336.9
MCM-41-2P
131.9 399.4 103.2 533.1
131.7 399.2 103.3 533.0 199.3
132.2 399.3 103.2 533.1
199.2
PdCl2
338.1
a
The binding energies are referenced to C1s (284.6 eV) and the energy
differences were determined with an accuracy of ꢁ0.2 eV.
on the basis of its Pd3d5/2 binding energy only. However, the
binding energy of Cl2p in the MCM-41-2P-Pd(0) cannot be
detected, the shift (lower) of Pd3d5/2 binding energy together
with the change in color (from yellow to brown) suggests
that the reduction of the starting palladium(II) complex to
the lower valent state has taken place. The MCM-41-2P-
Pd(0) complex catalyst formed is stable in air, but for pro-
longed storage it is better stored under an atmosphere of
argon in which case no decomposition and deactivation are
noted over the period of six months at room temperature.
OSiMe3
OH
O
1.Toluene, 100 °C, 48 h
2. Me3SiCl, rt, 24 h
OH
+ (EtO)3Si(CH2)3NH2
Si(CH2)3NH2
OEt
O
OH
MCM-41-NH2
MCM-41
OSiMe3
PPh2
PPh2
O
Ph2PCH2OH
PdCl2, CH3COCH3
reflux, 72 h
Si(CH2)3N
OEt
Toluene, 105 °C, 24 h
O
MCM-41-2P
OSiMe3
.
PPh2
PdCl2
PPh2
H2NNH2 H2O, EtOH
C, 5 h
O
MCM-41-2P-Pd(0)
Si(CH2)3N
OEt
30 °
O
MCM-41-2P-Pd(II)
Scheme 1.

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M. Cai et al. / Tetrahedron 63 (2007) 4642–4647
Table 3. Sonogashira reactions of terminal alkynes with aryl iodidesa
In order to evaluate the catalytic activity of the first MCM-
41-supported bidentate phosphine palladium(0) complex
[MCM-41-2P-Pd(0)], the Sonogashira reactions of terminal
alkynes with aryl iodides were studied. The reactions were
performed under conditions similar to those used in the cor-
responding homogeneous reactions. The influences of bases,
solvents, and amounts of the catalyst on catalytic property of
the MCM-41-2P-Pd(0) complex were investigated by using
coupling reaction of iodobenzene with 1-hexyne. The results
are shown in Table 2. It was found that among the bases
tested, piperidine proved to be the most efficient. Among
the solvents used, piperidine was also the best choice. In-
creasing the amount of palladium catalyst could shorten
the reaction time, but did not increase the yield of 1-phenyl-
1-hexyne (entry 12). The low palladium concentration
usually led to a long period of reaction, which was consistent
with our experimental results (entries 13 and 14). Taken
together, excellent result was obtained when the coupling
reaction was carried out with 0.5 mol % of MCM-41-2P-
Pd(0) and 5 mol% of CuI in piperidine at room temperature
(entry 9).
Entry R1
R2
Time (h) Product Yieldb (%)
1
H
Ph
Ph
Ph
Ph
Ph
2
3a
3b
3c
3d
3e
3f
94
95
97
95
98
96
89
95
96
93
97
94
95
98
97
95
90
94
93
2
3
4-CH3
4-Cl
2.5
1.5
1.5
1.5
1.5
2.5
2
4
5
4-O2N
3-O2N
6
4-CH3CO Ph
7
8
9
2-CF3
3-CN
H
Ph
Ph
Me3Si
Me3Si
Me3Si
CH3OCH2
CH3OCH2
n-C4H9
n-C4H9
n-C4H9
n-C4H9
4-CH3OC6H4
4-BrC6H4
3g
3h
3i
2
10
11
12
13
14
15
16
17
18
19
4-CH3O
4-Cl
H
4-Cl
H
4-O2N
3-CN
2-CF3
H
3
3j
1.5
2
3k
3l
1.5
2
1.5
2
2.5
2
2.5
3m
3n
3o
3p
3q
3r
3s
4-CH3
a
All reactions were performed using 1.0 mmol of 1, 1.5 mmol of 2,
0.005 mmol of MCM-41-2P-Pd(0), and 0.05 mmol of CuI in 3 mL of
piperidine at room temperature under Ar.
b
Isolated yield based on 1 used.
To examine the scope for this coupling reaction, a variety of
terminal alkynes were coupled with various aryl iodides in
piperidine in the presence of a catalytic amounts of MCM-
41-2P-Pd(0) and CuI at room temperature (Scheme 2). The
experimental results are summarized in Table 3. As shown
in Table 3, the Sonogashira coupling reactions of aryl io-
dides with a variety of terminal alkynes proceeded smoothly
under very mild conditions giving the corresponding cou-
pling products in excellent yields. The coupling reaction of
aryl iodides with terminal alkynes catalyzed by polystyrene-
supported phosphine palladium complex was also very high
yielding, but it was necessary to pre-soak the catalyst with
a large amount of solvent and a higher temperature (60 ꢂC)
was required.3f The optimized catalyst system was quite
general and tolerant of a range of functional groups. For
the electron-deficient aryl iodides, the coupling reactions
were rapidly completed within 1.5 h, and the others required
slightly longer reaction times. The coupling reactions of
phenyl bromide with terminal alkynes were very slow under
the same conditions giving traces of cross-coupling products
after 24 h of reaction time and the coupling reactions of
phenyl chloride with terminal alkynes did not occur at all.
To further illustrate that bromoarenes were inert in the reac-
tion system, the coupling reaction of 4-nitrobromobenzene
with phenylacetylene was performed at 100 ꢂC, it was found
that only trace of 1-(4-nitrophenyl)-2-phenylethyne was
obtained and considerable amount of homocoupling product
of phenylacetylene was formed. The similar observation was
made by other groups using heterogeneous palladium cata-
lysts in Sonogashira reactions.3 In all reactions, only
0.5 mol% of MCM-41-2P-Pd(0) based on the aryl iodides
was used, the molar turnover numbers (TON) were larger
than those in the corresponding coupling reaction catalyzed
by other heterogeneous catalysts reported.3
Table 2. Sonogashira reaction of iodobenzene with 1-hexyne in the presence
of several bases and solventsa
Entry Base
Solvent
MCM-41-2P-Pd(0) Time Yieldb
(mol%)
(h)
(%)
1
2
3
4
5
6
7
8
Et3N
Et3N
Et3N
Et3N
BuNH2
BuNH2
BuNH2
Toluene
DMF
Dioxane
Et3N
DMF
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
10
6
7
3
7
6
3
5
2
5
2
1
7
24
76
81
80
85
82
78
86
88
98
86
94
96
92
88
Dioxane
BuNH2
Piperidine DMF
Piperidine Piperidine 0.5
Pyrrolidine DMF 0.5
Pyrrolidine Pyrrolidine 0.5
Piperidine Piperidine 1.0
Piperidine Piperidine 0.1
Piperidine Piperidine 0.05
9
10
11
12
13
14
The novel MCM-41-supported bidentate phosphine palla-
dium(0) catalyst can be easily recovered by simple filtration.
We also examined the reuse of the catalyst by using the cou-
pling reaction of iodobenzene with 1-hexyne. In general, the
continuous recycle of resin-supported palladium catalysts is
difficult owing to leaching of the palladium species from the
polymer supports, which often reduces their activity within
a five-recycle run. However, when the reaction of iodobenz-
ene with 1-hexyne was performed even with 0.5 mol % of
MCM-41-2P-Pd(0), the catalyst could be recycled 10 times
without any loss of activity. The reaction promoted by the 10
th recycled catalyst gave 3n in 96% yield (Table 4, entry 2).
The average yield of 3n in consecutive reactions promoted
by the 1–10 times recycled catalyst was 97% (entry 3).
The result is important from a practical point of view. The
a
All reactions were performed using 1.0 mmol of iodobenzene, 1.5 mmol
of 1-hexyne, 0.05 mmol of CuI, and 3.0 mmol of base in 3 mL of solvent
at room temperature under Ar.
b
Isolated yield based on the iodobenzene used.
R1
0.5 mol % MCM-41-2P-Pd(0)
5 mol % CuI
I
R1
R2
R2
+
Piperidine, r.t.
2
1
3
Scheme 2.

M. Cai et al. / Tetrahedron 63 (2007) 4642–4647
4645
Table 4. Sonogashira reaction of iodobenzene with 1-hexyne catalyzed by recycled catalyst
0.05 mmol MCM-41-2P-Pd(0)
(1st-10th use)
0.5 mmol CuI
I
C4H9
+
C4H9
15 mmol
Piperidine, r.t., 2 h
3n
10 mmol
Entry
Catalyst cycle
Isolated yield (%)
TON
1
2
3
First
Tenth
First to tenth consecutive
98
96
av 97
196
192
Total of 1940
possible reasons without palladium leaching from the
MCM-41-2P-Pd(0) catalyst may be (1) the heterogeneous
MCM-41-2P-Pd(0) catalyst was a highly stable phosphine
palladium complex due to the chelating action of the biden-
tate phosphine ligand on palladium. (2) The catalytic palla-
dium species was anchored on the inner surface of the
mesopore of MCM-41 support; so there was no strong com-
plexing and solvolytic action of the solvent. (3) Cleavages of
the Si–O and P–Pd bonds of MCM-41-2P-Pd(0) were not so
easy since the coupling reaction was performed at room
temperature. The high catalytic activity, excellent reusability,
and the easy accessibility of the MCM-41-2P-Pd(0) make
the catalyst a highly attractive supported palladium catalyst
for the parallel solution phase synthesis of diverse libraries
of compounds.
standard and CDCl3 as a solvent. 13C NMR spectra were
recorded on a Bruker AC-P400 (100 MHz) spectrometer in
CDCl3 as solvent. Microanalyses were measured using a
Yanaco MT-3 CHN microelemental analyzer. X-ray powder
diffraction patterns were obtained on Damx-rA (Rigaka).
X-ray photoelectron spectra were recorded on XSAM 800
(Kratos).
4.2. Preparation of MCM-41-NH2
Asolutionofg-aminopropyltriethoxysilane(2.20 g,10 mmol)
in dry chloroform (18 mL) was added to a suspension of
the mesoporous support MCM-41 (2.80 g) in dry toluene
(180 mL). The mixture was stirred for 48 h at 100 ꢂC. Then
the solid was filtered and washed with CHCl3 (2ꢃ20 mL),
and dried in vacuum at 160 ꢂC for 5 h. The dried white solid
was then soaked in a solution of Me3SiCl (4.36 g, 40 mmol)
in dry toluene (150 mL) at room temperature under stirring
for 24 h. Then the solid was filtered, washed with acetone
(3ꢃ20 mL) and diethyl ether (3ꢃ20 mL), and dried invacuum
at 120 ꢂC for 5 h to obtain 3.54 g of hybrid material MCM-41-
NH2. The nitrogen content was found to be 1.27 mmol/g by
elemental analysis.
3. Conclusions
In summary, we have developed a new reusable heteroge-
neous catalyst, MCM-41-2P-Pd(0), prepared from commer-
cially available and cheap g-aminopropyltriethoxysilane via
amino-functionalization of MCM-41, followed by reacting
with diphenylphosphinomethanol and palladium chloride
and then the reduction with hydrazine monohydrate. It effi-
ciently catalyzed the heterogeneous Sonogashira coupling
reaction of terminal alkynes with aryl iodides and can be
reused 10 times without any decrease in its catalytic activity.
The advantages of our heterogeneous catalytic system over
others are as follows: (1) the heterogeneous MCM-41-2P-
Pd(0) catalyst can be conveniently prepared from commer-
cially available reagents; (2) the reaction conditions are
very mild, i.e., only 0.5 mol% palladium catalyst and room
temperature; (3) excellent performance and reusability of
the catalyst.
4.3. Preparation of MCM-41-2P
A Schlenk flask was charged with paraformaldehyde
(0.701 g, 23.3 mmol), dry MeOH (20 mL), and diphenyl-
phosphine (4.340 g, 23.3 mmol). The reaction mixture was
heated to 60 ꢂC under Ar until the white suspension formed
a colorless solution. After removal of MeOH in vacuo the
remaining viscous oil was diluted in dry toluene (20 mL).
This solution was added to a suspension of MCM-41-NH2
(3.020 g) in dry toluene (60 mL) and the reaction mixture
was heated to 105 ꢂC under Ar for 24 h. In the cooler regions
of the flask, the water/toluene azeotrope separated indicating
the reaction progress. After cooling to room temperature,
the solid product was collected by filtration under Ar,
washed with dry toluene (4ꢃ30 mL), CH2Cl2/THF (1:1)
(2ꢃ30 mL), CH2Cl2 (2ꢃ30 mL), and dried in vacuo
(100 ꢂC) for 5 h to give 4.08 g of the light yellow MCM-
41-2P. The nitrogen and phosphine contents were found to
be 0.76 and 1.44 mmol/g, respectively.
4. Experimental
4.1. Materials
All chemicals were reagent grade and used as purchased.
The mesoporous material MCM-41 was prepared according
to the literature procedure.16 All reactions were performed
under an inert atmosphere of dry argon using distilled dried
solvents. All coupling products were characterized by com-
parison of their spectra and physical data with authentic
samples. IR spectra were determined on a Perkin–Elmer
683 instrument. 1H NMR spectra were recorded on a Bruker
AC-P400 (400 MHz) spectrometer with TMS as an internal
4.4. Preparation of MCM-41-2P-Pd(0) complex
To a solution of PdCl2 (0.216 g, 1.22 mmol) in acetone
(50 mL) was added the MCM-41-2P (2.01 g). The reaction
mixture was refluxed under Ar for 72 h. The product was
allowed to cool, then filtered. The yellow solid was washed

4646
M. Cai et al. / Tetrahedron 63 (2007) 4642–4647
with distilled water (3ꢃ30 mL) and acetone (3ꢃ30 mL),
then stirred with hydrazine monohydrate (1.6 g) and EtOH
(25 mL) at 30 ꢂC under Ar for 5 h. The resulting product
was filtered, washed with EtOH (3ꢃ25 mL) and Et2O
(3ꢃ25 mL), and dried under vacuum at 60 ꢂC to give
1.93 g of the brown MCM-41-2P-Pd(0). The nitrogen, phos-
phine, and palladium content was 0.58, 1.15, and
0.52 mmol/g, respectively.
4.5.6. 4-CH3COC6H4C^CPh (3f).17 White solid, 98–
99 ꢂC. IR (KBr): n (cmꢀ1) 3080, 2922, 2218, 1680, 1604,
1265, 833, 693. H NMR (400 MHz, CDCl3): d 7.95 (d,
J¼8.0 Hz, 2H), 7.61 (d, J¼8.0 Hz, 2H), 7.55 (d, J¼2.4 Hz,
2H), 7.38–7.36 (m, 3H), 2.62 (s, 3H). 13C NMR
(100 MHz, CDCl3): d 197.3, 136.2, 131.8, 131.7, 128.8,
128.5, 128.3, 128.2, 122.7, 92.7, 88.6, 26.6.
1
4.5.7. 2-CF3C6H4C^CPh (3g). Colorless liquid. IR (neat):
n (cmꢀ1) 3066, 2925, 2222, 1605, 1497, 1320, 756, 690. 1H
NMR (400 MHz, CDCl3): d 7.70–7.66 (m, 2H), 7.59–7.51
(m, 3H), 7.44–7.35 (m, 4H). 13C NMR (100 MHz,
CDCl3): d 133.7, 131.7, 131.4, 128.8, 128.4, 127.9, 125.9,
125.0, 122.8, 122.2, 121.6, 94.9, 85.4. Anal. Calcd for
C15H9F3: C, 73.19; H, 3.66. Found: C, 73.02; H, 3.39.
4.5. General procedure for the Sonogashira coupling
reaction
Aryl iodide (1.0 mmol), MCM-41-2P-Pd(0) (10 mg,
0.005 mmol Pd), piperidine (3 mL), and CuI (0.05 mmol)
were added to a flask under Ar, and the resulting mixture
was stirred at room temperature for 5 min. To this suspen-
sion was added terminal alkyne (1.5 mmol), and the reaction
mixture was stirred at room temperature for 1.5–3 h. The
mixture was diluted with Et2O (40 mL). The MCM-41-2P-
Pd(0) catalyst was separated from the mixture by filtration,
washed with distilled water (2ꢃ10 mL), EtOH (3ꢃ10 mL),
and Et2O (2ꢃ10 mL) and reused in the next run. The ethereal
solution was washed with water (2ꢃ10 mL) and dried over
MgSO4. The solvent was removed under vacuum, and the
residue was purified by flash chromatography on silica gel
to give the desired product.
4.5.8. 3-NCC6H4C^CPh (3h).18 White solid, 71–72 ꢂC. IR
(KBr): n (cmꢀ1) 3050, 2228, 2207, 1600, 1490, 891, 760,
1
680. H NMR (400 MHz, CDCl3): d 7.77 (t, J¼1.2 Hz,
1H), 7.72–7.69 (m, 1H), 7.58–7.51 (m, 3H), 7.43 (t,
J¼7.6 Hz, 1H), 7.39–7.33 (m, 3H). 13C NMR (100 MHz,
CDCl3): d 135.7, 134.9, 131.8, 131.4, 129.3, 129.0, 128.5,
124.9, 122.3, 118.2, 112.9, 91.9, 87.0.
4.5.9. PhC^CSiMe3 (3i).19 Colorless liquid. IR (neat):
1
n (cmꢀ1) 3080, 2159, 1598, 1488, 1250, 864, 757, 690. H
NMR (400 MHz, CDCl3): d 7.48–7.45 (m, 2H), 7.31–7.29
(m, 3H), 0.25 (s, 9H). 13C NMR (100 MHz, CDCl3):
d 132.0, 128.5, 128.2, 123.1, 105.1, 94.1, 0.01.
4.5.1. PhC^CPh (3a).17 White solid, 60–61 ꢂC. IR (KBr):
1
n (cmꢀ1) 3063, 1599, 1492, 756, 689. H NMR (400 MHz,
CDCl3): d 7.55–7.52 (m, 4H), 7.37–7.32 (m, 6H). 13C
NMR (100 MHz, CDCl3): d 131.6, 128.4, 128.3, 123.3,
89.4.
4.5.10. 4-CH3OC6H4C^CSiMe3 (3j).19 Colorless liquid.
IR (neat): n (cmꢀ1) 2156, 1606, 1508, 1249, 834, 756,
1
699. H NMR (400 MHz, CDCl3): d 7.41 (d, J¼8.8 Hz,
4.5.2. 4-CH3C6H4C^CPh (3b).17 White solid, 73–74 ꢂC.
IR (KBr): n (cmꢀ1) 3029, 2918, 2859, 2215, 1594, 1509,
818, 690. H NMR (400 MHz, CDCl3): d 7.53–7.51 (m,
2H), 6.81 (d, J¼8.8 Hz, 2H), 3.81 (s, 3H), 0.24 (s, 9H).
13C NMR (100 MHz, CDCl3): d 159.7, 133.5, 115.3,
113.8, 105.2, 92.5, 55.3, 0.08.
1
2H), 7.42 (d, J¼8.0 Hz, 2H), 7.36–7.27 (m, 3H), 7.14 (d,
J¼8.0 Hz, 2H), 2.36 (s, 3H). 13C NMR (100 MHz,
CDCl3): d 138.4, 131.6, 131.5, 129.1, 128.3, 128.1, 123.5,
120.2, 89.6, 88.7, 21.5.
4.5.11. 4-ClC6H4C^CSiMe3 (3k).19 Colorless liquid. IR
(neat): n (cmꢀ1) 3030, 2159, 1590, 1488, 1250, 844, 759,
1
685. H NMR (400 MHz, CDCl3): d 7.38 (d, J¼8.4 Hz,
2H), 7.26 (d, J¼8.4 Hz, 2H), 0.24 (s, 9H). 13C NMR
(100 MHz, CDCl3): d 134.6, 133.2, 128.6, 121.7, 103.9,
95.4, ꢀ0.07.
4.5.3. 4-ClC6H4C^CPh (3c).18 White solid, 82–83 ꢂC. IR
(KBr): n (cmꢀ1) 3048, 2213, 1587, 1495, 831, 730, 687.
1H NMR (400 MHz, CDCl3): d 7.54–7.51 (m, 2H), 7.46
(d, J¼8.4 Hz, 2H), 7.36–7.31 (m, 5H). 13C NMR
(100 MHz, CDCl3): d 134.3, 132.8, 131.6, 128.7, 128.5,
128.4, 122.9, 121.8, 90.3, 88.2.
4.5.12. PhC^CCH2OCH3 (3l). Colorless liquid. IR (neat):
n (cmꢀ1) 2930, 2237, 1599, 1490, 1357, 757, 691. 1H NMR
(400 MHz, CDCl3): d 7.46–7.44 (m, 2H), 7.32–7.30 (m, 3H),
4.32 (s, 2H), 3.46 (s, 3H). 13C NMR (100 MHz, CDCl3):
d 131.8, 128.4, 128.3, 122.7, 86.4, 84.9, 60.4, 57.7. Anal.
Calcd for C10H10O: C, 82.16; H, 6.84. Found: C, 81.93;
H, 6.61.
4.5.4. 4-O2NC6H4C^CPh (3d).17 Yellow solid, 120–
121 ꢂC. IR (KBr): n (cmꢀ1) 3082, 2217, 1592, 1511, 1495,
858, 765, 690. H NMR (400 MHz, CDCl3): d 8.23 (d,
1
J¼8.8 Hz, 2H), 7.67 (d, J¼8.8 Hz, 2H), 7.58–7.55 (m,
2H), 7.41–7.37 (m, 3H). 13C NMR (100 MHz, CDCl3):
d 146.9, 132.3, 131.8, 130.3, 129.3, 128.5, 123.7, 122.1,
94.7, 87.5.
4.5.13. 4-ClC6H4C^CCH2OCH3 (3m). Colorless liquid.
1
IR (neat): n (cmꢀ1) 3056, 2241, 1592, 1489, 1355, 828. H
NMR (400 MHz, CDCl3): d 7.37 (d, J¼8.4 Hz, 2H), 7.29
(d, J¼8.4 Hz, 2H), 4.31 (s, 2H), 3.45 (s, 3H). 13C NMR
(100 MHz, CDCl3): d 134.5, 133.0, 128.7, 121.1, 85.9,
85.3, 60.4, 57.8. Anal. Calcd for C10H9OCl: C, 66.50; H,
4.98. Found: C, 66.24; H, 4.79.
4.5.5. 3-O2NC6H4C^CPh (3e).18 Yellow solid, 69–70 ꢂC.
IR (KBr): n (cmꢀ1) 3081, 2210, 1597, 1530, 1517, 1347,
810, 759, 692. 1H NMR (400 MHz, CDCl3): d 8.38 (s,
1H), 8.19–8.16 (m, 1H), 7.82 (d, J¼7.6 Hz, 1H), 7.57–
7.51 (m, 3H), 7.40–7.37 (m, 3H). 13C NMR (100 MHz,
CDCl3): d 148.2, 137.2, 131.8, 129.4, 129.1, 128.5, 126.4,
125.2, 122.9, 122.2, 92.0, 86.9.
4.5.14. PhC^C(CH2)3CH3 (3n).17 Colorless liquid. IR
(neat): n (cmꢀ1) 3056, 2960, 2870, 2237, 1598, 1499, 752,
690. H NMR (400 MHz, CDCl3): d 7.40–7.38 (m, 2H),
1

M. Cai et al. / Tetrahedron 63 (2007) 4642–4647
4647
New York, NY, 1998; Chapter 5; (b) Sonogashira, K.
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Hundertmark, T.; Littke, A. F.; Buchwald, S. L.; Fu, G. C.
Org. Lett. 2000, 2, 1729; (d) Erdelyi, M.; Gogoll, A. J. Org.
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7.29–7.26 (m, 3H), 2.41 (t, J¼7.2 Hz, 2H), 1.62–1.56 (m,
2H), 1.53–1.46 (m, 2H), 0.95 (t, J¼7.2 Hz, 3H). 13C NMR
(100 MHz, CDCl3): d 131.6, 128.2, 127.5, 124.2, 90.4,
80.6, 30.9, 22.0, 19.1, 13.7.
4.5.15. 4-O2NC6H4C^C(CH2)3CH3 (3o).17 Yellow liquid.
IR (neat): n (cmꢀ1) 3081, 2934, 2873, 2230, 1594, 1519,
2. (a) de Miguel, Y. R. J. Chem. Soc., Perkin Trans. 1 2000, 4213;
(b) Shuttleworth, S. J.; Allin, S. M.; Wilson, R. D.; Nasturica,
D. Synthesis 2000, 1035; (c) Loch, J. A.; Crabtree, R. H.
Pure Appl. Chem. 2001, 73, 119; (d) Corain, B.; Kralik, M.
J. Mol. Catal. A: Chem. 2001, 173, 99.
3. (a) Lin, C.-A.; Luo, F.-T. Tetrahedron Lett. 2003, 44, 7565;
(b) Djakovitch, L.; Rollet, P. Tetrahedron Lett. 2004, 45,
1367; (c) Cai, M.-Z.; Song, C.-S.; Huang, X. Synth.
Commun. 1997, 27, 1935; (d) Bergbreiter, D. E.; Liu, Y.-S.
Tetrahedron Lett. 1997, 38, 7843; (e) Uozumi, Y.;
Kobayashi, Y. Heterocycles 2003, 29, 1255; (f) Gonthier,
E.; Breinbauer, R. Synlett 2003, 1049; (g) Tyrrell, E.; Al-
Saardi, A.; Millet, J. Synlett 2005, 487.
4. Kresge, C. T.; Leonowicz, M. E.; Roth, W. J.; Vartuli, J. C.;
Beck, J. S. Nature 1992, 359, 710.
5. Beck, J. S.; Vartuli, J. C.; Roth, W. J.; Leonowicz, M. E.;
Kresge, C. T.; Schmitt, K. D.; Chu, C. T.-W.; Olson, D. H.;
Sheppard, E. W.; McCullen, S. B.; Higgins, J. B.; Schlenker,
J. L. J. Am. Chem. Soc. 1992, 114, 10834.
6. Zhou, W.; Thomas, J. M.; Shephard, D. S.; Johnson, B. F. G.;
Ozkaya, D.; Maschmeyer, T.; Bell, R. G.; Ge, Q. Science
1998, 280, 705.
7. Maschmeyer, T.; Rey, F.; Sankar, G.; Thomas, J. M. Nature
1995, 378, 159.
8. Liu, C.-J.; Li, S.-G.; Pang, W.-Q.; Che, C.-M. Chem. Commun.
1997, 65.
9. Kantam, M. L.; Chowdari, N. S.; Rahman, A.; Choudary, B. M.
Synlett 1999, 1413.
1
854. H NMR (400 MHz, CDCl3): d 8.15 (d, J¼8.8 Hz,
2H), 7.52 (d, J¼8.8 Hz, 2H), 2.46 (t, J¼7.2 Hz, 2H), 1.63–
1.57 (m, 2H), 1.51–1.46 (m, 2H), 0.96 (t, J¼7.2 Hz, 3H).
13C NMR (100 MHz, CDCl3): d 146.5, 132.3, 131.2,
123.5, 96.8, 79.3, 30.5, 22.1, 19.3, 13.6.
4.5.16. 3-NCC6H4C^C(CH2)3CH3 (3p). Colorless liquid.
IR (neat): n (cmꢀ1) 3069, 2958, 2873, 2232, 1597, 1478,
896, 798, 683. 1H NMR (400 MHz, CDCl3): d 7.66 (s,
1H), 7.60–7.53 (m, 2H), 7.39 (t, J¼7.6 Hz, 1H), 2.42 (t,
J¼7.2 Hz, 2H), 1.61–1.56 (m, 2H), 1.50–1.45 (m, 2H),
0.96 (t, J¼7.2 Hz, 3H). 13C NMR (100 MHz, CDCl3):
d 135.7, 135.0, 130.7, 129.1, 125.7, 118.3, 112.6, 93.4,
78.5, 30.5, 22.0, 19.1, 13.7. Anal. Calcd for C13H13N: C,
85.26; H, 7.10. Found: C, 85.02; H, 6.91.
4.5.17. 2-CF3C6H4C^C(CH2)3CH3 (3q). Colorless liquid.
IR (neat): n (cmꢀ1) 3075, 2961, 2875, 2235, 1604, 1491,
1450, 765. 1H NMR (400 MHz, CDCl3): d 7.61 (d,
J¼7.6 Hz, 1H), 7.52 (d, J¼7.6 Hz, 1H), 7.44 (t, J¼7.6 Hz,
1H), 7.34 (t, J¼7.6 Hz, 1H), 2.45 (t, J¼7.2 Hz, 2H), 1.62–
1.57 (m, 2H), 1.52–1.46 (m, 2H), 0.95 (t, J¼7.2 Hz, 3H).
13C NMR (100 MHz, CDCl3): d 133.9, 131.6, 131.3,
127.2, 125.7, 125.0, 122.4, 96.7, 77.5, 30.5, 21.9, 19.3,
13.6. Anal. Calcd for C13H13F3: C, 69.05; H, 5.75. Found:
C, 68.87; H, 5.58.
4.5.18. 4-CH3OC6H4C^CPh (3r).17 White solid, 58–
59 ꢂC. IR (KBr): n (cmꢀ1) 3024, 2212, 1602, 1498, 1245,
835, 750, 690. H NMR (400 MHz, CDCl3): d 7.52–7.43
(m, 4H), 7.32–7.29 (m, 3H), 6.86–6.83 (m, 2H), 3.76 (s,
3H). 13C NMR (100 MHz, CDCl3): d 159.5, 133.0, 131.4,
128.3, 127.9, 123.4, 115.5, 113.9, 89.4, 88.1, 55.2.
10. Zhou, J. M.; Zhou, R. X.; Mo, L. Y.; Zhao, S. F.; Zheng, X. M.
J. Mol. Catal. A: Chem. 2002, 178, 289.
11. Mehnert, P. C.; Weaver, D. W.; Ying, J. Y. J. Am. Chem. Soc.
1998, 120, 12289.
12. Yang, H.; Zhang, G.; Hong, X.; Zhu, Y. J. Mol. Catal. A: Chem.
2004, 210, 143.
1
13. Mukhopadhyay, K.; Sarkar, B. R.; Chaudhari, R. V. J. Am.
Chem. Soc. 2002, 124, 9692.
4.5.19. 4-CH3C6H4C^CC6H4Br-4 (3s).17 White solid,
157–158 ꢂC. IR (KBr): n (cmꢀ1) 3026, 2920, 2859, 2216,
14. (a) Reetz, M. T.; Waldvogel, S. R. Angew. Chem., Int. Ed.
1997, 36, 865; (b) Reetz, M. T.; Lohmer, G.; Schwickardi,
R. Angew. Chem., Int. Ed. 1997, 36, 1526; (c) Mizugaki, T.;
Murata, M.; Ooe, M.; Ebitani, K.; Kaneda, K. Chem.
Commun. 2002, 52.
1
1594, 1509, 818. H NMR (400 MHz, CDCl3): d 7.48–
7.34 (m, 6H), 7.14 (d, J¼8.0 Hz, 2H), 2.36 (s, 3H). 13C
NMR (100 MHz, CDCl3): d 138.8, 132.9, 131.6, 131.5,
129.1, 122.5, 122.3, 120.0, 90.6, 87.7, 21.5.
15. (a) Arya, P.; Panda, G.; Rao, N. V.; Alper, H.; Bourque, S. C.;
Manzer, L. E. J. Am. Chem. Soc. 2001, 123, 2889; (b) Hudkins,
C. M. G.; Knights, K. A.; Johnson, B. F. G.; de Miguel, Y. R.;
Raja, R.; Thomas, J. M. Chem. Commun. 2001, 2624; (c)
Kayaki, Y.; Shimokawatoko, Y.; Ikariya, T. Adv. Synth. Catal.
2003, 345, 175.
Acknowledgements
Project 20462002 was supported by the National Natural
Science Foundation of China.
16. Lim, M. H.; Stein, A. Chem. Mater. 1999, 11, 3285.
17. Liang, B.; Dai, M.; Chen, J.; Yang, Z. J. Org. Chem. 2005, 70,
391.
References and notes
18. Colvin, E. W.; Hamill, B. J. J. Chem. Soc., Perkin Trans. 1
1977, 869.
19. Cai, M.; Zhou, Z.; Jiang, J. Eur. J. Org. Chem. 2006, 1400.
1. (a) Sonogashira, K. Metal-Catalyzed Cross-Coupling
Reactions; Diederich, F., Stang, P. J., Eds.; Wiley-VCH: