A novel ketone olefination via organozinc reagents in the presence of diphenyl phosphite

Article abstract of DOI:10.1039/c2ob06821d

Carbonyl compounds react with organozinc reagents in the presence of diphenyl phosphite to give the corresponding olefins. A variety of 1,3-dienes and unsaturated esters were obtained in moderate to excellent yields under mild conditions. The Royal Society of Chemistry 2012.

Full text of DOI:10.1039/c2ob06821d

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PAPER
A novel ketone olefination via organozinc reagents in the presence of diphenyl
phosphite†
Hua Cui, Ying Li and Songlin Zhang*
Received 31st October 2011, Accepted 12th January 2012
DOI: 10.1039/c2ob06821d
Carbonyl compounds react with organozinc reagents in the presence of diphenyl phosphite to give the
corresponding olefins. Avariety of 1,3-dienes and unsaturated esters were obtained in moderate to
excellent yields under mild conditions.
Introduction
Results and discussion
The olefination of carbonyl compounds is a very important trans-
formation in organic synthesis. The Wittig reaction,1 Julia reac-
tion2 and Peterson reaction,3 as well as their variants4 provide a
highly effective and general method. These reactions need ylides
which are generated by a stepwise procedure under basic con-
ditions. Several systems employing stoichiometric amounts of
organometallic reagents based on Ti or Cr have been researched
in the olefination reaction and some achieved great success.5
Another catalytic alternative which is based on Re,6 Fe,7 Ru,8
Co,9 Rh,10 or Cu11 carbene complexes also has been reported.
Recently, our group developed a new one-pot method for the
olefination of carbonyl compounds with Grignard reagents in the
presence of diethyl phosphite,12 which opens up the possibility
of olefination by organometallic reagents in the presence of
phosphite (Scheme 1).
Zinc is a relatively non-toxic and inexpensive metal. Although
ignored for many years, today organozinc reagents are one of the
most useful classes of organometallic reagents for organic syn-
thesis.13 Compared with Grignard reagents, organozinc reagents
are relatively stable, more selective, and tolerant to ester and
amide functional groups.14 On the other hand, allylic magnesium
reagents are difficult to prepare and are unstable, while allylic
zinc reagents are much more readily available. Therefore, the
attempt to introduce organozinc reagents to carbonyl olefination
is meaningful.
Initially, we investigated the reaction of benzophenone with
allylzinc bromide in the presence of different additives to opti-
mize the reaction. First, we use diethyl phosphate as the additive.
Strangely, the employment of diethyl phosphate affords only
10% of 3a after a reaction time of 24 h (Table 1, entry 1). Even
if the temperature was elevated to 50 °C, the yield remained poor
(Table 1, entry 2). Therefore, we investigated the effect of other
additives on the carbonyl olefination reaction. Triphenylphos-
phine, triethylphosphite, triethylphosphate, and 2-(diethoxyphos-
phoryl) acetate did not promote the reaction (Table 1, entries
3–6). When diisopropyl phosphite was used as the additive, the
desired product was detected, but the yield was very low
(Table 1, entry 7). To our delight, when diphenyl phosphite was
employed as the additive at 50 °C, 87% yield was obtained in
5 h (Table 1, entry 8). Performing the reaction at room tempera-
ture caused a slight decrease of the yield (Table 1, entry 9). Then
we tested the amount of allylzinc bromide and additive (Table 1,
entries 10–14). After some investigations, we concluded that the
use of 1.2 equiv. of diphenyl phosphite and 3 equiv. of allylzinc
bromide was found to be optimal. Encouraged by these efficient
experimental results, we further explored the scope of carbonyl
compounds and organozinc reagents. A selection of pertinent
results are collected in Tables 2–4.
As shown in Table 2, benzophenone and substituted benzo-
phenones are all workable substrates to react with allylzinc
bromide, giving a range of conjugated dienes with good to excel-
lent yields, and no obvious electronic effect was observed
(Table 2, entries 1–3, 6–10). Aliphatic ketone such as 2-adaman-
tanone reacting with allylzinc bromide in the same conditions
affords the corresponding diene in 85% yield (Table 2, entry 5).
Herein, we present a convenient method for the olefination of
ketones, via organozinc reagents in the presence of diphenyl
phosphite.
Key Laboratory of Organic Synthesis of Jiangsu Province, College of
Chemistry, Chemical Engineering and Materials Science of Soochow
University, Suzhou 215123, People’s Republic of China. E-mail:
zhangsl@suda.edu.cn
†Electronic supplementary information (ESI) available. See DOI:
10.1039/c2ob06821d
Scheme 1 Olefination of carbonyl compounds with Grignard reagents.
2862 | Org. Biomol. Chem., 2012, 10, 2862–2869
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Table 1 Optimization of reaction conditionsa
According to our previous work,12 a similar mechanism was
proposed (Scheme 2). It revealed that the six-centered transition
state was formed in the reaction. The P anion abstracts the H of
the methylene group and the –ZnBr of 7 was the assistant.
Conclusions
2a
Entry Additive (equiv.)
(equiv.) Time (h) Yieldb (%)
In summary, we have developed a novel olefination of carbonyl
compounds with organozinc reagents. A range of conjugated
dienes and unsaturated esters could be readily obtained under
mild conditions. Further investigation of the usage of other orga-
nometallic reagents in olefination reactions is under way in our
group.
1
2
3
(EtO)2P(O)H (1.2)
(EtO)2P(O)H (1.2)
Ph3P (1.2)
3
3
3
3
3
3
3
3
3
3
3
3
4
2
24
24
24
24
24
24
24
5
5
5
5
5
10c
31
—
—
—
—
22
87
79c
75
74
65
45
31
4
5
(EtO)3P (1.2)
(EtO)3PO (1.2)
6
7
8
9
10
11
12
13
14
(EtO)2P(O)CH2COOEt(1.2)
(i-PrO)2P(O)H (1.2)
(PhO)2P(O)H (1.2)
(PhO)2P(O)H (1.2)
(PhO)2P(O)H (1.5)
(PhO)2P(O)H (1)
(PhO)2P(O)H (0.8)
(PhO)2P(O)H (1.2)
(PhO)2P(O)H (1.2)
Experimental section
General methods
5
5
All chemicals were purchased from Aldrich, Alfa or Acros
chemical company and used thus, without further purification.
Petroleum ether (PE) used refers to the 60–90 °C boiling point
fraction of petroleum. THF was distilled from sodium benzophe-
none under nitrogen. All reactions were conducted under a nitro-
gen atmosphere. Metallic zinc and all solvents were purchased
from commercial source, without further purification before use.
The flash column chromatography was carried out on Merck
silica gel (300–400 mesh). The IR spectra was measured on a
varian 1000 FT-IR spectrometer as KBr disks (4000–400 cm−1).
1H and 13C NMR spectra were recorded on a Varian Mercury
400 or 300 MHz spectrometer as solutions in CDCl3. Chemical
shifts in 1H NMR spectra are reported in parts per million (ppm,
δ) downfield from the internal standard Me4Si (TMS). Chemical
shifts in 13C NMR spectra are reported relative to the central line
of the chloroform signal (δ = 77.50 ppm). High-resolution mass
spectra were obtained with a GCT-TOF instrument.
a To a solution of 1a (0.5 mmol) in THF (3 mL) was added 2a
(1.5 mmol) in THF under a nitrogen atmosphere at room temperature,
and the mixture was stirred for 30 minutes, then the additive (0.6 mmol)
was added to this mixture and stirred at 50 °C. b Isolated yield based on
1a after silica gel chromatography. c At room temperature.
When 9-fluorenone was applied, a slightly lower yield was
obtained (Table 2, entry 4). Acetophenone gave a mixture of
conjugated diene and 1,4-diene with a ratio of 63 : 37 (Table 2,
entry 11). When the reaction was performed with aldehyde as
substrate, (E)-alkenes were obtained as the only product,
however the yield was poor (Table 2, entry 12). Then, we tested
other two organozinc reagents 2b and 2c, corresponding dienes
and diyne were obtained at an acceptable yield accompanied by
corresponding alcohols (Table 2, entries 13–15). However, when
aliphatic and aromatic organozinc reagents 2d and 2e react with
benzaldehyde and acetophenone respectively, desired products
were not detected (Table 2, entries 16, 17).
Moreover, we were pleased to find that the reaction was suc-
cessfully extended to Reformatsky reagents. A range of α,β-un-
saturated esters were obtained at good to excellent yields
(Table 3, entries 1–6). When the two aryl groups of ketones are
not symmetrical, a modest (E)/(Z) ratio was found (Table 3,
entry 5). When the reaction of 4a with acetophenone was investi-
gated, a mixture of conjugated and unconjugated products was
obtained at a ratio of 58 : 42 with 76% total yield (Table 3, entry
7). Aldehyde such as piperonal only gave a 44% yield in the
reaction. But the selectivity was very good, only the thermody-
namically more stable (E)-isomer was observed (Table 3, entry
8).
General procedure for the synthesis of organozinc reagents.
Alkyl bromide (128 μL, 1.5 mmol) and zinc powder (0.1170 g,
1.8 mmol) in dry THF (3 mL) under a nitrogen atmosphere at
room temperature (for 4b and 4c, 5% I2 was added to trigger the
reaction). The mixture was stirred for about 15 minutes, and zinc
powder disappeared. The stirring was continued to 0.5 h. 2d and
2e were prepared according to Knochel’s method.16 The concen-
tration of organozinc reagents was determined by titration with
I2.17
General procedure for the olefination reaction. A solution of
organozinc reagent in THF (1.5 mmol) was added to a solution
of carbonyl compounds (0.5 mmol) in dry THF (3 mL) under a
nitrogen atmosphere at room temperature. The mixture was
stirred for about 30 minutes. Then diphenyl phosphite
(0.6 mmol) was added (the reaction was monitored by TLC).
The reaction mixture was stirred for 5 h at 50 °C and then was
quenched with dilute hydrochloric acid. The resulting mixture
was extracted with diethyl ether (3 × 10 mL), and dried over
anhydrous Na2SO4. The solvent was removed by evaporation
under reduced pressure. Purification by column chromatography
on silica gel afforded olefins (300–400 mesh, petroleum ether
and ethyl acetate as eluent).
Then we tested two other Reformatsky regents 4b and 4c.
Acetophenone and substituted acetophenones react with 4b to
give unconjugated esters with fair to good yields (Table 4,
entries 1–4). Otherwise, when 4c was used in this reaction, only
the unconjugated product 5kd was obtained with medium yield
(Table 4, entry 5).
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Table 2 Olefination of carbonyl compounds with organozinc reagentsa
Entry
1
Substrate
Zinc reagent
Product
Yield (%)b
87
2
3
2a
2a
85
92
4
2a
71
5
6
2a
2a
85
86c
7
2a
78c
8
9
2a
2a
88c
82c
10
11
2a
2a
86c
82 (63 : 37)
12
13
2a
2b
31
41
1a
1b
1a
14
15
33
35
16
17
—
—
1k
a To a solution of carbonyl compounds (0.5 mmol) in THF (3 mL) was added organozinc reagent (1.5 mmol) in THF under a nitrogen atmosphere at
room temperature, and the mixture was stirred for 30 minutes, then diphenyl phosphite (0.6 mmol) was added to this mixture and stirred at 50 °C for
5 h. b Isolated yield based on carbonyl compounds after silica gel chromatography. c Whether it is a Z or E configuration can not be determined by
1H NMR.
1,1-Diphenylbuta-1,3-diene (3a).12 The title compound was
δ 7.38–7.16 (m, 10H), 6.71 (d, J = 11.0 Hz, 1H), 6.44 (td, J =
obtained according to the general procedure. Colourless oil;
Yield: 87%; IR (KBr): 3080, 3056, 3026, 1666, 1619, 1598,
10.5 Hz, J = 16.9 Hz, 1H), 5.38 (d, J = 16.8 Hz, 1H), 5.11 (d, J
= 10.1 Hz, 1H). 13C NMR (CDCl3, 100 MHz): δ 143.64,
142.58, 140.14, 135.46, 130.93, 129.03, 128.71, 128.68, 128.10,
1
1493, 1445, 905, 765, 699 cm−1; H NMR (400 MHz, CDCl3):
2864 | Org. Biomol. Chem., 2012, 10, 2862–2869
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Table 3 Olefination of carbonyl compounds with Reformatsky reagent
Table 4 Olefination of carbonyl compounds with Reformatsky
reagents 4b and 4ca
4aa
Entry
1
Substrate
Product
Yield (%)b
Reformatsky
reagent
Yield
(%)b
Entry
1
Substrate
Product
1a
89
80
1k
73
2
1b
2
3
4b
4b
4b
61
3
4
1c
82
65
82
1d
5
6
7
1g
1h
1k
68 E/Z = 61 : 39c
4
5
87
45
88d
1k
76 (58 : 42)
a To a solution of carbonyl compounds (0.5 mmol) in THF (3 mL) was
added 4b or 4c (1.5 mmol) in THF under a nitrogen atmosphere, and the
mixture was stirred for 30 minutes at 50 °C, then diphenyl phosphite
(0.6 mmol) was added to this mixture and stirred at 50 °C for 5 h.
b Isolated yield based on carbonyl compounds after silica gel
chromatography.
8
43
a To a solution of carbonyl compounds (0.5 mmol) in THF (3 mL) was
added 4a (1.5 mmol) in THF under a nitrogen atmosphere, and the
mixture was stirred for 30 minutes at 50 °C, then diphenyl phosphite
(0.6 mmol) was added to this mixture and stirred at 50 °C for 5 h.
b Isolated yield based on carbonyl compounds after silica gel
chromatography. c The ratio Z/E was obtained from 1H NMR
spectroscopy.15 d Whether it is a Z or E configuration can not be
determined from 1H NMR spectroscopy.
Scheme 2 Possible mechanism for olefination of carbonyl compounds.
1,1-bis(4-Methoxyphenyl)buta-1,3-diene (3c).12 The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 92%; IR (KBr): 3035, 3002, 1659, 1605, 1505,
1463, 1287, 908, 831, 780 cm−1; 1H NMR (400 MHz CDCl3): δ
7.21 (d, J = 8.6 Hz, 2H), 7.13 (d, J = 8.4, 2H), 6.91 (d, J = 8.4
Hz, 2H), 6.81 (d, J = 8.6 Hz, 2H), 6.59 (d, J = 11.0 Hz, 1H),
6.46 (td, J = 10.4 Hz, J = 16.7 Hz, 1H), 5.33 (d, J = 16.6 Hz,
1H), 5.07 (d, J = 9.9 Hz, 1H), 3.83 (s, 3H), 3.79 (s, 3H). 13C
NMR (CDCl3, 100 MHz): δ 159.51, 159.21, 142.72, 135.60,
135.42, 132.46, 131.95, 129.19, 127.04, 117.64, 113.87, 113.81,
55.59. HRMS (EI+) calcd for C18H18O2 (M+): 266.1307; found:
266.1306.
128.02, 127.90, 119.15. HRMS (EI+) calcd for C16H14 (M+):
206.1096; found: 206.1096.
1,1-bis(4-Chlorophenyl)buta-1,3-diene (3b).12 The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 85%; IR (KBr): 3033, 1668, 1590, 1488, 1401,
1
908, 765, 730 cm−1; H NMR (400 MHz, CDCl3): δ 7.36 (d, J
= 8.0 Hz, 2H), 7.24 (d, J = 8.3 Hz, 2H), 7.17 (d, J = 8.3 Hz,
2H), 7.12 (d, J = 8.0 Hz, 2H), 6.67 (d, J = 11.0 Hz, 1H), 6.38
(td, J = 10.5 Hz, J = 16.9 Hz, 1H), 5.42 (d, J = 16.7 Hz, 1H),
5.18 (d, J = 10.0 Hz, 1H). 13C NMR (75 MHz, CDCl3): δ
141.06, 140.59, 137.99, 134.75, 134.02, 132.16, 129.74, 129.66,
129.22, 129.03, 128.91, 120.35. HRMS (EI+) calcd for
C16H1235Cl2 (M+): 274.0316; found: 274.0316; HRMS(EI+)
calcd for C16H1237Cl2 (M+): 276.0287; found: 276.0280.
9-Allylidene-9H-fluorene (3d).18 The title compound was
obtained according to the general procedure. Yellow oil; Yield:
71%; IR (KBr): 3061, 1659, 1609, 1476, 1448, 938, 917, 760,
1
730 cm−1; H NMR (300 MHz CDCl3): δ 7.94 (d, J = 7.4 Hz,
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1H), 7.73–7.67 (m, 3H), 7.60–7.47 (m, 1H), 7.37–7.22 (m, 4H),
7.15 (d, J = 11.7 Hz, 1H), 5.68 (d, J = 16.5 Hz, 1H), 5.56 (d, J =
9.9 Hz, 1H). 13C NMR (CDCl3, 75 MHz): δ 141.28, 139.68,
139.45, 137.39, 135.65, 133.09, 128.35, 128.28, 127.42, 127.25,
127.20, 125.45, 123.84, 120.43, 120.17, 119.87. HRMS (EI+)
calcd for C16H12 (M+): 204.0939; found: 204.0942.
HPLC); IR (KBr): 3048, 1609, 1596, 1490, 1444, 860, 840,
1
770, 700 cm−1; H NMR (300 MHz, CDCl3): δ 7.41–7.28 (m,
5H), 7.18 (d, J = 4.8 Hz, 1H), 6.91–6.89 (m, 1H), 6.76–6.62 (m,
2H), 6.30 (td, J = 10.5 Hz, J = 17.1 Hz, 1H), 5.36 (d, J = 16.9
Hz, 1H), 5.08 (d, J = 10.1 Hz, 1H). 13C NMR (CDCl3,
75 MHz): δ 147.08, 139.04, 137.49, 137.74, 130.43, 128.67,
128.22, 127.94, 127.54, 126.75, 125.26, 118.87. HRMS (EI+)
calcd for C14H12S (M+): 212.0660, found: 212.0662.
Tricyclo[3.3.1.13,7]decane, 2-(2-propen-1-ylidene) (3e).19 The
title compound was obtained according to the general procedure.
Colourless oil; Yield: 85%; IR (KBr): 3042, 2908, 1674, 987,
2-(1-Phenylbuta-1,3-dienyl)naphthalene (3j). The title com-
pound was obtained according to the general procedure. White
solid; Yield: 86%; Compound purity: 98% (confirmed by
HPLC); IR (KBr): 3055, 1627, 1597, 1504, 1444, 899, 818,
1
968, 951, 890 cm−1; H NMR (400 MHz, CDCl3): δ 6.63 (td, J
= 10.6 Hz, J = 16.8 Hz, 1H), 5.78 (d, J = 11.0 Hz, 1H), 5.10 (d,
J = 16.8 Hz, 1H), 4.93 (d, J = 9.1 Hz, 1H), 3.03 (s, 1H), 3.38 (s,
1H), 1.96–1.74 (m, 12H). 13C NMR (CDCl3, 75 MHz): δ
152.70, 132.63, 118.25, 114.14, 40.89, 40.03, 39.19, 37.40,
33.04, 28.75. HRMS (EI+) calcd for C13H18 (M+): 174.1409;
found: 174.1410.
1
763, 700 cm−1; H NMR (300 MHz, CDCl3): δ 7.87–7.21 (m,
12H), 6.83 (dd, J = 11.0 Hz, J = 17.4 Hz, 1H), 6.55–6.43 (m,
1H), 5.43 (d, J = 16.8 Hz, 1H), 5.14 (t, J = 8.8 Hz, 1H). 13C
NMR (CDCl3, 75 MHz): δ 143.37, 143.32, 142.28, 139.88,
139.68, 137.37, 135.27, 133.57, 133.46, 133.08, 132.95, 130.77,
129.71, 129.30, 129.19, 128.72, 128.51, 128.30, 127.97, 127.85,
127.77, 127.27, 126.42, 126.37, 126.25, 125.63, 119.13, 119.05.
HRMS (EI+) calcd for C20H16 (M+): 256.1252, found: 256.1252.
1,2-Dichloro-4-(1-phenylbuta-1,3-dienyl)benzene
(3f). The
title compound was obtained according to the general procedure.
Colourless oil; Yield: 86%; Compound purity: 100% (confirmed
by HPLC); IR (KBr): 3058, 1549, 1493, 1469, 1445, 945, 908,
1
765, 700 cm−1; H NMR (300 MHz, CDCl3): δ 7.47–7.05 (m,
1-(Penta-2,4-dien-2-yl)benzene (3ka), 1-(penta-1,4-dien-2-yl)
benzene (3kb).12 The title compound was obtained according to
the general procedure. Colourless solid; Yield; 82%; IR (KBr):
8H), 6.70 (t, J = 10.7 Hz, 1H), 6.47–6.32 (m, 1H), 5.44 (d, J =
16.8 Hz, 1H), 5.20 (dd, J = 5.4 Hz, J = 9.7 Hz, 1H). 13C NMR
(CDCl3, 75 MHz): δ 142.44, 141.34, 141.04, 140.79,139.92,
138.74, 134.70, 134.32, 132.68, 132.38, 131.81, 131.55, 130.49,
130.30, 130.10, 129.99, 129.77, 129.44, 128.65, 128.15,128.09,
127.72, 127.03, 120.33, 120.27. HRMS (EI+) calcd for
C16H1235Cl2 (M+): 274.0316; found: 274.0316; HRMS (EI+)
calcd for C16H1237Cl2 (M+): 276.0287; found: 276.0280.
1
3081, 3057, 1599, 1494, 1445, 912, 863, 758, 698 cm−1; H
NMR (300 MHz, CDCl3): δ 7.46–7.21 (m, 5H), 5.90 (tdd, J =
6.6 Hz, J = 10.1 Hz, J = 16.7 Hz, 1H), 5.39 (s, 1H), 5.14–5.05
(m, 3H), 3.25 (d, J = 6.5 Hz, 2H). 13C NMR (75 MHz, CDCl3):
δ 146.77, 141.39, 136.66, 128.74, 127.92, 126.46, 116.95,
113.63, 39.97. HRMS (EI+): calcd. for C11H12 (M+): 144.0939;
found: 144.0938.
1-Methoxy-4-(1-phenylbuta-1,3-dienyl)benzene
(3g).20 The
title compound was obtained according to the general procedure.
Colourless oil; Yield: 72%; IR (KBr): 3055, 1604, 1510, 1462,
(E)-1-Bromo-4-(buta-1,3-dienyl)benzene (3l).22 The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 31%; IR (KBr): 3051, 2962, 1638, 1501, 1407,
1
1442, 1290, 966, 904, 832 cm−1; H NMR (300 MHz, CDCl3):
1
δ 7.40–7.13 (m, 7H), 6.93–6.80 (m, 2H), 6.65 (dd, J = 4.9, J =
10.9 Hz, 1H), 6.47–6.34 (m, 1H), 5.36 (dd, J = 9.0 Hz, J = 16.4
Hz, 1H), 5.10 (t, J = 11.9 Hz, 1H), 3.84–3.79 (m, 3H). 13C
NMR (CDCl3, 75 MHz): δ 159.47, 159.19, 143.09, 142.94,
142.75, 140.11, 135.36, 134.94, 131.90, 130.63, 129.96, 128.98,
128.51, 128.37, 127.95, 127.71, 127.57, 127.18, 121.02, 120.93,
118.47, 117.92,133.85, 133.78, 55.52, 55.50. HRMS (EI+) calcd
for C17H16O (M+): 236.1201; found: 236.1201.
807, 680 cm−1; H NMR (300 MHz, CDCl3): δ 7.42 (d, J = 8.3
Hz, 1H), 7.25 (d, J = 8.3 Hz, 1H), 6.75 (dd, J = 10.7 Hz, J =
15.1 Hz, 1H), 6.54–6.41 (m, 2H), 5.34 (d, J = 17.0 Hz, 1H),
5.20 (d, J = 10.5 Hz, 1H). 13C NMR (75 MHz, CDCl3): δ
134.30, 133.49, 129.14, 128.95, 127.72, 125.21, 118.76, 115.80.
HRMS (EI+): calcd for C11H10O2 (M+): 207.9888; found:
208.9612.
4-Methyl-1,1-diphenylpenta-1,3-diene (3ab).23 The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 41%; IR (KBr): 3045, 2973, 1614, 1505, 1463,
1-Methyl-3-(1-phenylbuta-1,3-dienyl)benzene (3h).21 The title
compound was obtained according to the general procedure. Col-
ourless oil; Yield: 88%; IR (KBr): 3055, 3025, 1666, 1601,
1
908, 835 cm−1; H NMR (300 MHz, CDCl3): δ 7.38–7.26 (m,
1
1492, 1445, 904, 787, 700 cm−1; H NMR (400 MHz, CDCl3):
10H), 6.87 (d, J = 11.2 Hz, 1H), 5.92 (d, J = 10.5 Hz, 1H), 1.89
(s, 3H), 1.76 (s, 3H). 13C NMR (CDCl3, 75 MHz): δ 143.39,
140.49, 140.01, 137.95, 130.87, 130.43, 128.41, 127.72, 127.30,
127.19, 124.78, 123.49, 26.79, 18.92. HRMS (EI+) calcd for
C18H18 (M+): 234.1409; found: 234.1412.
δ 7.38–7.03 (m, 9H), 6.70 (d, J = 10.9 Hz, 1H), 6.49–6.39 (m,
1H), 5.38 (d, J = 16.8 Hz, 1H), 5.12 (d, J = 9.9 Hz, 1H). 13C
NMR (CDCl3, 75 MHz): δ 143.72, 143.69, 142.58, 142.53,
140.17, 139.99, 138.19, 138.16, 135.52, 135.44, 131.38, 130.86,
128.87, 128.83, 128.78, 128.66, 128.62, 128.57, 128.53, 128.48,
128.02, 127.97, 127.90, 127.79, 125.32, 118.92, 118.89, 21.93,
21.90. HRMS (EI+) calcd for C17H16 (M+): 220.1252; found:
220.1253.
1,1-bis(4-Chlorophenyl)buta-1,3-diene (3bb). The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 33%; Compound purity: 99% (confirmed by
HPLC); IR (KBr): 3032, 1593, 1492, 1440, 915, 863, 765,
1
2-(1-Phenylbuta-1,3-dienyl)thiophene (3i). The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 82%; Compound purity: 100% (confirmed by
697 cm−1; H NMR (300 MHz, CDCl3): δ 7.35 (d, J = 8.2 Hz,
2H), 7.24 (d, J = 8.8 Hz, 2H), 7.17–7.11 (m, 4H), 6.83 (d, J =
11.4 Hz, 1H), 5.85 (d, J = 11.4 Hz, 1H), 1.88 (s, 3H), 1.77
2866 | Org. Biomol. Chem., 2012, 10, 2862–2869
This journal is © The Royal Society of Chemistry 2012

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Ethyl 3-(4-methoxyphenyl)-3-phenylacrylate (5g).29 The title
compound was obtained according to the general procedure. Col-
ourless oil; Yield: 68%; IR (KBr): 3058, 2980, 1720, 1604,
(s, 3H). 13C NMR (CDCl3, 75 MHz): δ 141.36, 139.37, 138.38,
137.39, 133.34, 133.10, 132.09, 128.80, 128.71, 128.58, 125.51,
122.93, 26.76, 18.91. HRMS (EI+) calcd for C18H1635Cl2 (M+):
302.0629; found: 302.0630; HRMS (EI+) calcd for C18H1637Cl2
(M+): 304.0600; found: 304.0642.
1511, 1462, 1251, 874, 833, 774, 699 cm−1
;
1H NMR
(300 MHz, CDCl3): δ 7.37–7.15 (m, 7H), 6.90 (d, J = 7.6 Hz,
1H), 6.83 (d, J = 7.8 Hz, 1H), 6.31 (s, 1H; E isomer), 6.27 (s,
1H; Z isomer), 4.06 (dq, J = 7.0 Hz, J = 14.2 Hz , 2H), 3.82 (d,
J = 9.9 Hz, 3H), 1.17 (t, J = 7.1 Hz, 3H; Z isomer), 1.10 (t, J =
7.1 Hz, 3H; E isomer). 13C NMR (CDCl3, 100 MHz): δ 166.50,
161.00, 159.98, 156.82, 156.52, 141.78, 139.51, 133.34, 131.26,
131.18, 129.99, 129.57, 129.32, 128.80, 128.54, 128.23, 128.08,
117.12, 115.60, 114.00, 113.46, 60.24, 60.12, 55.56, 55.45,
14.40, 14.28. HRMS (EI+) calcd for C18H18O3 (M+): 282.1256;
found: 282.1256.
1,1-Diphenylbut-1-en-3-yne (3ac).24 The title compound was
obtained according to the general procedure. Colourless oil;
Yield: 35%; IR (KBr): 3287, 3057, 3025, 1598, 1495, 1443,
1
849, 774, 763, 729, 697 cm−1; H NMR (300 MHz CDCl3): δ
7.44–7.30 (m, 10H), 6.02 (s, 1H), 3.00 (s, 1H). 13C NMR
(CDCl3, 100 MHz): δ 154.72, 141.35, 139.10, 130.17, 128.78,
128.56, 128.22, 106.25, 82.69, 81.76. HRMS (EI+) calcd for
C16H12 (M+): 204.0939; found: 204.0938.
Ethyl 3,3-diphenylacrylate (5a).25 The title compound was
obtained according to the general procedure. Colourless oil;
Yield: 89%; IR (KBr): 3057, 3026, 1723, 1617, 1575, 1492,
Ethyl 3-phenyl-3-m-tolylacrylate (5h).30 The title compound
was obtained according to the general procedure. Colourless oil;
Yield: 88%; IR (KBr): 3048, 2979, 1720, 1603, 1511, 1493,
1445, 875, 771, 697 cm−1 1H NMR (400 MHz, CDCl3): δ
;
1444, 833, 774, 699 cm−1 1H NMR (300 MHz, CDCl3): δ
;
7.36–7.21 (m, 10H), 6.36 (s, 1H), 4.04 (q, J = 6.9 Hz, 2H), 1.10
(t, J = 7.0 Hz, 3H). 13C NMR (CDCl3, 75 MHz): δ 166.36,
156.74, 141.05, 139.25, 129.64, 129.37, 128.62, 128.54, 128.35,
128.12, 117.73, 60.30, 14.26. HRMS (EI+) calcd for C17H16O2
(M+): 252.1150; found: 252.1152.
7.37–7.00 (m, 9H), 6.35 (s, 1H), 4.05 (dq, J = 2.3 Hz, J = 7.0
Hz , 2H), 2.35–2.32 (m, 3H), 1.11 (t, J = 7.1 Hz, 3H). 13C NMR
(CDCl3, 100 MHz): δ 166.62, 157.19, 157.07, 141.37, 141.29,
139.56, 139.41, 138.45, 137.84, 130.66, 130.10, 129.78, 129.58,
129.31, 128.80, 128.75, 128.51, 128.29, 128.21, 126.75, 126.06,
117.85, 117.79, 60.46, 21.86, 14.47. HRMS (EI+) calcd for
C18H18O2 (M+): 266.1307; found: 266.1305.
Ethyl 3,3-bis(4-chlorophenyl)acrylate (5b).26 The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 80%; IR (KBr): 3025, 1721, 1619, 1589, 1491,
(E)-ethyl 3-phenylbut-2-enoate (5ka).31 The title compound
was obtained according to the general procedure. Colourless oil;
Yield: 32%; IR (KBr): 3024, 1714, 1629, 1446, 1273, 873, 767,
1
1402, 880, 830, 768 cm−1; H NMR (300 MHz, CDCl3): δ 7.36
(d, J = 8.4 Hz, 2H), 7.30 (d, J = 8.6 Hz, 2H), 7.20 (d, J = 8.6
Hz, 2H), 7.13 (d, J = 8.4 Hz, 2H), 6.34 (s, 1H), 4.07 (q, J = 7.1
Hz, 2H), 1.15 (t, J = 7.1 Hz, 3H). 13C NMR (CDCl3, 75 MHz):
δ 165.85, 154.26, 139.08, 137.06, 136.00, 134.66, 130.79,
129.72, 128.96, 128.52, 118.38, 60.54, 14.26. HRMS (EI+)
calcd for C17H1435Cl2O2 (M+): 320.0371; found: 320.0371;
HRMS (EI+) calcd for C17H1437Cl2O2 (M+): 322.0341; found:
322.0350.
1
694 cm−1; H NMR (300 MHz, CDCl3): δ 7.49–7.26 (m, 5H),
6.13 (s, 1H), 4.22 (q, J = 7.1 Hz, 2H), 2.58 (s, 3H), 1.32 (t, J =
7.1 Hz, 3H). 13C NMR (CDCl3, 75 MHz): δ 167.21, 155.74,
142.46, 129.19, 128.71, 126.52, 117.40, 60.08, 18.18, 14.58.
HRMS (EI+) calcd for C12H14O2 (M+): 190.0994; found:
190.0993.
Ethyl 3-phenylbut-3-enoate (5kb).31 The title compound was
obtained according to the general procedure. Colourless oil;
Yield: 44%; IR (KBr): 3085, 1734, 1627, 1495, 1445, 906, 860,
Ethyl 3,3-diphenylacrylate (5c).27 The title compound was
obtained according to the general procedure. Colourless oil;
Yield: 82%; IR (KBr): 3039, 2969, 1688, 1592, 1495, 752,
1
776, 733, 701 cm−1; H NMR (300 MHz, CDCl3): δ 7.44–7.25
1
691 cm−1; H NMR (400 MHz, CDCl3): δ 7.24 (d, J = 8.0 Hz,
(m, 5H), 5.54 (s, 1H), 5.23 (s, 1H), 4.11 (q, J = 7.1 Hz, 2H),
3.51 (s, 2H), 1.18 (t, J = 7.0 Hz, 3H). 13C NMR (CDCl3,
100 MHz): δ 171.77, 141.42, 140.26, 128.80, 128.19, 126.24,
116.60, 61.21, 41.77, 14.52. HRMS (EI+) calcd for C12H14O2
(M+): 190.0994; found: 190.0995.
2H), 7.15 (d, J = 7.9 Hz, 2H), 6.91 (d, J = 7.8 Hz, 2H), 6.84 (d,
J = 7.9 Hz, 2H), 6.23 (s, 1H), 4.07 (q, J = 6.9 Hz, 2H), 3.82 (d,
J = 8.2 Hz, 6H), 1.16 (t, J = 6.7 Hz, 3H). 13C NMR (CDCl3,
75 MHz): δ 161.39, 155.65, 154.57, 151.38, 128.73, 126.17,
125.79, 124.94, 109.79, 108.61, 108.12, 54.82, 50.29, 50.17,
9.12. HRMS (EI+) calcd for C19H20O4 (M+): 312.1362; found:
312.1408.
(E)-ethyl 3-(benzo[d][1,3]dioxol-5-yl)acrylate (5n).32 The title
compound was obtained according to the general procedure.
White solid; Yield: 67%; IR (KBr): 3062, 2980, 1709, 1604,
Ethyl 2-(9H-fluoren-9-ylidene)acetate (5d).28 The title com-
pound was obtained according to the general procedure. Yellow
solid; Yield: 65%; IR (KBr): 3062, 2980, 1713, 1600, 1450,
1503, 1447, 1250, 980, 931, 853, 810 cm−1
;
1H NMR
(300 MHz, CDCl3): δ 7.59 (d, J = 15.9 Hz, 1H), 7.03–6.79 (m,
2H), 6.80 (d, J = 7.9 Hz, 1H), 6.26 (d, J = 15.9 Hz, 1H), 6.00 (s,
2H), 4.25 (q, J = 7.1 Hz, 2H), 1.33 (t, J = 7.1 Hz, 3H). 13C
NMR (CDCl3, 75 MHz): δ 167.39, 149.76, 148.54, 144.49,
129.11, 124.59, 116.42, 108.74, 106.69, 101.76, 60.61, 14.56.
HRMS (EI+) calcd for C12H12O4 (M+): 220.0736; found:
220.0740.
1
869, 780, 730 cm−1; H NMR (300 MHz, CDCl3): δ 8.89 (d, J
= 7.8 Hz, 1H), 7.62 (dd, J = 7.5 Hz, J = 15.5 Hz, 3H),
7.42–7.22 (m, 4H), 6.74 (s, 1H), 4.34 (q, J = 7.1 Hz, 2H), 1.39
(t, J = 7.1 Hz, 3H). 13C NMR (CDCl3, 75 MHz): δ 166.52,
148.46, 142.71, 140.94, 139.05, 135.39, 131.07, 130.75, 129.41,
128.25, 127.66, 121.44, 119.97, 119.77, 114.14, 60.90, 14.58.
HRMS (EI+) calcd for C17H14O2 (M+): 250.0994; found:
250.0991.
Ethyl 2,2-dimethyl-3-phenylbut-3-enoate (5kc).33 The title
compound was obtained according to the general procedure.
This journal is © The Royal Society of Chemistry 2012
Org. Biomol. Chem., 2012, 10, 2862–2869 | 2867

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Colourless oil; Yield: 73%; IR (KBr): 3083, 3056, 1731, 1626,
Institutions, the National Natural Science Foundation of China
(No. 21072143) for financial support.
1
1493, 1444, 1255, 909, 776, 703 cm−1; H NMR (300 MHz,
CDCl3): δ 7.27–7.15 (m, 5H), 5.32 (s, 1H), 5.15 (s, 1H), 4.10 (q,
J = 7.1 Hz, 2H), 1.39 (s, 6H), 1.17 (t, J = 7.1 Hz, 3H). 13C
NMR (CDCl3, 75 MHz): δ 176.69, 153.44, 142.02, 128.18,
128.04, 127.27, 114.66, 60.78, 47.80, 26.14, 14.21. HRMS
(EI+) calcd for C14H18O2 (M+): 218.1307; found: 218.1315.
Notes and references
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Ethyl 3-(4-chlorophenyl)-2,2-dimethylbut-3-enoate (5p). The
title compound was obtained according to the general procedure.
Colourless oil; Yield: 61%; Compound purity: 100% (confirmed
by HPLC); IR (KBr): 3024, 2980, 1729, 1630, 1489, 1399,
1
1253, 908, 908, 835 cm−1; H NMR (300 MHz, CDCl3): δ 7.24
3 (a) D. J. Ager, Org. Reactions, 1990, 38, 1; (b) L. F. van Staden,
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Soc. Jpn., 2005, 78, 195.
(d, J = 8.5 Hz, 2H), 7.09 (d, J = 8.5 Hz, 2H), 5.33 (s, 1H), 5.14
(s, 1H), 4.10 (q, J = 7.1 Hz, 2H), 1.38 (s, 6H), 1.18 (t, J = 7.0
Hz, 3H). 13C NMR (CDCl3, 75 MHz): δ 176.42, 152.30,
140.43, 133.21, 129.56, 128.19, 115.29, 61.07, 47.71, 26.03,
14.22. HRMS (EI+) calcd for C14H1735ClO2 (M+): 252.0917;
found: 252.0916; HRMS (EI++) calcd for C14H1737ClO2 (M+):
254.0888; found: 254.0888.
6 (a) W. A. Herrmann and M. Wang, Angew. Chem., Int. Ed. Engl., 1991,
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Ethyl 3-(4-methoxyphenyl)-2,2-dimethylbut-3-enoate (5q). The
title compound was obtained according to the general procedure.
Colourless oil; Yield: 82%; Compound purity: 99% (confirmed
by HPLC); IR (KBr): 3024, 1729, 1609, 1511, 1464, 1247, 909,
1
836 cm−1; H NMR (300 MHz, CDCl3): δ 7.09 (d, J = 8.5 Hz,
2H), 6.81 (d, J = 8.5 Hz, 2H), 5.27 (s, 1H), 5.12 (s, 1H), 4.11 (q,
J = 7.1 Hz, 2H), 3.79 (s, 3H), 1.38 (s, 6H), 1.18 (t, J = 7.0 Hz,
3H). 13C NMR (CDCl3, 75 MHz): δ 176.79, 158.88, 152.88,
134.38, 129.22, 114.05, 113.39, 60.91, 55.37, 47.84, 26.12,
14.23. HRMS (EI+) calcd for C16H20O3 (M+): 248.1412; found:
248.1414.
Ethyl 2-(3H-inden-1-yl)-2-methylpropanoate (5r). The title
compound was obtained according to the general procedure. Col-
ourless oil; Yield: 87%; Compound purity: 98% (confirmed by
HPLC); IR (KBr): 3073, 2975, 1736, 1636, 1399, 907, 776,
1
699 cm−1; H NMR (300 MHz, CDCl3): δ 7.45 (d, J = 7.1 Hz,
1H), 7.32 (d, J = 7.3 Hz, 1H), 7.25–7.15 (m, 2H), 6.36 (s, 1H),
4.11 (q, J = 7.1 Hz, 2H), 3.35 (s, 2H), 1.59 (s, 6H), 1.13 (t, J =
7.0 Hz, 3H). 13C NMR (CDCl3, 100 MHz): δ 177.08, 148.21,
145.24, 143.74, 127.98, 126.29, 124.86, 124.34, 120.88, 61.30,
43.87, 37.76, 25.76, 14.54. HRMS (EI+) calcd for C15H18O2
(M+): 230.1307; found: 230.1308.
Ethyl 2-methyl-3-phenylbut-3-enoate (5kd).34 The title com-
pound was obtained according to the general procedure. Colour-
less oil; Yield: 45%; IR (KBr): 3073, 2977, 1733, 1628, 1503,
1
1446, 767, 701 cm−1; H NMR 300 MHz, CDCl3): δ 7.40–7.25
(m, 5H), 5.39 (s, 1H), 5.23 (s, 1H), 4.10 (q, J = 7.1 Hz, 2H),
3.67 (q, J = 7.1 Hz, 1H), 1.39 (d, J = 7.08 Hz, 3H), 1.15 (t, J =
7.1 Hz, 3H). 13C NMR (CDCl3, 75 MHz): δ 174.66, 148.29,
141.29, 128.51, 127.82, 126.70, 114.11, 60.87, 44.77, 17.22,
14.26. HRMS (EI+) calcd for C13H16O2 (M+): 204.1150; found:
204.1151.
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Acknowledgements
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We gratefully acknowledge A Project Funded by the Priority
Academic Program Development of Jiangsu Higher Education
2868 | Org. Biomol. Chem., 2012, 10, 2862–2869
This journal is © The Royal Society of Chemistry 2012

View Article Online
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