Palladium Nanoparticles Anchored on Magnesium Organosilicate: An Effective and Selective Catalyst for the Heck Reaction

Article abstract of DOI:10.1055/s-0040-1705938

A new and effective palladium catalyst supported on a magnesium organosilicate for application in the Heck reaction is presented. A group of compounds comprising 22 examples were synthesized in moderate to high yields (up to 99%) within a short time. The palladium supported on magnesium organosilicate catalyst was characterized as an amorphous solid by SEM, containing around 33% of palladium inside the solid, and even with this low quantity of palladium, the catalyst was very efficient in the Heck reaction. Besides, based on the Scherrer equation, the crystallite size of the synthesized palladium nanoparticles was ultrasmall (around 1.3 nm). This strategy is a simple and efficient route for the formation of C-C bonds via the Heck cross-coupling reaction.

Full text of DOI:10.1055/s-0040-1705938

SYNTHESIS
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart
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020, 52, A–F
paper
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en
Synthesis
B. F. dos Santos et al.
Paper
Palladium Nanoparticles Anchored on Magnesium Organosilicate:
An Effective and Selective Catalyst for the Heck Reaction
Beatriz F. dos Santosa
Beatriz A. L. da Silvaa
X
R2
0
0
0
0
-
0
0
0
3
-1
6
8
5
-
6
3
1
6
R2
LACOB-Pd1 (10% or 15% w/w)
NaOAc, NMP, N , 9 h
Aline R. de Oliveirab
Maria H. Sarragiottob
+
R3
R3
2
R1
R1
Andrelson W. Rinaldib
Nelson Luís C. Domingues*a
X = Cl, Br, I, SO
2
Na
Wide reaction scope
22 examples
30–99% yield
Heck reaction
R1 = H, 4-OMe, 4-Me, 4-NO
0
0
0
0
-
0
0
0
3
-
3
9
5
4
-
0
4
7
X
2
, 4-COMe, 4-CO
2 2
Me, 4-F, 2-NO , 4-CHO
R2 = Ph, CO
R3 = H, Me, Ph
2
Et, CN
a
Organic Catalysis and Biocatalysis Laboratory – LACOB,
Federal University of Grande Dourados – UFGD, Dourados/MS,
Brazil
nelsondomingues@ufgd.edu.br
State University of Maringá – UEM, Maringá/PR, Brazil
b
Corresponding Author
Received: 25.06.2020
Accepted after revision: 16.09.2020
Published online: 22.10.2020
S
Me
Cl
DOI: 10.1055/s-0040-1705938; Art ID: ss-2020-m0350-op
NMe
2
Abstract A new and effective palladium catalyst supported on a
magnesium organosilicate for application in the Heck reaction is pre-
sented. A group of compounds comprising 22 examples were synthe-
sized in moderate to high yields (up to 99%) within a short time. The
palladium supported on magnesium organosilicate catalyst was charac-
terized as an amorphous solid by SEM, containing around 33% of palla-
dium inside the solid, and even with this low quantity of palladium, the
catalyst was very efficient in the Heck reaction. Besides, based on the
Scherrer equation, the crystallite size of the synthesized palladium
nanoparticles was ultrasmall (around 1.3 nm). This strategy is a simple
and efficient route for the formation of C–C bonds via the Heck cross-
coupling reaction.
Chlorprothixene (II)
antipsychotic
O
NMe2
Tamoxifen (I)
anticancer
OH
OH
Cl
O
HO
HO
OH
OH
OH
Resveratrol (III)
bioactive natural product
ε-Viniferin (IV)
bioactive natural product
Figure 1 Bioactive molecules containing styrene nucleus
Key words cross-coupling, Heck reaction, palladium, heterogeneous
catalyst, organosilicates
Over the past decades, solid supports such as alumina,9
11
The palladium-catalyzed arylation of olefins, known as
silica,10 mesoporous materials,
active carbon and
12
13
14
Heck reaction, is a selective method for the formation of a
graphene, polymers, and magnetic nanoparticles have
been employed in material sciences and chemistry to ob-
tain heterogeneous catalysts. Because of the range of solid
supports presented, various methodologies have been de-
scribed in the literature for the heterogenization of homo-
geneous catalysts. The classical Lindlar catalyst is an exam-
ple of a heterogeneous catalyst that consists of palladium
deposited on calcium carbonate and is widely used in hy-
1
new C–C bond. The Heck reaction has been intensively
studied and used for the synthesis of pharmaceutical prod-
2
ucts (Figure 1, I, II). Besides, some styrene derivatives are
3
also ubiquitous molecules in nature (III, IV). Recent devel-
opments have shown that many challenges in organic syn-
thesis can be overcome through the Heck reaction, such as
asymmetric synthesis, reactions with Csp3 organic ha-
4
5
6
15
lides, and even highly stereoselective reactions. However,
in the majority of cases, Heck cross-coupling reactions are
drogenation industrial processes. In this sense, Xu and co-
workers performed the Heck reaction using Pd@PANI as a
7
16
carried out by using high-cost palladium catalysts. Nowa-
heterogeneous catalyst.
days, researchers are putting efforts into the development
of environmentally friendly heterogeneous palladium cata-
lysts with excellent recyclability and negligible leaching,
thereby reducing costs (catalysts and the process) and envi-
ronmental pollution.8
The introduction of new and stable heterogeneous cata-
lytic supports is a popular research topic in the science of
catalysis. In this category of supports, phyllosilicates have
become important and efficient tools in catalytic organic
synthesis, the most important being the synthetic talc
1
7
(
magnesium organosilicates). It is used as a fine powder in
©
2020. Thieme. All rights reserved. Synthesis 2020, 52, A–F
Georg Thieme Verlag KG, Rüdigerstraße 14, 70469 Stuttgart, Germany

B
Synthesis
B. F. dos Santos et al.
Paper
the paper, rubber, cosmetic, and pharmaceutical industries,
because of its inertness, whiteness, low thermal and elec-
trical conductivity, and adsorption capacity of organic sub-
stances. Although magnesium organosilicates with organ-
ic functionalities have been reported in the literature, there
are limited studies on the applications of this material in
organic reactions. Thus, as part of our investigation into ef-
ficient synthetic methodologies, we wish to introduce a
practical and low-cost heterogeneous catalytic support in
organic synthesis affording a wide spectrum of use.
Because of their physicochemical properties, magne-
sium organosilicates could be a promising support for the
synthesis of heterogeneous catalysts. Herein, we introduced
synthetic talc as a novel, eco-friendly, and inexpensive het-
erogeneous catalytic support for the LACOB-Pd1 catalyst
synthesis and its application in the Heck reaction. The
LACOB-Pd1 catalyst is bench-stable and the reaction was
performed with a broad substrate scope in a shorter time
than in previous reports.19
Table 1 Optimization of the Reaction Conditionsa
I
1
8
LACOB-Pd1
+
base, solvent, time
1
a
2a
3a
Entry Base
LACOB-Pd1 Solvent
Temp
(°C)
Time
(h)
Yieldb
(%)
(
% w/w)
1
2
3
4
5
6
K
2
CO
3
5
5
EtOH
EtOH
EtOH
EtOH
NMP
NMP
NMP
80
80
4
4
4
9
9
9
9
20
0
3
Et N
K
K
2
2
CO
CO
3
3
20
5
80
14
45
83c
80
NaOAc
NaOAc
NaOAc
5
110
110
110
–
0c
>99c
7
10
a
Reaction conditions: 1a (1 equiv), 2a (2 equiv), base (1 equiv), LACOB-
Pd1, solvent.
b
Yield of isolated product.
Reaction performed with styrene (1.1 mmol) and base (1.5 mmol) under
We initially prepared the LACOB-Pd1 catalyst as de-
scribed in the Experimental Section (see Supporting Infor-
mation, SI). Then, the catalytic activity was assessed in the
arylation reaction of various olefins by aryl halides. Initially,
as presented in Table 1, we selected the reaction between
iodobenzene (1a) and styrene (2a) for optimizing the reac-
tion conditions. First, the Heck reaction was performed us-
ing two bases (K CO and Et N) in EtOH as the solvent (en-
c
an N atmosphere.
2
(200), which are characteristic of the face-centered cubic
2
1
(fcc) structure of Pd nanoparticles. These data indicate
0
2+ 22
that the Pd element exists in the form of Pd and not Pd .
On the basis of the half-width of the (111) reflection, the
average crystallite size (1.3 nm) of the synthesized palladi-
um nanoparticles was estimated through the Scherrer
2
3
3
tries 1 and 2). The Heck product 3a was only observed
when an inorganic base was employed (entry 1). We initial-
ly selected EtOH as the solvent due to its green properties.
Thus, we increased the catalytic loading to 20% w/w, but
this did not improve the yield (entry 3). To improve the re-
sults, we performed the reaction for 9 h and this produced a
small increase in the yield (entry 4). On the basis of previ-
ous studies, we changed the base to NaOAc, the solvent to
NMP, and the temperature to 110 °C and, gratifyingly, we
obtained the Heck product in 83% yield (entry 5). The sol-
vent is important in the Heck reaction and usually dipolar
23
equation. The morphology of the LACOB-Pd1 catalyst was
investigated by SEM analysis (Figure 2B) and showed that
most of the prepared nanoparticles were formed uniformly.
0
aprotic solvents are employed because these accelerate Pd
formation.
2
0
Following this satisfactory result, we assessed the effi-
ciency of the LACOB-Pd1 catalyst by conducting a blank re-
action (without catalyst), but no product was observed (Ta-
ble 1, entry 6). Finally, we doubled the catalytic loading (en-
try 7) and obtained the Heck product quantitatively. It
should be noted that the LACOB-Pd1 catalyst could be di-
rectly used in the Heck reaction and no previous treatment
was needed to activate the catalyst.
The characteristics of the synthesized catalyst were de-
termined by X-ray diffraction (XRD), scanning electron mi-
croscopy (SEM), and energy-dispersive spectroscopy (EDS)
analyses (Figure 2). As shown in Figure 2A, two new reflec-
tions appear at 2θ = 40.32° and 46.44° for the LACOB-Pd1
catalyst, corresponding to the reflection planes (111) and
Figure 2 LACOB-Pd1 catalyst analysis by XRD (A), SEM (B), and EDS (C)
©
2020. Thieme. All rights reserved. Synthesis 2020, 52, A–F

C
Synthesis
B. F. dos Santos et al.
Paper
EDS of the catalyst is shown in Figure 2C. It clearly indicates
the presence of Pd, along with other elements including ox-
ygen, nitrogen, and magnesium.
Having established the optimized reaction conditions,
we performed the reaction with different haloarenes and
olefins (Table 2). Initially, a catalytic loading of 10% w/w
was established for all reactions; however, for some entries,
Table 2 LACOB-Pd1-Catalyzed Heck Cross-Coupling of Aryl Halides 1
with Olefins 2
a
X
2
R2
R
LACOB-Pd1 (10% w/w)
+
R3
R3
NaOAc (1.5 equiv)
2
1
R1
R
NMP, 110 °C, N , 9 h
1
2
3
1
5% w/w was used to maximize the yields. As presented in
Entry
R1
X
R2, R3
3: Yield (%)
b
Table 2, Heck cross-coupling products were achieved in
yields up to 99%. As already described by Jagtap,20 the less
crowded structure is generally preferred in the Heck reac-
tion, and the trans product is usually favored. The coupling
reactions of the electron-deficient and electron-rich
haloarenes with styrene provided the Heck products (en-
tries 1, 4, 5, and 6) in excellent yields in the presence of
electron-donating substituents (3b and 3c). Moderate to
good yields were obtained when weakly electron-with-
drawing groups were employed (3e–g; entries 7–9). Inter-
estingly, we noticed that -methyl styrene and 1,1-di-
phenylethylene were unreactive, and, thus, no Heck prod-
uct was obtained using these reagents (entries 2 and 3),
probably due to increased steric hindrance of the starting
materials. The application scope for olefins was also tested.
To evaluate the efficacy of this method, the Heck reaction
was investigated by using ethyl acrylate instead of styrene
under the same reaction conditions (entries 10–16). Reac-
tions of ethyl acrylate with electron-rich iodobenzenes af-
forded the corresponding products 3i and 3j in high yields
1
2
3
4
5
6
7
8
9
H
I
Ph, H
Ph, Me
Ph, Ph
Ph, H
Ph, H
Ph, H
Ph, H
Ph, H
Ph, H
3a: >99
trace
H
H
I
I
trace
4-OMe
4-Me
I
3b: >99c
3c: 88c
3d: 30
I
4-NO
2
I
4-COMe
I
3e: 65
3f: 50c
4-CO
4-F
H
2
Me
I
I
3g: 87c
3h: 82
3i: 99c
3j: 98c
1
0
1
I
CO
CO
CO
2
2
2
Et, H
Et, H
Et, H
1
4-OMe
4-Me
I
12
13
I
2-NO2
4-COMe
I
CO Et, H
2
3k: 98
3l: 81c
14
15
16
17
I
CO
CO
CO
2
2
2
Et, H
Et, H
Et, H
4-CO
2
Me
I
3m: 88c
3n: 68c
3o: 55c
4-F
I
4-CHO
4-CHO
4-CHO
H
Br
Br
Cl
SO
I
Ph, H
CO Et, H
(
entries 11 and 12). 1-Iodo-2-nitrobenzene was found to be
a suitable substrate for this reaction, giving product 3k in
8% yield (entry 13). In the presence of iodobenzenes bear-
18
2
3p: 63c
9
no reactionc,d
1
2
2
9
0
1
2
Ph, H
Ph, H
CN, H
ing electron-deficient substituents (entries 14–16), moder-
ate to good yields were obtained for compounds 3l–n. Aryl
bromides were also employed, but only gave the Heck prod-
ucts in moderate yields (3o and 3p; entries 17 and 18). The
reactions of styrene with aryl chloride (entry 19) and ben-
zenesulfinic acid sodium salt (entry 20) were also tested,
but the Heck cross-coupling product was not obtained in
these reactions, even after a reaction time of 24 hours.
Other unsaturated starting materials (e.g., acrylonitrile
and cyclohex-2-en-1-one) were also tested in the Heck re-
action (Table 2, entries 21 and 22); however, a product only
emerged when acrylonitrile was used (3q). The moderate
yield is explained by the conjugation of the double bond
with the nitrile group, making nitrogen a strong ligand for
palladium.
no reactionc
2
Na
H
3q: 57
2
H
I
cyclohexenone
trace
a
Reaction conditions: 1 (1 equiv), 2 (1.1 equiv), NaOAc (1.5 equiv), LACOB-
Pd1 (0.1 equiv, 10% w/w), NMP, 110 °C, 9 h, under N
Yield of isolated product.
Reaction performed with LACOB-Pd1 (15% w/w).
Reaction time: 24 h.
2
.
b
c
d
Due to the high cost of palladium salts, we sought to re-
cycle and reuse the catalyst in the Heck reaction. Since the
LACOB-Pd1 catalyst is insoluble in NMP, we reacted iodo-
benzene with styrene under the standard conditions
(Scheme 1). At the end of the first reaction, the catalyst was
recovered by simple centrifugation, then successively
rinsed with ethyl acetate, distilled water (to remove excess
base), and acetone, and finally dried at room temperature.
Another reaction was then performed again under the pre-
vious conditions. Unfortunately, the catalyst could only be
recovered once, since the yield decreased by 33% in the sec-
ond cycle.
It should be noted that all alkene products were stereo-
selectively produced in the E-form. We did not observe any
cis-isomer, indicating a very high selectivity degree for the
catalyst (see SI). To prove this statement, the reaction be-
tween iodobenzene and styrene was performed under the
1
same conditions as in Table 2, entry 1, and analyzed by H
NMR without further purification. The absence of the signal
at  = 6.60 proves that the cis-isomer is not formed in the
reaction (Figure 3).
©
2020. Thieme. All rights reserved. Synthesis 2020, 52, A–F

D
Synthesis
B. F. dos Santos et al.
Paper
This mixture formed a white suspension. Then, 0.5 M NaOH solution
was slowly added until the pH reached 10.5 under stirring at 25 °C.
The suspension obtained was aged for 1 week at 25 °C and the gel
formed was centrifuged, washed with distilled H O, and dried at 65
2
°
C. Then, in a flask, the magnesium organosilicate support (0.1 g) and
KOH (0.1 g, dissolved in distilled H O) were placed in ethanol (5 mL)
2
and the mixture was stirred for 10 min. Subsequently, salicylaldehyde
(
0.1 g, 94 L) was added and the mixture was stirred at 25 °C for 2 h.
NaBH was added until the solution became white and turbid. The re-
4
action was stirred overnight. After this period, the white solid was
centrifuged and washed with distilled H O to give the ligand. The
2
LACOB-Pd1 catalyst was prepared to treat all the resulting support
that was obtained with NaOH (0.1 g) in ethanol (5 mL) and the mix-
ture was stirred at 25 °C for 15 min. Then, Pd(OAc) (0.1 g) was added
2
and the mixture was stirred for 2 h. The black solid that formed was
centrifuged and washed with chloroform.
Figure 3 1H NMR spectrum of the crude reaction mixture when using
iodobenzene and styrene, showing the absence of the cis-isomer
Styrenes 3 by Heck Reaction; General Procedure
In a 5 mL flask were placed the palladium catalyst (10% or 15% w/w),
the alkene 2 (1.1 mmol), the haloarene 1 (1 mmol), and NaOAc (1.5
mmol). The mixture was magnetically stirred in NMP (4 mL) at 110 °C
I
LACOB-Pd1 (10% w/w)
+
in an oil bath for 9 h under a N atmosphere. The progress of the reac-
2
NaOAc (1.5 equiv)
tion was monitored by TLC (hexane/EtOAc, 90:10). After this time, the
solution was cooled to room temperature, diluted with EtOAc (20 mL),
2
NMP, 110 °C, N , 9 h
Initial use: >99%
1st reuse: 67%
and washed with H O (3 × 20 mL). The organic phase was separated,
2
dried over Na SO , and concentrated under vacuum. The obtained
products were purified by column chromatography (silica gel,
hexane/EtOAc, 90:10).
2
4
Scheme 1 Recyclability of the LACOB-Pd1 catalyst in the Heck cross-
coupling reaction
(
E)-1,2-Diphenylethene (3a)16
In conclusion, we introduced a new and selective palla-
dium catalyst anchored on synthetic talc. The LACOB-Pd1
catalyst is accessible, well defined, and stable in air and its
synthesis is very simple and practical. It was effectively ap-
plied in the Heck reaction using many haloarenes and ole-
fins, with moderate to excellent yields obtained. Regarding
its reusability, this was only possible for the first cycle, al-
though this does not depreciate the procedure. We are ac-
tively expanding the scope and use of this immobilized pal-
ladium catalyst to other cross-coupling and related reac-
tions.
White solid; yield: 178 mg (>99%); mp 130 °C.
IR (KBr): 3020, 1596, 1495, 1451, 963, 764, 690 cm–1
.
1
H NMR (300 MHz, CDCl ):  = 7.54–7.52 (m, 4 H), 7.39–7.35 (dd, J =
3
10.5, 4.8 Hz, 4 H), 7.28–7.26 (m, 2 H), 7.12 (s, 2 H).
1
3
C NMR (75 MHz, CDCl ):  = 137.55, 128.92, 127.87, 126.75.
3
MW: 180.25 g/mol, C14H12
.
(E)-1-Methoxy-4-styrylbenzene (3b)16
White solid; yield: 208 mg (>99%); mp 131 °C.
1
H NMR (300 MHz, CDCl ):  = 7.52–7.45 (m, 4 H), 7.38–7.33 (m, 2 H),
3
7
3
.27–7.22 (m, 1 H), 7.11–6.96 (q, J = 16.3 Hz, 2 H), 6.94–6.89 (m, 2 H),
.84 (s, 3 H).
The catalyst preparation was carried out using dry starting material
under pressure. All other reactions were carried out using chemical
reagents and solvents without any specific treatment. The reactions
were monitored by TLC (MACHEREY-NAGEL, SIL G/UV254) and were
visualized by fluorescence quenching with UV light at 254 nm. The
purification of the compounds was performed by column chromatog-
raphy using hexane/EtOAc. H and C NMR spectra were recorded of
samples in CDCl3 on a Bruker (300 MHz and 75 MHz, respectively)
spectrometer. The IR spectra were recorded on a Jasco FT/IR 4100
type A spectrophotometer.
13C NMR (75 MHz, CDCl ):  = 159.49, 137.84, 130.34, 128.86, 128.40,
127.92, 127.43, 126.81, 126.45, 114.33, 55.54.
MW: 210.27 g/mol, C15H14O.
3
(
E)-1-Methyl-4-styrylbenzene (3c)16
White solid; yield: 171 mg (88%); mp 112 °C.
H NMR (500 MHz, CDCl ):  = 7.52–7.51 (d, J = 7.4 Hz, 2 H), 7.43–7.42
1
13
1
3
(d, J = 8.1 Hz, 2 H), 7.37–7.34 (dd, J = 10.6, 4.7 Hz, 2 H), 7.27–7.24 (dd,
J = 8.7, 6.0 Hz, 1 H), 7.19–7.17 (d, J = 7.9 Hz, 2 H), 7.12–7.05 (m, 2 H),
2
.37 (s, 3 H).
LACOB-Pd1 Catalyst
13
C NMR (125 MHz, CDCl ):  = 137.55, 137.52, 134.58, 129.40,
3
The magnesium organosilicate support synthesis was performed fol-
128.65, 127.73, 127.40, 126.44, 126.40, 21.25.
1
7
lowing the reports published by Jasra et al. In a beaker, MgCl (8.36
2
MW: 194.28 g/mol, C15H14
.
g) was dissolved in methanol (200 mL) and the solution was stirred at
2
5 °C. In another beaker, APTES (9.8 g, 10.35 mL) was placed in meth-
(
E)-1-Nitro-4-styrylbenzene (3d)16
Yellow solid; yield: 68 mg (30%); mp 159 °C.
anol (50 mL). This solution was added dropwise to the MgCl solution.
2
©
2020. Thieme. All rights reserved. Synthesis 2020, 52, A–F

E
Synthesis
B. F. dos Santos et al.
Paper
1
1
H NMR (300 MHz, CDCl ):  = 8.25–8.21 (m, 2 H), 7.66–7.63 (m, 2 H),
H NMR (300 MHz, CDCl ):  = 7.68–7.63 (d, J = 16.0 Hz, 1 H), 7.41–
3
3
7
.58–7.55 (m, 2 H), 7.44–7.33 (m, 3 H), 7.32–7.26 (d, J = 16.3 Hz, 1 H),
7.38 (d, J = 8.2 Hz, 2 H), 7.17–7.15 (m, 2 H), 6.41–6.36 (d, J = 16.0 Hz, 1
H), 4.28–4.21 (q, J = 7.1 Hz, 2 H), 2.34 (s, 3 H), 1.34–1.30 (t, J = 7.2 Hz,
3 H).
7.18–7.12 (d, J = 16.3 Hz, 1 H).
1
3
C NMR (75 MHz, CDCl ):  = 146.96, 144.06, 136.38, 133.52, 129.12,
3
1
3
129.07, 129.01, 127.24, 127.08, 126.49, 124.37.
C NMR (75 MHz, CDCl ):  = 167.39, 144.81, 140.80, 131.93, 129.82,
3
1
28.27, 117.35, 60.60, 21.65, 14.56.
MW: 225.25 g/mol, C14H11NO2.
MW: 190.24 g/mol, C12H14O2.
(
E)-1-(4-Styrylphenyl)ethanone (3e)24
Ethyl (E)-3-(2-Nitrophenyl)acrylate (3k)27
Light yellow solid; yield: 144 mg (65%); mp 146 °C.
1
Yellow oil; yield: 217 mg (98%).
H NMR (300 MHz, CDCl ):  = 7.98–7.95 (m, 2 H), 7.61–7.54 (m, 4 H),
.42–7.37 (m, 2 H), 7.34–7.28 (m, 1 H), 7.27–7.11 (dd, J = 32.0, 15.9
3
1
7
H NMR (300 MHz, CDCl ):  = 8.08–7.97 (dd, J = 19.1, 12.0 Hz, 2 H),
3
Hz, 2 H), 2.62 (s, 3 H).
7.66–7.59 (m, 2 H), 7.56–7.47 (ddd, J = 13.9, 7.2, 4.0 Hz, 1 H), 6.36–
6.30 (d, J = 15.8 Hz, 1 H), 4.27–4.20 (q, J = 7.1 Hz, 2 H), 1.32–1.28 (t, J =
1
3
C NMR (75 MHz, CDCl ):  = 197.76, 142.21, 136.88, 136.12, 131.66,
3
7
.1 Hz, 3 H).
129.10, 129.02, 128.55, 127.63, 127.04, 126.71, 26.83.
1
3
C NMR (75 MHz, CDCl ):  = 165.99, 148.44, 140.02, 133.79, 130.68,
MW: 222.29 g/mol, C16H14O.
3
1
30.52, 129.31, 125.06, 123.43, 61.09, 14.42.
Methyl (E)-4-Styrylbenzoate (3f)25
MW: 221.21 g/mol, C11H11NO4.
Light yellow solid; yield: 119 mg (50%); mp 157 °C.
Ethyl (E)-3-(4-Acetylphenyl)acrylate (3l)28
1
H NMR (300 MHz, CDCl ):  = 8.05–8.02 (m, 2 H), 7.59–7.53 (t, J = 8.2
3
Light yellow solid; yield: 177 mg (81%); mp 38 °C.
Hz, 4 H), 7.41–7.36 (dd, J = 10.1, 4.6 Hz, 2 H), 7.33–7.27 (ddd, J = 11.7,
1
5.7, 2.8 Hz, 1 H), 7.26–7.10 (q, J = 16.3 Hz, 2 H), 3.93 (s, 3 H).
H NMR (300 MHz, CDCl ):  = 7.94–7.91 (m, 2 H), 7.67–7.62 (d, J =
3
1
3
16.1 Hz, 1 H), 7.57–7.55 (m, 2 H), 6.50–6.45 (d, J = 16.0 Hz, 1 H), 4.27–
C NMR (75 MHz, CDCl ):  = 167.11, 142.03, 136.95, 131.43, 130.24,
3
4
.20 (q, J = 7.1 Hz, 2 H), 2.57 (s, 3 H), 1.33–1.28 (t, J = 7.1 Hz, 3 H).
1
29.00, 128.46, 127.76, 127.46, 127.01, 126.54, 52.31.
1
3
C NMR (75 MHz, CDCl ):  = 197.47, 166.62, 143.15, 138.93, 138.10,
MW: 238.29 g/mol, C16H14O2.
3
1
29.01, 128.28, 120.96, 60.92, 26.84, 14.46.
E)-1-Fluoro-4-styrylbenzene (3g)16
MW: 218.25 g/mol, C13H14O3.
(
White solid; yield: 172 mg (87%).
Methyl (E)-4-(3-Ethoxy-3-oxoprop-1-enyl)benzoate (3m)29
1
H NMR (300 MHz, CDCl ):  = 7.53–7.47 (m, 4 H), 7.41–7.36 (t, J = 7.4
3
White solid; yield: 206 mg (88%).
Hz, 2 H), 7.31–7.27 (dd, J = 7.4, 5.3 Hz, 1 H), 7.13–7.00 (m, 4 H).
1H NMR (300 MHz, CDCl
d, J = 16.1 Hz, 1 H), 7.58–7.55 (d, J = 8.5 Hz, 2 H), 6.53–6.48 (d, J = 16.0
):  = 8.05–8.02 (d, J = 8.4 Hz, 2 H), 7.71–7.65
3
1
3
C NMR (75 MHz, CDCl ):  = 164.18, 160.91, 137.37, 133.74, 133.69,
3
(
1
1
28.94, 128.70, 128.67, 128.26, 128.15, 127.90, 127.68, 126.66,
15.99, 115.70.
Hz, 1 H), 4.30–4.23 (q, J = 7.1 Hz, 2 H), 3.91 (s, 3 H), 1.35–1.31 (t, J = 7.1
Hz, 3 H).
MW: 198.24 g/mol, C14H11F.
1
3
C NMR (75 MHz, CDCl ):  = 166.73, 166.65, 143.34, 138.86, 131.49,
3
1
30.29, 128.09, 120.84, 60.95, 52.49, 14.48.
Ethyl Cinnamate (3h)1
MW: 234.25 g/mol, C13H14O4.
Yellow oil; yield: 144 mg (82%).
1
H NMR (300 MHz, CDCl ):  = 7.72–7.67 (d, J = 16.0 Hz, 1 H), 7.54–
.50 (m, 2 H), 7.39–7.35 (dd, J = 6.5, 3.6 Hz, 3 H), 6.47–6.42 (d, J = 16.0
3
Ethyl (E)-3-(4-Fluorophenyl)acrylate (3n)1
7
Light yellow oil; yield: 132 mg (68%).
Hz, 1 H), 4.30–4.23 (q, J = 7.1 Hz, 2 H), 1.37–1.32 (t, J = 7.2 Hz, 3 H).
1
1H NMR (300 MHz, CDCl
):  = 7.65–7.60 (d, J = 16.0 Hz, 1 H), 7.52–
.45 (m, 2 H), 7.09–7.01 (m, 2 H), 6.36–6.31 (dd, J = 16.0, 0.5 Hz, 1 H),
3
3
C NMR (75 MHz, CDCl ):  = 167.25, 144.83, 134.65, 130.45, 129.09,
3
7
4
1
28.27, 118.46, 60.73, 14.54.
.28–4.21 (q, J = 7.1 Hz, 2 H), 1.34–1.29 (t, J = 7.1 Hz, 3 H).
MW: 176.22 g/mol, C11H12O2.
1
3
C NMR (75 MHz, CDCl ):  = 167.03, 165.70, 162.37, 143.43, 130.91,
3
1
30.86, 130.15, 130.03, 118.21, 118.18, 116.33, 116.05, 60.72, 14.48.
Ethyl (E)-3-(4-Methoxyphenyl)acrylate (3i)26
MW: 194.21 g/mol, C11H11FO2.
Light yellow oil; yield: 204 mg (99%).
1
H NMR (300 MHz, CDCl ):  = 7.66–7.61 (d, J = 16.0 Hz, 1 H), 7.47–
.44 (m, 2 H), 6.91–6.84 (m, 2 H), 6.33–6.27 (d, J = 16.0 Hz, 1 H), 4.28–
.21 (q, J = 7.1 Hz, 2 H), 3.81 (s, 3 H), 1.34–1.30 (t, J = 7.2 Hz, 3 H).
3
E)-4-Styrylbenzaldehyde (3o)30
(
7
4
Light yellow solid; yield: 114 mg (55%); mp 106 °C.
1H NMR (300 MHz, CDCl
):  = 10.00 (s, 1 H), 7.89–7.86 (m, 2 H), 7.67–
.65 (d, J = 8.3 Hz, 2 H), 7.57–7.54 (m, 2 H), 7.43–7.31 (m, 3 H), 7.30–
1
3
3
C NMR (75 MHz, CDCl ):  = 167.55, 161.53, 144.46, 129.90, 127.35,
3
7
7
1
15.90, 114.50, 60.53, 55.53, 14.56.
.12 (dd, J = 38.6, 16.3 Hz, 2 H).
MW: 206.24 g/mol, C12H14O3.
1
3
C NMR (75 MHz, CDCl ):  = 191.89, 143.62, 136.74, 135.51, 132.40,
3
1
30.47, 129.06, 128.74, 127.52, 127.13.
Ethyl (E)-3-(p-Tolyl)acrylate (3j)26
MW: 208.26 g/mol, C15H12O.
Light yellow oil; yield: 186 mg (98%).
©
2020. Thieme. All rights reserved. Synthesis 2020, 52, A–F

F
Synthesis
B. F. dos Santos et al.
Paper
Ethyl (E)-3-(4-Formylphenyl)acrylate (3p)26
(4) Patel, H. H.; Sigman, M. S. J. Am. Chem. Soc. 2015, 137, 3462.
(
(
(
(
(
5) Liu, X.-L.; Li, B.; Gu, Z.-H. J. Org. Chem. 2015, 80, 7547.
6) Cong, H.; Fu, G. C. J. Am. Chem. Soc. 2014, 136, 3788.
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9) Wali, A.; Pillai, S. M.; Satish, S. React. Kinet. Catal. Lett. 1997, 60,
189.
Light yellow solid; yield: 129 mg (63%); mp 49 °C.
1
H NMR (300 MHz, CDCl ):  = 10.03 (s, 1 H), 7.93–7.89 (m, 2 H), 7.74–
3
7
4
.67 (dd, J = 12.0, 10.0 Hz, 3 H), 6.58–6.53 (d, J = 16.0 Hz, 1 H), 4.33–
.25 (q, J = 7.2 Hz, 2 H), 1.38–1.33 (t, J = 7.2 Hz, 3 H).
1
3
C NMR (75 MHz, CDCl ):  = 191.76, 166.62, 143.07, 140.33, 137.30,
3
130.39, 128.70, 121.64, 61.08, 14.48.
(
(
(
10) Khajehzadeh, M.; Moghadam, M. J. Organomet. Chem. 2018, 863,
MW: 204.23 g/mol, C12H12O3.
60.
11) Liu, Y.; Bai, X.; Li, S. Microporous Mesoporous Mater. 2018, 260,
40.
12) Taher, A.; Lee, D.-J.; Lee, I.-M.; Rahman, M. L.; Sarker, M. S. Bull.
Korean Chem. Soc. 2016, 37, 1478.
(13) Sato, T.; Ohno, A.; Sarkar, S. M.; Uozumi, Y.; Yamada, Y. M. A.
ChemCatChem 2015, 7, 2141.
(14) Ghorbani-Choghamarani, A.; Tahmasbi, B.; Noori, N.; Faryadi, S.
C. R. Chim. 2017, 20, 132.
Cinnamonitrile (3q)16
White solid; yield: 74 mg (57%).
1
H NMR (300 MHz, CDCl ):  = 7.48–7.43 (m, 5 H), 7.41–7.36 (d, J =
3
16.7 Hz, 1 H), 5.90–5.85 (d, J = 16.7 Hz, 1 H).
1
3
C NMR (75 MHz, CDCl ):  = 150.80, 133.72, 131.47, 129.36, 127.62,
3
118.45, 96.54.
(
(
(
(
(
15) Huang, L.; Subramanian, R.; Wang, J.; Kwon Oh, J.; Ye, Z. Mol.
Catal. 2020, 488, 110923.
16) Yu, L.; Huang, Y.; Wei, Z.; Ding, Y.; Su, C.; Xu, Q. J. Org. Chem.
MW: 129.16 g/mol, C H N.
9
7
2
015, 80, 8677.
17) Patel, H. A.; Sharma, S. K.; Jasra, R. V. J. Mol. Catal. A: Chem. 2008,
86, 31.
18) Moura, K. O.; Pastore, H. O. Microporous Mesoporous Mater.
014, 190, 292.
Funding Information
2
The author N.L.C.D thanks the Fundação de Apoio ao Desenvolvimen-
to do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul
2
(
–
FUNDECT/Brazil - Chamada FUNDECT/CNPq No 15/2014 – PRONEM
MS) and the Conselho Nacional de Desenvolvimento Científico e
19) (a) Houdayer, A.; Schneider, R.; Billaud, D.; Ghanbaja, J.;
Lambert, J. Appl. Organomet. Chem. 2005, 19, 1239. (b) Somjit,
V.; Wong Chi Man, M.; Ouali, A.; Sangtrirutnugul, P.;
Ervithayasuporn, V. ChemistrySelect 2018, 3, 753.
Tecnológico (Chamada CNPq No 12/2017 – Bolsas de Produtividade
em Pesquisa – PQ) for financial support and a fellowship. Further-
more, the authors N.L.C.D. and B.F.S thank the Coordenação de Aper-
feiçoamento de Pessoal de Nível Superior (CAPES/Brazil) for
research fellowship (Auxílio No 2209/2015, Processo No
(
20) (a) Jagtap, S. Catalysts 2017, 7, 267. (b) Sherwood, J.; Clark, J. H.;
Fairlamb, I. J. S.; Slattery, J. M. Green Chem. 2019, 21, 2164.
21) Khan, M.; Khan, M.; Kuniyil, M.; Adil, S. F.; Al-Warthan, A.;
Alkhathlan, H. Z.; Tremel, W.; Tahir, M. N.; Siddiqui, M. R. H.
Dalton Trans. 2014, 43, 9026.
a
(
23038.008241/2014-89, Programa CAPES-FAPCO) and a scholarship.Fu
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22) Xuan, S.; Jiang, W.; Gong, X. Dalton Trans. 2011, 40, 7827.
23) Mekkaoui, A. A.; Jennane, S.; Aberkouks, A.; Boualy, B.; Mehdi,
A.; Ait Ali, M.; El Firdoussi, L.; El Houssame, S. Appl. Organomet.
Chem. 2019, 33, e5117.
Supporting Information
Supporting information for this article is available online at
(
(
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24) Sore, H. F.; Boehner, C. M.; MacDonald, S. J. F.; Norton, D.; Fox, D.
https://doi.org/10.1055/s-0040-1705938. Su
p
p
orting Inform ationS
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p
p
ortingI
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form atio
n
J.; Spring, D. R. Org. Biomol. Chem. 2009, 7, 1068.
25) Okita, T.; Asahara, K. K.; Muto, K.; Yamaguchi, J. Org. Lett. 2020,
22, 3205.
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©
2020. Thieme. All rights reserved. Synthesis 2020, 52, A–F