Application of dimeric orthopalladate complex of homoveratrylamine as an efficient catalyst in the Heck cross-coupling reaction

Article abstract of DOI:10.1016/j.jorganchem.2009.04.003

The [Pd{C₆H₂(CH₂CH₂NH₂)-(OMe)₂,3,4} (μ-Br)]₂ complex of homoveratrylamine was synthesized and its application in the Heck coupling reaction was studied. This complex had been demonstrated to be active and efficient catalyst for the Heck reaction of aryl iodides, bromides and even chlorides. The cross-coupled products were produced in excellent yields in a short reaction time using catalytic amounts of [Pd{C₆H₂(CH₂CH₂NH₂)-(OMe)₂,3,4} (μ-Br)]₂ complex in N-methyl-2-pyrrolidinone (NMP at 130 °C).

Full text of DOI:10.1016/j.jorganchem.2009.04.003

Journal of Organometallic Chemistry 694 (2009) 2548–2554
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Application of dimeric orthopalladate complex of homoveratrylamine
as an efficient catalyst in the Heck cross-coupling reaction
b
a
a
Abdol R. Hajipour a,b, , Kazem Karami , Azadeh Pirisedigh , Arnold E. Ruoho
*
a Department of Pharmacology, University of Wisconsin, Medical School, 1300 University Avenue, Madison, 53706-1532 WI, USA
b Pharmaceutical Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156, Islamic Republic of Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
The [Pd{C6H2(CH2CH2NH2)-(OMe)2,3,4} (l-Br)]2 complex of homoveratrylamine was synthesized and its
Received 25 February 2009
Received in revised form 6 April 2009
Accepted 7 April 2009
application in the Heck coupling reaction was studied. This complex had been demonstrated to be active
and efficient catalyst for the Heck reaction of aryl iodides, bromides and even chlorides. The cross-cou-
pled products were produced in excellent yields in a short reaction time using catalytic amounts of
Available online 16 April 2009
[Pd{C6H2(CH2CH2NH2)-(OMe)2,3,4} (
l-Br)]2 complex in N-methyl-2-pyrrolidinone (NMP at 130 °C).
Ó 2009 Elsevier B.V. All rights reserved.
Keywords:
Orthopalladate
Homoveratrylamine
Catalyst
Heck reaction
1. Introduction
nitrogen-donor ligands [39]. For several years only aryl iodides
and aryl bromides were employed in the Heck reaction. Various ef-
forts have been made to find better catalysts for coupling aryl chlo-
rides which are readily available and industrially important
compounds by the Heck reaction. The aryl chlorides react very
slowly with palladium catalysts [40,41] due to the strength of
the C–Cl bond which delays the oxidation addition to Pd(II) com-
plexes [40,42,43]. However cyclopalladated Pd(II) complexes as
thermally stable catalysts can activate aryl chlorides [40,44–49].
Herein we report the synthesis of the orthopalladated complex
Cyclopalladated complexes are important starting materials in
organometallic chemistry [1,2]. Palladacycles have been known
over 30 years [3–8] and have acquired great interest due to their
applications in many areas including organic synthesis [9–12],
material science [13] and as biologically active compounds [14].
More recently, examples of their utility in homogeneous catalysis
or as building blocks in macromolecular chemistry have also been
published [15–17]. Furthermore, palladium derivatives have been
widely used in organic synthesis for formation of carbon–carbon
and carbon-heteroatom bonds [18–22] because of their versatility,
compatibility with most functional groups and relative low toxicity
[23,24]. Vinylation of aryl halides, commonly called the Heck reac-
tion [25–27], which was discovered in 1971 has become an excel-
lent tool for the synthesis of elaborated styrene derivatives [28,29].
Phospha-palladacycles, first published by Shaw and co-workers
[30], Mason and co-workers [4], Alyea et al. [31] and Heck and
co-workers [32] were investigated their application as excellent
catalysts in C–C coupling reactions [33–35]. The air-moisture and
thermal-stabilities of the catalysts have significant importance
[36,37].
[Pd{C6H2(CH2CH2NH2)-(OMe)2,3,4}(
l-Br)]2 (3), from homoverat-
rylamine (1) and Pd(OAc)2 using the method reported by Vicente
et al. [50,51] (Schemes 1 and 2).
2. Results and discussion
2.1. Synthesis and characterization of the palladacycle 3
By refluxing a mixture of homoveratrylamine with Pd(OAc)2 in
acetonitrile, impure complex 2 can be isolated (Scheme 1). It has
been reported in the literature that products of cyclopalladation
of some primary amines using Pd(OAc)2 are difficult to isolate as
solid or to purify and that their reactions with NaBr allow to isolate
pure the corresponding bromo complex [51a]. As this was our case,
pure palladacycle 3 was produced in 81.6% yield as an orange pow-
der by reacting crude complex 2 with NaBr in acetone. This cyclo-
palladation method has been reported by Vicente et al. to prepare
five- [50] and six-membered [51] cyclopalladated primary amines.
However, the cost and sensitivity of phosphines to air and mois-
ture resulted in development of new catalytic systems such as pal-
ladium complexes bearing N-heterocyclic carbene ligands [38] or
* Corresponding author. Address: Department of Pharmacology, University of
Wisconsin, Medical School, 1300 University Avenue, Madison, 53706-1532 WI, USA.
E-mail address: haji@cc.iut.ac.ir (A.R. Hajipour).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.04.003

A.R. Hajipour et al. / Journal of Organometallic Chemistry 694 (2009) 2548–2554
2549
6
1
5
4
NaBr
Pd(OAc)2
NH2
NH2
NH2
2
MeO
Pd
MeO
Pd
Acetone, RT
MeO
CH3CN, Reflux
3
Br
AcO
OMe
OMe
OMe
2
2
2
1
3
Scheme 1. The synthesis route for preparation of orthopalladate complex 3.
H
O
O
OMe
H2C
OMe
X
R'
R'=H, Me
R
R'
Palladacycle
NMP, 130oC
R''
H
R
R''
X= Br, I, Cl
R= OMe, COMe, COH, Cl
CN
R''= H, Me
H
R
Scheme 2. The Heck cross-coupling reaction.
2.2. Heck coupling reaction of aryl halides
gave excellent yields of the desired products (Table 3, entries 1–
13). Acrylate also gave excellent yields (Table 3, entries 14–23).
This system was also employed for coupling of 4-chloro-acetophe-
none and styrene at 130 °C (Table 3, entries 8). Using substrates
containing electron withdrawing groups also produced the coupled
products (Table 3, entries 2–4, 8, 17, 18, 20, 23). Based on the re-
sults, production of exclusively the trans isomers and complete
conversions (100%) by this method are great advantages of the pre-
sented catalyst (Table 3).
The application of complex 3 as a catalyst for the Heck cross-
coupling reaction was examined by optimizing both base and sol-
vent effects (Table 1).
The Heck reaction was carried out in N-methyl-2-pyrrolidone
(NMP) by the reaction of bromobenzene with styrene in the pres-
ence of various bases (Table 1, entries 1–4). We found that K2CO3
gave the best results for this reaction and other bases such as
Na2CO3, Cs2CO3 and triethylamine (Et3N) were not suitable (Table
1, entries 1–3). Several organic solvents such as toluene, acetoni-
trile and N,N0-dimethylformamide (DMF) were examined also, (Ta-
ble 1, entries 4–7) however, none of them were as efficient as NMP
for the Heck reaction (Table 1, entry 5). Finally, 1-methyl-2-pyro-
lidinone (NMP) at 130 °C under nitrogen atmosphere was selected
as the optimal reaction condition (Table 1, entry 4). Various cata-
lyst concentrations were also tested (Table 2) and 0.4 mol% giving
the best result.
3. Experimental
3.1. General
All melting points were measure using a Gallenkamp melting
apparatus and are uncorrected. 1H-NMR spectra were recorded
using 500 and 400 MHz in CDCl3 solutions at room temperature
(TMS was used as an internal standard) on a Bruker, Avance 500
instrument (Rheinstetten, Germany) and Varian 400 NMR. FT-IR
spectra were recorded on a spectrophotometer (Jasco-680, Japan).
Spectra of solids were carried out using KBr pellets. Vibrational
These optimized reaction conditions were applied in the Heck
reaction for a variety of aryl halides with different olefins. The re-
sults are summarized in Table 3. Styrene and para-methyl styrene
Table 1
Optimization of reaction condition on Heck reaction of bromobenzene with styrene.
Br
2
Entry
Base
Solvent
Temperature (°C)
Time (h)
Conversion (%)
1
2
3
4
5
6
7
Et3N
NMP
NMP
NMP
NMP
DMF
CH3CN
Toluene
130
130
130
130
130
80
6
6
6
2.5
6
0
Cs2CO3
Na2CO3
K2CO3
K2CO3
K2CO3
K2CO3
30
Trace
100
70
0
6
6
110
0

2550
A.R. Hajipour et al. / Journal of Organometallic Chemistry 694 (2009) 2548–2554
Table 2
Optimization of catalyst concentration.
Br
Palladacycle
K2CO3, NMP, N 2
Mol% catalyst 3
Time (h:min)
Temperature (°C)
Conversion (%)
None
0.01
0.03
0.05
0.1
0.2
0.4
0.8
6
6
6
4
3:30
3:30
2:30
2:45
130
130
130
130
130
130
130
130
0
42
55
100
100
100
100
100
transition frequencies are reported in wave numbers (cmꢀ1 in the
range 400–4000 cmꢀ1). Homoveratrylamine, palladium acetate,
and all of the olefins and aryl halides were purchased from Merck
and Aldrich and used as received.
3.3.2. trans-4-Cyanostilbene (2)
M.p. 117–119 °C; [53] found 114–117 °C.1H NMR (400 MHz,
ppm, CDCl3): d = 7.65 (d, 2H, J = 8.2 Hz), 7.60 (d, 1H, J = 8 Hz),
7.55 (d, 2H, J = 7.2 Hz), 7.41 (t, 2H, J = 7.2 Hz), 7.34–7.35 (br d,
1H), 7.23 (d, 1H, J = 16.2 Hz), 7.10 (d, 1H, 16.4 Hz). 13C NMR
(400 MHz, ppm, CDCl3): d = 141.9, 136.3, 132.5, 132.4, 128.9,
3.2. Synthesis of complex 3
128.7, 126.9, 126.8, 126.7, 119.0, 110.6. IR (KBr, cmꢀ1):
2924, 2226, 1602.
m 3044,
A 50 mL round bottom flask was charged with 199 mg of
homoveratrylamine (1.1 mmol), 250 mg of Pd(OAc)2 (1.1 mmol)
and 20 mL of acetonitrile and refluxed for 4 h. The resulting sus-
pension was filtered through a plug of MgSO4, the solvent was re-
moved under reduced pressure, then 2 mL of CH2Cl2 and 15 mL of
n-hexane or 7 mL of Et2O was added to give complex 2 as a yellow
precipitate which was filtered off, washed with water and air dried.
Yield: 47.2%. To a solution of complex 2 (0.2 mmol) in 25 mL of
acetone was added NaBr (1.94 mmol) and the suspension was stir-
red for 8 h, then acetone was evaporated, 10 mL of CH2Cl2 was
added and then was filtered through a plug of MgSO4. The filtrate
was concentrated to 2 mL under reduced pressure using a rotary
evaporator and 15 mL of n-hexane or 7 mL of Et2O was added.
The produced suspension was filtered off and air dried to afford
the complex 3 as orange solid, yield: 81.6%, Decomp.: 140 °C. 1H
NMR (500 MHz, CDCl3, ppm): d, 6.85 (br d, 1H, C6H2), 6.77 (br d,
1H, C6H2), 3.92 (s, 3H, OMe), 3.89 (s, 3H, OMe), 3.10 (br m, 2H,
NH2), 2.88 (m, 2H, CH2), 2.65 (m, 2H, CH2) ppm. IR (KBr, cmꢀ1):
3250–3268 (N–H). 13C NMR (75 MHz, MeOH, ppm): 148.5, 148.0,
129.0, 120.1, 110.0, 55.8, 41.1, 24.9 Anal. Calc. for
C20H28Br2N2O4Pd2: C, 32.767; H, 3.85; N, 3.82. Found: C, 32.55;
H, 4.11; N, 3.80%.
3.3.3. trans-4-Acetylstilbene (3)
[52]
M.p. 140–144 °C;
found 135–140 °C.1H NMR (500 MHz,
ppm, CDCl3): d = 8.01 (d, 2H, J = 8.3 Hz), 7.64 (d, 2H, J = 8.3 Hz),
7.59 (d, 2H, J = 7.5 Hz), 7.44 (t, 2H, J = 7.6 Hz), 7.35 (t, 1H,
J = 7.1 Hz), 7.28 (d, 1H, J = 16.3 Hz), 7.19 (d, 1H, 16.3 Hz). 13C
NMR (400 MHz, ppm, CDCl3): d = 197.5, 142.0, 136.7, 136.0,
131.5, 128.9, 128.8, 128.3, 127.5, 126.8, 126.5. IR (KBr, cmꢀ1):
3019, 2960, 1678, 1600.
m
3.3.4. trans-3-Acetylstilbene (4)
M.p. 70–74 °C.1H NMR (500 MHz, ppm, CDCl3): d = 8.15 (s, 1H),
7.89 (d, 1H, J = 7.7 Hz), 7.76 (d, 1H, J = 7.6 Hz), 7.58 (d, 2H,
J = 7.6 Hz), 7.51 (t, 1H, J = 7.7 Hz), 7.43 (t, 2H, J = 7.6 Hz), 7.35 (t,
1H, J = 7.2 Hz), 7.24 (d, 1H, 16 Hz), 7.19 (d, 1H, 16 Hz). 13C NMR
(400 MHz, ppm, CDCl3): d = 165.9, 137.9, 137.6, 136.9, 130.9,
130.0, 129.0, 128.8, 128.0, 127.6, 127.5, 126.7, 126.2, 26.8. IR
(KBr, cmꢀ1):
m 3055, 2960, 1682, 1590.
3.3.5. trans-3-Chlorostilbene (5)
M.p. 64–69 °C. 1H NMR (400 MHz, ppm, CDCl3): 7.53 (d, 1H,
J = 7.2 Hz), 7.41–7.39 (m, 3H), 7.37–7.23 (m, 5H), 7.13 (d, 1H,
J = 16.4 Hz), 7.05 (d, 1H, J = 16.4 Hz). 13C NMR (400 MHz, ppm,
CDCl3): d = 139.3, 136.8, 134.7, 130.2, 129.9, 128.8, 128.1, 127.5,
3.3. General procedure for the Heck reaction of aryl halides with olefins
Under nitrogen atmosphere, K2CO3 (2.2 mmol), olefin (5 mmol),
aryl halide (2 mmol), and NMP (5 mL) were added respectively to a
Schlenk tube equipped with a magnetic stirring bar. 0.008 mmol of
complex (5.8 mg) was added to the Schlenk tube. The mixture was
stirred at 130 °C and monitored by TLC (EtOAc:Hexane, 30:70).
After completing the reaction, the mixture was diluted with ether
and water. The organic layer was washed with brine, dried over
Na2SO4, and concentrated under reduced pressure. Residue was
purified by recrystallization using ethanol and water.
127.2, 126.7, 126.3, 124.8. IR (KBr, cmꢀ1):
m 3045, 2950, 1589.
3.3.6. trans-1-Styrylnaphthalene (6)
M.p. 58–60 °C.1H NMR (500 MHz, ppm, CDCl3): d = 8.31 (d, 1H,
J = 8.3 Hz), 7.97 (d, 1H, J = 15.8 Hz), 7.88 (d, 1H, J = 8.2 Hz), 7.83
(d, 1H, J = 7.2 Hz), 7.69 (d, 2H, J = 7.4), 7.63–7.55 (m, 3H), 7.49 (t,
2H, J = 7.5 Hz), 7.38 (t, 1H, J = 7.3 Hz), 7.24 (d, 1H, J = 16 Hz). 13C
NMR (400 MHz, ppm, CDCl3): d = 136.7, 134.2, 133.9, 132.8,
130.7, 130.4, 129.5, 128.7, 127.5, 126.4, 126.1, 125.7, 125.6,
124.7, 123.8, 123.4. IR (KBr, cmꢀ1):
m 3045, 1593.
3.3.1. trans-Stilbene (1)
M.p. 122–123 °C; [52] found 121–122 °C. 1H NMR (500 MHz,
ppm, CDCl3): d = 7.61 (d, 2H, J = 7.4 Hz), 7.45 (t, 2H, J = 7.6 Hz),
7.35 (t, 1H, J = 7.6 Hz), 7.20 (s, 1H). 13C NMR (400 MHz, ppm, CDCl3)
3.3.7. trans-9-Styrylphenanthrene (7)
M.p. 104–108 °C. 1H NMR (400 MHz, ppm, CDCl3): d = 8.77 (d,
1H, J = 8 Hz), 8.69 (d, 1H, 8 Hz), 8.28 (d, 1H, J = 8.8 Hz), 7.99 (s,
1H), 7.94 (d, 1H, J = 8.8 Hz), 7.90 (d, 1H, 16 Hz), 7.74–7.61 (m,
6H), 7.44 (t, 2H, J = 7.6 Hz), 7.34 (t, 1H, J = 7.6 Hz), (d, 1H, 16 Hz).
d = 137.7, 128.7, 127.7, 127.7, 126.6. IR (KBr, cmꢀ1):
m 3076, 1596,
1494.

A.R. Hajipour et al. / Journal of Organometallic Chemistry 694 (2009) 2548–2554
2551
Table 3
Heck reaction of aryl halides with olefin using catalyst 3.a
Entry
1
Ar-X
Olefin
Product
Time (h)
2.5
Yield (%)b
95
Br
Br
2
3
8
85
80
NC
O
NC
O
O
CH3
10
H3C
Br
Br
O
4
5
6
4
88
81
90
H3C
H3C
Cl
Cl
0.5
Br
Br
1
Br
7
1.5
75
O
O
CH3
8
9
4
85
96
CH3
Cl
I
2.5
MeO
MeO
I
10
2
97

2552
A.R. Hajipour et al. / Journal of Organometallic Chemistry 694 (2009) 2548–2554
Table 3 (continued)
Entry
11
Ar-X
Olefin
Product
Time (h)
3
Yield (%)b
96
Br
Br
H3C
H3C
CH3
12
2
91
H3C
H3C
Cl
CH3
13
14
15
16
17
18
19
20
4
95
92
90
91
83
80
92
94
Cl
Br
Br
O
O
O
O
O
O
O
O
3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
O
Br
OCH3
7
Cl
O
Cl
0.75
OCH3
O
Br
O
OCH3
1
H3C
H3C
Br
O
O
O
O
OCH3
4
H
H
Br
O
I
0.75
OCH3
OCH3
MeO
NC
MeO
NC
O
Br
0.5
(continued on next page)

A.R. Hajipour et al. / Journal of Organometallic Chemistry 694 (2009) 2548–2554
2553
Table 3 (continued)
Entry
21
Ar-X
Olefin
Product
Time (h)
2
Yield (%)b
92
O
Br
Br
H
O
OCH3
OCH3
OCH3
OCH3
CH3
CH3
H
O
O
22
1
88
CH3
CH3
O
O
O
O
Br
23
10
82
H3C
OCH3
H3C
OCH3
CH3
CH3
a
Reaction condition: aryl bromide; 2 mmol, olefin; 2.5 mmol, K2CO3; 1.1 mmol, catalyst; 3 0.008 mmol, temperature; 130 °C.
Isolated yield.
b
13C NMR (400 MHz, ppm, CDCl3): d = 137.6, 134.0, 132.2, 131.9,
3.3.12. Methyl trans-3-chlorocinnamate (16)
130.8, 130.5, 130.3, 128.8, 128.7, 127.1, 126.9, 126.8, 126.7, 126.6,
1H NMR (400 MHz, ppm, CDCl3): d = 7.64 (d, 1H, J = 16 Hz),
7.53–7.52 (br t, 1H), 7.41–7.25 (m, 3H), 6.45 (d, 1H, J = 16 Hz),
3.82 (s, 3H) 13C NMR (400 MHz, ppm, CDCl3): d = 175.3, 167.8,
143.2, 136.2, 135.1, 131.4, 127.8, 126.2, 119.2, 51.5. IR (KBr,
126.4, 124.7, 124.6, 123.2, 122.6. IR (KBr, cmꢀ1):
m 3045, 1593.
3.3.8. trans-4-Methoxystilbene (9)
cmꢀ1):
m 3034, 2940, 1718.
M.p. 135.5–137.1 °C; [52] found 130–135 °C.1H NMR (400 MHz,
ppm, CDCl3): d = 7.51–7.46 (m, 4H), 7.38–7.34 (br t, 3H), 7.11 (d,
1H, J = 16.4 Hz), 7.01 (d, 1H, J = 16.4 Hz), 6.93 (d, 1H, J = 8.4 Hz),
3.85 (s, 3H). 13C NMR (400 MHz, ppm, CDCl3) d = 159.3, 137.7,
130.2, 128.7, 128.2, 127.7, 127.2, 126.6, 126.3, 114.2, 55.3. IR
3.3.13. Methyl trans-4-acetylcinnamate (17)
M.p. 32–36 °C. 1H NMR (500 MHz, ppm, CDCl3): d = 7.99 (d, 1H,
J = 16 Hz), 7.84 (d, 2H, J = 8.4 Hz), 7.62 (d, 2H, J = 8.4 Hz), 6.54 (d,
1H, J = 16 Hz), 3.84 (s, 3H), 2.60 (s, 3H). 13C NMR (400 MHz, ppm,
CDCl3): d = 197.3, 166.8, 143.3, 138.7, 131.9, 129.8, 120.3, 51.9,
(KBr, cmꢀ1):
m 3055, 2960, 1580.
26.7. IR (KBr, cmꢀ1):
m 3036, 2950, 1720, 1639.
3.3.9. trans-1-(4-Methylstyryl)naphthalene (12)
M.p. 80–82 °C.1H NMR (400 MHz, ppm, CDCl3): d = 8.24 (d, 1H,
J = 8 Hz), 7.89 (d, 1H, J = 6.8 Hz), 7.82 (t, 2H, J = 7.5 Hz), 7.76 (d,
1H, J = 7.6 Hz), 7.61–7.48 (m, 5H), 7.23 (d, 2H, J = 7.6 Hz), 7.15 (d,
1H, 16 Hz), 2.4 (s, 3H). 13C NMR (400 MHz, ppm, CDCl3):
d = 137.7, 135.2, 134.9, 133.8, 131.7, 131.4, 129.5, 128.6, 127.9,
126.6, 126.0, 125.8, 125.7, 124.8, 123.8, 123.5, 21.4. IR (KBr,
3.3.14. Methyl trans-4-formylcinnamate (18)
M.p. 82–84 °C. 1H NMR (400 MHz, ppm, CDCl3): d = 10.05 (s,
1H), 7.92 (d, 2H, J = 8.4 Hz), 7.74 (d, 1H, J = 15.6 Hz), 7.69 (d, 2H,
J = 8.2 Hz), 6.57 (d, 1H, J = 15.8 Hz), 3.85 (s, 3H). 13C NMR
(400 MHz, ppm, CDCl3): d = 191.3, 168.8, 143.1, 140.0, 137.2,
cmꢀ1):
m
3040, 2915, 1520.
130.2, 128.0, 121.0, 52.5. IR (KBr, cmꢀ1):
1725, 1710.
m 3034, 2940, 2750,
3.3.10. trans-1-Chloro-3-(4-methylstyryl)benzene (13)
M.p. 100–106 °C 1H NMR (400 MHz, ppm, CDCl3): d = 7.50 (s,
1H), 7.46–7.36 (m, 4H), 7.23–7.18 (m, 3H), 7.10 (d, 1H,
J = 16.4 Hz), 7.00 (d, 1H, J = 16.4 Hz), 2.19 (s, 3H). 13C NMR
(400 MHz, ppm, CDCl3): d = 139.5, 138.0, 134.6, 134.0, 130.1,
129.9, 129.5, 129.0, 127.3, 126.6, 126.2, 126.1, 124.7, 21.3. IR
3.3.15. Methyl trans-4-methoxycinnamate (19)
M.p. 84–86 °C 1H NMR (400 MHz, ppm, CDCl3): d = 7.67 (d, 1H,
J = 16 Hz), 7.49 (d, 2H, J = 8.8 Hz), 6.92 (d, 2H, J = 8.8 Hz), 6.33 (d,
1H, J = 16 Hz), 3.85 (s, 3H), 3.81 (s, 3H). 13C NMR (400 MHz, ppm,
CDCl3): d = 169.8, 161.4, 144.5, 129.7, 127.1, 115.3, 114.3, 55.4,
(KBr, cmꢀ1):
m
3055, 2954, 1590.
51.6. IR (KBr, cmꢀ1):
m 3050, 2946, 1723, 1590.
3.3.11. trans-Methyl cinnamate (14)
3.3.16. Methyl trans-4-cyanocinnamate (20)
1H NMR (400 MHz, ppm, CDCl3): d = 7.71 (d, 1H, J = 16 Hz),
7.55–7.53 (m, 3H), 7.41–7.39 (m, 2H), 6.46 (d, 1H, J = 16 Hz), 3.82
(s, 3H). 13C NMR (400 MHz, ppm, CDCl3): d = 170.1, 153.8, 149.4,
M.p. 119–121 °C.1H NMR (400 MHz, ppm, CDCl3): d = 7.69 (t,
2H, J = 8.4 Hz), 7.62 (d, 1H, J = 8 Hz), 6.54 (d, 1H, 16 Hz), 3.84 (s,
3H). 13C NMR (400 MHz, ppm, CDCl3): d = 166.6, 142.4, 138.6,
132.7, 132.4, 130.3, 127.4, 123.03, 109.3, 48.3. IR (KBr, cmꢀ1):
3044, 2956, 1723, 1590.
m
132.7, 128.4, 121.4, 118.4, 113.4, 52.0. IR (KBr, cmꢀ1):
2956, 2225, 1720, 1639.
m 3044,

2554
A.R. Hajipour et al. / Journal of Organometallic Chemistry 694 (2009) 2548–2554
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3.3.17. (E)-Methyl 2-methyl-3-phenylacrylate (21)
1H NMR (500 MHz, ppm, CDCl3): d = 8.03 (s, 1H), 7.46–7.43 (m,
2H), 7.40–7.35 (m, 2H), 7.29–7.27 (m, 1H), 3.88 (s, 3H), 2.20 (d, 3H,
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3.3.18. (E)-Methyl 2-methyl-3-(naphthalen-1-yl)acrylate (22)
1H NMR (500 MHz, ppm, CDCl3): d = 8.30 (s, 1H), 8.01–7.99 (m,
1H), 7.92–7.90 (m, 1H), 7.88 (d, 1H, J = 8.2 Hz), 7.57–7.52 (m, 3H),
3.94 (s, 3H), 2.07 (d, 3H, J = 1.2 Hz). IR (KBr, cmꢀ1):
m 3056, 2948,
1716,1637.
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m 3024, 2956, 2215, 1725, 1639.
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4. Conclusion
We have successfully synthesized and characterized a new di-
meric complex of homoveratrylamine and employed the catalyst
for the Heck reaction. The homoveratrylamine complex was shown
to be efficient and effective catalyst for Heck cross-coupling reac-
tion with high chemoselectivity and yields in reasonable reaction
time.
Acknowledgments
We gratefully acknowledge the funding support received for
this project from the Isfahan University of Technology (IUT), IR
Iran. Further financial support from the Center of Excellence in
Sensor Research (IUT) is gratefully acknowledged.
Appendix A. Supplementary material
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Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.jorganchem.2009.04.003.
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