Controlled mono- and double-Heck reaction catalyzed by a dicarbene dipalladium complex

Article abstract of DOI:10.1016/j.tet.2013.05.030

The phosphine-free mono- and double-Heck reaction of terminal olefins with electron-deficient and electron-rich aryl halides (iodides and bromides) is described. These reactions are catalyzed by the dicarbene dipalladium complex 1 by controlling the stoichiometry of the aryl halide and the olefine, the loading of the palladium catalyst, as well as using different base, and with or without additive. The procedure of double-Heck reaction allows β,β- diarylation and β,β′-diarylation of terminal olefins and affords trisubstituted olefins in good to excellent yields.

Full text of DOI:10.1016/j.tet.2013.05.030

Tetrahedron 69 (2013) 6241e6250
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Controlled mono- and double-Heck reaction catalyzed by
a dicarbene dipalladium complex
,
a
a
Yunfei Li a, Gang Liu a, Changsheng Cao a , Shuzhan Wang , Yuling Li ,
*
,c,
Guangsheng Pang b, Yanhui Shi a
*
a School of Chemistry and Chemical Engineering and Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials,
Jiangsu Normal University, Xuzhou, Jiangsu 221116, PR China
b State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, Jilin 130012, PR China
c State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing, Jiangsu 210093, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
The phosphine-free mono- and double-Heck reaction of terminal olefins with electron-deficient and
electron-rich aryl halides (iodides and bromides) is described. These reactions are catalyzed by the di-
carbene dipalladium complex 1 by controlling the stoichiometry of the aryl halide and the olefine, the
loading of the palladium catalyst, as well as using different base, and with or without additive. The
Received 4 February 2013
Received in revised form 19 April 2013
Accepted 10 May 2013
Available online 24 May 2013
procedure of double-Heck reaction allows
b
,b
-diarylation and
b
,b
0-diarylation of terminal olefins and
affords trisubstituted olefins in good to excellent yields.
Keywords:
Ó 2013 Elsevier Ltd. All rights reserved.
Heck reaction
N-heterocyclic carbene
Palladium
Dinuclear
1. Introduction
cross-coupling reactions. The design and synthesis of binuclear
palladium complexes with di-NHC are of considerable interest
because the adjacent metals could function in a synergic manner in
their interactions with substrate molecules. We report now that
a di-NHC dipalladium complex is an appropriate precatalyst for the
controlled mono and diarylation of terminal alkenes under
phosphine-free conditions.
Palladium-catalyzed CeC cross-coupling reaction is one of the
most important classes of organometallic reactions and finds
widely applications in pharmaceuticals, fine chemicals, and natural
products.1 Among various coupling reactions, the MizorokieHeck
reaction is one of the most powerful methods for CeC bond for-
mation, and can be accomplished using a great amount of palla-
dium catalyst precursors under various reaction conditions.2 The
classical intermolecular Heck reaction is mainly limited to the
monoarylation of terminal alkenes, whereas the synthesis of tri-
substituted alkenens by diarylation has been scarcely investigated
and most synthetic protocols are only effective with aryl iodides or
acrylates.3 Therefore the development of an efficient process for
diarylation of more general terminal alkenes with aryl halides (esp.
cheap aryl bromides) would be desirable. Over the last years, the
chemistry of palladium N-heterocyclic carbene (NHC) complexes
has become an area of great interest and has been extensively
studied.4 We have been interested in the chemistry of bimetallic di-
NHC complexes concentrated on homodinuclear and hetero-
dinuclear complexes,5 with special emphasis on developing in-
expensive, user-friendly, and highly efficient precatalyst for CeC
2. Results and discussion
The structure of di-NHC dipalladium complex 1 used in this
study was shown in Chart 1. The synthesis of 1 was achieved by the
reaction of PdCl2 with bisimidazolium dichlorides in pyridine in the
presence of K2CO3 in 65% yield.6
N
N
N
N
Cl Pd Cl
N
Cl Pd Cl
N
* Corresponding authors. E-mail address: yhshi@jsnu.edu.cn (Y. Shi).
Chart 1. Palladium catalyst 1 used in this study.
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.05.030

6242
Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
2.1. Monoarylation of terminal alkenes
Table 1
From the previous result of screening the solvents, bases, cata-
lyst loadings, and temperatures, the mono-arylation of styrene
catalyzed by 1 can be effectively performed with 0.5 mol % of cat-
alyst with K3PO4 as base (1.5 equiv) in the solvent of dimethyl
acetamide (DMA) at 100 ꢀC in 5 h.6 To investigate the scope of the
reaction, the application of 1 in the mono-arylation of styrene with
a series of aryl halides was shown in Table 1. From the results we
can see that deactivated electron-rich aryl iodides and bromides are
coupled with styrene in good yields (Table 1, entries 2, 11, 13, 14).
Sterically hindered aryl iodide with ortho-substitution worked well
in the reaction, whereas, the yield decreased with ortho-substituted
bromide (Table 1, entries 14 vs 11). A wide variety of functional
groups were tolerated on the aromatic ring (Table 1, entries 2e10).
Unfortunately, the catalyst was not effective for aryl chloride. Fur-
thermore, the application of 1 in the coupling reaction of various
aryl halides with ethyl acrylate was shown in Table 2. The complex
1 was also highly active for the coupling of electron-rich and
electron-deficient aryl halides (iodides and bromides) with ethyl
acrylate. Steric effect still only plays role in the reaction of aryl
bromide (Table 2, entries 10 vs 13). A wide variety of functional
groups were tolerated in the coupling reaction with aryl halides.
From these results, it can be summarized that the mono-
arylation of terminal alkene with aryl iodides and bromides can
be performed efficiently with 0.5 mol % of the di-NHC di-Pd com-
plex 1 using K3PO4 as base in the solvent of DMA.
MizorokieHeck cross-coupling reactions of styrene with aryl halides
0.5 mol% 1,
1.5 eq. K3PO4
X
+
DMA, 110 C, 5 h
°
R
R
(X= Br, I)
1 eq.
1.2 eq.
2
Entrya
Aryl halide
Product
2 Yield (%)b
84 (2a)
1
2
3
Br
O
95 (2b)
82 (2c)
O
Br
Br
O
O
F3C
F
4
5
6
80 (2d)
86 (2e)
80 (2f)
F3C
F
Br
Br
Br
2.2. Diarylation of terminal alkene
F
F
To develop a general protocol for the diarylation of terminal
olefins, we initially tested the reaction of ethyl acrylate (1 equiv)
with bromobenzene (2.2 equiv) with tetra-n-butylammonium
bromide (TBAB) as additive and higher loading of Pd catalyst
(1 mol %) in DMA in presence of different bases (2.5 equiv) (Table 3).
The diarylated product was obtained in 10% when K3PO4 was used
as the base, and 18% of monoarylated product was observed at the
meanwhile (Table 3, entry 1). Cs2CO3 did not work for both diary-
lation (5%) and monoarylation (8%). Moreover, NaOH failed in dia-
rylation, whereas gave 65% of monoarylation product. However,
when NaOAc or K2CO3 was employed, the yield of diarylation was
dramatically increased to 88% or 82% and no monoarylated product
was detected for NaOAc. TBAB is necessary for the successful dia-
rylation, otherwise, only 76% of monoarylation product was ob-
tained with NaOAc under the same conditions (Table 3, entry 4). To
optimize the reaction conditions, a few other solvents including
toluene, DMF, DMSO, and TBAB were screened. DMA is the best
solvent tested for diarylation, and relatively low yield was observed
in DMF, toluene, and TBAB. No diarylation product was found in
DMSO used as solvent. Therefore, all diarylation reactions below
were carried with 1 mol % of Pd, TBAB (2 equiv), NaOAc (2.5 equiv)
in DMA at 120 ꢀC for 18 h.
OHC
7
8
68 (2g)
83 (2h)
OHC
Br
Br
Br
F
F
9
97 (2i)
Cl
10
11
93 (2j)
47 (2k)
Cl
Br
Br
I
O
O
12
13
83 (2a)
82 (2l)
Under the optimized conditions, the
b,b-diarylation of alkyl
acrylates was suitable to various aryl iodides and even less reactive
aryl bromides, however, electron-rich trimethoxy(vinyl)silane does
not couple at all (Table 4). Generally, the reactions of alkyl acrylates
with unactivated aryl iodides containing electron-donating sub-
stituents gave good yields of trisubstituted olefine (Table 4, entries
8e10), whilst, the reactions with aryl bromides gave diarylation
product in moderate to good yields (Table 4, entries 1e6). To further
determine the scope of this catalytic system with other kinds of
terminal olefins, different styrene substrates were chosen to react
with aryl bromides or iodides under identical conditions. These
reactions were afforded the desired product in good yield (Table 4,
entries 13e17).
I
I
14
88 (2k)
O
O
a
Reaction conditions: 0.005 mmol of 1, 1 mmol of aryl halides, 1.2 mmol of
styrene, and 1.5 mmol of K3PO4 in 2 mL of DMA.
b
Isolated yield.

Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
6243
Table 2
Table 3
MizorokieHeck cross-coupling reactions of ethyl acrylate with aryl halides
Diarylation of ethyl acrylate under different reactions
0.5 mol% 1,
1.5 eq. K3PO4
1 mol% 1,
2.5 eq. base,
2 eq. TBAB
X
+
CO2Et
A
CO2Et
Br
DMA, 110 C, 5 h
°
R
+
CO2Et
CO2Et
CO2Et
R
1 eq.
(X= Br, I)
solvent,
+
1.2 eq.
°
120 C, 12 h
Entrya
Aryl halide
Product
3 Yield (%)b
77 (3a)
B
2.2 eq.
Entrya
1 eq.
Solvent
Base
Additive
Product A (B) yieldb
1
2
3
4
5
6
7
Br
1
2
3
4
5
6
7
8
DMA
DMA
DMA
DMA
DMA
DMA
DMA
Toluene
DMF
K3PO4
K2CO3
NaOAc
NaOAc
Cs2CO3
NaOH
Na2CO3
NaOAc
NaOAc
NaOAc
NaOAc
TBAB
TBAB
TBAB
None
TBAB
TBAB
TBAB
TBAB
TBAB
TBAB
None
10 (18)
82 (8)
88 (0)
0 (76)
5 (8)
0 (65)
64 (10)
24 (7)
73 (5)
0 (8)
CO2Et
O2N
Cl
79 (3b)
74 (3c)
90 (3d)
75 (3e)
70 (3f)
67 (3g)
O2N
Br
CO2Et
Cl
F3C
OHC
F
Br
CO2Et
CO2Et
CO2Et
9
10
11
DMSO
TBAB
15 (10)
F3C
OHC
F
Br
Br
a
Reaction conditions: 0.005 mmol of 1, 1.1 mmol of aryl halide, 0.5 mmol of ethyl
acrylate, 1 mmol of TBAB, and 1.25 mmol of base in 2 mL of solvent.
b
Isolated yield.
aromatic groups. The catalytic reaction was first performed with
1.0 equiv of p-tolyl iodide and ethyl acrylate at 120 ꢀC. As expected,
only the monoarylation took place, affording (E)-ethyl 3-p-tolyla-
crylate within 4 h. Aftercooling to room temperature, the second aryl
halide was directly added to the crude mixture without isolation and
heated to 150 ꢀC again. Under these conditions, the unsymmetrical
triarylated acrylates were obtained in up to 70% isolated yields
(Table 5, entries 1e6). Furthermore, this one-pot strategy can be
applied to prepare unsymmetrical triarylated ethylenes when sty-
rene was used as the starting material instead of ethyl acrylate (Table
5, entries 7e11). In each run a mixture of E/Z isomers was obtained,
and the E/Z ratios of these products were determined by GCeMS.
Br
CO2Et
CO2Et
Br
F
F
Br
8
68 (3h)
CO2Et
F
F
O
9
86 (3i)
52 (3j)
O
Br
CO2Et
CO2Et
3. Conclusion
Br
I
10
We can conclude that the di-NHC dipalladium complex 1 are
efficient precatalyst for the phosphine-free monoarylation of ter-
minal alkenes using K3PO4 as base in DMA at 110 ꢀC. Both electron-
rich and electron-deficient aryl iodides and bromides could be
coupled with styrene or ethyl acrylate in good yield. A wide variety
of functional groups were tolerated in the coupling reaction. The
phosphine-free diarylation reaction of terminal alkenes can be
performed in the presence of TBAB as additive and NaOAc as base
with higher catalyst loading (1 mol %) in DMA at 120 ꢀC. The double
arylation of terminal olefins afforded trisubstituted olefins in good
to excellent yields. The protocol is applicable to the coupling of both
aryl iodides and bromides leading to symmetrical and un-
O
O
11
12
13
86 (3a)
84 (3k)
78 (3j)
CO2Et
I
CO2Et
CO2Et
I
O
O
symmetrical b,b-diarylated and b,b
0-diarylated alkenes.
Br
14
82 (3l)
CO2Et
4. Experimental section
4.1. General information
a
Reaction conditions: 0.005 mmol of 1, 1 mmol of aryl halides, 1.2 mmol of ethyl
acrylate, and 1.5 mmol of K3PO4 in 2 mL of DMA.
b
Isolated yield.
All reactions have been carried out under argon atmosphere.
The palladium complex was prepared according to our previous
procedure.6 DMA and DMF were distilled from anhydrous magne-
sium sulfate, and DMSO was distilled from calcium hydride. Tolu-
ene was distilled from sodium benzophenone ketyl prior to use. All
other reagents were commercially available and were used without
further purification. NMR spectra were recorded on a Bruker DPX
400 MHz spectrometer at room temperature and referenced to the
This methodology has also been extended to the synthesis of
unsymmetrical diarylated alkenes, which represent an even more
challenging task. Initially, ethyl acrylate was used as the starting
material employing a one-pot strategy to introduce two different

6244
Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
1 mol% 1, TBAB (2
Table 4
b,b-Diarylation of olefines with aryl halides
Ar
eq.), NaOAc (2.5 eq.)
Ar-X
+
R
Ar
°
DMA, 120 C, 18 h
R
2.2 eq.
1 eq.
4
(X= Br, I; R = Ar or CO2Et)
Entrya
Ar-X
Olefins
Product
4 Yield (%)b
88 (4a)
1
CO2Et
CO2Et
Br
CO2Et
Cl
2
69 (4b)
72 (4c)
89 (4d)
Cl
F3C
F
Br
Cl
F3C
F
CO2Et
CF3
3c
CO2Et
CO2Et
Br
CO2Et
F
4
Br
CO2Et
F
Br
Br
5
6
7
8
82 (4e)
40 (4f)
95 (4a)
90 (4g)
CO2Et
CO2Et
CO2Et
CO2Et
F
CO2Et
F
F
F
CO2Et
CO2Et
CO2Et
F
I
I
I
9
75 (4h)
CO2Et
CO2Et
O
10
84 (4i)
CO2Et
O
I
O
CO2Et

Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
6245
Table 4 (continued )
Entrya
Ar-X
Olefins
Product
4 Yield (%)b
CO2Bun
CO2Bun
11
12
13
14
86 (4j)
Br
Br
I
Si(OMe)3
0
Si(OMe)3
71 (4k)
87 (4k)
Br
15
16
82 (4l)
I
O
79 (4m)
O
I
I
O
O
O
Cl
17
76 (4n)
Cl
Cl
Cl
Cl
a
Reaction conditions: 0.005 mmol of 1, 0.5 mmol of olefin, 1 mmol of TBAB, 1.1 mmol of aryl halide, and 1.25 mmol of NaOAc in 2 mL of DMA.
Isolated yield.
The reaction was carried out for 24 h.
b
c
residual signals of the solvent. GCeMS was performed on an Agi-
lent 6890-5973N system with electron ionization (EI) mass spec-
volatile. The product was purified by flash column chromatography
on silica gel (eluent: dichloromethane/petroleum ether).
trometry. HRMS was recorded on
combined-type mass spectrometry.
a Fisher LTQ-Orbitrap XL
4.2.1. (E)-1,2-Diphenylethene (2a).7a White solid; 1H NMR
(400 MHz, CDCl3):
J¼7.6, 2H), 7.1 (s, 2H).
d
7.53 (d, J¼7.6, 4H), 7.37 (t, J¼7.6, 4H), 7.28 (d,
4.2. General procedure for the mono-arylation
In a typical run, a 5 mL of vial equipped with a magnetic bar was
charged with a mixture of aryl halide (1 mmol), olefins (1.2 mmol),
Pd catalyst (0.005 mmol, 4 mg), K3PO4 (1.5 mmol, 318 mg), and 2 mL
of DMA in argon. The reactionwas heated at 110 ꢀC for 5 h, then brine
was added into it. The resulting mixture was extracted with ethyl
acetate for three times, and the crude was obtained by removing
4.2.2. (E)-1-Methoxy-4-styrylbenzene (2b).7a White solid; 1H NMR
(400 MHz, CDCl3):
J¼7.2 Hz, 1H), 7.09e6.96 (m, 2H), 6.90 (d, J¼8.8 Hz, 2H), 3.83 (s, 3H).
d
7.50e7.45 (m, 4H), 7.35 (t, J¼7.6 Hz, 2H), 7.22 (d,
4.2.3. (E)-1-(4-Styrylphenyl)ethanone (2c).7a Yellow solid; 1H NMR
(400 MHz, CDCl3):
d
7.95 (d, J¼8.0 Hz, 2H), 7.60e7.53 (m, 4H), 7.38

6246
Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
1. 1 mol% 1, 2 eq. TBAB, 2.5 eq. NaOAc,
Table 5
b,
b
0-Diarylation of ethyl acrylate or styrene with aryl halides
R2
°
DMAC, 120 C, 4 h
R1
1 eq.
X
+
°
, 150 C, 15 h
2. 1 eq.
R2
X
R1
(X= Br, I; R1 = Ph or CO2Et)
1 eq.
Entrya
R1
Product
5 Yield (%)b
E/Z ratiod
X
X
R2
1c
CO2Et
88 (5a)
63:36
I
I
Br
CO2Et
F
2c
CO2Et
85 (5b)
81:19
F
Br
CO2Et
F
Br
3c
CO2Et
CO2Et
79 (5c)
75 (5d)
61:39
52:48
I
I
F
CO2Et
Cl
4c
Cl
Br
CO2Et
O
5c
CO2Et
86 (5e)
70 (5f)
71:29
51:49
I
I
O
Br
CO2Et
CO2Et
I
6c
CO2Et
7
8
9
Ph
Ph
Ph
87 (4j)
79 (5g)
89 (5h)
d
Br
Br
Br
80:20
83:17
Br
O
Br
O
Br

Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
6247
Table 5 (continued )
Entrya
R1
Product
5 Yield (%)b
E/Z ratiod
X
X
R2
F
10
Ph
85 (5i)
90:10
Br
Br
I
Cl
11
Ph
81 (5j)
63:37
Br
Cl
I
a
Reaction conditions: 0.005 mmol of 1, 0.5 mmol of olefin, 1 mmol of TBAB, 0.5 mmol of the first aryl halide, 0.5 mmol of the second aryl halide, and 1.25 mmol of NaOAc in
2 mL of DMA.
b
c
Isolated yield.
The reaction time of second step is 18 h.
The E/Z ratio was determined by GCeMS.
d
(t, J¼7.2 Hz, 2H), 7.31 (d, J¼7.2 Hz, 1H), 7.21e7.11 (m, 2H), 2.61 (s,
7.35 (t, J¼7.2 Hz, 2H), 7.25 (t, J¼4.0 Hz, 1H), 7.16 (d, J¼8.0 Hz, 2H),
7.11e7.02 (m, 2H).
3H).
4.2.4. (E)-1-Styryl-4-(trifluoromethyl)benzene (2d).7b White solid;
4.2.13. Ethyl cinnamate (3a).8a Yellow oil; 1H NMR (400 MHz,
1H NMR (400 MHz, CDCl3):
d
7.60 (s, 4H), 7.54 (d, J¼7.6 Hz, 2H), 7.38
CDCl3):
d
7.69 (d, J¼16.0 Hz, 1H), 7.52 (s, 2H), 7.37 (s, 3H), 6.44 (d,
(t, J¼7.6 Hz, 2H), 7.31 (d, J¼7.6, 1H), 7.22e7.10 (m, 2H).
J¼16.0 Hz, 1H), 4.29e4.23 (m, 2H), 1.33 (t, J¼7.2 Hz, 3H).
4.2.14. (E)-Ethyl 3-(4-nitrophenyl)acrylate (3b).8a Yellow solid; 1H
4.2.5. (E)-1-Fluoro-4-styrylbenzene (2e).7a White solid; 1H NMR
NMR (400 MHz, CDCl3):
6.55 (d, J¼16.0 Hz, 1H), 4.32e4.26 (m, 2H), 1.35 (t, J¼7.2 Hz, 3H).
d
8.25 (d, J¼8.8 Hz, 2H), 7.72e7.66 (m, 3H),
(400 MHz, CDCl3):
(d, J¼7.2 Hz, 1H), 7.10e7.00 (m, 4H).
d
7.51e7.46 (m, 4H), 7.37 (d, J¼7.2 Hz, 2H), 7.28
4.2.15. (E)-Ethyl 3-(4-chlorophenyl)acrylate (3c).8a White solid; 1H
4.2.6. (E)-1-Fluoro-3-styrylbenzene (2f).7c White solid; 1H NMR
NMR (400 MHz, CDCl3):
d
7.52 (d, J¼16.0 Hz, 1H), 7.34 (d, J¼8.4 Hz,
(400 MHz, CDCl3):
7.33e7.21 (m, 4H), 7.14e7.02 (m, 2H), 6.96 (t, J¼8.0 Hz, 1H).
d
7.52 (d, J¼7.6 Hz, 2H), 7.38 (t, J¼7.6 Hz, 2H),
2H), 7.25 (d, J¼8.0 Hz, 2H), 6.30 (d, J¼16.0 Hz, 1H), 4.19e4.14 (m,
2H), 1.24 (t, J¼7.2 Hz, 3H).
4.2.7. (E)-4-Styrylbenzaldehyde (2g).7b White solid; 1H NMR
4.2.16. (E)-Ethyl 3-(4-(trifluoromethyl)phenyl)acrylate (3d).8b White
d 7.70e7.62 (m, 5H), 6.50 (d,
J¼16.0 Hz, 1H), 4.30e4.25 (m, 2H), 1.34 (t, J¼7.2 Hz, 3H).
solid; 1H NMR (400 MHz, CDCl3):
(400 MHz, CDCl3):
d
7.52 (d, J¼7.6 Hz, 2H), 7.38 (t, J¼7.6 Hz, 2H),
7.33e7.21 (m, 4H), 7.14e7.02 (m, 2H), 6.96 (t, J¼8.0 Hz, 1H).
4.2.8. (E)-1-Fluoro-2-styrylbenzene (2h).7d White solid; 1H NMR
4.2.17. (E)-Ethyl 3-(4-formylphenyl)acrylate (3e).7b Yellow oil; 1H
(400 MHz, CDCl3):
(t, J¼7.6 Hz, 2H), 7.29e7.19 (m, 4H), 7.15e7.05 (m, 2H).
d
7.60 (t, J¼7.6 Hz,1H), 7.53 (d, J¼7.2 Hz, 2H), 7.36
NMR (400 MHz, CDCl3):
d
10.02 (s, 1H), 7.89 (d, J¼8.0 Hz, 2H),
7.72e7.66 (m, 3H), 6.54 (d, J¼16.0 Hz, 1H), 4.31e4.25 (m, 2H), 1.34
(t, J¼7.2 Hz, 3H).
4.2.9. (E)-1-Styrylnaphthalene (2i).7a Light yellow solid; 1H NMR
4.2.18. (E)-Ethyl 3-(4-fluorophenyl)acrylate (3f).8a Yellow oil; 1H
(400 MHz, CDCl3):
d
8.24 (d, J¼8.4 Hz, 1H), 7.93e7.88 (m, 2H), 7.82
(d, J¼8.0 Hz, 1H), 7.77 (d, J¼6.8 Hz, 1H), 7.63 (d, J¼7.6 Hz, 2H),
7.58e7.49 (m, 3H), 7.43 (t, J¼7.2 Hz, 2H), 7.34e7.30 (m, 1H), 7.17 (d,
J¼16.0 Hz, 1H).
NMR (400 MHz, DMSO):
2H), 7.09e7.04 (m, 2H), 6.35 (d, J¼16.0 Hz, 1H), 4.28e4.23 (m, 2H),
d
7.64 (d, J¼16.0 Hz, 1H), 7.52e7.49 (m,
1.33 (t, J¼7.2 Hz, 3H).
4.2.10. (E)-1-Chloro-4-styrylbenzene (2j).7a White solid; 1H NMR
4.2.19. (E)-Ethyl 3-(3-fluorophenyl)acrylate (3g).8c Yellow oil; 1H
(400 MHz, CDCl3):
2H), 7.36 (t, J¼7.6 Hz, 2H), 7.33e7.27 (m, 3H), 7.11e7.02 (m,
d
7.50 (d, J¼7.6 Hz, 2H), 7.44 (d, J¼8.8 Hz,
NMR (400 MHz, DMSO):
d
7.64 (d, J¼16.0 Hz, 1H), 7.52e7.49 (m,
2H), 7.09e7.04 (m, 2H), 6.35 (d, J¼16.0 Hz, 1H), 4.28e4.23 (m, 2H),
1.33 (t, J¼7.2 Hz, 3H).
2H).
4.2.11. (E)-1-Methoxy-2-styrylbenzene (2k).7e White solid; 1H NMR
4.2.20. (E)-Ethyl-3-(2-fluorophenyl) acrylate (3h).8d Yellow oil; 1H
(400 MHz, CDCl3):
d
7.60 (d, J¼7.6 Hz,1H), 7.55e7.47 (m, 3H), 7.35 (t,
NMR (400 MHz, CDCl3):
d
7.73 (d, J¼16.0 Hz, 1H), 7.45 (t, J¼7.2 Hz,
J¼7.6 Hz, 2H), 7.24 (d, J¼6.8 Hz, 2H), 7.11 (d, J¼16.4 Hz, 1H), 6.97 (t,
J¼7.6 Hz, 1H), 6.90 (d, J¼8.0 Hz, 1H), 3.88 (s, 3H).
1H), 7.26 (s, 1H), 7.09e6.99 (m, 2H), 6.45 (d, J¼16.0 Hz, 1H),
4.22e4.16 (m, 2H), 1.26 (t, J¼7.2 Hz, 3H).
4.2.12. (E)-1-Methyl-4-styrylbenzene (2l).7a White solid; 1H NMR
4.2.21. (E)-Ethyl 3-(4-methoxyphenyl)acrylate (3i).8e White solid;
1H NMR (400 MHz, CDCl3):
d
7.99 (d, J¼16.2 Hz, 1H), 7.49 (d,
(400 MHz, CDCl3):
d
7.50 (d, J¼7.2 Hz, 2H), 7.41 (d, J¼8.0 Hz, 2H),

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Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
J¼7.5 Hz, 1H), 7.33 (t, J¼7.7 Hz, 1H), 7.01e6.83 (m, 2H), 6.52 (d,
J¼16.2 Hz, 1H), 4.26 (m, 2H), 3.87 (s, 3H), 1.35 (s, 3H).
J¼8.8 Hz, 3H), 6.90 (d, J¼8.8 Hz, 2H), 6.84 (d, J¼9.2 Hz, 2H), 6.22 (s,
1H), 4.10e4.04 (m, 2H), 3.84 (s, 3H), 3.81 (s, 3H), 1.16 (t, J¼7.2 Hz,
3H).
4.2.22. (E)-Ethyl 3-(p-tolyl)acrylate (3j).8e Yellow oil; 1H NMR
(400 MHz, CDCl3):
d
7.63 (d, J¼16.0 Hz, 1H), 7.47 (d, J¼8.4 Hz, 2H),
4.3.10. Butyl 3,3-diphenylacrylate (4j).3b Yellow oil; 1H NMR
(400 MHz, CDCl3): d 7.35e7.29 (m, 6H), 7.26e7.24 (m, 2H), 7.14e7.12
6.89 (d, J¼8.4 Hz, 2H), 6.30 (d, J¼16.0 Hz, 1H), 4.27e4.22 (m, 2H),
2.83 (s, 3H), 1.32 (t, J¼7.2 Hz, 3H).
(m, 2H), 6.32 (s,1H), 3.92 (t, J¼6.4 Hz, 2H),1.39 (m, 2H),1.17 (m, 2H),
0.81 (t, J¼7.4 Hz, 3H).
4.2.23. (E)-Ethyl 3-(2-methoxyphenyl)acrylate (3k).8f Yellow oil; 1H
NMR (400 MHz, CDCl3):
1H), 7.33 (t, J¼6.8 Hz, 1H), 6.96e6.88 (m, 2H), 6.52 (d, J¼16.0 Hz,
1H), 4.28e4.22 (m, 2H), 3.86 (s, 3H), 1.33 (t, J¼6.8 Hz, 3H).
d
7.99 (d, J¼16.0 Hz, 1H), 7.49 (d, J¼8.0 Hz,
4.3.11. Ethene-1,1,2-triyltribenzene (4k).3b White solid; 1H NMR
(400 MHz, CDCl3):
7.13e7.06 (m, 3H), 7.02e6.95 (m, 2H).
d
7.50 (d, J¼7.6 Hz, 2H), 7.36e7.18 (m, 9H),
4.2.24. (E)-Ethyl 3-(naphthalen-1-yl)acrylate (3l).8g Yellow oil; 1H
4.3.12. 4,40,400-(Ethene-1,1,2-triyl)tris(methylbenzene) (4l).3b White
NMR (400 MHz, CDCl3):
1H), 7.88 (t, J¼7.6 Hz, 2H), 7.75 (d, J¼7.2 Hz, 1H), 7.60e7.46 (m, 3H),
d
8.54 (d, J¼16.0 Hz, 1H), 8.20 (d, J¼8.0 Hz,
solid; 1H NMR (400 MHz, CDCl3):
d
7.21 (d, J¼8.4 Hz, 2H), 7.15e7.08
(m, 6H), 6.94 (s, 4H), 6.87 (s, 1H), 2.38 (s, 3H), 2.35 (s, 3H), 2.27 (s,
3H).
6.54 (d, J¼16.0 Hz, 1H), 4.36e4.30 (m, 2H), 1.39 (t, J¼7.2 Hz, 3H).
4.3. Representative procedure for
olefins
b
,
b
-diarylation of terminal
4.3.13. 4,40,400-(Ethene-1,1,2-triyl)tris(methoxybenzene)
(4m).3b White solid; 1H NMR (400 MHz, CDCl3):
d
7.27 (d, J¼9.2 Hz,
2H), 7.15 (d, J¼8.4 Hz, 2H), 7.00 (d, J¼8.4 Hz, 2H), 6.88 (d, J¼8.8 Hz,
2H), 6.82 (d, J¼8.8 Hz, 2H), 6.80 (s, 1H), 6.70 (d, J¼8.8 Hz, 2H), 3.85
(s, 3H), 3.82 (s, 3H), 3.76 (s, 3H).
To a stirred solution of TBAB (1 mmol, 322 mg), sodium acetate
(102 mg, 1.25 mmol), and catalyst (4 mg, 0.005 mmol) in DMA
(2 mL) was added aryl halide (1.1 mmol) and olefin (0.5 mmol). The
mixture was stirred at 120 ꢀC for 18 h under argon. The solids were
removed by filtration, and rinsed with 10 mL of ethyl acetate. The
filtrate was concentrated under vacuum. The crude product was
purified by flash column chromatography using petroleum ether
(PE) and ethyl acetate (EA) as the eluent (PE/EA 30/1).
4.3.14. 4,40,400-(Ethene-1,1,2-triyl)tris(chlorobenzene) (4n).3b White
solid; 1H NMR (400 MHz, CDCl3):
d
7.31 (d, J¼8.4 Hz, 2H), 7.29 (d,
J¼8.8 Hz, 2H), 7.20 (d, J¼8.4 Hz, 2H), 7.13 (d, J¼8.8 Hz, 2H), 7.10 (d,
J¼8.4 Hz, 2H), 6.94 (d, J¼8.4 Hz, 2H), 6.87 (s, 1H).
4.4. Representative procedure for b,b
0-diarylation of terminal
olefins
4.3.1. Ethyl 3,3-diphenylacrylate(4a).3b Yellow oil; 1H NMR (400 MHz,
CDCl3):
d
7.39 (t, J¼3.2 Hz, 4H), 7.35e7.31 (m, 4H), 7.23e7.21 (m, 2H),
6.37 (s, 1H), 4.08e4.03 (m, 2H), 1.12 (t, J¼7.2 Hz, 4H).
In a typical run, a 5 mL of vial equipped with a magnetic bar was
charged with a mixture of the first aryl halide (0.5 mmol), olefine
(0.5 mmol), Pd catalyst (4 mg, 0.005 mmol), TBAB (322 mg,
1 mmol), NaOAc (102 mg, 1.25 mmol), and 2 mL of DMA in argon.
The reaction was heated at 120 ꢀC for 4 h. After cooling to room
temperature, the second aryl halide (0.5 mmol) was directly added
to the crude mixture without isolation. The reaction was heated at
150 ꢀC for 15 or 18 h again. The resulting mixture was extracted
with ethyl acetate for three times, and the crude was obtained by
removing volatile. The product was purified by flash column
chromatography on silica gel.
4.3.2. Ethyl 3,3-bis(4-chlorophenyl)acrylate (4b).3b White solid; 1H
NMR (400 MHz, CDCl3):
d
7.36 (d, J¼8.0 Hz, 2H), 7.30 (d, J¼8.0 Hz,
2H), 7.20 (d, J¼8.0 Hz, 2H), 7.13 (d, J¼8.0 Hz, 2H), 6.33 (s, 1H),
4.09e4.04 (m, 2H), 1.15 (t, J¼7.2 Hz, 3H).
4.3.3. Ethyl 3,3-bis(4-(trifluoromethyl)phenyl)acrylate (4c).9 White
solid; 1H NMR (400 MHz, CDCl3):
d 7.68e7.59 (m, 4H), 7.39e7.32
(m, 4H), 6.47 (s, 1H), 4.10e4.05 (m, 2H), 1.13 (t, J¼7.2 Hz, 3H).
4.3.4. Ethyl 3,3-bis(4-fluorophenyl)acrylate (4d).3b White solid; 1H
NMR (400 MHz, CDCl3):
d
7.28e7.24 (m, 2H), 7.19e7.16 (m, 2H),
4.4.1. (E)- and (Z)-Ethyl 3-phenyl-3-(p-tolyl)acrylate (5a).10a This
product was isolated as a yellow oily mixture of the two E/Z ste-
reoisomers, yield 88%, E/Z: 63:36.
7.10e6.99(m, 4H), 6.30(s,1H), 4.09e4.04 (m, 2H),1.15 (t, J¼7.2 Hz, 3H).
4.3.5. Ethyl 3,3-bis(3-fluorophenyl)acrylate (4e).3b White solid; 1H
NMR (400 MHz, CDCl3):
d
7.39e7.27 (m, 2H), 7.12e7.04 (m, 3H),
4.4.1.1. (E)-Ethyl 3-phenyl-3-(p-tolyl)acrylate. 1H NMR (400
7.00e6.90 (m, 3H), 6.38 (s,1H), 4.09e4.04 (m, 2H),1.15 (t, J¼7.2 Hz, 3H).
MHz, CDCl3): d 7.30e7.26 (m, 2H), 7.20e7.15 (m, 3H), 7.10e7.07 (m,
2H), 7.05e6.98 (m, 2H), 6.27 (s, 1H), 4.10e4.05 (m, 2H), 2.40 (s, 3H),
1.15 (t, J¼7.2 Hz, 3H).
4.3.6. Ethyl 3,3-bis(2-fluorophenyl)acrylate (4f).3b White solid; 1H
NMR (400 MHz, CDCl3): d 7.34e7.30 (m, 2H), 7.13e7.06 (m, 6H), 6.47
(s, 1H), 4.12e4.06 (m, 2H), 1.14 (t, J¼6.8 Hz, 3H).
4.4.1.2. (Z)-Ethyl
(400 MHz, CDCl3):
3-phenyl-3-(p-tolyl)acrylate. 1H
7.30e7.26 (m, 2H), 7.20e7.15 (m, 3H), 7.10e7.07
NMR
d
4.3.7. Ethyl 3,3-di-p-tolylacrylate (4g).3b Yellow oil; 1H NMR
(m, 2H), 7.05e6.98 (m, 2H), 6.34 (s, 1H), 4.10e4.04 (m, 2H), 2.36 (s,
3H), 0.97 (t, J¼7.2 Hz, 3H).
(400 MHz, CDCl3):
d
7.22e7.19 (m, 4H), 7.12 (t, J¼8.0 Hz, 4H), 6.32 (s,
1H), 4.10e4.05 (m, 2H), 2.40 (s, 3H), 2.36 (s, 3H), 1.16 (t, J¼7.2 Hz,
3H).
4.4.2. (E)- and (Z)-Ethyl 3-(4-fluorophenyl)-3-(p-tolyl)acrylate (5b).
This product was isolated as a yellow oily mixture of the two E/Z
stereoisomers, yield 85%, E/Z: 81:19, HRMS (ESI): m/z calcd for:
C18H17FO2, 307.1110, found: 307.1074.
4.3.8. Ethyl 3,3-di-o-tolylacrylate (4h).3b Yellow oil; 1H NMR
(400 MHz, CDCl3):
d 7.28e7.19 (m, 5H), 7.13 (s, 3H), 6.16 (s, 1H),
4.11e4.05 (m, 2H), 2.37 (s, 3H), 2.19 (s, 3H), 1.13 (t, J¼6.8 Hz, 3H).
4.4.2.1. (E)-Ethyl 3-(4-fluorophenyl)-3-(p-tolyl)acrylate. 1H NMR
4.3.9. Ethyl 3,3-bis(4-methoxyphenyl)acrylate (4i).3b White solid;
(400 MHz, CDCl3):
d
7.29e7.26 (m, 2H), 7.19 (d, J¼8.0 Hz, 2H), 7.08
1H NMR (400 MHz, CDCl3):
d
7.24 (d, J¼10.0 Hz, 2H), 7.15 (d,
(d, J¼8.0 Hz, 2H), 7.00 (t, J¼8.8 Hz, 2H), 6.26 (s, 1H), 4.09e4.04 (m,

Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
6249
2H), 2.39 (s, 3H), 1.14 (t, J¼7.2 Hz, 3H). 13C NMR (CDCl3, 100 MHz):
4.16e4.11 (m, 2H), 2.34 (s, 3H), 2.05 (s, 3H), 1.20 (t, J¼7.2 Hz, 3H). 13
C
NMR (CDCl3, 100 MHz): 166.4, 157.1, 142.2, 138.5, 136.1, 135.7, 130.6,
129.6, 129.2, 128.4, 127.4, 125.7, 119.4, 60.2, 21.4, 20.4, 14.2.
166.1,164.8,162.3, 155.8,138.3,137.3,135.8,130.3, 128.8,117.0,115.5,
60.1, 21.5, 14.1.
4.4.2.2. (Z)-Ethyl 3-(4-fluorophenyl)-3-(p-tolyl)acrylate. 1H NMR
(400 MHz, CDCl3): 7.29e7.26 (m, 2H), 7.19 (d, J¼8.0 Hz, 2H), 7.08 (d,
J¼8.0 Hz, 2H), 7.00 (t, J¼8.8 Hz, 2H), 6.26 (s, 1H), 4.09e4.04 (m, 2H),
2.39 (s, 3H), 1.14 (t, J¼7.2 Hz, 3H). 13C NMR (CDCl3, 100 MHz): 166.1,
164.8, 162.3, 155.8, 138.3, 137.3, 135.8, 130.3, 129.2, 117.0, 115.3, 60.1,
21.5, 14.1.
4.4.6.2. (Z)-Ethyl
(400 MHz, CDCl3):
1H), 4.03e3.98 (m, 2H), 2.34 (s, 3H), 2.08 (s, 3H), 1.07 (t, J¼7.2 Hz,
3H). 13C NMR (CDCl3, 100 MHz): 166.0, 155.9, 139.8, 138.9, 136.4,
135.4, 130.6, 129.8, 129.4, 128.4, 127.7, 125.4, 116.6, 59.9, 21.3, 19.6,
14.0.
3-(o-tolyl)-3-(p-tolyl)acrylate. 1H
7.28e7.19 (m, 4H), 7.15e7.04 (m, 4H), 6.50 (s,
NMR
d
4.4.3. (E)- and (Z)-Ethyl 3-(3-fluorophenyl)-3-(p-tolyl)acrylate
(5c). This product was isolated as a yellow oily mixture of the two
E/Z stereoisomers, yield 79%, E/Z: 61:39, HRMS (ESI): m/z calcd for:
C18H17FO2, 307.1110, found: 307.1088.
4.4.7. (E)- and (Z)-(1-(p-Tolyl)ethene-1,2-diyl)dibenzene (5g).10b,c This
product was isolated as a light yellow oily mixture of the two E/Z
stereoisomers, yield 79%, E/Z: 80:20.
4.4.7.1. (E)-(1-(p-Tolyl)ethene-1,2-diyl)dibenzene.10b 1H
(400 MHz, CDCl3):
NMR
4.4.3.1. (E)-Ethyl 3-(3-fluorophenyl)-3-(p-tolyl)acrylate. 1H NMR
d
7.34e7.33 (m, 4H), 7.25e7.21 (m, 2H), 7.15e7.10
(400 MHz, CDCl3):
d
7.31e7.26 (m, 1H), 7.21e7.17 (m, 2H), 7.15e6.97
(m, 6H), 7.04e7.02 (m, 2H), 6.95 (s, 1H), 2.37 (s, 3H).
(m, 5H), 6.32 (s, 1H), 4.11e4.05 (m, 2H), 2.40 (s, 1H), 1.15 (t, J¼7.2 Hz,
3H). 13C NMR (CDCl3, 100 MHz): 166.0, 163.9, 161.5, 155.4, 143.5,
135.4, 129.8, 129.2, 128.8, 124.1, 118.1, 116.1, 115.5, 60.2, 21.5, 14.1.
4.4.7.2. (Z)-(1-(p-Tolyl)ethene-1,2-diyl)dibenzene.10c 1H
(400 MHz, CDCl3): d 7.34e7.33 (m, 4H), 7.25e7.21 (m, 2H), 7.15e7.10
NMR
(m, 6H), 7.04e7.02 (m, 2H), 6.95 (s, 1H), 2.39 (s, 3H).
4.4.3.2. (Z)-Ethyl 3-(3-fluorophenyl)-3-(p-tolyl)acrylate. 1H NMR
(400 MHz, CDCl3):
d
7.31e7.26 (m, 1H), 7.21e7.17 (m, 2H), 7.15e6.97
4.4.8. (E)- and (Z)-(1-(4-Methoxyphenyl)ethene-1,2-diyl)dibenzene
(5h).10b,c This product was isolated as a light yellow oily mixture of
the two E/Z stereoisomers, yield 89%, E/Z: 83:17.
(m, 5H), 6.37 (s, 1H), 4.11e4.05 (m, 2H), 2.36 (s, 1H), 1.15 (t, J¼7.2 Hz,
3H). 13C NMR (CDCl3, 100 MHz): 166.0, 163.9, 161.5, 155.4, 143.4,
138.4, 129.9, 129.3, 128.2, 124.1, 117.1, 116.3, 115.3, 60.2, 21.3, 14.1.
4. 4. 8.1. (E) -(1-(4-Methoxyphenyl) ethene-1, 2-diyl)
4.4.4. (E)- and (Z)-Ethyl 3-(4-chlorophenyl)-3-(p-tolyl)acrylate
(5d). This product was isolated as a yellow oily mixture of the two
E/Z stereoisomers, yield 75%, E/Z: 52:48, HRMS (ESI): m/z calcd for:
C18H17ClO2, 323.0815, found: 323.0828.
dibenzene.10b 1H NMR (400 MHz, CDCl3):
d 7.36e7.31 (m, 3H),
7.25e7.20 (m, 3H), 7.14e7.10 (m, 3H), 7.06e7.02 (m, 2H), 6.98 (s,
1H), 6.92e6.80 (m, 3H), 3.77 (s, 3H).
4. 4. 8. 2. (Z)-(1-(4-Methoxyphenyl)e thene-1, 2-diyl)
4.4.4.1. (E)-Ethyl 3-(4-chlorophenyl)-3-(p-tolyl)acrylate. 1H NMR
dibenzene.10c 1H NMR (400 MHz, CDCl3):
d 7.36e7.31 (m, 3H),
(400 MHz, CDCl3):
d
7.30e7.26 (m, 2H), 7.24e7.18 (m, 4H), 7.13e7.07
7.25e7.20 (m, 3H), 7.14e7.10 (m, 3H), 7.06e7.02 (m, 2H), 6.96 (s,
1H), 6.92e6.80 (m, 2H), 6.75 (s, 1H), 3.77 (s, 3H).
(m, 2H), 6.29 (s, 1H), 4.10e4.04 (m, 2H), 2.39 (s, 3H), 1.15 (t,
J¼6.8 Hz, 3H). 13C NMR (CDCl3, 100 MHz): 166.0, 155.5, 139.7, 138.4,
136.1, 135.54, 135.52, 129.7, 129.2, 128.8, 128.6, 117.5, 60.2, 21.5, 14.1.
4.4.9. (E)- and (Z)-(1-(4-Fluorophenyl)ethene-1,2-diyl)dibenzene
(5i).10d,e This product was isolated as a light yellow oily mixture of
the two E/Z stereoisomers, yield 85%, E/Z: 90:10.
4.4.4.2. (Z)-Ethyl 3-(4-chlorophenyl)-3-(p-tolyl)acrylate. 1H NMR
(400 MHz, CDCl3): d 7.30e7.26 (m, 2H), 7.24e7.16 (m, 4H), 7.13e7.07
(m, 2H), 6.29 (s, 1H), 4.10e4.04 (m, 2H), 2.36 (s, 3H), 1.15 (t,
J¼6.8 Hz, 3H). 13C NMR (CDCl3, 100 MHz): 166.0, 155.5, 139.7, 138.4,
135.54, 135.52, 129.7, 129.2, 128.8, 128.6, 117.5, 60.2, 21.5, 14.1.
4.4.9.1. (E)-(1-(4-Fluorophenyl)ethene-1,2-diyl)dibenzene.10d 1H
NMR (400 MHz, CDCl3):
d 7.32e7.25 (m, 5H), 7.20e7.09 (m, 5H),
7.03e6.95 (m, 4H), 6.89 (s, 1H).
4.4.5. (E)- and (Z)-Ethyl 3-(4-methoxyphenyl)-3-(p-tolyl)acrylate
(5e).10a This product was isolated as a yellow oily mixture of the
two E/Z stereoisomers, yield 86%, E/Z: 71:29.
4.4.9.2. (Z)-(1-(4-Fluorophenyl)ethene-1,2-diyl)dibenzene.10e 1H
NMR (400 MHz, CDCl3):
d 7.32e7.25 (m, 5H), 7.20e7.09 (m, 5H),
7.03e6.95 (m, 5H).
4.4.5.1. (E)-Ethyl
NMR (400 MHz, CDCl3):
2H), 7.04 (d, J¼8.0 Hz, 2H), 6.78 (d, J¼8.0 Hz, 2H), 6.22 (s, 1H),
4.03e3.98 (m, 2H), 3.76 (s, 3H), 2.34 (s, 3H), 1.09 (t, J¼7.2 Hz, 3H).
3-(4-methoxyphenyl)-3-(p-tolyl)acrylate. 1H
4.4.10. (E)- and (Z)-(1-(4-Chlorophenyl)ethene-1,2-diyl)dibenzene
(5j).10b,c This product was isolated as a light yellow oily mixture of
the two E/Z stereoisomers, yield 81%, E/Z: 63:37.
d
7.20 (d, J¼8.8 Hz, 2H), 7.14 (d, J¼7.6 Hz,
4.4.10.1. (E)-(1-(4-Chlorophenyl)ethene-1,2-diyl)dibenzene.10b 1H
NMR (400 MHz, CDCl3): d 7.29e7.18 (m, 7H), 7.15e7.07 (m, 5H),
4.4.5.2. (Z)-Ethyl
3-(4-methoxyphenyl)-3-(p-tolyl)acrylate. 1H
NMR (400 MHz, CDCl3):
2H), 7.04 (d, J¼8.0 Hz, 2H), 6.78 (d, J¼8.0 Hz, 2H), 6.22 (s, 1H),
4.10e4.04 (m, 2H), 3.76 (s, 3H), 2.34 (s, 3H), 1.09 (t, J¼7.2 Hz, 3H).
d
7.20 (d, J¼8.8 Hz, 2H), 7.14 (d, J¼7.6 Hz,
7.01e6.96 (m, 2H), 6.93 (s, 1H).
4 . 4 .10 . 2 . ( Z ) - ( 1 - ( 4 - C h l o r o p h e nyl ) e t h e n e - 1, 2 - d i yl )
dibenzene.10c 1H NMR (400 MHz, CDCl3):
d 7.29e7.18 (m, 7H),
4.4.6. (E)- and (Z)-Ethyl 3-(o-tolyl)-3-(p-tolyl)acrylate (5f). This
product was isolated as a yellow oily mixture of the two E/Z ste-
reoisomers, yield 70%, E/Z: 51:49, HRMS (ESI): m/z calcd for:
C19H20O2, 303.1361, found: 303.1356.
7.15e7.07 (m, 5H), 7.01e6.96 (m, 2H), 6.96 (s, 1H).
Acknowledgements
We are grateful to the foundation of NSFC (21071121, 21172188,
and 21104064), Graduate Foundation (CXLX11_0909 and
CXLX11_0910), SRF for ROCS, SEM, PAPD, and the State Key
4.4.6.1. (E)-Ethyl 3-(o-tolyl)-3-(p-tolyl)acrylate. 1H NMR (400
MHz, CDCl3):
d 7.28e7.19 (m, 4H), 7.15e7.04 (m, 4H), 5.96 (s, 1H),

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Y. Li et al. / Tetrahedron 69 (2013) 6241e6250
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4. (a) Marion, N.; Nolan, S. P. Acc. Chem. Res. 2008, 41, 1440; (b) Wurtz, S.;
Glorius, F. Acc. Chem. Res. 2008, 41, 1523; (c) Herrmann, W. A.; Elison, M.;
Fischer, J.; Koecher, C.; Artus, G. R. J. Angew. Chem., Int. Ed. Engl. 1995, 34,
2371.
Laboratory of Inorganic Synthesis and Preparative Chemistry at Jilin
University (2013-03) for financial support.
5. (a) Cao, C.; Zhuang, Y.; Zhao, J.; Peng, Y.; Li, X.; Shi, Z.; Pang, G.; Shi, Y. Inorg.
Chim. Acta 2010, 363, 3914; (b) Zhao, J.; Yang, L.; Ge, K.; Chen, Q.; Zhuang, Y.;
Cao, C.; Shi, Y. Inorg. Chem. Commun. 2012, 20, 326; (c) Yang, L.; Zhao, J.; Li, Y.;
Ge, K.; Zhuang, Y.; Cao, C.; Shi, Y. Inorg. Chem. Commun. 2012, 22, 33.
6. Li, Y.; Yang, L.; Chen, Q.; Cao, C.; Guan, P.; Pang, G.; Shi, Y. Z. Anorg. Allg. Chem.
2013, 639, 575.
7. (a) Luo, F.; Pan, C.; Wang, W.; Ye, Z.; Cheng, J. Tetrahedron 2010, 66, 1399; (b) Xu,
H.-J.; Zhao, Y.-Q.; Zhou, X.-F. J. Org. Chem. 2011, 76, 8036; (c) Mochida, S.; Hir-
ano, K.; Satoh, T.; Miura, M. Org. Lett. 2010, 12, 5776; (d) Peng, Z.-Y.; Ma, F.-F.;
Zhu, L.-F.; Xie, X.-M.; Zhang, Z. J. Org. Chem. 2009, 74, 6855; (e) Cellaa, R.;
Stefani, H. A. Tetrahedron 2005, 61, 7438.
8. (a) Leung, P. S.-W.; Teng, Y.; Toy, P. H. Org. Lett. 2010, 12, 4996; (b) Chen, Y.;
Huang, L.; Ranade, M. A.; Zhang, X. P. J. Org. Chem. 2003, 68, 3714; (c) Fan, X.;
Zhang, H.-S.; Chen, L.; Long, Y.-Q. Eur. J. Med. Chem. 2010, 45, 2827; (d) Basu, B.;
Das, S.; Das, P.; Mandal, B.; Banerjee, D.; Almqvist, F. Synthesis 2009, 1137; (e)
Riccaboni, M.; La Porta, E.; Martorana, A.; Attanasio, R. Tetrahedron 2010, 66,
4032; (f) Colas, C.; Goeldner, M. Eur. J. Org. Chem. 1999, 1357; (g) Ren, G.; Cui, X.;
Yang, E.; Yang, F.; Wu, Y. Tetrahedron 2010, 66, 4022.
References and notes
1. (a) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457; (b) Buchwald, S. L.; Fu-
gami, K.; Hiyama, T.; Kosugi, M.; Miura, M.; Miyaura, N.; Muci, A. R.; Nomura,
M.; Shirakawa, E.; Tamao, K. In Cross-coupling Reactions: A Practical Guide;
Miyaura, N., Ed.; Springer: Berlin, Germany, 2002; Vol. 219; (c) Handbook of
Organopalladium Chemistry for Organic Synthesis; Nigishi, E.-I., Ed.; Wiley-In-
terscience: New York, NY, 2002; Vol. 1; (d) Hassan, J.; Sevignon, M.; Gozzi, C.;
Schulz, E.; Lemaire, M. Chem. Rev. 2002, 102, 1359; (e) Beleskaya, I. P.; Che-
prakov, A. V. Chem. Rev. 2000, 100, 3009; (f) Beccalli, E. M.; Broggini, G.; Mar-
tinelli, M.; Sottocornola, S. Chem. Rev. 2007, 107, 5318; (g) Colby, D. A.; Bergman,
R. G.; Ellman, J. A. Chem. Rev. 2010, 110, 624.
2. (a) The MizorokieHeck Reaction; Oestreich, M., Ed.; John Wiley & Sons Ltd:
Chichester, UK, 2009; (b) Knowles, J. P.; Whiting, A. Org. Biomol. Chem. 2007, 5,
31; (c) Shibadaki, M.; Vogl, E. M.; Ohshima, T. Adv. Synth. Catal. 2004, 346, 1533;
(d) Dounay, A. B.; Overman, L. E. Chem. Rev. 2003, 103, 2945; (e) Ruan, J.; Xiao, J.
Acc. Chem. Res. 2011, 44, 614; (f) Torborg, C.; Beller, M. Adv. Synth. Catal. 2009,
351, 3027; (g) Nicolaou, K. C.; Bulger, P. G.; Sarlah, D. Angew. Chem., Int. Ed. 2005,
44, 4442; (h) Whitcombe, N. J.; Hii, K. K.; Gibson, S. E. Tetrahedron 2001, 57,
7449.
9. Nakasato, Y.; Saku, O.; Atsumi, E.; Sugimoto, Y.; Ishida, H. U.S. Patent
20,090,203,667, 2009.
10. (a) Calo, V.; Nacci, A.; Monopoli, A.; Laera, S.; Cioffi, N. J. Org. Chem. 2003, 68,
2929; (b) Zhang, W.; Liu, M.; Wu, H.; Ding, J.; Cheng, J. Tetrahedron Lett. 2008,
49, 5214; (c) Corsico, E. F.; Rossi, R. A. J. Org. Chem. 2004, 69, 6427; (d) Xu, X.;
Chen, J.; Gao, W.; Wu, H.; Ding, J.; Su, W. Tetrahedron 2010, 66, 2433; (e) Sun, C.-
L.; Wang, Y.; Zhou, X.; Wu, Z.-H.; Li, B.-J.; Guan, B.-T.; Shi, Z.-J. Chem.dEur. J.
2010, 16, 5844.
3. (a) Botella, L.; Najera, C. Tetrahedron Lett. 2004, 45, 1833; (b) Xu, D.; Lu, C.; Chen,
W. Tetrahedron 2012, 68, 1466; (c) Calo, V.; Nacci, A.; Monopoli, A.; Lopez, L.; di
Cosmo, A. Tetrahedron 2001, 57, 6071; (d) Itami, K.; Nokami, T.; Ishimura, Y.;
Mitsudo, K.; Kamei, T.; Yoshida, J. J. Am. Chem. Soc. 2001, 123, 11577; (e) Itami,
K.; Mineno, M.; Muraoka, N.; Yoshida, J. J. Am. Chem. Soc. 2004, 126, 11778; (f)
Itami, K.; Tonogaki, K.; Ohashi, Y.; Yoshida, J. Org. Lett. 2004, 6, 4093.