An efficient palladium(II) catalyst for oxidative Heck-type reaction under base-free conditions

Article abstract of DOI:10.1016/j.tet.2013.04.084

An efficient catalytic system for the palladium-catalyzed oxidative Heck reaction between arylboronic acids and various alkenes has been developed. Using the bis(aminoalkoxy)palladium complex of N,N-dimethylethanolamine as a catalyst, a series of substituted alkenes were obtained in moderate to excellent yields under mild reaction conditions. This protocol could be tolerated to arylboronic acids containing electron-donating or withdrawing groups and a wide range of olefins, such as acrylate, allyl esters, allyl ethers and alkenylphosphonate. A plausible reaction mechanism of the oxidative Heck reaction was proposed.

Full text of DOI:10.1016/j.tet.2013.04.084

Tetrahedron 69 (2013) 5123e5128
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
An efficient palladium(II) catalyst for oxidative Heck-type reaction
under base-free conditions
*
*
Xia Mi, Mengmeng Huang , Hai Guo, Yangjie Wu
College of Chemistry and Molecular Engineering, Henan Key Laboratory of Chemical Biology and Organic Chemistry,
Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou 450052, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient catalytic system for the palladium-catalyzed oxidative Heck reaction between arylboronic
acids and various alkenes has been developed. Using the bis(aminoalkoxy)palladium complex of N,N-
dimethylethanolamine as a catalyst, a series of substituted alkenes were obtained in moderate to ex-
cellent yields under mild reaction conditions. This protocol could be tolerated to arylboronic acids
containing electron-donating or withdrawing groups and a wide range of olefins, such as acrylate, allyl
esters, allyl ethers and alkenylphosphonate. A plausible reaction mechanism of the oxidative Heck re-
action was proposed.
Received 22 February 2013
Received in revised form 11 April 2013
Accepted 17 April 2013
Available online 23 April 2013
Keywords:
Oxidative Heck reaction
Bis(aminoalkoxy)palladium
Substituted alkenes
Base-free
Ó 2013 Elsevier Ltd. All rights reserved.
N,O-ligand
1. Introduction
(Cat.I, Fig. 1), the catalytic activity of which was investigated in
Sonogashira reaction in our previous report.10 Furthermore, a possi-
Substituted alkenes are ubiquitous structural motifs in natural
products, pharmaceutical intermediates and organic materials.1 One
of the useful method for preparation of the substituted alkenes is the
palladium(II)-catalyzed oxidative Heck reaction. During the past
decade, this type of reaction has received much attentionin synthetic
chemistry for its ability to form carbonecarbon bonds with relatively
mild reaction conditions and excellent chemoselectivity.2 Especially,
arylboronic acids as nucleophilic organometallic reagents are pop-
ularly used in organic synthesis because of their commercial avail-
ability, stability, low toxicity and easy removal of boron-derived
byproducts.3 Since the oxidative Heck reaction of arylboronic acids
was discovered by Heck in 1975,4 a considerable number of catalytic
systems have been developed by Jung5 and Larhed6 et al. using
Pd(OAc)2 in the presence of oxidant, such as metal salt,6a,7 quinone6f,g
or oxygen.5,6bee At the same time, a lot of bidentate nitro-
genous5b,6b,c,d,g and phosphine ligands6e,f et al. were employed for
optimizing the reaction conditions. Up to now, only a few premade
palladium(II)-ligand complexes were used for the oxidative Heck
reaction under base-free conditions,8,9 for example, dimeric tri-
dentate NHCeamidateealkoxide palladium(II) complexes were
successfully applied in the asymmetric oxidative Heck reactions.9
Herein we will describe a base-free oxidative Heck-type reaction
catalyzed by the palladium complex of N,N-dimethylethanolamine
ble reaction mechanism will be also proposed.
Fig. 1. The palladium complex of N,N-dimethylethanolamine (Cat.I).
2. Results and discussion
To begin our research, n-butyl acrylate 1a and phenylboronic
acid 2a were chosen as model substrates. The feasibility of this
reaction was tested in the presence of Cat.I under various reaction
conditions. Among several oxidants screened benzoquinone (BQ)
was found to be the best one for the oxidative Heck reaction (Table
1, entries 1e6). The polarity of the solvents greatly influenced the
conversion of the reaction. The polar solvent DMF was the best
choice for this reaction, and gave an excellent yield (93%, Table 1,
entry 6). Less polar solvents, such as toluene could impede this
process and lead to the formation of a trace amount of product
(Table 1, entry 7). Interestingly, THF and mixed solvent DMSO/
CH3NO2, respectively, gave comparative yields with DMF (Table 1,
* Corresponding authors. Fax: þ86 (371) 67767993; e-mail addresses: hmm@
zzu.edu.cn (M. Huang), wyj@zzu.edu.cn (Y. Wu).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.04.084

5124
X. Mi et al. / Tetrahedron 69 (2013) 5123e5128
Table 1
Screening of reaction conditions for oxidative Heck reaction of n-butyl acrylate 1a and phenylboronic acid 2aa
Entry
Oxidant
Solvent
T (ꢀC)
Yieldb (%)
1
2
3
4
5
6
7
8
O2
DMF
DMF
DMF
DMF
DMF
DMF
Toluene
THF
Dioxane
CH3NO2
DMSO
DMSO/CH3NO2 (1:1)
DMF
DMF
DMF
DMF
DMF
50
50
50
50
50
50
50
50
50
50
50
50
80
30
50
50
50
11
10
5
Ag2O
Cu(OAc)2
AgOAc
K2S2O8
BQ
BQ
BQ
BQ
BQ
BQ
BQ
BQ
BQ
BQ
BQ
BQ
45
76
93
Trace
84
48
52
85
91
95
87
95
51
93
9
10
11
12
13
14
15c
16d
17e
a
Reaction conditions: n-butyl acrylate (0.5 mmol), phenylboronic acid (1.0 mmol), alkoxopalladium complex (2 mol %), oxidant (2 equiv), under N2 in 1.5 mL solvent, 3 h.
Isolated yield.
12 h.
Pd(OAc)2 (2 mol %) as a catalyst, 10 mol % N,N-dimethylethanolamine as a ligand.
Under air.
b
c
d
e
entries 8 and 12). Increasing the reaction temperature to 80 ꢀC or
palladiumeligand system. Surprisingly, the reaction could proceed
smoothly under air atmosphere to give the same yield comparing
with that under nitrogen atmosphere (Table 1, entry 17).
Under the optimized conditions, the scope of the oxidative Heck
reaction between phenylboronic acid and alkenes was examined.
Various alkenes could be converted to (E)-isomers of phenyl
substituted alkenes with a high regioselectivity. Electron-deficient
acrylates, except for 1f, which gave a low yield of 67% due to the
steric effect (Table 2, entry 6), reacted smoothly to afford oxidative
Heck products in high yields (Table 2, entries 1e5). At the same
prolonging the reaction time to 12 h, there was little yield im-
provement (Table 1, entries 13 and 15). A significant drop of yield
(87%) was observed by reducing the reaction temperature to 30 ꢀC
(Table 1, entry 14). To determine whether the precomposed com-
plex was necessary, a large excess N,N-dimethylethanolamine was
added as a ligand to the reaction catalyzed by Pd(OAc)2 under the
same conditions (Table 1, entry 16), however, the yield rapidly re-
duced to 51%. This result indicated that the premade complex has
a
higher catalytic activity than a corresponding premixed
Table 2
Cross-coupling reactions of various alkenes 1 with phenylboronic acid 2a under the optimized conditionsa
Entry
1
Olefin
Product
Yieldb (%)
93
1a
3aa
2
86
1b
3ba
3
4
97
95
1c
3ca
3da
1d

X. Mi et al. / Tetrahedron 69 (2013) 5123e5128
5125
Table 2 (continued )
Entry
Olefin
Product
Yieldb (%)
5
6
82
67
1e
1f
3ea
3fa
3ga
7
72
1g
8
53
87
66
1h
1i
3ha
3ia
3ja
9
10
1j
11
83
1k
3ka
12
13
14
93
1l
3la
59(7:5)c
1m
1n
3ma
Ph
36
Ph
3na
15
98
1o
3oa
a
Reaction conditions: olefins (0.5 mmol), phenylboronic acid (1.0 mmol), alkoxopalladium complex (2 mol %), BQ (2 equiv), under air in 1.5 mL DMF, 3 h.
b
c
Isolated yield.
The ratio of Heck and migrated products was 7:5 by 1H NMR analysis.

5126
X. Mi et al. / Tetrahedron 69 (2013) 5123e5128
Table 3 (continued)
time, alkenes with stronger electron-withdrawing groups gave
higher yields. Satisfyingly, the reaction of less active allyl ethers (1g
and 1h) with phenylboronic acid 2a could also proceed smoothly
under the same conditions to give the desired products in moderate
yields (Table 2, entries 7 and 8). Furthermore, the oxidative pro-
cedure was also successfully extended to styrene derivatives (Table
2, entries 9e13). The product 3ja was only obtained in a 66% yield
because of the steric effect (Table 2, entry 10). Alkene 1l containing
pentafluorine group could give a yield of 93% (Table 2, entry 12). In
addition, two isomers were obtained in the ratio of 7:5 from the
reaction of the styrene derivative 1m with phenylboronic acid 2a
owing to the formation of allyl palladium complexes (Table 2, entry
13). It was worth noting that diethylvinylphosphonate 1o was tol-
erated and gave an excellent yield (Table 2, entry 15).
Entry
ArB(OH)2
Yieldb (%)
9
46
2j
10
81
2k
In order to further explore the universality of this catalytic
system, a series of arylboronic acids were investigated under the
given conditions. As shown in Table 3, this protocol was proven to
be efficient for coupling n-butyl acrylate 1a with various arylbor-
onic acids bearing electron-donating or withdrawing groups and
a
Reaction conditions: olefins (0.5 mmol), arylboronic acid (1.0 mmol), alkox-
opalladium complex (2 mol %), BQ (2 equiv), under air in 1.5 mL DMF, 3 h.
b
Isolated yield.
the corresponding coupling products were obtained in moderate to
excellent yields. The reactions 1a with arylboronic acids containing
electron-withdrawing groups (Table 3, entries 7, 8 and 10) gave
good yields, except of that with 2j (Table 3, entry 9). Gratifyingly,
halide groups (Cl and Br) were also tolerated and afforded the ox-
idative Heck-type compound in 87% and 93% yields without any
Suzuki coupling and classical Heck coupling compounds. However,
2-methylphenylboronic acid 2g only gave 23% yield, indicating that
the steric hindrance on the arylboronic acid has a great effect on the
reaction (Table 3, entry 6).
Based on previous reports, a possible reaction mechanism for
the oxidative Heck coupling reaction was proposed, as shown in
Scheme 1. Initially, the palladium(II) complex A could react with
phenylboronic acid to form the PdII intermediate B. Then the in-
termediate B is expected to be able to undergo the oxidative ad-
Table 3
Cross-coupling reactions of n-butyl acrylate 1a with various arylboronic acids 2
under the optimized conditionsa
Entry
1
ArB(OH)2
Yieldb (%)
75
2b
dition by the alkene to give the intermediate C. The process of b-H
elimination gives the desired Heck cross-coupling product. Finally
the hydride palladium complex D generated at the same time is
oxidized to palladium(II) by the oxidant BQ to get back into the
catalytic cycle.
2
3
43
87
2c
2d
4
5
6
7
63
46
23
87
2e
2f
Scheme 1. The proposed mechanism for oxidative Heck reaction.
3. Conclusions
2g
In summary, an efficient catalyst was developed for the oxida-
tive Heck reaction between arylboronic acids and various alkenes
under base-free conditions in high regioselectivity. It was found
that yields of alkenes and boronic acids containing electron-
withdrawing groups were generally higher than those with
electron-donating groups. The catalytic system could be also ap-
plied for diethylvinylphosphonate and give excellent yield of target
product. A plausible reaction mechanism of the oxidative Heck
reaction was proposed.
2h
2i
8
93

X. Mi et al. / Tetrahedron 69 (2013) 5123e5128
5127
4. Experimental
4.73e4.71 (m, 2H), 2.10 (s, 3H); 13C NMR (100 MHz, CDCl3):
170.88, 136.20, 134.23, 128.62, 128.09, 126.62, 123.17, 65.10, 21.03.
d
4.1. General information
4.2.8. (3-Phenylprop-2-enyl)oxy-benzene
(3ha).14 White
(53%); mp 66e67 ꢀC (lit. 62e63 ꢀC); 1H NMR (400 MHz, CDCl3):
solid
Unless otherwise noted, all reactions were carried out under air
atmosphere and reagents were commercially available and used
without further purification. Organic solvents have been purified
prior to use. 1H and 13C NMR spectra were recorded on a Bruker
DPX-400 spectrometer with CDCl3 as the solvent and TMS as an
internal standard. Melting points were measured on a WC-1 mi-
croscopic apparatus and were uncorrected. All of the products were
known and the purified compounds were identified by comparison
of melting points, 1H NMR, 13C NMR spectra with the literature.
d
7.41e7.39 (m, 2H), 7.33e7.27 (m, 5H), 6.97e6.93 (m, 3H), 6.73 (d,
J¼15.7 Hz, 1H), 6.45e6.38 (m, 1H), 4.70e4.69 (m, 2H); 13C NMR
(100 MHz, CDCl3):
d 158.59, 136.43, 132.92, 129.44, 128.54, 127.84,
126.53, 124.50, 120.86, 114.76, 68.53.
4.2.9. (E)-1,2-Diphenylethene
(3ia).8a White
solid
(87%);
7.51
mp 123e124 ꢀC (lit. 123e124 ꢀC); 1H NMR (400 MHz, CDCl3):
(d, J¼8.2 Hz, 4H), 7.37e7.34 (m, 4H), 7.27e7.23 (m, 2H), 7.11 (s, 2H);
13C NMR (100 MHz, CDCl3):
137.29, 128.64, 127.58, 126.47.
d
d
4.2. General procedure for palladium-catalyzed oxidative
Heck reaction of alkene and arylboronic acid (Tables 2 and 3)
4.2.10. (E)-2-Methylstilbene (3ja).8a White solid (66%); mp 30 ꢀC
(lit. 31e32 ꢀC); 1H NMR (400 MHz, CDCl3):
7.59 (d, J¼7.1 Hz, 1H),
d
Under air atmosphere, a mixture of olefin (0.5 mmol), arylbor-
onic acid (1.0 mmol), alkoxopalladium complex (4 mg, 2 mol %),
oxidant (1.0 mmol) and DMF (1.5 mL) was stirred at 50 ꢀC for 3 h.
The reaction mixture was cooled to room temperature, and then
directly purified by preparative thin layer chromatography on silica
gel using petroleum ether/ethyl acetate as an eluent to give desired
compounds.
7.52 (d, J¼7.8 Hz, 2H), 7.38e7.31 (m, 3H), 7.28e7.17 (m, 4H), 6.99 (d,
J¼16.4 Hz, 1H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3):
d 137.61,
136.33, 135.73, 130.32, 129.94, 128.61, 127.52, 127.47, 126.48, 126.13,
125.29, 19.84.
4.2.11. (E)-3-Nitrostilbene
(3ka).8a Yellow
solid
(83%);
8.34
mp 108e109 ꢀC (lit. 106e107 ꢀC); 1H NMR (400 MHz, CDCl3):
d
(s, 1H), 8.08e8.06 (m, 1H), 7.77 (d, J¼7.8 Hz, 1H), 7.53e7.48 (m, 3H),
4.2.1. (E)-Butyl 3-phenylpropenoate (3aa).8a Yellow oil (93%); 1H
7.39e7.35 (m, 2H), 7.31e7.28 (m, 1H), 7.19 (d, J¼15.2 Hz, 1H), 7.11 (d,
NMR (400 MHz, CDCl3):
d
7.68 (d, J¼15.7 Hz, 1H), 7.53e7.51 (m, 2H),
J¼16.6 Hz, 1H); 13C NMR (100 MHz, CDCl3):
d 148.72, 139.14, 136.24,
132.21, 131.74, 129.52, 128.82, 128.50, 126.80, 126.07, 121.99, 120.86.
7.38e7.25 (m, 3H), 6.44 (d, J¼16.1 Hz, 1H), 4.20 (t, J¼6.8 Hz, 2H),
1.69e1.62 (m, 2H), 1.46e1.39 (m, 2H), 0.96 (t, J¼7.3 Hz, 3H); 13C
NMR (100 MHz, CDCl3):
d
167.13, 144.56, 134.49, 130.22, 128.89,
4.2.12. (E)-1,2,3,4,5-Pentafluoro-6-styrylbenzene
solid (93%); mp 136e137 ꢀC (lit. 134 ꢀC); 1H NMR (400 MHz, CDCl3):
7.52 (d, J¼6.9 Hz, 2H), 7.45e7.30 (m, 4H), 6.97 (t, J¼17.1 Hz, 1H);
19F NMR (376 MHz, CDCl3):
(3la).22 White
128.06, 118.31, 64.45, 30.79, 19.22, 13.78.
d
4.2.2. (E)-tert-Butyl 3-phenylpropenoate (3ba).5b Yellow oil (86%);
d
ꢁ142.74 (dd, J¼21.4, 7.5 Hz), ꢁ156.53
1H NMR (400 MHz, CDCl3):
d
7.59 (d, J¼15.8 Hz, 1H), 7.51e7.50 (m,
(t, J¼20.8 Hz, 1F), ꢁ162.95 (td, J¼21.1, 7.5 Hz).
2H), 7.37e7.35 (m, 3H), 6.37 (d, J¼15.8 Hz,1H), 1.54 (s, 9H); 13C NMR
(100 MHz, CDCl3):
d
166.33, 143.54, 134.95, 129.95, 128.82, 127.96,
4.2.13. (E)-1,2-Diphenylprop-1-ene and 2,3-diphenyl-1-propene
120.21, 80.50, 28.21.
(3ma).15,16 Mixture: white solid (59%); 1H NMR (400 MHz,
CDCl3):
d 7.51e7.49 (m, 2H), 7.42e7.39 (m, 2H), 7.36e7.32 (m, 6H),
4.2.3. Ethyl (E)-3-phenyl-2-propenoate (3ca).11 Yellow oil (97%); 1H
7.28e7.27 (m, 1H), 7.24e7.15 (m, 7H), 6.82e6.80 (m, 1H), 5.47 (1H),
NMR (400 MHz, CDCl3): 7.69 (d, J¼16.0 Hz, 1H), 7.54e7.51 (m, 2H),
d
5.00e4.98 (m, 1H), 3.81 (s, 2H), 2.26 (s, 3H); 13C NMR (100 MHz,
7.39e7.37 (m, 3H), 6.44 (d, J¼16.0 Hz, 1H), 4.27 (q, J¼7.1 Hz, 2H),
CDCl3): d 148.74, 148.67, 134.90, 134.68, 130.17, 128.78, 127.64,
114.83, 112.92, 62.77, 61.82, 16.36, 16.30.
1.34 (t, J¼7.0 Hz, 3H); 13C NMR (100 MHz, CDCl3):
d
167.03, 144.60,
134.51, 130.23, 128.90, 128.07, 118.33, 60.52, 14.34.
4.2.14. Triphenylethylene (3na).17 Yellow oil (36%); 1H NMR
(400 MHz, CDCl3):
(m, 3H), 7.03e7.01 (m, 2H), 6.98e6.94 (m, 1H); 13C NMR (100 MHz,
CDCl3): 143.31, 142.47, 140.24, 137.26, 130.27, 129.42, 128.50,
4.2.4. Phenyl (E)-3-phenyl-2-propenoate (3da).12 Yellow solid
(95%); 1H NMR (400 MHz, CDCl3):
d 7.35e7.27 (m, 8H), 7.22e7.19 (m, 2H), 7.12e7.09
d
7.88 (d, J¼16.1 Hz, 1H),
7.60e7.58 (m, 2H), 7.43e7.39 (m, 5H), 7.27e7.23 (m, 1H), 7.18e7.16
d
(m, 2H), 6.64 (d, J¼16.0 Hz, 1H); 13C NMR (100 MHz, CDCl3):
128.08, 128.04, 127.83, 127.48, 127.38, 127.28, 126.62.
d
165.38, 150.80, 146.55, 134.18, 130.68, 129.43, 128.98, 128.29,
125.77, 121.62, 117.32.
4.2.15. Diethyl (E)-2-phenyl-ethenylphosphonate (3oa).18 Yellow oil
(98%); 1H NMR (400 MHz, CDCl3):
d
7.56e7.46 (m, 3H), 7.39e7.38
(m, 3H), 6.26 (t, J¼17.6 Hz, 1H), 4.17e4.09 (m, 4H), 1.38e1.34 (m,
6H); 13C NMR (100 MHz, CDCl3):
148.74, 148.67, 134.90, 134.68,
4.2.5. Methyl 2-benzylacrylate (3ea).25 Yellow oil (82%); 1H NMR
(400 MHz, CDCl3):
J¼15.8 Hz, 1H), 6.32e6.24 (m, 1H), 4.73e3.72 (m, 2H), 2.09 (s, 3H);
13C NMR (100 MHz, CDCl3):
21.05, 65.12, 123.23, 126.66, 128.13,
128.62, 134.26, 136.26, 170.88.
d
7.39e7.38 (m, 2H), 7.33e7.24 (m, 3H), 6.65 (d,
d
130.17, 128.78, 127.64, 114.83, 112.92, 61.82, 62.77, 16.36, 16.30.
d
4.2.16. (E)-Butyl 3-(4-hydroxyphenyl)acrylate.3b Pale yellow solid
(75%); mp 76e78 ꢀC (lit. 74e76 ꢀC); 1H NMR (400 MHz, CDCl3):
4.2.6. Ethyl (2E)-3-phenylbut-2-enoate (3fa).13 Yellow oil (67%); 1H
NMR (400 MHz, CDCl3): 7.50e7.46 (m, 2H), 7.40e7.25 (m, 3H),
d
7.65 (d, J¼15.7 Hz, 1H), 7.44 (d, J¼8.3 Hz, 2H), 6.88 (d, J¼8.3 Hz,
d
2H), 6.32 (d, J¼16.1 Hz,1H), 4.23 (t, J¼6.6 Hz, 2H),1.75e1.67 (m, 2H),
6.14 (q, J¼1.3 Hz, 1H), 4.22 (q, J¼7.2 Hz, 2H), 2.58 (d, J¼1.3 Hz, 3H),
1.51e1.41 (m, 2H), 0.98 (t, J¼7.6 Hz, 3H); 13C NMR (100 MHz, CDCl3):
1.32 (t, J¼7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3):
d
166.92, 155.56,
d 168.40, 158.41, 145.04, 130.39, 127.45, 116.31, 115.83, 64.94, 31.17,
142.24, 129.00, 128.51, 126.32, 117.18, 59.88, 17.97, 14.37.
19.60, 14.14.
4.2.7. (E)-Cinnamyl acetate (3ga).8a Yellow oil (72%); 1H NMR
4.2.17. (E)-Butyl 3-(4-methoxyphenyl)acrylate.3b Yellow oil (43%);
(400 MHz, CDCl3):
d
7.40e7.38 (m, 2H), 7.34e7.30 (m, 2H),
1H NMR (400 MHz, CDCl3):
d
7.66 (d, J¼16.0 Hz, 1H), 7.50 (d,
7.27e7.25 (m, 1H), 6.65 (d, J¼16.1 Hz, 1H), 6.32e6.26 (m, 1H),
J¼9.0 Hz, 2H), 6.92 (d, J¼8.6 Hz, 2H), 6.63 (d, J¼16.0 Hz, 1H), 4.22 (t,

5128
X. Mi et al. / Tetrahedron 69 (2013) 5123e5128
J¼6.9 Hz, 2H), 3.86 (s, 3H), 1.75e1.67 (m, 2H), 1.51e1.40 (m, 2H),
4.23 (t, J¼6.7 Hz, 2H), 1.74e1.66 (m, 2H), 1.50e1.40 (m, 2H), 0.97 (t,
0.98 (t, J¼7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3):
d
167.45, 161.34,
J¼7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3):
d 166.51, 142.67, 137.89,
144.21, 129.69, 127.25, 115.81, 114.32, 64.27, 55.38, 30.84, 19.23,
13.77.
132.22, 131.90, 131.57, 131.25, 128.17, 127.91, 125.88, 125.84, 125.20,
122.50, 120.92, 64.73, 30.75, 1920, 13.72.
4.2.18. (E)-Butyl 3-(4-tert-butylphenyl)acrylate.21 Yellow oil (87%);
1H NMR (400 MHz, CDCl3):
d
7.67 (d, J¼15.8 Hz, 1H), 7.47 (d,
Acknowledgements
J¼8.3 Hz, 2H), 7.40 (d, J¼8.5 Hz, 2H), 6.41 (d, J¼16.1 Hz, 1H), 4.20 (t,
We thank the National Science Foundation of China (No
21172200) for financial support given to this research.
J¼6.7 Hz, 2H), 1.72e1.67 (m, 2H), 1.50e1.41 (m, 2H), 1.35 (s, 9H),
0.99 (t, J¼7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3):
d 167.34, 153.76,
144.47,131.73,127.91,125.86,117.35, 64.38, 34.89, 31.17, 30.81,19.23,
13.78.
References and notes
4.2.19. (E)-Butyl 3-(4-methylphenyl)acrylate.19 Yellow oil (63%); 1H
1. (a) Grimsdale, A. C.; Chan, K. L.; Martin, R. E.; Jokisz, P. G.; Holmes, A. B. Chem.
Rev. 2009, 109, 897; (b) Mochida, S.; Hirano, K.; Satoh, T.; Miura, M. Org. Lett.
2010, 12, 5776; (c) Paek, S.-M. Molecules 2012, 17, 3348; (d) Ledwon, P.; Kuznik,
W.; Lapkowski, M.; Majchrzak, M. New J. Chem. 2012, 36, 2347; (e) Greger, H. J.
Nat. Prod. 2012, 75, 2261; (f) Robles, O.; Serna-Saldívar, S. O.; Gutierrez-Uribe, J.
A.; Romo, D. Org. Lett. 2012, 14, 1394; (g) Vamshikrishna, K.; Srihari, P. Tetra-
hedron 2012, 68, 1540.
2. (a) Beletskaya, I. P.; Cheprakov, A. V. Chem. Rev. 2000, 100, 3009; (b) Jia, C.-G.;
Piao, D.-G.; Oyamada, J.; Lu, W.-J.; Kitamura, T.; Fujiwara, Y. Science 2000, 287,
1992; (c) Dounay, A. B.; Overman, L. E. Chem. Rev. 2003, 103, 2945; (d) Nicolaou,
K. C.; Bulger, P. G.; Sarlah, D. Angew. Chem., Int. Ed. 2005, 44, 4442; (e) Karimi, B.;
Behzadnia, H.; Elhamifar, D.; Akhavan, P. F.; Esfahani, F. K.; Zamani, A. Synthesis
2010, 1399; (f) Bras, J. L.; Muzart, J. Chem. Rev. 2011, 111, 1170; (g) Su, Y.-L.; Jiao,
N. Curr. Org. Chem. 2011, 15, 3362.
NMR (400 MHz, CDCl3):
d
7.65 (d, J¼16.0 Hz, 1H), 7.42 (d, J¼7.8 Hz,
2H), 7.18 (d, J¼7.8 Hz, 2H), 6.39 (d, J¼16.0 Hz, 1H), 4.20 (t, J¼6.7 Hz,
2H), 2.36 (s, 3H), 1.72e1.64 (m, 2H), 1.47e1.40 (m, 2H), 0.96 (t,
ꢀ
J¼7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3):
d 167.32, 144.56, 140.61,
131.77, 129.61, 128.05, 117.22, 64.35, 30.82, 21.46, 19.22, 13.77.
4.2.20. (E)-Butyl 3-(3-methylphenyl)acrylate.20 Yellow oil (46%); 1H
NMR (400 MHz, CDCl3):
d
7.65 (d, J¼16.1 Hz, 1H), 7.34e7.25 (m, 3H),
7.19 (d, J¼7.3 Hz, 1H), 6.43 (d, J¼16.1 Hz, 1H), 4.21 (t, J¼6.7 Hz, 2H),
2.37 (s, 3H), 1.73e1.65 (m, 2H), 1.47e1.41 (m, 2H), 0.97 (t, J¼7.3 Hz,
3H); 13C NMR (100 MHz, CDCl3):
d 167.22, 144.76, 138.55, 134.47,
3. (a) Ishiyama, T.; Miyaura, N. J. Organomet. Chem. 2003, 680, 3; (b) Lindh, J.;
ꢁ
Enquist, P.-A.; Pilotti, A.; Nilsson, P.; Larhed, M. J. Org. Chem. 2007, 72, 7957.
131.07, 128.78, 118.10, 64.42, 30.82, 21.34, 19.24, 13.78.
4. Dieck, H. A.; Heck, R. F. J. Org. Chem. 1975, 40, 1083.
5. (a) Jung, Y. C.; Mishra, R. K.; Yoon, C. H.; Jung, K. W. Org. Lett. 2003, 5, 2231; (b)
Yoo, K. S.; Yoon, C. H.; Jung, K. W. J. Am. Chem. Soc. 2006, 128, 16384; (c) Yoo, K.
S.; Park, C. P.; Yoon, C. H.; Sakaguchi, S.; O’Neill, J.; Jung, K. W. Org. Lett. 2007, 9,
3933.
6. (a) Andappan, M. M. S.; Nilsson, P.; Larhed, M. Mol. Div. 2003, 7, 97; (b) An-
dappan, M. M. S.; Nilsson, P.; Schenck, H.; Larhed, M. J. Org. Chem. 2004, 69,
5212; (c) Andappan, M. M. S.; Nilsson, P.; Larhed, M. Chem. Commun. 2004, 218;
(d) Enquist, P.-A.; Lindh, J.; Nilsson, P.; Larhed, M. Green Chem. 2006, 8, 338; (e)
4.2.21. (E)-Butyl 3-(2-methylphenyl)acrylate.23 Yellow oil (23%); 1H
NMR (400 MHz, CDCl3):
d
7.97 (d, J¼15.8 Hz, 1H), 7.55 (d, J¼7.3 Hz,
1H), 7.30e7.25 (m, 1H), 7.23e7.18 (m, 1H), 7.11e7.12 (m, 1H), 6.36 (d,
J¼15.8 Hz, 1H), 4.22 (t, J¼6.7 Hz, 2H), 2.44 (s, 3H), 1.74e1.64 (m, 2H),
1.49e1.36 (m, 2H), 0.97 (t, J¼7.4 Hz, 3H); 13C NMR (100 MHz,
CDCl3):
d 167.21, 142.27, 137.64, 133.45, 130.78, 129.96, 126.40,
€
€
Lindh, J.; Savmarker, J.; Nilsson, P.; Sjoberg, P. J. R.; Larhed, M. Chem.dEur. J.
2009, 15, 4630; (f) Odell, L. R.; Lindh, J.; Gustafsson, T.; Larhed, M. Eur. J. Org.
126.33, 119.31, 64.44, 30.79, 19.81, 19.23, 13.78.
€
Chem. 2010, 2270; (g) Nordqvist, A.; Bjorkelid, C.; Andaloussi, M.; Jansson, A.
M.; Mowbray, S. L.; Karlen, A.; Larhed, M. J. Org. Chem. 2011, 76, 8986.
ꢀ
4.2.22. (E)-Butyl 3-(4-chlorophenyl)acrylate.19 Pale yellow solid
(87%); mp 35e36 ꢀC (lit. 30e32 ꢀC); 1H NMR (400 MHz, CDCl3):
7. (a) Liu, Y.; Li, D.; Park, C.-M. Angew. Chem., Int. Ed. 2011, 50, 7333; (b) Inamoto,
K.; Kawasaki, J.; Hiroya, K.; Kondo, Y.; Doi, T. Chem. Commun. 2012, 4332; (c)
Zhang, Y.-X.; Li, Z.-J.; Liu, Z.-Q. Org. Lett. 2012, 14, 226.
8. (a) Leng, Y.-T.; Yang, F.; Wei, K.; Wu, Y.-J. Tetrahedron 2010, 66, 1244; (b) Likhar,
P. R.; Roy, M.; Roy, S.; Subhas, M. S.; Kantam, M. L.; Sreedhar, B. Adv. Synth. Catal.
2008, 350, 1968; (c) Delcamp, J. H.; Brucks, A. P.; White, M. C. J. Am. Chem. Soc.
2008, 130, 11270.
9. (a) Sakaguchi, S.; Yoo, K. S.; O’Neill, J.; Lee, J. H.; Stewart, T.; Jung, K. W. Angew.
Chem., Int. Ed. 2008, 47, 9326; (b) Yoo, K. S.; O’Neill, J.; Sakaguchi, S.; Giles, R.;
Lee, J. H.; Jung, K. W. J. Org. Chem. 2010, 75, 95.
10. Mi, X.; Huang, M.-M.; Feng, Y.-J.; Wu, Y.-J. Synlett 2012, 1257.
11. Aggarwal, V. K.; Fulton, J. R.; Sheldon, C. G.; Vicente, J. J. Am. Chem. Soc. 2003,
125, 6034.
12. Zhang, L.-L.; Zhang, G.-Y.; Zhang, M.-L.; Cheng, J. J. Org. Chem. 2010, 75, 7472.
13. Paraskar, A. S.; Sudalai, A. Tetrahedron 2006, 62, 4907.
14. Trivedi, R.; Tunge, J. A. Org. Lett. 2009, 11, 5650.
15. Wu, S.; Ma, H.-C.; Jia, X.-J.; Zhong, Y.-M.; Lei, Z.-Q. Tetrahedron 2011, 67, 250.
16. Shono, T.; Kurashige, R.; Mukaiyama, R.; Tsubouchi, A.; Takeda, T. Chem.dEur. J.
2007, 13, 4074.
17. Nunes, C. M.; Steffens, D.; Monteiro, A. L. Synlett 2007, 103.
18. Lai, C.-B.; Xi, C.-J.; Chen, W.-X.; Hua, R.-M. Tetrahedron 2006, 62, 6295.
19. Zhang, W.; Qi, H.-L.; Li, L.-S.; Wang, X.; Chen, J.; Peng, K.-S.; Wang, Z.-H. Green
Chem. 2009, 11, 1194.
d
7.62 (d, J¼16.0 Hz, 1H), 7.45 (d, J¼8.6 Hz, 2H), 7.35 (d, J¼8.6 Hz,
2H), 6.41 (d, J¼16.1 Hz,1H), 4.21 (t, J¼6.7 Hz, 2H), 1.73e1.65 (m, 2H),
1.49e1.39 (m, 2H), 0.96 (t, J¼7.2 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d 166.85, 143.10, 136.13, 133.00, 129.22, 129.18, 118.93, 64.57,
30.78, 19.21, 13.76.
4.2.23. (E)-Butyl 3-(4-bromophenyl)acrylate.21 Pale yellow solid
(93%); mp 37 ꢀC; 1H NMR (400 MHz, CDCl3):
d
7.61 (d, J¼16.1 Hz,
1H), 7.52 (d, J¼8.3 Hz, 2H), 7.39 (d, J¼8.3 Hz, 2H), 6.43 (d, J¼16.1 Hz,
1H), 4.21 (t, J¼6.9 Hz, 2H), 1.73e1.65 (m, 2H), 1.49e1.39 (m, 2H),
0.96 (t, J¼7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3):
d 167.22, 143.54,
133.81, 132.52, 129.81, 124.84, 119.43, 64.96, 31.15, 19.59, 14.13.
4.2.24. (E)-Methyl 4-(3-butoxy-3-oxoprop-1-en-1-yl)benzoate.24
-
White solid (46%); mp 55 ꢀC (lit. 55e56 ꢀC); 1H NMR (400 MHz,
CDCl3):
d
8.05 (d, J¼7.8 Hz, 2H), 7.69 (d, J¼16.2 Hz, 1H), 7.59 (d,
20. Xie, G.-L.; Chellan, P.; Mao, J.-C.; Chibale, K.; Smith, G. S. Adv. Synth. Catal. 2010,
J¼8.3 Hz, 2H), 6.52 (d, J¼6.9 Hz, 1H), 4.22 (t, J¼8 Hz, 2H), 3.93 (s,
3H), 1.74e1.66 (m, 2H), 1.48e1.41 (m, 2H), 0.97 (t, J¼7.3 Hz, 3H); 13C
352, 1641.
21. Zhou, X.-Y.; Luo, J.-Y.; Liu, J.; Peng, S.-M.; Deng, G.-J. Org. Lett. 2011, 13, 1432.
22. Zhang, X.-G.; Fan, S.-L.; He, C.-Y.; Wan, X.-L.; Min, Q.-Q.; Yang, J.; Jiang, Z.-X. J.
Am. Chem. Soc. 2010, 132, 4506.
NMR (100 MHz, CDCl3):
d 166.66, 166.48, 143.14, 138.69, 131.31,
130.10, 127.91, 120.69, 64.69, 52.32, 30.73, 19.20, 13.77.
23. Shi, M.; Qian, H.-X. Tetrahedron 2005, 61, 4949.
24. Xiong, Z.-C.; Wang, N.-D.; Dai, M.-J.; Li, A.; Chen, J.-H.; Yang, Z. Org. Lett. 2004, 6,
3337.
~ ~
25. Najera, C.; Mancheno, B.; Yus, M. Tetrahedron Lett. 1989, 30, 3837.
4.2.25. (E)-Butyl 3-(4-triflurophenyl)acrylate.3b Yellow oil (81%); 1H
NMR (400 MHz, CDCl3):
d
7.71e7.60 (m, 5H), 6.51 (d, J¼16.0 Hz, 1H),