Guan et al.
FULL PAPER
1.98—1.92 (m, 6H), 1.92—1.83 (m, 2H), 1.46—1.28
(m, 20H), 0.89 (t, J=7.0 6H); FT-IR (film) ν: 2955,
2927, 2855, 1465, 1438,+1377, 1257, 722, 671, 542
(71), 97 (69), 83 (66), 41 (43), 57 (40), 125 (37).
EI-HRMS calcd for C19H37Br (M+) 344.2079, found
344.2084.
tion of imidazole (1.36 g, 20 mmol) in THF (10 mL).
The mixture was stirred for 30 min (when the exother-
mic reaction subsided), water was added to the milky
mixture. The mixture was extracted with EtOAc,
washed with water and brine, and dried over anhydrous
Na2SO4. The solvent was removed on a rotary evapora-
tor to give the N-acyl-imidazole 22 (1.65 g, 9.2 mmol,
92%) as a yellowish solid.
-1
cm ; EI-MS m/z: 344 (M , 13), 111 (100), 69 (92), 55
Methyl (R)-10-tert-butyldimethylsilyloxy-4-hydr-
-1
-1
oxy-dec-6-ynoate (19) n-BuLi (2.5 mol•L , in hex-
n-BuLi (2.5 mol•L , in hexanes, 3.5 mL, 8.75 mmol)
anes, 0.48 mL, 1.2 mmol) was added to a solution of
alkyne 17 (130 mg, 1.0 mmol) in dry THF (3 mL)
stirred at -78 ℃ under argon. The mixture was
stirred at the same temperature for 20 min. BF3•Et2O
(0.15 mL, 1.2 mmol) was then added. Stirring was con-
tinued at -78 ℃ for another 20 min before neat ep-
oxide 5 (130 mg, 1.0 mmol) was introduced. The mix-
ture was stirred at -78 ℃ for 2 h. Aq. sat. NH4Cl was
added. The mixture was extracted with Et2O, washed
with water and brine, and dried over anhydrous Na2SO4.
Removal of the solvent by rotary evaporation and col-
umn chromatography (5∶ 1 PE/EtOAc) on silica gel
gave alcohol 19 (213 mg, 0.65 mmol, 65%) as a color-
was added to a solution of Ph3PCH3I (3.35 g, 8.7 mmol)
in dry THF (50 mL) stirred at ambient temperature. The
mixture was stirred at the same temperature for 7 h. A
solution of the above prepared 22 (0.729 g, 4.05 mmol)
in dry THF (10 mL) was added. Stirring was continued
at ambient temperature for 1 h. Aq. sat. NaHCO3 was
added. The mixture was extracted with Et2O, washed
with water and brine, and dried over anhydrous Na2SO4.
Removal of the solvent by rotary evaporation and col-
umn chromatography (EtOAc) on silica gel afforded the
known7 Wittig reagent 16 (1.141 g, 2.94 mmol, 73%
from 22) as a colorless oil.
Dess-Martin periodinane (67 mg, 0.16 mmol) and
NaHCO3 (20 mg, 0.24 mmol) were added to solution of
alcohol 20 (15 mg, 0.08 mmol) in CH2Cl2 (3 mL) stirred
at ambient temperature. The mixture was stirred at the
same temperature for 1 h 20 min before being diluted
with Et2O. Solids were filtered off through Celite. The
filtrate and washings were combined and centrated on a
rotary evaporator. The residue was chromatographed
(3∶ 1 PE/EtOAc) on silica gel to give aldehyde 15 (12
mg, 0.066 mmol, 83% from 20) as a colorless oil. [α]D27
+21.7 (c 0.27, CHCl3); 1H NMR (CDCl3, 400 MHz) δ:
7.27 (s, 1H), 4.63—4.56 (m, 1H), 2.67—2.61 (m, 2H),
2.58—2.46 (m, 6H), 2.42—2.33 (m, 1H), 2.13—2.04
(m, 1H); 13C NMR (CDCl3, 100 MHz) δ: 200.4, 176.8,
81.3, 77.8, 74.9, 42.6, 28.5, 26.5, 25.5, 11.9; FT-IR
(film) ν: 2923, 2852, 2731, 1770, 1727, 1461, 1418,
less oil. [α]27 +3.19 (c 0.75, CHCl3); 1H NMR (CDCl3,
D
300 MHz) δ: 3.626 (t, J=5.8 Hz, 2H), 3.633 (s, 3H),
2.44 (t, J=7.6 Hz, 2H), 2.35—2.27 (m, 2H), 2.22—
2.18 (m, 3H), 1.82—1.76 (m, 2H), 1.66—1.62 (m, 3H),
0.84 (s, 9H), 0.02 (s, 6H); 13C NMR (CHCl3, 75 MHz) δ:
174.3, 83.0, 75.7, 69.5, 61.6, 51.7, 31.9, 31.0, 30.4, 27.8,
25.9, 18.3, 15.1, -5.4; FT-IR (film) ν: 3463, 2952,
2929, 2857, 1741, 1472, 1437, 1361, 1256, 1103, 8+36,
- 1
776, 663 cm ; ESI-MS m/z: 351.2 ([M+Na] );
ESI-HRMS calcd for C17H32O4SiNa ([M + Na] +
)
351.1962, found 351.1968.
(R)-6-(Dihydrofuran-2-one-5-yl)-hex-4-yn-1-ol (20)
A solution of 19 (37 mg, 0.11 mmol) and p-TsOH•H2O
(2 mg, 0.01 mmol) in toluene (1.0 mL) was stirred at
ambient temperature for 5 h. The mixture was diluted
with Et2O, washed with water and brine, and dried over
anhydrous Na2SO4. Removal of the solvent by rotary
evaporation and column chromatography (3∶ 1 PE/
EtOAc) on silica gel afforded the lactone-alcohol 20 (17
mg, 0.093 mmol, 85%) as a colorless oil. [α]2D7 +17.7
(c 0.75, CHCl3); 1H NMR (CDCl3, 400 MHz) δ: 4.65—
4.59 (m, 1H), 3.73 (t, J=6.2 Hz, 2H), 2.68—2.49 (m,
4H), 2.43—2.35 (m,1H), 2.31—2.26 (m, 2H), 2.16—
2.06 (m, 1H), 1.77—1.70 (m, 2H); 13C NMR (CDCl3,
75 MHz) δ: 177.1, 82.7, 78.0, 74.3, 61.5, 31.2, 28.5,
26.4, 25.5, 15.2; FT-IR (film) ν: 3420, 2925, 1769, 1458,
-1
1353, 1176, 1017, 920, 849, 801, 650 cm .
A solution of the above prepared aldehyde 15 (10
mg, 0.055 mmol) and the Wittig reagent 16 (46 mg,
0.12 mmol) in CHCl3 (2 mL) was stirred at ambient
temperature for 24 h. The solvent was removed on a
rotary evaporator. The residue was chromatographed
(3∶ 1 PE/EtOAc) on silica gel to deliver enone 14 (a
1∶ 4 mixture of (Z)/(E) isomers, 15 mg, 0.05 mmol,
91%) as a colorless oil. Pure sample of the major isomer
(E)-14 could be obtained by repeated chromatography,
which gave the following data: [α]2D4 +12.48 (c 0.40,
-1
1
1421, 1352, 1180, 1031, 922, 649 cm ; ESI-MS m/z:
CHCl3); H NMR (CDCl3, 300 MHz) δ: 6.81 (dt, J=
205.0 ([M+Na]+). ESI-HRMS calcd for C10H14O3Na
15.8, 6.3 Hz, 1H), 6.14 (d, J=16.0 Hz, 1H), 4.67—4.48
(m, 1H), 2.63—2.52 (m, 6H) 2.51—2.28 (m, 5H),
2.15—2.04 (m, 1H), 1.65—1.54 (m, 2H), 1.37—1.22
(m, 6H), 0.88 (t, J=6.6 Hz, 3H);13C NMR (CDCl3, 75
MHz) δ: 200.7, 176.8, 144.3, 131.1, 81.6, 77.9, 75.0,
40.3, 31.6, 31.4, 28.9, 28.5, 26.5, 25.4, 24.1, 22.5, 17.7,
14.0; FT-IR (film) ν: 2954, 2927, 2855, 1778, 1695,
1672, 1-630, 1460, 1371, 1351, 1216, 1+178, 1035, 977,
([M+Na]+) 205.0835, found 205.0845.
5-((E/Z)-8-Oxo-tetradec-6-en-2-ynyl)-dihydro-fur-
an-2-one (14) A mixture of n-hexanoic acid 18 (13.0
g, 100 mmol) and SOCl2 (59 mL) was heated to reflux
for 2 h. Excess SOCl2 was distilled off and the acid hal-
ide 21 (9.0 g, 60 mmol, 60%) was isolated by distilla-
tion as a colorless liquid with pungent smell. A portion
of the 21 (1.48 g, 10 mmol) was added slowly to a solu-
1
919 cm ; ESI-MS m/z: 291.1 ([M+H] ), 313.1 ([M+
1616
© 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2010, 28, 1613— 1617