The Journal of Organic Chemistry
Page 4 of 8
and the resulting reaction mixture was stirred overnight at
127.50, 127.45, 127.08, 116.91, 98.24; HRMS (ESI+, m/z): calcd.
for C11H11O2 [M+H]+: 175.0759, found 175.0760.
40°C.The reaction mixture was cooled to room temperature,
filtered over a Celite pad, and eluted with DCM. The solvents
were removed using under reduced pressure. The crude product
was purified by column chromatography on silica gel (hex-
anes/ethyl acetate).
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Vinyl 2-benzyl-3-butenoate (1g). The product was isolated as a
colourless oil from a silica column eluted by EtOAc/hexanes
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(1:10) in 20% yield (121 mg); H NMR (400 MHz, CDCl3): δ
7.23 – 7.08 (m, 6H), 5.84-5.75 (m, 1H), 5.13 – 5.01 (m, 2H), 4.79
(dd, J = 14.0, 1.7 Hz, 1H), 4.49 (dd, J = 6.3, 1.7 Hz, 1H), 3.35-
3.29 m, 1H), 3.06 (dd, J = 13.7, 7.7 Hz, 1H), 2.81 (dd, J = 13.7,
7.3 Hz, 1H); 13C NMR (100 MHz, CDCl3): δ 170.4, 141.2, 138.2,
134.5, 129.1, 128.4, 126.6, 118.3, 98.1, 51.7, 38.2; HRMS (ESI+,
m/z): calcd. for C13H15O2 [M+H]+: 203.1072, found 203.1073.
Vinyl 3-phenyl-4-pentenoate (1a). The product was isolated as a
colourless oil from a silica column eluted by EtOAc/hexanes
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(1:10) in 70% yield (424 mg); H NMR (400 MHz, CDCl3): δ
7.28-7.23 (m, 2H), 7.18-7.12 (m, 4H), 5.99 – 5.86 (m, 1H), 5.06 –
4.97 (m, 2H), 4.79 (dd, J = 14.0, 1.6 Hz, 1H), 4.48 (dd, J = 6.3,
1.6 Hz, 1H), 3.84 (q, J = 7.4 Hz, 1H), 2.82 – 2.69 (m, 2H).; 13C
NMR (100 MHz, CDCl3): δ 168.9, 142.1, 141.1, 139.9, 128.7,
127.5, 126.9, 115.1, 97.8, 45.3, 39.9; HRMS (ESI+, m/z): calcd.
for C13H15O2 [M+H]+: 203.1072, found 203.1070.
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Vinyl 2-phenyl-5-hexenoate (1h). The product was isolated as a
colourless oil from a silica column eluted by EtOAc/hexanes
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(1:10) in obtained with 20% yield (130 mg); H NMR (400 MHz,
CDCl3): δ 7.26 – 7.18 (m, 5H), 7.16 (dd, J = 10.0, 3.9 Hz, 1H),
5.75-5.65 (m, 1H), 4.95-4.76 (m, 2H), 4.78 (dd, J = 14.0, 1.6 Hz,
1H), 4.47 (dd, J = 6.3, 1.6 Hz, 1H), 3.55 (t, J = 7.6 Hz, 1H), 2.18-
2.09 (m, 1H), 1.96 (dd, J = 14.3, 6.9 Hz, 2H), 1.87 – 1.76 (m,
1H); 13C NMR (100 MHz, CDCl3): δ 171.0, 141.3, 138.1, 137.3,
128.7, 128.0, 127.5, 115.6, 97.9, 50.5, 32.3, 31.4; HRMS (ESI+,
m/z): calcd. for C14H17O2 [M+H]+: 217.1228, found 217.1229.
Vinyl 3-propyl-4-pentenoate (1b). The product was isolated as a
colourless oil from a silica column eluted by EtOAc/hexanes
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(1:10) in 12% yield (60,5 mg); H NMR (400 MHz, CDCl3): δ
7.19 (dd, J = 14.0, 6.3 Hz, 1H), 5.67-5.58 (m, 1H), 5.06 – 5.00 (m,
2H), 4.88 (dd, J = 14.0, 1.6 Hz, 1H), 4.54 (dd, J = 6.3, 1.4 Hz,
1H), 2.59 – 2.55 (m, 1H), 2.38 (ddd, J = 23.2, 15.0, 8.6 Hz, 2H),
1.35 (ddt, J = 20.4, 6.0, 5.4 Hz, 4H), 0.85 (t, J = 6.7 Hz, 3H); 13C
NMR (100 MHz, CDCl3): δ 169.6, 141.2, 140.7, 115.3, 97.5,
39.9, 39.8, 36.6, 20.0, 13.9; HRMS (ESI+, m/z): calcd. for
C10H17O2 [M+H]+: 169.1228, found 169,1228.
General procedure for the synthesis of 3-substituted-4-
pentenoic acids. To the mixture of allylic alcohol (10 mmol) and
triethyl orthoacetate (50 mmol) in toluene (30 mL) was added
propionic acid (0.5 mmol). The mixture was heated at 150oC for
15 hrs. The mixture was cooled and concentrated under reduced
pressure. The crude product was dissolved in methanol (5mL) and
a solution of potassium hydroxide (100 mmol) in water (25 mL)
was added. The mixture was refluxed for 2 hours.After cooling,
the solution was washed with ethyl ether and acidified with con-
centrated HCl to pH 2. The acidic solution was extracted with
ethyl acetate (3 x 20 mL) and combined organic phases were dried
over MgSO4, filtered and concentrated under vacuum. The crude
acid was purified by column chromatography on silica gel (hex-
anes/ethyl acetate).
Vinyl 3-(benzyloxymethyl)-4-pentenoate (1c). The product was
isolated as a colourless oil from a silica column eluted by
EtOAc/hexanes (1:10) in 63% yield (465 mg); 1H NMR (400
MHz, CDCl3): δ 7.35-7.21 (m, 6H), 5.82-5.73 (m, 1H), 5.19 –
5.09 (m, 2H), 4.86 (dd, J = 14.0, 1.5 Hz, 1H), 4.55 (dd, J = 6.3,
1.6 Hz, 1H), 4.51 (s, 2H), 3.54-3.50 (m, 1H), 3.42-3.38 (m, 1H),
2.96-2.94 (m, 1H), 2.71 – 2.64 (m, 1H), 2.48-2.42 (m, 1H); 13C
NMR (100 MHz, CDCl3): δ 169.5, 141.2, 138.2, 137.5, 128.4,
127.6, 127.5, 116.5, 97.6, 73.1, 72.6, 40.1, 36.3, HRMS (ESI+,
m/z): calcd. for C15H19O3 [M+H]+: 247.1334, found 247.1333.
Vinyl 2-cyclopent-1-acetate (1d). The product was obtained
from commercially available 2-cyclopent-1-acetic acid, the prod-
uct was isolated as a colourless oil from a silica column eluted by
EtOAc/hexanes (1:10) in 42% yield (190 mg); 1H NMR (400
MHz, CDCl3): δ 7.23 (dd, J = 14.0, 6.3 Hz, 1H), 5.72 (td, J = 4.3,
2.0 Hz, 1H), 5.61 (ddd, J = 5.8, 4.1, 2.0 Hz, 1H), 4.82 (dd, J =
14.0, 1.4 Hz, 1H), 4.50 (dd, J = 6.3, 1.4 Hz, 1H), 3.13 – 2.99 (m,
1H), 2.46 – 2.18 (m, 4H), 2.16 – 2.03 (m, 1H), 1.47-1.38 (m, 1H);
13C NMR (100 MHz, CDCl3): δ 169.9, 141.1, 133.3, 131.8, 97.5,
41.8, 40.0, 31.8, 29.6; HRMS (ESI+, m/z): calcd. for C9H13O2
[M+H]+: 153.0915, found 153.0917.
3-Phenyl-4-pentenoic acid. The product was obtained with 85%
yield (1.5 g) as a white crystals from hexane; mp 47 °C (Lit 48
°C); 1H NMR (400 MHz, CDCl3): δ 7.30-7.20 (m, 5H), 6.03-5.94
(m, 1H), 5.11-5.06 (m, 2H), 3.86 (q, J = 7.2 Hz, 1H), 2.78 (dd, J =
16.0, 7.6 Hz, 2H); 13C NMR (100 MHz, CDCl3): δ 177.9, 142.1,
139.9, 128.7, 127.5, 126.8, 115.0, 45.2, 39.9. The 1H and 13C
NMR data were in accordance with those reported in the litera-
ture.
3-Propyl-4-pentenoic acid. The product was isolated as an yel-
lowish oil from a silica column eluted by EtOAc/hexanes (15:85)
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in with 78% yield (1.1 g); H NMR (400 MHz, CDCl3): δ 11.06
Vinyl 2-phenyl-4-pentenoate (1e). The product was isolated as a
colourless oil from a silica column eluted by EtOAc/hexanes
(s, 1H), 5.71 – 5.56 (m, 1H), 5.06-5.00 (m, 2H), 2.60 – 2.46 (m,
1H), 2.35 (ddd, J = 23.2, 15.0, 8.6 Hz, 2H), 1.32 (ddt, J = 20.4,
6.0, 5.4 Hz, 4H), 0.89 (t, J = 6.7 Hz, 3H); 13C NMR (100 MHz,
CDCl3): δ 179.2, 140.7, 115.1, 39.9, 39.8, 36.6, 20.0, 13.9. The 1H
and 13C NMR data were in accordance with those reported in the
literature.
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(1:10) in 71% yield (430.2 mg); H NMR (400 MHz, CDCl3): δ
7.27 – 7.19 (m, 5H), 7.16 (dd, J = 12.3, 4.6 Hz, 1H), 5.71-5.61
(m, 1H), 5.04-4.96 (m, 2H), 4.79 (dd, J = 14.0, 1.6 Hz, 1H), 4.48
(dd, J = 6.3, 1.6 Hz, 1H), 3.62 (dd, J = 8.4, 7.1 Hz, 1H), 2.82 –
2.71 (m, 1H), 2.51-2.44 (m, 1H); 13C NMR (100 MHz, CDCl3): δ
178.3, 142.2, 140.2, 128.9, 127.8, 127.1, 115.3, 45.5, 40.2; HRMS
(ESI+, m/z): calcd. for C13H15O2 [M+H]+: 203.1072, found
203.1071.
3-(Benzyloxymethyl)-4-pentenoic acid. The product was isolat-
ed as an yellowish oil from
a silica column eluted by
EtOAc/hexanes (15:85) in 62% (1.36 g); 1H NMR (400 MHz,
CDCl3): δ 7.33-7.26 (m, 5H), 5.74-5.65 (m, 1H), 5.09-5.01 (m,
2H), 4.45 (s, 3H), 4.10 (d, J = 6.0 Hz, 1H), 4.02 (d, J = 6.0 Hz,
1H), 3.45 – 3.37 (m, 1H), 3.32 (dd, J = 9.3, 7.3 Hz, 1H), 2.83 (dd,
J = 13.4, 6.5 Hz, 1H), 2.56 (dd, J = 15.7, 6.0 Hz, 1H), 2.32 (dd, J
= 15.7, 7.9 Hz, 1H).; 13C NMR (100 MHz, CDCl3): δ 177.9,
138.4, 137.8, 132.5, 128.7, 128.6, 127.8, 116.6, 73.3, 72.8, 40.2.
The 1H and 13C NMR data were in accordance with those reported
in the literature.
Vinyl 2-vinylbenzoate (1f). The product was obtained from
commercially available 2-vinylbenzoic acid and isolated as an
yellowish oil from a silica column eluted by EtOAc/hexanes
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(1:10) in 68% yield (355 mg); H NMR (400 MHz, CDCl3): δ
7.91 (dd, J = 7.9, 1.1 Hz, 1H), 7.53 (d, J = 7.9 Hz, 1H), 7.49 –
7.35 (m, 3H), 7.28 (td, J = 7.8, 1.2 Hz, 1H), 5.59 (dd, J = 17.4, 1.2
Hz, 1H), 5.31 (dd, J = 11.0, 1.2 Hz, 1H), 4.97 (dd, J = 14.0, 1.6
Hz, 1H), 4.63 (dd, J = 6.3, 1.6 Hz, 1H); 13C NMR (100 MHz,
CDCl3): δ 164.04, 141.38, 140.48, 135.69, 132.79, 130.64,
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