10744
Q.-Q. Xu et al. / Tetrahedron 69 (2013) 10739e10746
yield). Rf (Petroleum ether/ethyl acetate¼2:1) 0.45. [
0.30, DMSO). 1H NMR (400 MHz, CDCl3)
a
]
20 þ104.7 (c
1.8 mmol) in THF (2 mL) and stirred for 3 h at rt. The reaction
mixture was quenched with satd NH4Cl aq solution (5 mL), and was
extracted with AcOEt (20 mLꢂ3). The combined organic layer was
washed with brine (20 mL), dried over Na2SO4, The solvent was
removed under reduced pressure, and the crude product was pu-
rified by column chromatography (Petroleum ether/ethyl acetate
10:1) to give 17 as colorless oil (153 mg, 91%). Rf (Petroleum ether/
D
d
7.23 (d, J¼8.2 Hz, 2H),
6.76 (d, J¼8.2 Hz, 2H), 6.24 (d, J¼16.2 Hz, 1H), 6.04 (d, J¼16.2 Hz,
1H), 5.88 (dd, J¼17.3,10.7 Hz,1H), 5.69e5.53 (m, 2H), 5.38 (br s,1H),
5.09e4.95 (m, 2H), 2.21 (d, J¼5.7 Hz, 2H), 1.51 (br s, 1H), 1.30 (s, 6H),
1.16 (s, 3H). 13C NMR (100 MHz, CDCl3)
d 154.9, 145.5, 140.9, 135.2,
130.5,127.3,126.8,123.2,115.4,112.2, 71.0, 43.8, 42.6, 29.8, 23.5. ESI-
MS: Calcd for C18H23Oþ2 [MꢁH]: 271.1, found: 271.2, HRMS(ESI):
Calcd for C18H25Oþ2 [MþH]: 273.1849, found: 273.1849.
27.5
20
ethyl acetate¼5:1) 0.49. [
a
]
ꢁ12.4 (c 1.03, CHCl3). [lit.:10
[a]
D
D
ꢁ16.9 (c 1.23, CHCl3)]. 1H NMR (400 MHz, CDCl3)
5.71 (dd, J¼17.2,
d
10.8 Hz, 1H), 5.18 (dd, J¼10.9, 1.3 Hz, 1H), 5.07 (m, 2H), 3.39 (d,
J¼10.6 Hz, 1H), 3.33 (d, J¼10.6 Hz, 1H), 1.90 (m, 2H), 1.67 (s, 3H), 1.58
4.1.14. (S)-3-(((tert-Butyldiphenylsilyl)oxy)methyl)-3-methylpent-4-
en-1-ol(14f). DIBALH (26 mL, 39.2 mmol, 1.5 M in toluene) was
added dropwise to the stirred solution of 6f (7.80 g, 17.8 mmol) in
CH2Cl2 (50 mL) at ꢁ40 ꢀC, and the solution was stirred for 3 h. The
reaction was quenched with satd NH4Cl aq solution (30 mL) very
slowly, and the mixture was diluted with 1 N HCl (50 mL) and was
extracted with AcOEt (200 mLꢂ3). The combined organic layer was
washed with brine and dried over Na2SO4. The solvent was re-
moved under reduced pressure, and the crude product was purified
by column chromatography (Petroleum ether/ethyl acetate 10:1) to
(s, 3H), 1.34 (m, 2H), 1.03 (s, 3H). 13C NMR (100 MHz, CDCl3)
d 143.8,
131.4, 124.5, 114.7, 70.0, 42.3, 37.1, 25.6, 22.4, 19.4, 17.5. ESI-MS:
Calcd for C11H21Oþ [MþH]: 169.1, found: 169.2.
4.1.18. (S,E)-1-(3,6-Dimethyl-3-vinylhepta-1,5-dien-1-yl)-4-
methoxybenzene (20). IBX (420 mg, 1.5 mmol) and 17 (168 mg,
1 mmol) were dissolved in DMSO (5 mL) and stirred overnight at rt.
The reaction mixture was quenched with satd NaHCO3 aq solution
(5 mL), and was extracted with AcOEt (20 mLꢂ3). The combined
organic layer was washed with brine (20 mL), dried over Na2SO4,
The solvent was removed under reduced pressure, and the crude
product was purified by column chromatography (Petroleum ether)
give 14f as colorless oil (6.17 g, 94%). Rf (Petroleum ether/
27.5
Dichloromethane¼5:1) 0.17. [
a]
þ7.3 (c 1.00, CHCl3). 1H NMR
D
(400 MHz, CDCl3)
d
7.64 (m, 4H), 7.41 (m, 6H), 5.85 (dd, J¼17.7,
10.9 Hz, 1H), 5.11 (dd, J¼10.9, 1.1 Hz, 1H), 5.02 (dd, J¼17.6, 1.1 Hz,
1H), 3.67 (m, 2H), 3.46 (d, J¼9.7 Hz, 1H), 3.39 (d, J¼9.7 Hz, 1H), 1.87
(br s, 1H), 1.76 (m, 2H), 1.07 (s, 9H), 1.03 (s, 3H). 13C NMR (100 MHz,
gave the corresponding aldehyde as colorless oil (156 mg, 94%). Rf
27.5
(Petroleum ether) 0.28. [
a
]
þ9.5 (c 1.00, CHCl3).
D
To a solution of the resulting aldehyde (210 mg, 1.26 mmol) in
5 mL of THF was added (4-methoxybenzyl)magnesium chloride
(0.25 M in THF, 10 mL, 2.5 mmol) at 0 ꢀC over 15 min. The mixture
was stirred at rt for 2 h, and then the reaction was quenched with
2 mL of satd NH4Cl aq solution. The resulting mixture was extracted
with AcOEt (15 mLꢂ3). The combined organic phase was washed
with brine and dried (Na2SO4). The solvent was removed under
reduced pressure, and the crude product was purified by column
chromatography (Petroleum ether/ethyl acetate 20:1) to afford the
corresponding adduct as colorless oil (316 mg, 87%). Rf (Petroleum
ether/ethyl acetate¼10:1) 0.61 (two isomers). 1H NMR (400 MHz,
CDCl3)
d 144.2, 135.7, 133.2, 129.6, 127.6, 113.1, 71.4, 59.6, 41.2, 40.2,
26.8, 20.5, 19.3. ESI-MS: Calcd for C23H32O2SiNaþ [MþNa]: 391.2,
found: 391.2, HRMS(ESI): Calcd for
391.2069, found: 391.2066.
C
23H32O2SiNaþ [MþNa]:
4.1.15. (S)-((2-(2-Bromoethyl)-2-methylbut-3-en-1-yl)oxy)(tert-bu-
tyl)diphenylsilane (15f). To a solution of 14f (6.4 g 17 mmol) and
carbon tetrabromide (8.4 g 25.5 mmol) in 40 mL of dry CH2Cl2 was
added Ph3P (6.83 g, 26 mmol), and the reaction mixture was stirred
at rt under Ar for 30 min. The CH2Cl2 was removed under reduced
pressure, and the crude product was purified by column chroma-
tography (Petroleum ether) to give 15f as pale yellow oil (15.8 g,
CDCl3)
d
7.12 (d, J¼8.5 Hz, 2H), 6.83 (d, J¼8.5 Hz, 2H), 5.83 (m, 1H),
5.19 (t, J¼9.9 Hz, 1H), 5.10 (m, 2H), 3.77 (s, 3H), 3.48 (m, 1H), 2.81 (d,
J¼13.9 Hz, 1H), 2.10 (m, 1H), 1.92 (m, 2H), 1.68 (s, 3H), 1.59 (s, 3H),
86%). Rf (Petroleum ether) 0.76. [
a
]
27.5 ꢁ3.9 (c 0.95, CHCl3). 1H NMR
D
(400 MHz, CDCl3)
10.9 Hz, 1H), 5.11 (dd, J¼10.9, 1.1 Hz, 1H), 5.02 (dd, J¼17.6, 1.1 Hz,
1H), 3.44 (d, J¼9.6 Hz, 1H), 3.38 (d, J¼9.6 Hz, 1H), 3.31 (m, 2H), 2.10
d
7.67 (m, 4H), 7.42 (m, 6H), 5.79 (dd, J¼17.6,
1.48 (m, 2H), 1.07 (s, 3H). 13C NMR (100 MHz, CDCl3)
d 158.0, 143.7,
143.5, 131.7, 131.7, 131.2, 131.2, 130.8, 130.1, 129.3, 124.8, 124.7, 114.7,
114.1, 113.8, 113.8, 113.7, 78.9, 78.3, 55.1, 44.6, 44.4, 37.5, 37.3, 36.8,
25.6, 22.7, 22.6, 17.5, 17.3. ESI-MS: Calcd for C19H29Oþ2 [MþH]: 289.2,
found: 289.2.
(m, 2H), 1.09 (s, 9H), 1.06 (s, 3H). 13C NMR (100 MHz, CDCl3)
d 142.6,
135.6,133.3, 129.6, 127.6, 113.9, 70.8, 43.3, 40.8, 29.3, 26.8, 20.1, 19.3.
To a solution of the adduct (300 mg, 1.04 mmol) in 15 mL of dry
4.1.16. (S)-tert-Butyl((2,5-dimethyl-2-vinylhex-4-en-1-yl)oxy)diphe-
nylsilane (16). A solution of the (2-methylprop-1-en-1-yl)magne-
sium bromide (37 mL,18.5 mmol, 0.5 m in THF) and TMEDA
(2.64 mL, 17.6 mmol) was added dropwise (at a rate of around 5 mL/
h) by using a syringe pump to a solution of 15f (4.0 g, 9.27 mmol)
and FeCl3 (0.15 g, 0.93 mmol) in THF (30 mL) at 0 ꢀC. After further
30 min at 0 ꢀC, the reaction mixture was quenched with satd NH4Cl
aq solution (10 mL), and was extracted with AcOEt (150 mLꢂ3). The
combined organic layer was washed with brine and dried over
Na2SO4. The solvent was removed under reduced pressure, and the
crude product was purified by column chromatography (Petroleum
pyridine was added MeSO2Cl (93
m
l,1.14 mmol, d¼1.48 mg/mL), and
the mixture was stirred at rt overnight. H2O (5 mL) was added, and
the product was extracted with AcOEt (30 mLꢂ3). The extracts
were washed with brine and dried (Na2SO4). The solvent was re-
moved under reduced pressure and the crude product was purified
by column chromatography (Petroleum ether/ethyl acetate 20:1) to
give the mesylated compound as colorless oil (0.18 g, 89%). Rf (Pe-
troleum ether/ethyl acetate¼20:1) 0.15 (two isomers). 1H NMR
(400 MHz, CDCl3)
d
7.14 (d, J¼8.4 Hz, 2H), 6.85 (d, J¼8.4 Hz, 2H),
5.84 (m, 1H), 5.26 (m, 1H), 5.18e5.07 (m, 2H), 4.82 (m, 1H), 3.78 (s,
3H), 3.00 (m, 1H), 2.77e2.68 (m, 1H), 2.10 (s, 3H), 1.95 (m, 2H), 1.67
(s, 3H), 1.59 (s, 3H), 1.51 (m, 2H), 1.17 (s, 3H). 13C NMR (100 MHz,
ether) to give 16 as pale yellow oil (3.02 g, 80%). Rf (Petroleum
27.5
ether) 0.85. [
d
a]
ꢁ1.2 (c 1.00, CHCl3). 1H NMR (400 MHz, CDCl3)
CDCl3) d 158.6, 141.9, 141.7, 131.6, 130.6, 129.8, 124.3, 115.7, 115.5,
D
7.71e7.61 (m, 4H), 7.38 (m, 6H), 5.80 (dd, J¼17.6, 10.8 Hz, 1H), 5.08
114.0, 92.3, 92.1, 55.2, 44.5, 38.4, 37.3, 35.7, 25.7, 22.6, 18.9, 17.8, 17.7.
ESI-MS: Calcd for C20H30O4SNaþ [MþNa]: 389.1, found: 389.0.
To a solution of the mesylated product (320 mg, 0.09 mmol) in
5 mL of dry DMSO was added t-BuOK (196 mg, 1.75 mmol) in one
portion, and the mixture was stirred at rt for 5 h. The mixture was
poured into 20 mL of H2O, and the product was extracted with
AcOEt (20 mLꢂ3). The combined extracts were washed with brine
and dried (Na2SO4). The solvent was removed under reduced
(m, 1H), 5.02 (d, J¼10.8 Hz,1H), 4.99 (d, J¼17.6 Hz,1H), 3.40 (m, 2H),
1.87 (m, 2H), 1.67 (s, 3H), 1.57 (s, 3H), 1.42 (m, 2H), 1.06 (s, 9H), 1.02
(s, 3H). 13C NMR (100 MHz, CDCl3)
d 144.5, 135.6, 133.7, 131.0, 129.4,
127.5, 125.0, 112.7, 71.0, 42.1, 37.0, 26.8, 25.7, 22.7, 20.2, 19.4, 17.6.
4.1.17. (S)-2,5-Dimethyl-2-vinylhex-4-en-1-ol (17). TBAF (1 M in
THF, 2 mL, 2 mmol) was added to a solution of 16 (406 mg,