C(sp2)-C(sp2) cross coupling reaction catalyzed by a palladacycle phosphine complex: A simple and sustainable protocol in aqueous media

Article abstract of DOI:10.1007/s12039-015-0958-z

The Heck reactions of various aryl halides with olefins using {[Ph₂PCH₂PPh₂CH = C(O)(C₁₀H₇)] PdCl₂} as efficient catalyst has been investigated. The mononuclear palladacycle complex showed excellent activity in aqueous phase including the C(sp ²)-C(sp ²) cross coupling reactions. The advantages of the protocol are high yields, short reaction time, a cleaner reaction profile and notable simplicity.

Full text of DOI:10.1007/s12039-015-0958-z

J. Chem. Sci. Vol. 127, No. 11, November 2015, pp. 1919–1926. ꢀc Indian Academy of Sciences.
DOI 10.1007/s12039-015-0958-z
C(sp2)–C(sp2) cross coupling reaction catalyzed by a palladacycle
phosphine complex: A simple and sustainable protocol in aqueous media
∗
SEYYED JAVAD SABOUNCHEI and MARJAN HOSSEINZADEH
Faculty of Chemistry, University of Bu–Ali Sina, Hamedan, 65174 Iran
e-mail: jsabounchei@yahoo.co.uk
MS received 6 June 2015; revised 25 July 2015; accepted 4 August 2015
Abstract. The Heck reactions of various aryl halides with olefins using {[Ph2PCH2PPh2CH=C(O)(C10H7)]
PdCl2} as efficient catalyst has been investigated. The mononuclear palladacycle complex showed excellent
2
2
activity in aqueous phase including the C(sp )–C(sp ) cross coupling reactions. The advantages of the protocol
are high yields, short reaction time, a cleaner reaction profile and notable simplicity.
Keywords. Palladium complex; Heck cross-coupling reaction; low catalyst loading; aerobic conditions.
2
1
1
. Introduction
has been reported in our previous work, as a catalyst
precursor for Heck cross-coupling in aqueous environ-
ments. This complex gives a high catalytic activity
and a cleaner reaction profile in the coupling reac-
tions of various aryl halides and olefins under aerobic
conditions.
Heck reaction, one of the most widely adopted methods
for the construction of carbon-carbon bonds in modern
organic chemistry, is commonly carried out in the pres-
ence of a palladium complex.1 The resulting prod-
ucts play a significant role in the synthesis of bioactive
–4
compounds and organic products and are exploited in
pharmaceutical industry applications.5 Development 2. Experimental
,6
in this area is based on designing selective and stable
2
.1 General
palladium complex ctalysts with high turnover. Design-
ing a suitable ligand is one of the first and important
factor for this purpose. Among several types of ligand,
All chemicals obtained from commercial suppliers were
reagent grade and used without further purification.
Fourier transform IR spectra were recorded on a Shi-
madzu 435-U-04 spectrophotometer, in the 200-4000
cm region. NMR spectra were obtained on 500 MHz
and 90 MHz Bruker spectrometers in CDCl as sol-
phosphines exhibited the highest activity and selectivity
in the Heck reactions.7–13
Palladium-phosphine catalytic systems being
employed in Heck coupling reactions have shown
−1
14–17
3
high efficiency in the formation of C–C bonds.
A
vent. Melting points were determined using an SMP3
apparatus.
number of Pd catalysts, usually simple palladium com-
plexes associated with appropriate ligands, can catalyze
this reaction under various reaction conditions. Among
them, palladacycle complexes have been extensively
applied in coupling reactions as effective catalysts,
2
.2 General procedure for Mizoroki-Heck reaction
due to their ready preparation and modification, high
A reaction tube was charged with the required aryl
halide (1 mmol), ethyl acrylate (2.2 mmol) or styrene
activity and relative stability.1
8–20
For these reasons,
this field is still challenging and in its infancy and the
development of novel and greener protocols for the
Heck cross-coupling reaction are desirable.
In this context, we were interested to explore the use
of a five-membered chelate ring palladacycle, which
(2.2 mmol), Pd catalyst (0.001 mol%) and base (1.5
mmol) in NMP/H O or DMF/H O (2 mL, 1:1). The
2
2
reaction mixture was stirred for the required period
◦
of time at 110 C until completion of the reaction,
as monitored by TLC. After completion of the reac-
tion, the mixture was diluted with n-hexane (15 mL)
and water (15 mL). The combined organic phase was
dried with CaCl , solvent was removed and the product
was recrystallized from ethanol. Yields were calculated
2
∗
For correspondence
1919

1920
Seyyed Javad Sabounchei and Marjan Hosseinzadeh
against consumption of the aryl halides and pure prod- 2.3f 4-styrylbenzonitrile: [Table 4, entry 8 (Yield:
1
13
◦
1
ucts were identified by FTIR, H and C NMR spec- 0.167 g, 83%); 2f] White solid, M.P. 117–118 C, H
troscopy and melting point analysis (See supplementary NMR (ppm): 7.52–7.64 (m, 6H), 7.39 (t, 2H, J = 7.50
13
information).
Hz), 7.32 (t, 1H, J = 7.40 Hz), 7.07-7.23 (m, 2H). C
NMR (ppm): δ 142.26, 136.70, 132.94, 132.83, 129.31,
1
29.10, 127.36, 127.30, 127.15, 119.51 and 110.98.25
2
.3 Characterization of cross-coupling products
2
.3a (E)-Ethyl 3-phenylacrylate: [Table 4, entries 1 2.3g cinnamaldehyde: [Table 4, entries 1 (Yield:
(
Yield: 0.151 g, 84%), 3 (0.144 g, 80%), 9 (0.135 g, 0.104 g, 79%), 3 (0.092 g, 70%), 9 (0.082 g, 62%); 3a]
1
1
7
7
1
3
1
5%); 1a] Light yellow liquid, H NMR (ppm): δ = Light yellow liquid, H NMR (ppm): 6.68 (doublet of
.68 (d, 1H, J = 16.03 Hz), 7.36–7.52 (m, 5H), 6.43 (d, doublet, 1H, J = 7.75 Hz), 7.40–7.54 (m, 6H), 9.67 (d,
13
H, J = 16.01 Hz), 4.26 (q, 2H, J = 7.16 Hz), 1.33 (t, 1H, J = 7.75 Hz). C NMR (ppm): δ 128.38, 128.48,
13
H, J = 7.10 Hz). C NMR (ppm): δ = 167.39 (s, CO), 129.02, 131.17, 133.96, 152.64 and 193.57.
44.99, 134.91, 130.63, 129.29, 128.46, 118.72, 60.90
The following compounds gave data consistent
with those published: Table 4: (E)-Ethyl 3-(4-
methylphenyl)acrylate [entries 2 (Yield: 0.151 g,
22
(
CH ), and 14.74 (CH ).
2 3
7
8%), 4 (0.141 g, 73%), 10 (0.122, 63%); 1b],26
2
.3b (E)-Ethyl 3-(4-nitrophenyl)acrylate: [Table 4, (E)-Ethyl 3-(4-acetylphenyl)acrylate [entries 5 (Yield:
entry 7 (Yield: 0.187 g, 83%); 1e] Light yellow solid, 0.175 g, 79%), 11 (0.155 g, 70%); 1c],27 (E)-
◦
1
M.P. 136–137 C, H NMR (ppm): δ 8.23 (d, 2H, J 1-(4-styrylphenyl)ethanone [entries 5 (Yield: 0.172,
2
4,28
=
8.72 Hz), 7.65-7.71 (m, 3H), 6.47 (d, 1H, J = 16.06 79%), 11 (0.146 g, 67%); 2c],
1-methoxy-4-
Hz), 4.28 (q, 2H, J = 7.09 Hz), 1.34 (t, 3H, J = 7.11 styrylbenzene [entries 6 (Yield: 0.130 g, 63%), 12
13
29
Hz). C NMR (ppm): δ = 166.43 (s, CO), 148.92, (0.121 g, 59%); 2d], (E)-1-nitro-4-styrylbenzene
2
9–31
1
42.02, 141.02, 129.03, 124.59, 123.04, 61.43 (CH ), [entry 7 (Yield: 0.179, 81%); 2e],
(E)-3-(4-
nitrophenyl)acrylaldehyde [entry 7 (Yield: 0.136,
2
23
and 14.68 (CH ).
3
24
7
7%); 3e].
2
.3c (E)-Ethyl 3-(4-cyanophenyl)acrylate: [Table 4,
1
3
. Results and Discussion
entry 8 (Yield: 0.168 g, 82%); 1f] Colorless solid, H
NMR (ppm): δ = 7.67 (d, 2H, J =6.06 Hz), 7.59-7.66
It is well established that palladium complexes con-
taining phosphine ligands, which combine both good
donor strength and π–accepting capacity, always
have a high catalytic activity in Heck cross-coupling
(
7
m, 3H), 6.51 (d, 1H, J = 16.03 Hz), 4.28 (q, 2H, J =
13
.12 Hz), 1.34 (t, 3H, J = 7.05 Hz). C NMR (ppm):
δ 166.54 (CO), 142.53, 139.19, 133.06, 128.79, 122.33,
1
18.77, 113.79, 61.35 (CH ), and 14.68 (CH ).
2 3
18–20,32–37
reactions.
Therefore we have attempted to use
2
2
the palladium(II) complex as catalyst in C(sp )–C(sp )
cross coupling reaction (scheme 1). The ability to use
small amounts of catalyst and still achieve high yields
is a great concern in cross coupling reactions due to the
high cost of metals and ligands.
The catalytic activity of the palladacycle com-
plex was assessed in the Heck cross-coupling reac-
tion, initially by studying the coupling of 1-bromo-4-
nitrobenzene with styrene as a model reaction. Var-
2
.3d (E)-1,2-diphenylethene: [Table 4, entries 1
(Yield: 0.143 g, 81%), 3 (0.127 g, 72%), 9 (0.121 g,
◦
1
6
9%); 2a] Colorless plates, M.P. 122–124 C, H NMR
(
ppm): δ 7.50 (d, 4H, J = 7.7 Hz), 7.34 (t, 4H, J = 7.6
Hz), 7.25 (t, 2H, J = 7.4 Hz), 7.10 (s, 2H). 13C NMR
24
(
ppm): δ 137.81, 129.18, 129.15, 128.09, 126.99.
2.3e 1-methyl-4-styrylbenzene: [Table 4, entries 2 ious parameters including solvent, base and catalyst
(
Yield: 0.148 g, 78%), 4 (0.140 g, 74%), 10 (0.120 loading were screened to optimize the reaction condi-
◦
1
g, 63%); 2b] White plates, M.P. 116–117 C, H NMR tions. Initially, the coupling reaction was set up in the
(
ppm): δ 7.52 (d, 2H, J = 7.26 Hz), 7.43 (d, 2H, J presence of DMF solvent, K CO base and 0.01 mol%
2
3
◦
=
=
8.08 Hz), 7.36 (t, 2H, J = 7.84 Hz), 7.25 (t, 1H, J catalyst loading at 130 C for 3 h (the obtained yield
7.34 Hz), 7.18 (d, 2H, J = 7.90 Hz), 7.05-7.12 (m, was 81%). As shown in scheme 1, the results of this
2
H), 2.37 (s, 3H). 13C NMR (ppm): δ = 159.32 (s, reaction indicate that the Pd(II) complex catalyzed the
CO), 137.97, 137.93, 134.96, 129.84, 129.10, 129.04, olefin coupling reaction with 1-bromo-4-nitrobenzene
1
24
28.11, 127.85, 126.86, 126.83 and 21.72 (CH ).
to form exclusively trans stilbene as established by
3

A five-membered Pd(II) catalyst in water
1921
Catalyst, Styrene
Solvent, Base, Heat
R
R
X
O
Catalyst, ethyl acrylate
Solvent, Base, Heat
R
OEt
R= -H, -Me, -OMe, -COMe, -CN, -NO2
X= Cl, Br, I
Cl
Cl
PPh
2
Catalyst =
CH
P
Ph
2
O
2
2
Scheme 1. C(sp )-C(sp ) cross-coupling reaction.
1H NMR and 13C NMR analysis. No other coupling using 0.001 mol% of catalyst (table 1). No significant
products (cis or gem isomers) were observed. This improvement in the reaction results was observed upon
is in agreement with general Mizoroki-Heck coupling further increasing the quantity of catalyst. As this cata-
reaction so that the linear isomers (E-isomer) is favor- lyst is not sensitive to oxygen, the reactions were carried
able and were selectively obtained as confirmed by out in the air atmosphere.
spectroscopic analysis.38
The effect of catalyst loading was investigated, mize the effect of different solvents and bases (tables 2
using different quantities of the catalyst ranging from and 3). Water, H O/DMF, methanol, DMF, NMP, H O/
.0005 to 0.10 mol%. The best results were obtained NMP and dioxane were investigated, and the best
Additional studies were carried out in order to opti-
2
2
0
Table 1. Optimization of catalyst concentration.
Catalyst
Solvent, Base, Heat
Y
Y
ArX
+
Ar
Entry
Catalyst (mol%)
Time (h)
Reaction conditiona, b
Isolated yield (%)
a
b
NRc
90
89
81
85
80
85
68
73
1
2
None
0.10
10
3
Styrene , ethyl acrylate
a
Styrene
Ethyl acrylate
Styrene
Ethyl acrylate
Styrene
Ethyl acrylate
Styrene
Ethyl acrylate
b
a
3
4
5
0.01
0.001
0.0005
3
3
5
b
a
b
a
b
a
Reaction conditions: 1-bromo-4-nitrobenzene (1 mmol), Styrene (2.2 mmol), K2CO3 (1.5 mmol),
◦
DMF (2 ml), in the air, 130 C.
b
Reaction conditions: 1-bromo-4-nitrobenzene (1 mmol), ethyl acrylate (2.2 mmol), Cs2CO3 (1.5
◦
mmol), NMP (2 ml), in the air, 130 C.
c
No Reaction.

1922
Seyyed Javad Sabounchei and Marjan Hosseinzadeh
[a]
Table 2. Optimization of base and solvent for Heck cross-coupling reaction of 1-bromo-4-nitrobenzene with styrene.
Br
Catalyst (0.001 mol%)
Solvent, Base, Heat
O N
2
+
O N
2
◦
Entry
Base
Solvent
Temp ( C)
Time (h)
Isolated yield (%)
1
2
3
4
5
6
7
8
9
1
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
Cs2CO3
Na2CO3
NaOAc
NaF
methanol
DMF
DMF/H2O
H2O
60
10
4
4
5
6
9
6
10
10
12
63
81
81
66
72
60
77
68
55
59
130
110
90
130
110
110
110
110
110
NMP
dioxane
DMF/H2O
DMF/H2O
DMF/H2O
DMF/H2O
0
[a] Reaction conditions: 1-bromo-4-nitrobenzene (1 mmol), Styrene (2.2 mmol), base (1.5 mmol) and 2 mL solvent.
yields were observed with water/DMF (2 mL, 1:1) and generated in the oxidative addition mechanistic step,
water/NMP (2 mL, 1:1) for styrene and ethyl acry- were found to be more effective than the other bases
late, respectively (tables 2 and 3). By testing different such as Na CO , NaOAc and NaF that afforded moder-
2
3
◦
temperatures in the range of 60 to 130 C, a change ate yield of coupling products.
in yield was observed. The highest yield was obtained
at 110 C. Base has a main function in Mizoroki-Heck halides and olefins at the determined optimized condi-
The reaction was then investigated with different aryl
◦
reaction mechanism to neutralize the acidic condition tions and the results are summarized in table 4. We used
of hydrogen halide in the reductive elimination step and aryl iodide to test the catalytic activity of the Pd(II)
39,40
regenerate the catalyst to continue catalytic cycle.
Inorganic bases such as K CO and Cs CO , because
catalyst.
The time of reaction for aryl iodide was shorter
2
3
2
3
of their excellent capability to neutralize protons than that for aryl bromides (3 h) and very good to
Table 3. Optimization of base and solvent for Heck cross-coupling reaction of 1-bromo-4-nitrobenzene with ethyl
[a]
acrylate.
O
Br
O
Catalyst (0.001 mol%)
Solvent, Base, Heat
OEt
+
OEt
O N
2
O N
2
◦
Entry
Base
Solvent
Temp ( C)
Time (h)
Isolated yield (%)
1
2
3
4
5
6
7
8
9
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
K2CO3
Na2CO3
NaOAc
NaF
methanol
DMF
NMP
NMP/H2O
H2O
dioxane
NMP/H2O
NMP/H2O
NMP/H2O
NMP/H2O
60
10
7
4
4
5
12
6
10
12
12
55
71
83
84
69
65
75
62
54
48
130
130
110
90
110
110
110
110
110
10
[a] Reaction conditions: 1-bromo-4-nitrobenzene (1 mmol), Ethyl acrylate (2.2 mmol), base (1.5 mmol) and 2 mL solvent.

A five-membered Pd(II) catalyst in water
1923
Table 4. aH,be,cck cross-coupling reaction of aryl halides with olefins catalyzed by Pd
complexes.
Entry
Aryl halide
Product
time (h)
Yield (%)e
I
1
1a
3
3
3
84
81
79
2
3
a
a
I
H C
3
2
3
1b
3
3
78
78
2b
Br
1a
4
4
4
80
72
70
2
3
a
a
Br
H C
4
3
1b
4
4.5
73
74
2b
Br
O
CH3
5
6
7
1c
4
4
79
79
2c
Br
H CO
3
1d
4
4
67
63
2d
Br
O N
2
1e
3
3
4
83
81
77
2
3
e
e
Br
NC
8
9
1f
4
4
82
83
2f
Cl
1a
4
4
6
75
69
62
2
3
a
a
Cl
Cl
H C
1
0
1
3
1b
6
6
63
63
2b
O
CH3
1
1c
4
5
70
67
2c

1924
Seyyed Javad Sabounchei and Marjan Hosseinzadeh
Table 4.
(continued)
Aryl halide
Entry
Product
time (h)
Yield (%)e
Cl
H CO
12
3
1d
4.5
4
61
59
2d
a
Reaction conditions for 1: aryl halide (1 mmol), ethyl acrylate (2.2 mmol), Cs2CO3
1.5 mmol), NMP/H2O (2 mL), catalyst (0.001 mol%), 110 C.
◦
(
b
Reaction conditions for 2: aryl halide (1 mmol), styrene (2.2 mmol), K2CO3 (1.5
◦
mmol), DMF/H2O (2 mL), catalyst (0.001 mol%), 110 C.
c
Reaction conditions for 3: aryl halide (1 mmol), acrylaldehyde (2.2 mmol), Cs2CO3
◦
(
1.5 mmol), DMF/H2O (2 mL), catalyst (0.001 mol%), 110 C.
All reactions were carried out under aerobic conditions.
Isolated yield.
d
e
excellent yields were obtained. As shown in table 4, seen that results obtained by using this Pd complex in
Heck reaction of activated aryl bromides such as 4- most Heck reactions are similar to or slightly better than
nitrobromobenzene and 4-bromobenzonitrile with ethyl those of related bidentate chelating Pd complexes.4
acrylate and styrene under similar conditions under- The advantages associated with this complex is the free-
went to afford the corresponding products in 81– dom to easily modulate electronic and steric properties
8–53
83% yields (table 4, entries 7 and 8; 1e (83%), 2e simply by changing (i) the size of metallocyclic ring,
(
81%), 1f (82%) and 2f (83%)) whereas, inactivated (ii) the nature of metallated carbon (aliphatic and/or
aryl bromides such as 4-methylbromobenzene and 4- aromatic groups), (iii) the type of donor group (C-, P-,
methoxybromobenzene gave 63–74% yields (table 4, S-, O-, N- coordinated) and (iv) the nature of the ligands
entries 4 and 6; 1b (73%), 2b (74%), 1d (67%) and 2d (halides and bidentate ligands).
(63%)). It is well known that the electron-withdrawing
For example, Huynh et al. have modified a six homo-
groups on the aryl ring increases the reaction rate dicarbene Pd(II) complex to increase the reaction
and electron donating substituent makes the oxidative time of the corresponding olefin and thereby decrease
addition step more difficult.41
the catalyst loading (0.05 mol%). But contrary to
50
Although a number of reported catalysts in literature the expectations, poor results in terms of yield have
need to be used in high loadings, and showed little or been achieved for Heck reaction using this modified
no activity with aryl chloride substrates,4
2–44
there is complex. Yen et al. used [PdBr (NHC)(CH CN)]
51
2 3
much attention in industry to couple aryl chlorides with as a catalyst for multiple vinylation of aryl halides
olefins due to the economical aspect of aryl chlorides with olefins. It is important to note that this complex
and the challenge to activate the C–Cl bond.4
5–47
As does not provide satisfactory results as by using other
expected, a low reactivity was observed when we used commercially Pd catalysts (such as Pd(OAc) , PdCl ,
2
2
54
both of electron rich and deficient aryl chloride sub- etc.). By comparison, it can be seen that this Pd
strates in coupling reactions (table 4, entries 11 and 12; complex has displayed some outstanding superiority
1c (70%), 2c (67%), 1d (61%) and 2d (59%)). While as catalyst such as green condition, low catalyst load-
aryl bromides or iodides reacted readily, aryl chlorides ing and short reaction times. Considering table 5, it is
showed slower reaction rates due to the stronger C-Cl obvious that this Pd complex (entry 1) has shown good
bond. Aryl chlorides with electron-withdrawing groups catalytic activity for the Heck coupling reaction in the
(table 4, entry 11) reacted more easily than those with presence of 0.001 mol% catalyst in green optimized
electron donating groups (table 4, entry 12).
As shown in table 5, the Heck reaction of both mol%) (entries 2-6),
electron-rich and electron-deficient aryl chlorides also C(O)C H C H )PdCl ]
condition compared to the other catalysts (0.002-1
48–52
and [({Ph PCH PPh CH}
reported previously. The
2 2 2
53
6
4
6
5
2
proceeded smoothly to furnish the desired products activity of our catalyst in Heck coupling reactions is
with good to excellent yields. For better comparison of significantly improved. As shown in table 5, our cata-
the catalyst with the same one, as well as the optimal lyst is superior to some of the previously reported cat-
conditions, results of Heck reaction using other cata- alysts in terms of reaction condition, reaction time and
lysts is presented in table 5. On the whole, it can be yield.

A five-membered Pd(II) catalyst in water
1925
Table 5. Comparison with other catalytic systems.
Pd]
[
Entry [Ref.]
Pd catalyst
(mol%) Reaction conditions
Aryl halide/ Olefin
Time (h) Yield (%)a
1
[This Work]
0.001
K2CO3, DMF/
Water, 110 C
Iodobenzene/ Styrene
Bromobenzene/ Styrene
Chlorobenzene/ Styrene
-Bromoanisole/ Ethyl acrylate
3
4
4
4
81
72
69
67
◦
4
2 48
3 49b
4 50
0.001 K CO , DMF, 130 C
◦
Chlorobenzene/ Styrene
Chlorobenzene/ Ethyl acrylate
24
24
62
71
2
3
◦
0.01 NaOAC, DMF, 95 C
Iodobenzene/ Styrene
24
48
56
41
◦
0.05 NaOAC, DMF, 150 C
Chlorobenzene/
tert-butyl acrylate
5 51
1
1
NaOAC, DMF, 110 C
◦
4-bromoanisole/
tert-butyl acrylate
17
24
53
72
6 52c
NaOAC, DMF, 140 C
◦
4-Bromoanisole/
tert-butyl acrylate
5
3
◦
7
8
0.002 NaOAC, DMF, 95 C
Iodobenzene/ Styrene
Iodobenzene/ Styrene
20
4
69
86
54d
◦
Pd(OAc)2
0.001 (Et)3N, IL, 100 C
4
. Conclusion
respectively. In comparison with previously reported
catalysts, the salient features of the proposed catalyst
48
In this research, a palladacycle complex containing include high efficiency and simplicity, which leads to
bidentate phosphine ligand was used as an efficient short reaction time, high yields and a cleaner reaction
2
2
and well-defined catalyst for the C(sp )-C(sp ) cross- profile.
coupling reactions under ambient atmosphere. The
described Pd(II) catalyst was observed to be stable and
showed high catalyst activity in Heck cross-coupling
reactions in water/DMF (2 mL, 1:1) and water/NMP (2 The supplementary data contain IR, H and C NMR
mL, 1:1) solvent systems for styrene and ethyl acrylate, spectra of Heck coupling products (figures S1–S15).
Supplementary Information
1
13

1926
Seyyed Javad Sabounchei and Marjan Hosseinzadeh
Supplementary Information is available at www.ias.ac. 29. Aksin Ö, Tüerkmen H, Artok L, Cetinkaya B, Ni C Y,
in/chemsci.
Büeyüekgüengöer O and Öezkal E 2006 J. Organomet.
Chem. 691 3027
0. Mu B, Li T, Xu W, Zeng G, Liu P and Wu Y 2007
Tetrahedron 63 11475
1. (a) Inamoto K, Kuroda J –I, Hiroya K, Noda Y,
Watanabe M and Sakamoto T 2006 Organometallics 25
3
References
3
1
2
. Heck R F and Nolley J P 1972 J. Org. Chem. 37 2320
. Dupont J, Pfeffer M and Spencer J 2001 Eur. J. Inorg.
Chem. 2001 1917
3
095; (b) Widegren J A and Finke R G 2003 J. Mol.
Catal. A 198 317; (c) Peris E, Loch J A, Mata J and
Crabtree R H 2001 Chem. Commun. 201
3
. Albrecht M and Van Koten G 2001 Angew. Chem., Int.
Ed. 40 3750
3
3
3
3
2. Frey G D, Schütz J, Herdtweck E and Herrmann W A
2
005 Organometallics 24 4416
3. Milde B, Schaarschmidt D, Ecorchard P and Lang H
012 J. Organomet. Chem. 706 52
4. Phan N T S, Sluys M V D and Jones C W 2006 Adv.
Synth. Catal. 348 609
2
5
6
. Miyaura N and Suzuki A 1995 Chem. Rev. 95 2457
. Littke A F and Fu G C 2002 Angew. Chem., Int. Ed. 41
4. Skar z˙ y n´ ska A, Trzeciak A M and Siczek M 2011 Inorg.
Chim. Acta 365 204
5. Sabounchei S J, Hosseinzadeh M, Panahimehr M,
Nematollahi D, Khavasi H R and Khazalpour S 2015
Transit. Metal Chem. 1
6. Sabounchei S J, Ahmadi M, Nasri Z, Shams E,
Salehzadeh S, Gholiee Y, Karamian R, Asadbegy M and
Samiee S 2013 C. R. Chimie 16 159
7. (a) Pascu S I, Coleman K S, Cowley A R, Green M
L H and Rees N H 2005 New J. Chem. 29 385; (b)
Gibson S, Foster D F, Eastham G R, Tooze R P and
Cole-Hamilton D J 2001 Chem. Commun. 779; (c) Frey
G D, Reisinger C P, Herdtweck E and Herrmann W A
4
176
. Morales-Morales D, Redó R, Yung C and Jensen C M
000 Chem. Commun. 1619
. Littke A F and Fu G C 1999 J. Org. Chem. 64 10
. Shaughnessy K H, Kim P and Hartwig J F 1999 J. Am.
Chem. Soc. 121 2123
7
2
8
9
3
1
1
0. Ehrentraut A, Zapf A and Beller M 2000 Synlett 1589
1. Portnoy M, Ben-David Y, Rousso I and Milstein D 1994
Organometallics 13 3465
3
1
2. Ohff M, Ohff A, Van der Boom M E and Milstein D
1997 J. Am. Chem. Soc. 119 11687
13. Bedford R B 2003 Chem. Commun. 1787
2005 J. Organomet. Chem. 690 3193
1
4. Stevens P D, Fan J, Gardimalla H M, Yen M and Gao Y
3
8. Ben-David Y, Portnoy M, Gozin M and Milstein D 1992
Organomettalics 11 1995
9. Li H, Wu Y -J, Xu C and Tian R –Q 2007 Polyhedron
2005 Org. Lett. 7 2085
1
1
1
5. Zhu M and Diao G 2011 J. Phys. Chem. 115 24743
6. Karimi B and Enders D 2006 Org. Lett. 8 1237
7. Elhamifar D, Karimi B, Rastegar J and Banakar M H
3
26 4389
4
4
0. Jutand A 2004 Pure Appl. Chem. 76 565
1. Whitcombe N J, Hii K K M and Gibson S E 2001
Tetrahedron 57 7449
2013 ChemCatChem 5 2418
18. Aizawa S -I, Hase T and Wada T 2007 J. Organomet.
Chem. 692 813
4
4
4
4
2. Ren G, Cui X, Yang E, Yang F and Wu Y 2010 Tetrahe-
1
9. Dupont J and Pfeffer M 2008 In Palladacycles: Synthe-
sis, Characterization and Applications (New York: John
Wiley)
dron 66 4022
3. Huynh H V, Ho J H H, Neo T C and Koh L L 2005 J.
Organomet. Chem. 690 3854
4. Hajipour A R and Rafiee F 2011 J. Organomet. Chem.
2
2
2
0. Overman L E and Poon D J 1997 Angew. Chem. 36
518
696 2669
1. Sabounchei S J, Panahimehr M, Ahmadi M, Nasri Z and
Khavasi H R 2013 J. Organomet. Chem. 723 207
2. (a) Imashiro R and Seki M 2004 J. Org. Chem. 69 4216;
5. Davison J B, Simon N M and Sojka S A 1984 J. Mol.
Catal. 22 349
4
4
6. Yi C and Hua R 2006 Tetrahedron Lett. 47 2573
7. Xu H -J, Zhao Y -Q and Zhou X –F 2011 J. Org. Chem.
(b) Carmichael A J, Earle M J, Holbrey J D, McCormac
P B and Seddon K R 1999 Org. Lett. 1 997; (c) Chen Y,
Huang L Y, Ranade M A and Zhang X P 2003 J. Org.
Chem. 68 3714
7
6 8036
8. Sabounchei S J, Ahmadi M, Azizi T and Panahimehr M
014 Synlett 25 336
4
2
2
3. Huang X, Xie L and Wu H 1988 J. Org. Chem. 53
4
862
49. Shaw B L 2004 Chem. Commun. 12 1361
50. Huynh H V and Jothibasu R 2011 J. Org. Chem. 696
3369
2
4. Zhou L and Wang L 2006 Synthesis 16 2653
25. Iyer S, Kulkarni G M and Ramesh C 2004 Tetrahedron
6
0 2163
51. Yen S K, Koh L L, Hahn F E, Huynh H V and Hor T A
2006 Organometallics 25 5105
52. Han Y, Huynh H V and Koh L L 2007 J. Org. Chem.
2
2
2
6. Casalnuovo A L and Calabrese J C 1990 J. Am. Chem.
Soc. 112 4324
7. Caló V, Nacci A, Monopoli A, Laera S and Cioffi N
692 3606
2003 J. Org. Chem. 68 2929
53. Shaw B 1998 Chem. Commun. 17 1863
8. Solodenko W, Mennecke K, Vogt C, Gruhl S and 54. Wang Y, Luo J and Liu Z 2013 J. Organomet. Chem.
Kirschning A 2006 Synthesis 11 1873
739 1