Vol. 30, No. 3 (2018)
Palladium(II) Acetate as Catalyst in Transvinylation Reactions of Hydroxycinnamic Acid and Its Derivatives 591
1
3
1
1
1
(
(
6.1 Hz, Ph-CH-CH-CO). C NMR (125 MHz, CDCl
3
, δ, ppm):
(1C, Ar-C), 120.70 (1C, Ar-C), 114.22 (1C, benz-CH), 97.63
(1C, CH -Vin), 26.04 (3C, (CH )-C), 26.00 (3C, (CH )-C),
18.65 (1C, C-CH ), 18.60 (1C, C-CH ), -3.91 (2C, (CH -Si),
-3.95 (2C, (CH -Si). HRMS (EI): m/z: calcd. for C23 Si
[M] , 434.2309; found 434.2306.
Synthesis of vinyl 2,2-dimethylbenzo[d][1,3]dioxol-
cinnamate (16): In a two-necked flask, compound 15 (1.0
mmol, 220 mg), vinyl acetate (16 mmol, 1.4 g, 1.5 mL) and
palladium(II) acetate (0.1 mmol, 9 mg) were added. After
stirring for 10 min at room temperature, potassium hydroxide
(0.1 mmol, 6 mg) was added and the mixture was stirred for
4 h at 40 °C. The reaction mixture was filtered through celite
and the filtrate was concentrated by an evaporator and purified
by column chromatography to give compound 16 as a pale
64.3 (1C, carboxylic-C), 158.4 (1C, Ar-C), 146.5 (1C, Ph-C),
41.5 (1C,Ar-C), 130.1 (1C, CH-Vin), 127.5 (2C,Ar-C), 120.7
2
3
3
3
3
)
3 2
2C,Ar-C), 114.3 (1C, benz-C), 97.5 (1C, CH
CH )-C), 18.3 (1C, C-CH ), -4.3 (2C, (CH -Si). HRMS (EI):
Si [M] , 304.1495; found 304.1488.
2
-Vin), 25.7 (3C,
3
)
2
H
38
O
4
2
+
3
3
)
3 2
+
m/z: calcd. for C17
H
24
O
3
Synthesis of vinyl 4-tert-butyldimethylsiloxy-3-methoxy-
cinnamate (12): 4-tert-Butyldimethylsiloxy-3-cinnamic acid
11) (1.0 mmol, 317 mg) was placed into a two-necked flask.
To this vinyl acetate (16 mmol, 1.4 g, 1.5 mL) and palladium(II)
acetate (0.1 mmol, 9 mg) were also added and the reaction
mixture was stirred for 30 min at room temperature. Then,
KOH (0.1 mmol, 6 mg) was added and the reaction mixture
was stirred for 4 h at 40 °C. The mixture was filtered through
celite and the filtrate was concentrated using evaporator and
purified with column chromatography over silica to give 50 %
(
yellow oil (84 %). TLC (n-hexane: EtOAc, 4: 1 v/v): R = 0.64.
f
-1
IR (film, νmax, cm ): 3087 (C-H, alkene), 2992 (C-H, methyl),
the desired product 12. (n-hexane:EtOAc, 30:1, R
f
= 0.40). IR
film, νmax, cm ): 3086 (C-H, alkene), 3047 (C-H, aromatic),
929 (C-H, methyl), 1727 (C=O, carbonyl), 1511 (C=C, aromatic),
1727 (C=O, carboxyl, 1496 (C=C, aromatic), 951 (C-H, vinyl),
-1
1
(
2
1
809 (C-H, vinyl terminal). H NMR (500 MHz, CDCl
3
, δ, ppm):
1.69 (s, 6H, (CH ) -C), 4.61 (dd, 1H, J = 6.3, 1.7 Hz, CH-C-
3
2
1
146 (C-O, ester), 1036 (C=CH
CDCl , δ, ppm): 0.12 (s, 6H, (CH
.78 (s, 3H, CH -O), 4.56 (dd, 1H, J = 6.3, 1.7 Hz, CH-C-vinyl),
.90 (dd, 1H, J = 14.0, 1.4 Hz, CH-C-vinyl), 6.26 (d, 1H, J =
5.5 Hz, CO-CH-CH-Ph), 6.80 (d, 1H, J = 8.0 Hz), 6.99 (t,
H, J = 4.9 Hz), 7.37 (1H, dd, J = 14.3, 6.3 Hz), 7.67 (d, 1H,
2
, vinyl). H NMR (500 MHz,
vinyl), 4.96 (dd, 1H, J = 13.7, 1.7 Hz, CH-C-vinyl), 6.25 (d,
1H, J = 15.5 Hz, CO-CH-CH-Ph), 6.71-7.01 (m, 3H, Ar-H),
7.42 (dd, 1H, J = 13.7, 6.3 Hz, O-CH-vinyl), 7.69 (d, 1H, J =
3
3 2
) -Si)), 0.94 (s, 9H, (CH C),
)
3 3
3
4
1
2
3
13
13
15.5 Hz, Ph-CH-CO). C NMR C NMR (125 MHz, CDCl ,
3
δ, ppm): 164.4 (1C, C=O, carboxyl), 150.1 (1C, Ar-C), 148.4
(1C, Phenyl-C), 146.8 (1C, Ar-C), 141.5 (1C, CH-vin), 128.1
13
J = 16.0 Hz, Ph-CH-CH-CO). C NMR (125 MHz, CDCl
3
, δ,
(1C, C-(CH
(1C, Ar-C), 108.6 (1C, Ar-C), 106.5 (1C, Benz-C), 97.6 (1C,
CH -Vin), 26.0 (2C, CH -C). HRMS (EI): m/z: calcd. for C14
[M] , 246.0892; found, 246.0899.
3
)
2 2
O ), 124.8 (1C, Ar-C), 119.2 (1C, Ar-C), 113.9
ppm): 164.3 (1C, carboxylic-C), 151.3 (1C, Ar-C), 148.1 (1C,
Ph-CH), 146.9 (1C, Ar-C), 141.5 (1C, CH-Vin), 128.1 (1C,
Ar-C), 122.7 (1C, Ar-C), 121.2 (1C, Ar-C), 114.3 (1C, Ar-C),
2
+
3
H O
14 4
1
2
11.0 (1C, benz-CH), 97.5 (1C, CH
5.7 (3C, (CH )-C), 18.6 (1C, C-CH
Si [M] , 334.1600; found
2
-Vin), 55.5 (1C, CH
3
-O),
-Si).
Synthesis of vinyl 3,4-diacetoxycinnamate (18): In a
two-necked flask compound 17 (1 mmol, 290 mg), THF (1 mL),
vinyl acetate (16 mmol, 1.4 g, 1.5 mL) and palladium(II) acetate
(0.1 mmol, 9 mg) were added. The reaction mixture was stirred
for 30 min at room temperature. Thereafter, 10 % w/w of sulfuric
acid in THF (1 drop) was added and the mixture was stirred
for 4 h at 40 ºC. The mixture was filtered through celite and
the filtrate was extracted with ethyl acetate (15 mL × 3) then
washed with saturated brine (15 mL × 2). The organic layer
was dried over sodium sulfate and concentrated using an evapo-
rator. Purification was done by column chromatography to
give compound 18 as pale yellow oil (84 %). TLC (n-hexane:
3
3
), -4.5 (2C, (CH
)
3 2
+
HRMS (EI): m/z: calcd. for C18
34.1605.
Synthesis of vinyl 3,4-di-tert-butyldimethylsiloxycinna-
H
26
O
4
3
mate (14): To a two-neck flask, 3,4-di-tert-butyldimethylsiloxy-
cinnamic acid (13) (613 mg, 1.5 mmol), vinyl acetate (2.3 mL,
2
added. The reaction mixture was stirred at room temperature
for 10 min and subsequently, KOH (10 mg, 0.15 mmol) was
added. The reaction mixture was stirred at 40 ºC for 4 h, then
diluted with 20 mL of EtOAc, filtered through celite and concen-
trated by evaporator under reduced pressure. Purification was
done over column chromatography on silica gel (n-hexane:
EtOAc, 5:1, v/v) to give 580 mg of compound 14, as yellow
4 mmol) and palladium(II) acetate (18 mg, 0.15 mmol) were
-1
EtOAc, 3: 1 v/v): R
alkene), 2932 (C-H, methyl), 1722 (C=O, carbonyl), 1506 (C=C,
aromatic), 1167 (C-O, ester), 903 (C=CH
f
= 0.30. IR (film, νmax, cm ): 3090 (C-H,
1
2
, vinyl). H NMR
),
liquid. (R
f
= 0.82 on n-hexane:EtOAc, 4:1, v/v). Yield: 81 %.
(500 MHz, CDCl , δ, ppm): 2.31 (s, 3H, CH ), 2.32 (s, 3H, CH
3
3
3
-1
IR (film, νmax, cm ): 3005 (C-H, alkene), 2958 (C-H, methyl),
4.65 (dd, 1H, J = 6.3, 1.7 Hz, CH-C-vinyl), 4.98 (dd, 1H, J =
13.7, 1.7 Hz, CH-C-vinyl), 6.40 (d, 1H, J = 16.0 Hz, CO-CH-
CH-Ph), 7.24 (d, 1H, J = 8.6 Hz, O-CH-vinyl), 7.38-7.45 (m,
1
1
713 (C=O, ester), 1558 (C=C, aromatic), 1508 (C=C, aromatic),
269 (Si-CH ), 1152 (C-O, ester), 1092 (Si-O), 915 (C=CH
, δ, ppm): 0.22 (s, 6H,
-Si), 0.99 (s, 9H, (CH C), 1.00
C), 4.62 (dd, 1H, J = 6.6, 1.4 Hz, CH-C-vinyl),
.97 (dd, 1H, J = 14.0, 1.4 Hz, CH-C-vinyl), (6.25 (d, 1H, J =
3
2
,
1
13
Vinyl). H NMR (500 MHz, CDCl
3
3H, aromatic-H), 7.73 (d, 1H, J= 16.0 Hz, Ph-CH-CO). C NMR
(CH
3
)
2
-Si), 0.23 (s, 6H, (CH
)
3 2
3
)
3
(125 MHz, CDCl , δ, ppm): 168.0 (1C, C=O, acetyl), 167.9
3
(s, 9H, (CH
3
)
3
(1C, C=O, acetyl), 163.4 (1C, C=O, ester), 144.6 (1C, Ar-C),
143.8 (1C, phenyl-C), 142.5 (1C, Ar-C), 141.2 (1C, CH-vin),
132.8 (1C, Ar-C), 126.6 (1C, Ar-C), 124.0 (1C, Ar-C), 122.9
4
1
7
6.0 Hz, CO-CH-CH-Ph), 6.83 (d, 1H, J = 9.2 Hz, Ar-H),
.03-7.05 (m, 2H,Ar-H), 7.42 (dd, 1H, J = 13.7, 6.3 Hz, O-CH-
(1C,Ar-C), 117.7 (1C, benz-C), 97.9 (1C, CH
CH ), 20.5 (1C, CH ). HRMS (EI): m/z: calcd. for C15
[M] : 290.0790; found: 290.0786.
2
-Vin), 20.6 (1C,
13
vinyl), 7.67 (d, 1H, J = 16.0 Hz, Ph-CH-CH-CO). C NMR
3
+
3
H
14
O
6
(
(
(
125 MHz, CDCl , δ, ppm): 164.41 (1C, Carboxylic-C), 150.08
1C, Ar-C), 147.40 (1C, Ph-CH), 146.81 (1C, Ar-C), 141.54
1C, CH-Vin), 127.84 (1C, Ar-C), 122.78 (1C, Ar-C), 121.32
3
Synthesis of vinyl 3,4-dibenzyloxycinnamate (20): In a
two-necked flask, compound 19 (1.0 mmol, 360 mg), vinyl