6194
T. Ikawa et al. / Tetrahedron 60 (2004) 6189–6195
þ
0
.20 mm). Triethylsilyloxydecane (3) was added to the
(M þH, 40%), 241 (32), 238 (23). HRMS (FAB, NBA)
þ
filtrate and then stirred at room temperature for 24 h. The
reaction mixture was concentrated under reduced pressure.
The ratio of the substrate (3) and 1-decanol (4) was
Calcd for C H O (M þH) 243.2317. Found 243.2324.
1
5 31 2
4.1.10. General procedure for cleavage of the THP ether
(5) using commercial 10% Pd/C in the absence of
hydrogen (Table 6, part 1, entries 1, 3, 5, 7 and 9). A
mixture of the THP ether (5) (60.6 mg, 0.25 mmol) and 10%
Pd/C (6.1 or 60.8 mg) in methanol (1 mL) or ethanol
(10 mL) was stirred at room temperature for 24 h. The
reaction mixture was filtered through a membrane filter
(Millipore, Millex -LG, 0.20 mm or -LH, 0.45 mm), and the
solvent was removed in vacuo. The ratio of the substrate (5)
and 1-decanol (4) was confirmed by H NMR of the crude
mixture in CDCl3.
1
confirmed by H NMR of the crude mixture in CDCl .
3
4
.1.6. General procedure for cleavage of the TES ether
3) in the filtrate (Table 3, part 2, entries 5, 6 and 9). After
two vacuum/H cycles to remove air from the reaction tube,
(
2
w
[
a suspension of the Amberlite IRA-45 (68 mg) and] 10%
w
Pd/C (6.8 mg, 10 wt% of the substrate) in methanol (1 mL)
was stirred under hydrogen atmosphere at ambient pressure
1
(balloon) and temperature (ca. 20 8C) for 24 h. The
solution was filtered through a membrane filter (Millipore,
w
Millex -LG, 0.20 mm). Triethylsilyloxydecane (3) was
added to the filtrate and then stirred under air at room
temperature for 24 h. The solution was concentrated under
reduced pressure. The ratio of the substrate (3) and
1-decanol (4) was confirmed by H NMR of the crude
mixture in CDCl3.
4.1.11. General procedure for cleavage of the THP ether
(5) using 10% Pd/C in the presence of hydrogen (Table 6,
part 2, entries 2, 4, 6, 8 and 10). After two vacuum/H2
cycles to remove air from the reaction tube, a stirred mixture
of the 2-tetrahydropyranyl-1-decanyl ether (5) (60.6 mg,
1
0.25 mmol) and 10% Pd/C (6.1 or 60.8 mg) in methanol
4
.1.7. General procedure for acid catalyzed cleavage of
(1 mL) or ethanol (10 mL) was hydrogenated at ambient
pressure (balloon) and temperature (ca. 20 8C) for 24 h. The
reaction mixture was filtered through a membrane filter
the TES ether (3) (Table 4). To a mixture of hydrogen
chloride (10 mL of 5% HCl in MeOH, 0.014 mmol) with an
additive indicated in Table 4 in methanol (1 mL) was added
triethylsilyloxydecane (3) (68.1 mg, 0.25 mmol) and stirred
w
(Millipore, Millex -LG, 0.20 mm or -LH, 0.45 mm), and the
filtrate was concentrated in vacuo. The ratio of the substrate
1
at room temperature for 24 h. [The solution was filtered
w
(5) and 1-decanol (4) was confirmed by H NMR of the
crude mixture in CDCl3.
through
a membrane filter (Millipore, Millex -LG,
.20 mm)] The solution (or filtrate) was concentrated
0
under reduced pressure. The ratio of the substrate (3) and
1-decanol (4) was confirmed by H NMR of the crude
mixture in CDCl3.
4.1.12. General procedure for cleavage of the THP ether
(5) in the filtrate (Table 7). After two vacuum/H cycles to
1
2
remove air from the reaction tube, a suspension of [the
w
Amberlite IRA-45 (61 mg) and] 10% Pd/C (60.8 mg,
4
.1.8. General procedure for the pH measurement of the
100 wt% of the substrate) in methanol (1 mL) was stirred
under hydrogen atmosphere at ambient pressure
(balloon) and temperature (ca. 20 8C) for 24 h. The reaction
mixture was filtered through a membrane filter (Millipore,
suspension of commercial 10% Pd/C (Table 5). A
suspension of 10% Pd/C (1.0 g) in 10 mL of methanol
was stirred at room temperature under each condition for
w
2
4 h. The pH of the slurry was measured by Horiba D-21
Millex -LH, 0.45 mm). 2-Tetrahydropyranyl-1-decanyl
pH meter that was calibrated before each set of
measurements.
ether (5) was added to the filtrate and then stirred under
air at room temperature for 24 h. The reaction mixture was
concentrated under reduced pressure. The ratio of the
substrate (5) and 1-decanol (4) was confirmed by H NMR
of the crude mixture in CDCl3.
1
4
.1.9. Preparation of 2-tetrahydropyranyl-1-decanyl
1
7
ether (5). To an ice-cold solution of 1-decanol (4)
1.58 g, 10 mmol) and dihydropyrane (3.7 mL, 40 mmol)
(
in dry dichloromethane (10 mL) was added p-toluene-
sulfonic acid monohydrate (19.0 mg, 0.1 mmol). The
mixture was stirred at 0 8C for 10 min, the ice bath was
removed, and the solution was stirred at room temperature
for 1.5 h. The mixture was partitioned between ether
4.1.13. Preparation of 1-triisopropylsilyloxy-3-phenyl-2-
1
8
propene (7). To a solution of cinnamylalcohol (671 mg,
5 mmol) and imidazole (408 mg, 6 mmol) in dichloro-
methane (20 mL) at room temperature was added triiso-
propylsilyl chloride (1.16 g, 6 mmol). The mixture was
stirred at room temperature for 24 h. Methanol (1 mL) was
then added to quench the excess of triisopropylsilyl
(
20 mL) and brine (20 mL). The organic layer was washed
with saturated sodium carbonate solution (20 mL), water
40 mL) and brine (20 mL£2), dried with anhydrous
Na SO , and evaporated in vacuo. The crude product was
(
chloride, and after 30 min a saturated aqueous NH Cl
4
solution (20 mL) was added. The aqueous layer was
extracted with ether (20 mL£3) and the combined the
organic layer was washed with brine (20 mL), dried with
anhydrous Na SO , filtered and concentrated in vacuo. The
2
4
purified by flash column chromatography on silica gel
elution with hexane/ether 20:1 to afford 2.30 g (95%) of
2
-tetrahydropyranyl-1-decanyl ether (5) as a colorless oil.
2
4
crude product was purified by flash column chromatography
on silica gel elution with hexane to afford 593 mg (41%) of
1-triisopropylsilyloxy-3-phenyl-2-propene (7) as a colorless
oil.
1
H NMR (CDCl ): d 4.58 (t, J¼3.4 Hz, 1H), 3.90–3.85 (m,
3
1
1
6
H), 3.76–3.70 (m, 1H), 3.53–3.47 (m, 1H), 3.41–3.35 (m,
H), 1.87–1.79 (m, 1H), 1.75–1.69 (m, 1H), 1.63–1.49 (m,
1
3
H), 1.35–1.26 (m, 14H), 0.88 (t, J¼6.8 Hz, 3H). C NMR
1
(
CDCL ): d 98.8, 67.7, 62.3, 31.9, 30.8, 29.7, 29.6, 29.5,
3
H NMR (CDCl ): d 7.42–7.24 (m, 5H), 6.67 (d,
3
2
9.3, 26.2, 25.5, 22.6, 19.7, 14.1. MS (FAB, NBA) m/z 243
J¼15.6 Hz, 1H), 6.34 (dt, J¼15.6, 4.9 Hz, 1H), 4.46 (dd,