Pd-catalyzed heck reactions of aryl bromides with 1,2-diarylethenes

Article abstract of DOI:10.1590/S0103-50532011000700026

A catalytic system composed of Pd(OAc)₂ and P(o-tol)₃ was found to be effective for the Heck reaction of aryl bromides with diarylethylenes. Using K₂CO₃ as a base and DMF as a solvent, trisubstituted olefins were obtained in good to excellent yields. Aryl bromides containing an electron-withdrawing group in para position were less reactive for the Heck coupling reaction and gave substantial amount of homocoupling by-product suggesting that oxidative addition is not the rate-determining step. Electron withdrawing group substituent in the para position of stilbene affects the regioselectivity of the reaction. In this case, the phenyl group from the Ph-Pd complex migrates preferentially to the same carbon of the double bond to which the phenyl is bonded. Finally, a one pot sequential double Heck arylation of styrene was performed, giving trisubstituted olefin with an overall yield of 73percent.

Full text of DOI:10.1590/S0103-50532011000700026

J. Braz. Chem. Soc., Vol. 22, No. 7, 1389-1394, 2011.
Printed in Brazil - ©2011 Sociedade Brasileira de Química
0103 - 5053 $6.00+0.00
Short Report
S
Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
Jones Limberger, Silvia Poersch and Adriano L. Monteiro*
Laboratory of Molecular Catalysis, Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS),
Av. Bento Gonçalves, 9500, CP 15003, 91501-970 Porto Alegre-RS, Brazil
Um sistema catalítico composto por Pd(OAc)2 e P(o-tol)3 foi aplicado na reação de Heck entre
brometos de arila e diariletenos. Utilizando-se K2CO3 como base e DMF como solvente, olefinas
triarilsubstituídas foram obtidas com rendimentos de bons a excelentes. Brometos de arila com
substituintes eletroretiradores foram menos ativos para a reação de acoplamento Heck e levaram
à formação de produto de homoacoplamento em quantidades substanciais, indicando que a adição
oxidativa não deve ser a etapa lenta da reação. A presença de substituintes no diarileteno afetou
drasticamente a seletividade da reação. Realizou-se também a dupla arilação do estireno, levando
diretamente à olefina triarilsubstituída, com rendimento de 73%.
A catalytic system composed of Pd(OAc)2 and P(o-tol)3 was found to be effective for the Heck
reaction of aryl bromides with diarylethylenes. Using K2CO3 as a base and DMF as a solvent,
trisubstituted olefins were obtained in good to excellent yields. Aryl bromides containing an
electron-withdrawing group in para position were less reactive for the Heck coupling reaction
and gave substantial amount of homocoupling by-product suggesting that oxidative addition is not
the rate-determining step. Electron withdrawing group substituent in the para position of stilbene
affects the regioselectivity of the reaction. In this case, the phenyl group from the Ph-Pd complex
migrates preferentially to the same carbon of the double bond to which the phenyl is bonded.
Finally, a one pot sequential double Heck arylation of styrene was performed, giving trisubstituted
olefin with an overall yield of 73%.
Keywords: Heck reaction, palladium, trisubstituted olefins, double arylation
Introduction
monoarylation of disubstituted olefins or direct diarylation
of monosubstituted olefins, have been reported. Arylation
of disubstituted alkenes without an electron-withdrawing
group conjugated to the C=C double bond (e.g., α- or
β-methylstyrene,10,12 1,1-diphenylethene and trans-
stilbene)13-15 has also been investigated. However, to the
best of our knowledge, no example using substituted
stilbenes has been described. Recently, we reported the
Heck arylation of trans-stilbene using Pd(OAc)2/P(o-tol)3
and K2CO3 as a base.16 Using this methodology, we were
able to obtain a triarylolefin intermediate for tamoxifen
synthesis at 98% of yield with 87% of stereoselectivity
for the Z isomer. Here we describe the Heck reaction of
trans-stilbene derivatives and 1,1-diphenylethene with aryl
halides in order to obtain substituted triarylethenes. We also
report our findings concerning the influence of halide or
olefin electro-donating and withdrawing groups on activity,
regio and stereoselectivity.
Palladium-catalyzed Heck cross-coupling reactions
are one of the most efficient methods for the construction
of C−C bonds and have found widespread use in organic
synthesis.1 Most Heck reactions involves arylation of
monosubstituted alkenes (especially acrylates and styrene
derivatives) to allow synthesis of disubstituted olefins with
regio and stereoselective control. In contrast, fewer studies
have been conducted on the arylation of disubstituted
olefins or double arylation of mono-substituted olefins,
to yield trisubstituted products. Stereocontrol during
the synthesis of highly substituted double bonds is a
significant challenge in organic synthesis,2 and the Heck
reaction remains an important alternative. In this context,
some examples of regio and stereoselective syntheses
of trisubstituted α,β-unsaturated compounds, such as
nitriles,3,4 cinnamates5-10 and aldehydes,11 through either
*e-mail: adriano.monteiro@ufrgs.br

1390
Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
Experimental
P(o-tol)3 (6.1 mg, 0.02 mmol), evacuated and black-filled
with argon. Then, DMF (3 mL), bromoanisole (0.5 mmol,
94 mg) and K2CO3 (138 mg, 1.0 mmol) were added.
The reaction mixture was stirred at 130 °C for 5 h and
conversion, regio- and diasteroselectivity were determined
by GC and GC-MS analysis.
Procedure for Heck reaction coupling of stilbenes and
aryl bromides
An oven-dried resealable Schlenk flask was charged
with trans-stilbene (0.5 mmol), Pd(OAc)2 (2.2 mg,
0.01 mmol), P(o-tol)3 (6.1 mg, 0.02 mmol), evacuated
and black-filled with argon. Then, DMF (3 mL), aryl
bromide (0.75 mmol) and K2CO3 (138 mg, 1.0 mmol) were
added. The reaction mixture was stirred at 130 °C for the
desired time. Conversion, regio and diasteroselectivity
were determined by the techniques: gas chromatography
(GC), gas chromatography-mass spectrometry (GC-MS)
Results and Discussion
Recently, we reported the Heck arylation of trans-
stilbene to obtain a tamoxifen intermediate.16 In that
report, the catalyst system was composed of Pd(OAc)2 and
P(o-tol)3. Classical bases for the Heck reaction, such as Et3N
or NaOAc, gave only moderate yields and selectivities, and
the best results were obtained using K2CO3 as a base. Due
to high steric demands, coupling of trans-stilbene with
aryl bromides required higher temperature (130 °C) and
reaction time (48 h) than those necessary for coupling with
styrene. Using these optimized conditions, triphenylethene
was obtained at 89% yield from coupling phenyl bromide
and trans-stilbene (Table 1, entry 1).
1
and H and 13C nuclear magnetic resonance (NMR).
Coupling products were compared with authentic standards
obtained from Suzuki coupling of E-bromostylbenes
with aryl boronic acids (triphenylethene and 1-aryl-1,2-
diphenylethenes)17 or from Heck coupling of aryl bromides
with 1,1-diphenylethene (1-aryl-2,2-diphenylethenes).
The GC yields were obtained using 0.5 mmol of olefin
while the isolated yields were obtained using higher scale
(1.5 mmol of olefin).
Coupling of 4-bromoanisole with trans-stilbene
resulted in 1,2-diphenyl-1-(4-metoxyphenyl)ethene at
79% yield with an E:Z ratio of 83:17 (Table 1, entry 2).
This stereoselectivity is higher than previously reported
for the arylation of trans-stilbene with 4-bromoanisole
in the presence of 0.2% catalyst [Pd(C3H5)Cl]2 and
cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphanylmethyl)-
cyclopentane (Tedicyp) as the phosphine ligand (75%
yield and E:Z = 61:39).13 It is important to point out
that in the presence of phosphine-free nanoparticles,
coupling of phenyl chloride with trans-stilbene gave
only the E-isomer.18 Depending on the experimental
conditions, the Heck reaction is believed to use a neutral
or cationic (or polar) mechanism.19,20 In Scheme 1, a
simplified catalytic cycle for the Heck reaction is shown,
based on the neutral mechanism proposed by Heck with
Pd(OAc)2 associated with monophosphine ligands as the
precursor,21,22 and adapted by us for the particular case
of trans-stilbene derivatives as alkenes. As shown in
Scheme 1, stereoselecitvity of the Heck reaction is defined
by syn-elimination. In the case of coupling 4-bromoanisol
with trans-stilbene (Ar = 4-MeOC6H4 and Ar1 = Ph in
Scheme 1), syn-elimination leads to a trisubstituted
alkene with both phenyl groups of the stilbene derivative
on the same side, even though only the E steroisomer is
expected. The presence of the Z isomer can be explained
by a Pd-H catalyzed isomerization process that may be due
to (i) isomerization of the starting alkene; (ii) postreaction
isomerization of the trisubstituted alkene product;
(iii) isomerization of the coordinated alkene to the Pd-H
Procedure for competitive Heck reaction coupling of trans-
stilbene and aryl halides
An oven-dried resealable Schlenk flask was charged
with trans-stilbene (0.5 mmol), Pd(OAc)2 (2.2 mg,
0.01 mmol) and P(o-tol)3 (6.1 mg, 0.02 mmol), evacuated
and black-filled with argon. Then, DMF (3 mL), two aryl
halides (0.25 mmol each) and K2CO3 (138 mg, 1.0 mmol)
were added. The reaction mixture was stirred at 130 °C
for 5 h and conversion, regio and diasteroselectivity were
determined by GC and GC-MS analysis.
Procedure for competitive Heck reaction coupling of trans-
stilbene, 1-nitro-4-styrylbenzene and 1-(4-methoxystyryl)
benzene with bromobenzene
An oven-dried resealable Schlenk flask was charged
with two olefins (0.25 mmol + 0.25 mmol), Pd(OAc)2
(2.2 mg, 0.01 mmol), and P(o-tol)3 (6.1 mg, 0.02 mmol),
evacuated and black-filled with argon. Then, DMF (3 mL),
bromobenzene (0.5 mmol, 78 mg) and K2CO3 (138 mg,
1.0 mmol) were added. The reaction mixture was stirred at
130 °C for 5 h and conversion, regio- and diasteroselectivity
were determined by GC and GC-MS analysis.
Procedure for competitive Heck reaction coupling of trans-
stilbene and 1,1-diphenylethene with bromoanisole
An oven-dried resealable Schlenk flask was charged
with trans-stilbene (0.25 mmol, 45 mg), 1,1-diphenylethene
(0.25 mmol, 45 mg), Pd(OAc)2 (2.2 mg, 0.01 mmol), and

Vol. 22, No. 7, 2011
Limberger et al.
1391
Table 1. Pd-catalyzed Heck reaction of trans-stilbene derivatives with aryl bromidesa
Ph
Ar
Ar
Ph
Pd(OAc)2, P(o-tol)3
Ar
Ar'Br
+
+
K2CO3, DMF, 130 °C
Ar'
Ar'
Ph
entry
1
Ar
Ar’
Ph
Yield / %b
Ph
-
-
96 [89]
2
3
4
Ph
4-MeO-C6H4
79 (E:Z = 83:17)
4-MeO-C6H4
Ph
47
48 (E:Z = 14:86)
4-NO2-C6H4
Ph
75 [68]
21 (E:Z < 1:99)
aReaction conditions for GC analysis: stilbene (0.5 mmol), aryl bromide (0.75 mmol), K2CO3 (1 mmol), Pd(OAc)2 (2 mol %), P(o-tol)3 (4 mol %), DMF
o
(3 mL), 130 C, 48 h; reaction conditions for isolated yields: stilbene (1.5 mmol), aryl bromide (2.25 mmol), K2CO3 (3 mmol), Pd(OAc)2 (2 mol %),
P(o-tol)3 (4 mol %), DMF (9 mL), 130 oC, 48 h; byields refer to GC yields (with undecane as an internal standard) and values in square brackets refer to
yields of isolated products.
complex before alkene dissociation. Regardless of the
isomerization process, an approximately equal mixture of
E and Z isomers is expected if the isomerization reaction
is under thermodynamic control.
methoxy group had no influence on the olefin insertion step.
However, an effect on regioselectivity was observed when
trans-stilbene containing a strong electron-withdrawing
group was use (Table 1, entry 4). In this case, the phenyl
group from the Ph-Pd complex migrates preferentially to
the same carbon of the double bond to which the phenyl
is bonded. This result can be explained by the fact that the
major pathway for syn insertion is the selective migration
of the aryl moiety onto the more charge-deficient carbon
of the alkene, which is the β-carbon in the case of an aryl
with a nitro group in the para position.
In order to evaluate the reactivity of different aryl
halides, competition experiments were carried out
(Table 2). A mixture of aryl bromide and bromobenzene
were subjected to the Heck reaction protocol with trans-
stilbene and activity was evaluated at low conversions
(< 20%), to compare initial rates. Similar reactivity was
Next, the coupling of bromobenzene with substituted
trans-stilbenes was examined (Table 1, entries 3 and 4).
When an aryl group different than phenyl is used for
coupling with trans-stilbene (Ar1 ≠ Ph in Scheme 1),
two syn insertion approaches are possible, and, thus, two
regioisomers can be formed. No significant effects on
regioselectivity in terms of steric effects are expected for
substituents at the para position. Therefore, assuming
the same mechanism for both alkenes, the regioisomer
distribution basically depends on the electronic effects of
the group present on the trans-stilbene derivative. In the case
of 4-methoxystilbene, the two regioisomers are obtained at
almost the same proportion (Table 1, entry 3), indicating the

1392
Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
Scheme 1. Simplified catalytic cycle for the Heck reaction with trans-stilbene derivatives (tri-o-tolylphosphine ligands are omitted for clarity).
Table 2. Pd-catalyzed competitive Heck reaction of trans-stilbene with different aryl bromidesa
R2
R1
Ph
R1
R1
Ph
Ph
Pd(OAc)2, P(o-tol)3
R2
R2
+
+
+
+
Ph
K2CO3, DMF, 130 °C
Br
3
Br
1
2
R2
entry
R1
Ph
Ph
Ph
Ph
H
R2
Selectivity 1:2
49:51
Selectivity 2:3
96:4
1
2
3
4
5
OMe
COMe
CN
59:41
54:46
69:31
16:84
CF3
58:42
39:61
COMe
34:66
100:0
aAverage of 2 runs; reaction conditions: stilbene (0.5 mmol), bromobenzene (0.25 mmol), aryl bromide (0.25 mmol), K2CO3 (1 mmol), Pd(OAc)2 (2 mol %),
P(o-tol)3 (4 mol %), DMF (3 mL), 130 oC, 5 h, all reactions were performed up to 20% conversion.
observed for coupling trans-stilbene with 4-bromoanisol
or bromobenzene (Table 2, entry 1). However, the coupling
product obtained from the reaction with bromobenezene
is preferentially formed over those obtained from aryl
bromides containing an electron-withdrawing group
(Table 2, entries 2-4). It is worthwhile to mention that when
aryl bromides containing an electron-withdrawing group
was use, a significant amount of homocoupling product
is formed. Oxidative addition has been also postulated as
the first step in the catalytic cycle for the homocoupling
of aryl halides.23 Therefore, as expected for the aryl
bromides containing an electron-withdrawing group, the
oxidative addition is faster but homocoupling of aryl
bromide is the major reaction (Table 2, entries 3 and 4).
For purpose of comparison, the competitive reaction
of 4-bromoacethophenone with bromobenzene using
styrene as olefin partner instead of stilbene was carried
out (Table 2, entries 5 and 6). In the presence of styrene,
no homocoupling product was observed, and the Heck
coupling product obtained from the activated aryl halide
was the major product (Table 2, entry 5). These results
clearly indicate that oxidative addition is not the rate

Vol. 22, No. 7, 2011
Limberger et al.
1393
limiting step, which is more likely due to steric effects
from the diarylalkene in the coordination and/or migratory
insertion steps. In order to confirm this conclusion, the Heck
reaction of bromobenzene with iodobenzene was compared.
The reaction of the aryl halides with stilbene was carried
out separately and analyzed at the same reaction time (6 h).
Indeed, bromobenzene gave a two times faster reaction rate
for the formation of the Heck coupling product. Again, we
were able to confirm the tendency of activated halides to
form homocoupling products. For the bromobenezene, the
Heck coupling:homocoupling ratio observed was 93:7 and
for the iodobenzene was 43:57.
The effect of a substituent group on the stilbene
derivative was also evaluated (Scheme 2). A mixture of
trans-1-aryl-2-phenylethene and trans-stilbene was each
subjected to the Heck reaction protocol with bromobenzene,
and the activity was evaluated at low conversions (< 20%),
to compare initial rates. Similar reactivity was observed
for coupling bromobenzene with trans-4-metoxystilbene
or trans-stilbene (51:49). However, the coupling product
obtained from the reaction, trans-1-aryl-2-phenylethene
containing a nitro group, is slightly preferred over those
obtained from trans-stilbene (62:38).
In addition, we compared 1,1- and 1,2-diphenylethene
(Scheme 3). A mixture of 1,1-diphenylethene and trans-
stilbene was each subjected to the Heck reaction protocol
with 4-bromoanisol. No significant difference was observed
and similar reactivity was obtained for the two olefins, as
indicated by the fact that 1,2-diphenyl-1-arylethene and
1,1-diphenyl-2-arylethene were obtained at a ratio of 45:55.
We have recently described a sequential and selective
Pd-catalyzed double-Heck arylation of ethylene that
results in non-symmetrical nitro-stilbene analogues of
trans-resveratrol at excellent yields.24 A catalytic system
consisting of Pd(OAc)2 and P(o-tol)3 became possible
to carry out two consecutive Heck arylations without
losing activity from the first to the second Heck reaction.
This approach is also used in the present work to obtain
a trisubstituted olefin from styrene in a one pot protocol
(Scheme 4).Arylation of styrene was carried out at 80 oC to
R
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Pd(OAc)2, P(o-tol)3
Ph
+
+
+
+
K2CO3, DMF, 130 oC
Ph
Br
Ph
R
R
R = OMe
R = NO2
2%
49%
38%
49%
11%
51%
Scheme 2. Pd-catalyzed competitive Heck reaction of bromobenzene with different trans-stilbene derivatives.
Ph
Ph
Ph
Ph
OMe
Ph
Ph
Ph
Pd(OAc)2, P(o-tol)3
+
+
+
K2CO3, DMF, 130 °C
Ph
MeO
MeO
Br
45%
E/Z = 82:18
55%
Scheme 3. Pd-catalyzed competitive Heck reaction of 1,1-diphenylethene and stilbene with p-bromoanisole.
MeO
PhBr, K2CO3, DMF
Ph
4-MeOC6H4Br
Pd(OAc)2, P(o-tol)3
Ph
Ph
80 °C, overnight
K2CO3, 130 °C, 48 h
Ph
Ph
not isolated
95%
E/Z = 94:6
73%
E/Z = 74:26
Scheme 4. Pd-catalyzed Heck double-arylation of styrene.

1394
Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
give the stilbene.After the first Heck arylation, no isolation
or additional catalyst loading is required for the second
Heck arylation reaction. For the second Heck reaction, the
only difference was the addition of 4-bromoanisol and base
and the raising of the temperature to 130 oC, resulting in the
trisubstituted olefin at 73% yield. Because the stilbene was
obtained at an E:Z ratio of 94:6, regioselectivity obtained
for this trisubstituted olefin (74:26) was lower than that
obtained using pure trans-stilbene (83:17, Table 1, entry 2).
The main by-product obtained was a triphenylethene
generated from the coupling of stilbene with unreacted
bromobenzene.
References
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Conclusions
In summary, the Heck arylation of diarylethylenes
giving triarylolefins with good to excellent yields wiht a
simple Pd(OAc)2/P(o-tol)3 catalytic system is described.
The electron withdrawing group substituent in the para
position of stilbene affect the regioselectivity of the
reaction is also described. In this case, the phenyl group
from the Ph-Pd complex migrates preferentially to the same
carbon of the double bond to which the phenyl is bonded.
Through competitive Heck reactions, it was possible to
determine that (i) oxidative addition is not involved in the
rate-determining step; and (ii) electron-withdrawing groups
in the olefin slightly increase the reaction rate. Finally,
a one-pot Heck double arylation of styrene, resulting in
1,2-diphenyl-1-(4-methoxyphenyl)ethene at 73% yield is
described.
11. Nejjar, A.; Pinel, C.; Djakovitch, L.; Adv. Synth. Catal. 2003,
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Supplementary Information
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Acknowledgements
We thank the Conselho Nacional de Desenvolvimento
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Grande do Sul (PRONEX-FAPERGS) and the Instituto
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Catalise) for partial financial support. We also thank the
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Submitted: December 21, 2010
Published online: March 29, 2011

J. Braz. Chem. Soc., Vol. 22, No. 7, S1-S12, 2011.
Printed in Brazil - ©2011 Sociedade Brasileira de Química
0103 - 5053 $6.00+0.00
Supplementary Information
SI
Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
Jones Limberger, Silvia Poersch and Adriano L. Monteiro*
Laboratory of Molecular Catalysis, Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS),
Av. Bento Gonçalves, 9500, CP 15003, 91501-970 Porto Alegre-RS, Brazil
3.75 (s, 3H), 6.68 (d, 2H, J 8.80 Hz), 6.92 (s, 1H), 6.96
Ph
(d, 2H, J 8.88 Hz), 7.38-7.20 (m, 10H). GC-MS m/z (%):
287 (22), 286 (100, M+), 271 (7), 253 (7), 239 (8), 228
(9), 215 (6), 178 (8), 165 (38).
Ph
Ph
1,1,2-triphenylethene: white solid, mp 70-73 ºC
1
(72-73 °C)7. H NMR1,2 (300 MHz, CDCl3) d ppm 6.96
Ph
(s, 1H), 7.06-7.00 (m, 2H), 7.16-7.07 (m, 3H), 7.24-7.17
(m, 2H), 7.39-7.26 (m, 8H) 13C NMR1,2 (75 MHz, CDCl3)
d ppm 126.7, 127.4, 127.5, 127.6, 127.9, 128.1, 128.2,
128.6, 129.5, 130.4, 137.3, 140.3, 142.5, 143.4. GC-MS
m/z (%): 257 (21), 256 (100, M+), 241 (21), 204 (9), 178
(53), 165 (21), 152 (13).
Ph
OMe
1-((Z)-1-(4-methoxyphenyl)-2-phenylvinyl)benzene:
GC-MS m/z (%): 287 (24), 286 (100, M+), 253 (11), 228
(10), 215 (9), 178 (17), 165 (25), 126 (11), 119 (16).
OMe
Ph
Ph
Ph
Ph
NO2
1-methoxy-4-((E)-1,2-diphenylvinyl)benzene: oil.
1H NMR2-4 (300 MHz, CDCl3) d ppm 3.82 (s, 3H), 6.85 (d,
2H, J 8.93 Hz), 6.90 (s, 1H), 7.03-6.98 (m, 2H), 7.15-7.07
(m, 3H), 7.23-7.18 (m, 2H), 7.26 (d, 2H, J 8.92 Hz), 7.35-
7.30 (m, 1H). 13C-NMR4 (75 MHz, CDCl3) d ppm 55.1,
113.5, 126.3, 126.4, 127.3, 127.8, 128.5, 128.7, 129.3,
130.3, 135.9, 137.5, 140.4, 142.0, 159.1. GC-MS m/z (%):
287 (24), 286 (100, M+), 255 (12), 228 (11), 215 (9), 178
(16), 165 (26), 126 (12), 120 (21).
1-(2-(4-nitrophenyl)-1-phenylvinyl)benzene: yellow
solid , mp 148-151 °C (148-150 °C)5. 1H NMR1 (300 MHz,
CDCl3) d ppm 7.00 (s, 1H), 7.14 (d, 2H, J 8.97 Hz), 7.21-
7.16 (m, 2H), 7.49-7.30 (m, 8H), 7.98 (d, 2H, J 8.91 Hz).
13C NMR1,5 (75 MHz, CDCl3) d ppm 123.2, 125.6, 127.8,
128.2, 128.3, 128.4, 128.9, 129.9, 130.1, 139.2, 142.3,
144.2, 145.8, 146.9. GC-MS m/z (%): 302 (22), 301 (100,
M+), 254 (30), 253 (38), 239 (27), 178 (18), 165 (27), 126
(16), 113 (11).
Ph
Ph
Ph
Ph
OMe
NO2
1-methoxy-4-(2,2-diphenylvinyl)benzene: white
solid obtained with with 80% of purity (20% of
4-methoxystilbene). 1H NMR5,6 (300 MHz, CDCl3) d ppm
1-((Z)-2-(4-nitrophenyl)-2-phenylvinyl)benzene: yellow
crystals , mp 160-163 °C. H NMR (300 MHz, CDCl3)
1
d ppm 7.08-7.01 (m, 2H), 7.10 (s, 1H), 7.22-7.17 (m, 3H),
*e-mail: adriano.monteiro@ufrgs.br

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J. Braz. Chem. Soc.
7.32-7.26 (m, 2H), 7.38-7.34 (m, 2H), 7.40 (dd, 2H, J 6.94,
1.86 Hz), 8.19 (dd, 2H, J 6.88, 1.88 Hz). 13C NMR (75
MHz, CDCl3) d ppm 123.7, 127.4, 127.5, 128.0, 128.2,
128.4, 129.4, 130.1, 131.4, 136.3, 140.4, 142.0, 146.9,
147.6. GC-MS (IE, 70 eV) m/z (%): 302 (24), 301 (100,
M+), 253 (36), 239 (27), 215 (12), 179 (26), 165 (23), 126
(20), 113 (14).
CF3
Ph
Ph
1-(trifluoromethyl)-4-((E)-1,2-diphenylvinyl)benzene:
GC-MS (IE, 70 eV) m/z (%):2,7 325 (22), 324 (100, M+),
309 (17), 283 (21), 253 (21), 246 (16), 178 (35), 165 (17),
126 (16).
COMe
References
Ph
Ph
1. Xiao, Q.; Ma, J.; Yang, Y.; Zhang, Y.; Wang, J. B.; Org. Lett.
2009, 11, 4732.
1-(4-((E)-1,2-diphenylvinyl)phenyl)ethanone: GC-MS
(IE, 70 eV) m/z (%):3 299 (22), 298 (100, M+), 283 (60),
255 (27), 253 (29), 239 (28), 207 (20), 178 (15), 152 (9),
120 (14).
2. Nunes, C. M.; Steffens, D.; Monteiro, A. L.; Synlett 2007, 103.
3. Cacchi, S.; Fabrizi, G.; Goggiamani,A.; Persiani, D.; Org. Lett.
2008, 10, 1597.
4. Wu, M.-J.; Wei, L.-M.; Lin, C.-F.; Leou, S.-P.; Wei, L.-L.;
Tetrahedron 2001, 57, 7844.
CN
5. Rodriguez-Escrich, S.; Reddy, K. S.; Jimeno, C.; Colet, G.;
Rodriguez-Escrich, C.; Sola, L.;Vidal-Ferran,A.; Pericas, M.A.;
J. Org. Chem. 2008, 73, 5340.
Ph
Ph
6. Huang, L. F.; Chen, C. W.; Luh, T.Y.; Org. Lett. 2007, 9, 3663.
7. Terao, Y.; Nomoto, M.; Satoh, T.; Miura, M.; Nomura, M.;
J. Org. Chem. 2004, 69, 6942.
4-((E)-1,2-diphenylvinyl)benzonitrile: GC-MS (IE,
70 eV) m/z (%):3 282 (23), 281 (100, M+), 266 (21), 253
(11), 203 (17), 179 (28), 165 (14), 126 (13).
Figure S1. Mass spectrum of 1,1,2-triphenylethene.

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Figure S2. 1H NMR spectrum of 1,1,2-triphenylethene.
Figure S3. 13C (APT) NMR spectrum of 1,1,2-triphenylethene.

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Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
Figure S4. Mass spectrum of 1-methoxy-4-((E)-1,2-diphenylvinyl)benzene.
Figure S5. Mass spectrum of 1-((Z)-1-(4-methoxyphenyl)-2-phenylvinyl)benzene.

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Figure S6. Mass spectrum of 1-methoxy-4-(2,2-diphenylvinyl)benzene.
Figure S7. 1H NMR spectrum of 1-methoxy-4-((E)-1,2-diphenylvinyl)benzene.

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Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
Figure S8. 13C (APT) NMR spectrum of 1-methoxy-4-((E)-1,2-diphenylvinyl)benzene.
Figure S9. 1H NMR spectrum of 1-methoxy-4-(2,2-diphenylvinyl)benzene with 80% of purity (20% of 4-methoxystilbene).

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Figure S10. A: GC chromatogram with analysis of Heck reaction between 4-metoxi-stilbene and bromobenzene; B: GC chromatogram of the same sample
after addition of 1-methoxy-4-((E)-1,2-diphenylvinyl)benzene (97%).

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Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
Figure S11. Mass spectrum of 1-(2-(4-nitrophenyl)-1-phenylvinyl)benzene.
Figure S12. Mass spectrum of 1-((Z)-2-(4-nitrophenyl)-2-phenylvinyl)benzene.

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Figure S13. 1H NMR spectrum of 1-(2-(4-nitrophenyl)-1-phenylvinyl)benzene.
Figure S14. 13C (APT) NMR spectrum of 1-(2-(4-nitrophenyl)-1-phenylvinyl)benzene.

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Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
Figure S15. 1H NMR spectrum of 1-((Z)-2-(4-nitrophenyl)-2-phenylvinyl)benzene.
Figure S16. 13C (APT) NMR spectrum of 1-((Z)-2-(4-nitrophenyl)-2-phenylvinyl)benzene.

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Figure S17. A: GC chromatogram with analysis of Heck reaction between 4-nitro-stilbene and bromobenzene; B: GC analysis of the same sample after
addition of 1-((Z)-2-(4-nitrophenyl)-2-phenylvinyl)benzene.
Figure S18. Mass spectrum of 1-(4-((E)-1,2-diphenylvinyl)phenyl)ethanone.

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Pd-Catalyzed Heck Reactions of Aryl Bromides with 1,2-Diarylethenes
J. Braz. Chem. Soc.
Figure S19. Mass spectrum of 4-((E)-1,2-diphenylvinyl)benzonitrile.
Figure S20. Mass spectrum of 1-(trifluoromethyl)-4-((E)-1,2-diphenylvinyl)benzene.