UV [MeOH, nm (log )]: 225 (3.62), 271 (3.19). IR (film): 1647,
1
3.4.6. 4-O-tert-Butyldiphenylsilyl-(E)-p-coumaryl alcohol (21)
To a solution of 20 (5.00 g, 12.0 mmol) in dry THF (120 mL),
a solution of diisobutylaluminium hydride (DIBAL-H ,1.0 M in
THF, 26.4 mL, 2.20 equiv.) was added drop wise and the mixture
was stirred at 0 °C for 3 h. The resulting mixture was poured into
saturated aqueous NH4Cl and extracted with EtOAc. The EtOAc
extract was washed with brine then dried over anhydrous Na2SO4
and filtered. Removal of the solvent under reduced pressure gave
a residue, which was purified by normal-phase silica gel CC [180
g, n-hexane–EtOAc (15:1, v/v)] to give 21 (4.20 g, 90%); as a
colorless oil. Positive-ion ESIMS: m/z 411 [M + Na]+. High-
resolution positive-ion ESIMS: Calcd for C25H28O2SiNa [M +
Na]+: 411.1750. Found: 411.1750. IR (film): 3476, 1643, 1257,
1173, 1111 cm–1. 1H NMR (400 MHz, CDCl3) : 1.08 (9H, s, tert-
Bu), 4.23 (1H, d, J = 5.0 Hz, H-9), 6.15 (1H, dd, J = 5.0, 16.0 Hz,
H-8), 6.46 (1H, d, J = 16.0 Hz, H-7), 6.70 (2H, d, J = 8.7 Hz, H-
1508, 1458, 1396, 1172, 1111 cm–1. H NMR (400 MHz, CDCl3)
: 1.11 (18H, s, tert-Bu), 3.97–4.06 (2H, m, H2-9'), 4.71 (1H, d, J
= 6.9 Hz, H-7), [5.15 (1H, dd, J = 1.4, 11.9 Hz), 5.20 (1H, dd, J =
1.4, 18.3 Hz),H2-9], 5.90 (1H, ddd, J = 6.9, 11.9, 18.3 Hz, H-8),
6.07 (1H, dt, J = 16.0, 6.4 Hz, H-8'), 6.39 (1H, d, J = 16.0 Hz, H-
8'), [6.71 (2H, d, J = 8.7 Hz), 6.75 (2H, d, J = 8.7 Hz), H-3,5 and
H-3',5'], [7.07 (2H, d, J = 8.7 Hz), 7.11 (2H, d, J = 8.7 Hz), H-2,6
and H-2',6'], 7.34–7.50 (12H, m, arom.), 7.71–7.73 (8H, m,
arom.). 13C NMR (100 MHz, CDCl3) C: 19.4, 19.8 (2C each,
both s, tert-Bu), 26.46, 26.49 (6C each, both q, tert-Bu), 68.8 (t,
C-9'), 81.4 (d, C-7), 116.0 (t, C-9), 119.6, 119.7 (2C each, both d,
C-3,5 and C-3',5'), 124.0 (d, C-8'), 127.4, 127.9 (2C each, both C-
2,6 and C-2',6'), 127.71, 127.74 (8C each, both d, arom.), 129.79
(s, C-1'), 129.83, 129.9 (4C each, both d, arom.), 132.0 (d, C-7'),
132.8, 132.9 (2C each, both s, arom.), 133.3 (s, C-1), 135.4,
135.5 (8C each, both d, arom.), 138.9 (d, C-7), 155.0, 155.2 (2C
each, both s, C-4 and C-4').
3,5), 7.11 (2H, d, J = 8.7 Hz, H-2,6), 7.33–7.44 (6H, m, arom.),
13
7.68–7.70 (4H, m, arom.). C NMR (100 MHz, CDCl3) C: 19.4
(s, tert-Bu), 26.4 (3C, q, tert-Bu), 63.9 (t, C-9), 119.8 (2C, d, C-
3,5), 126.2 (d, C-8), 127.4 (2C, d, C-2,6), 127.8 (4C, d, arom.),
129.6 (s, C-1), 129.9 (2C, d, arom.), 131.1 (d, C-7), 132.7 (2C, s,
arom.), 135.5 (4C, d, arom.), 155.4 (s, C-4).
3.4.8.2. Compound 23. Colorless oil, []D25 –5.1 (c 3.75, CHCl3).
Positive-ion ESIMS: m/z 781 [M + Na]+. High-resolution
positive-ion ESIMS: Calcd for C50H54O3Si2Na [M + Na]+:
781.3504. Found: 781.3504.
25
3.4.7. 4-O-tert-Butyldiphenylsilyl-(E)-p-coumaryl bromide
(22)
3.4.8.3. Compound 23'. Colorless oil, []D +5.1 (c 5.75,
CHCl3). Positive-ion ESIMS: m/z 781 [M + Na]+. High-resolution
positive-ion ESIMS: Calcd for C30H54O3Si2Na [M + Na]+:
781.3504. Found: 781.3508.
To a solution of the alcohol 21 (3.90 g, 10.0 mmol) in dry
diethyl ether (Et2O, 100 mL), phosphorus tribromide (PBr3, 1.05
mL, 1.10 mmol) was added drop wise at 0 °C. After stirring for 3
h, the reaction mixture was poured into saturated aqueous
NaHCO3, and extracted with n-hexane. The n-hexane extract was
washed with brine then dried over anhydrous Na2SO4 and
filtered. Removal of the solvent under reduced pressure gave 22
(4.30 g, 95%); as a colorless oil. Positive-ion ESIMS: m/z 371 [M
– Br]+. High-resolution positive-ion ESIMS: Calcd for C25H27OSi
[M – Br]+: 371.1826. Found: 371.1825. IR (film): 1639, 1605,
1508, 1258, 1111 cm–1. 1H NMR (400 MHz, CDCl3) : 1.07 (9H,
s, tert-Bu), 4.10 (2H, d, J = 7.8 Hz, H2-9), 6.17 (1H, dt, J = 15.6,
7.8 Hz, H-8), 6.50 (1H, d, J = 15.6 Hz, H-7), 6.69 (2H, d, J = 8.7
3.4.9. Deprotection of phenylpropanoid ((±)-18, 18, or 18')
To a solution of (±)-18 (194.5 mg, 0.50 mmol) in dry THF
(2.0 mL) in the presence of acetic acid (AcOH, 36.0 mg, 34.3
L), tetra-n-butylammonium fluoride (1 M in THF, 0.6 mL) was
added dropwise at 0 °C. After stirring for 3 h, the reaction
mixture was poured into brine, then extracted with EtOAc. The
organic layer was washed with saturated aqueous NaHCO3 and
brine, then dried over anhydrous Na2SO4 and filtered. Removal
of the solvent under reduced pressure gave a residue, which was
purified by normal-phase silica gel CC [10 g, n-hexane–EtOAc
(2:1, v/v)] to give (±)-25 (69.0 mg, 92%). According to a similar
procedure, optically active 25 (68.0 mg, 90%) or 25' (71.0 mg,
94%) was obtained from 18 or 18' (194.5 mg, 0.50 mmol).
Hz, H-3,5), 7.11 (2H, d, J = 8.7 Hz, H-2,6), 7.33–7.43 (6H, m,
13
arom.), 7.67–7.70 (4H, m, arom.). C NMR (100 MHz, CDCl3)
C: 19.5 (s, tert-Bu), 26.5 (3C, q, tert-Bu), 34.3 (t, C-9), 120.0
(2C, d, C-3,5), 123.1 (d, C-8), 127.9 (6C, d, C-2,6 and arom.),
128.9 (s, C-1), 130.0 (2C, d, arom.), 132.7 (2C, s, arom.), 134.4
(d, C-7), 135.5 (4C, d, arom.), 156.0 (s, C-4).
3.4.9.1. Racemic 1'-hydroxychavicol ((±)-25). Colorless oil.
Negative-ion ESIMS: m/z 149 [M – H]–. High-resolution
negative-ion ESIMS: Calcd for C9H9O2 [M – H]–: 149.0597.
Found: 149.0595. UV [MeOH, nm (log )]: 229 (4.94), 273
(4.38). IR (film): 3422, 1639, 1512, 1447, 1377, 1238, 1173 cm–1.
1H NMR (400 MHz, CD3OD) : 4.93 (1H, d, J = 6.0 Hz, H-7),
[4.99 (1H, dd, J = 1.4, 10.5 Hz), 5.14 (1H, dd, J = 1.4, 17.4 Hz),
H2-9], 5.90 (1H, ddd, J = 6.0, 10.5, 17.4 Hz, H-8), 6.64 (2H, d, J
= 8.2 Hz, H-3,5), 7.06 (2H, d, J = 8.2 Hz, H-2,6). 13C NMR (100
MHz, CD3OD) C: 75.8 (d, C-7), 114.3 (t, C-9), 116.0 (2C, d, C-
3,5), 128.9 (2C, d, C-2,6), 135.4 (s, C-1), 142.4 (d, C-8), 157.9
(s, C-4).
3.4.8. Coupling reaction of secondary alcohol ((±)-18, 18, or
18') and bromide 22
A solution of (±)-18 (780 mg, 2.00 mmol) in dry THF (10
mL) was treated with sodium hydride (NaH, 50.4 mg, 1.05
equiv.) at room temperature for 30 min. Then the reaction
mixture was treated with 22 (900 mg, 2.0 mmol, 1.00 equiv.) and
sodium iodide (NaI, 30.0 mg, 0.20 mmol, 0.1 equiv.) at room
temperature for 12 h. The resulting mixture was poured into
saturated aqueous NH4Cl and extracted with EtOAc. The organic
layer was washed with brine then dried over anhydrous Na2SO4
and filtered. Removal of the solvent under reduced pressure gave
a residue, which was purified by normal-phase silica gel CC [50
g, n-hexane–EtOAc (40:1, v/v)] to give (±)-23 (1.00 g, 66%).
According to the similar procedure, optically active 23 (590 mg,
78%) or 23' (570 mg, 75%) was obtained from 18 or 18' (390
mg, 1.00 mmol).
3.4.9.2. Compound 25. Colorless oil, []D24 –49.5 (c 1.00, EtOH).
Negative-ion ESIMS: m/z 149 [M – H]–. High-resolution
negative-ion ESIMS: Calcd for C9H9O2 [M – H]–: 149.0597.
Found: 149.0595.
24
3.4.9.3. Compound 25'. Colorless oil, []D +49.5 (c 1.00,
EtOH). Negative-ion ESIMS: m/z 149 [M – H]–. High-resolution
negative-ion ESIMS: Calcd for C9H9O2 [M – H]–: 149.0597.
Found: 149.0595.
3.4.8.1. Racemic compound (±)-23. Colorless oil. Positive-ion
ESIMS: m/z 781 [M + Na]+. High-resolution positive-ion ESIMS:
Calcd for C50H54O3Si2Na [M + Na]+: 781.3504. Found: 781.3501.