A. A. Dos Santos, W. Francke / Tetrahedron: Asymmetry 17 (2006) 2487–2490
2489
(0.5 g) for 30 min, filtered and concentrated under reduced
pressure. The resulting oil was diluted with anhydrous
THF (100 mL), and freshly redistilled 2,6-lutidine
(4.68 mL, 40.18 mmol) was added. The flask was purged
with argon, and the mixture was stirred vigorously for
20 min. Lindlar catalyst (2 g, 10% Pd on carbon) was then
added to the reaction mixture, and stirring was continued
for 30 min, followed by further stirring for 12 h under an
atmosphere of dry hydrogen. The mixture was filtered,
the solvent removed under reduced pressure and the
residue diluted with diethyl ether (50 mL). The resulting
solution was sequentially washed with hydrochloric
acid (3 · 10 mL, 1 mol/L), aqueous sodium bicarbonate
(10 mL, 5% m/v) and brine (10 mL). The organic layer
was dried over magnesium sulfate and filtered. The solvent
was removed under reduced pressure, and the residue was
distilled under vacuum (bp 58–59 ꢁC, 0.4 mmHg) to yield
4.03 g (70%) of 2 as a pale oil. CAS 61720-57-8. 1H
NMR (CDCl3) d 1.2 (6H, d, J = 6.4 Hz), 2.56 (2H, t,
J = 6.6 Hz), 2.78 (2H, t, J = 6.9 Hz), 4.98 (1H, hept,
J = 6.1 Hz), 9.78 (1H, s). 13C NMR (DEPT 135, CDCl3)
d 22.2, 27.4, 30.0, 39.0, 68.6, 200.5. MS (70 eV) m/z (rel
int.) 85 (44), 74 (16), 57 (12), 55 (10), 43 (100), 41 (66).
93 (17), 91 (16), 85 (27), 83 (20), 81 (48), 79 (47), 74 (83),
73 (57), 69 (22), 67 (48), 55 (59), 45 (18), 43 (100), 41 (80).
3.4. Preparation of (R)-(ꢀ)-5-(dec-1-ynyl)-tetrahydrofuran-
2-one 5
The procedure was the same as described in Section 3.3.
but employing (S)-(ꢀ)-BINOL to afford 1.17 g (81% yield)
23
of (R)-5 as a colourless oil. CAS 72151-69-0. ½aꢂD ¼ ꢀ6:0
21
(c 2.6, CHCl3) (lit.:17 ½aꢂD ¼ ꢀ6:5 (c 5.5, CHCl3)). Spectro-
scopic data were the same as for (S)-5.
3.5. Preparation of (S)-(+)-5-(Z)-(dec-1-enyl)-tetrahydro-
furan-2-one 1
Under an argon atmosphere, (S)-(+)-5-(dec-1-ynyl)-tetra-
hydrofuran-2-one (5, 0.8 g, 3.6 mmol), pentane (50 mL)
and freshly distilled quinoline (0.17 mL) were introduced
sequentially into a 100 mL round-bottomed flask, and the
mixture was cooled to 0 ꢁC. Lindlar catalyst (0.177 g, 5%
Pd on calcium carbonate poisoned with lead acetate) was
added to the solution, and the mixture was stirred at 0 ꢁC
for 5 h under a hydrogen atmosphere followed by removal
of the solvent. Celite (ꢁ1 g) was added to the mixture and
stirring maintained for an additional 20 min at 0 ꢁC. The
mixture was filtered, the residue was extracted with pentane
(2 · 5 mL) and the resulting solution was sequentially
washed with hydrochloric acid (2 · 10 mL) and brine
(10 mL). The organic layer was dried over magnesium sul-
fate and filtered under reduced pressure. The crude mate-
rial was purified by flash chromatography [Merck, silica
60, 240–400 mesh; hexane/ethyl ether 7:3] affording
0.68 g of (S)-1 (89% yield) as a colourless oil. CAS
3.3. Preparation of (S)-(+)-5-(dec-1-ynyl)-tetrahydrofuran-
2-one 5
Under an atmosphere of argon, 1-decyne (4.65 mL,
25.86 mmol), toluene (13 mL) and neat diethylzinc
(2.65 mL, 25.86 mmol) were introduced sequentially into
a 250 mL two-necked flask. The mixture was heated for
12 h at reflux and the resulting white slurry cooled to
room temperature. (R)-(+)-BINOL (0.71 g, 2.48 mmol,
10 mol %), diethyl ether (100 mL) and Ti(O–iPr)4
(1.93 mL, 6.46 mmol) were added sequentially. After stir-
ring for an additional 30 min at room temperature, a solu-
tion of isopropyl 4-oxobutanoate (2, 0.75 g, 6.46 mmol) in
toluene (20 mL) was added dropwise by means of a syringe
pump over a period of 2 h. The solution was stirred at
room temperature for 10 h, Celiteꢂ (ꢁ3 g) was added and
the mixture was stirred for an additional 30 min. The slurry
23
26
64726-93-8. ½aꢂD ¼ þ60:0 (c 2.0, CHCl3) (lit.:1 ½aꢂD
¼
1
þ70:5 (c 5.5 CHCl3)). H NMR (CDCl3) d 0.85 (3H, t,
J = 6.8 Hz), 1.20–1.30 (12H, m), 2.02–2.14 (2H, m), 2.31–
2.39 (1H, m), 2.49–2.56 (2H, m), 5.22 (1H, tdd, J = 8.3,
6.6, 1.0 Hz), 5.42 (1H, ddt, J = 10.7, 8.6, 1.5 Hz), 5.64
(1H, dtd, J = 10.9, 7.7, 1.0 Hz). 13C NMR (CDCl3) d
14.48, 23.05, 28.23, 29.41, 29.60, 29.63, 29.71, 29.80,
29.82, 32.26, 76.83, 127.64, 136.25, 177.52. MS (70 eV)
m/z (rel int.) 224 M+ (1), 126 (22), 125 (16), 111 (100), 98
(19), 95 (22), 81 (49), 67 (42), 55 (62), 43 (43), 41 (100).
was filtered on a Buchner funnel, and the residue was ex-
¨
tracted with diethyl ether (3 · 50 mL). The resulting solu-
tion was sequentially washed with hydrochloric acid
(10 mL, 0.5 mol/L), aqueous sodium bicarbonate (10 mL,
10% m/v) and brine (10 mL). The organic layer was dried
over magnesium sulfate, filtered and the solvent was re-
moved under reduced pressure. The crude material was
purified by flash chromatography [Merck, silica 60, 240–
400 mesh; dichloromethane/hexane/ethyl acetate 20:5:1];
3.6. Preparation of (R)-(ꢀ)-(5Z)-(dec-1-enyl)-tetrahydro-
furan-2-one 1
The procedure as described in Section 3.5. was used but
affording 1.17 g of (S)-5 (81% yield) as a colourless
employing (R)-(ꢀ)-5-(dec-1-ynyl)-dihydrofuran-2(3H)-one
23
oil. CAS 72151-70-3. ½aꢂD ¼ þ6:0 (c 4.64, CHCl3). 1H
5 to afford 0.73 g (91% yield) of (R)-1 as a colourless oil.
23
NMR (CDCl3) d 0.84 (3H, t, J = 6.8 Hz), 1.24–1.36
(11H, m), 1.47 (2H, quint, J = 7.5 Hz), 2.12 (3H, td,
J = 7.1, 2.3 Hz), 2.23 (1H, td, J = 7.1, 2.3 Hz), 2.41–2.50
(2H, m), 2.55–2.67 (1H, m), 5.10 (1H, ddt, J = 7.4, 5.6,
1.9 Hz). 13C NMR (CDCl3) d 14.3, 18.9, 22.8, 28.1, 28.4,
29.0, 29.2, 29.3, 30.3, 31.9, 69.9, 76.7, 89.0, 176.4. MS
(70 eV) m/z (rel int.) 223 M+1+ (1.7), 222 M+ (1.2), 221
(2.4), 165 (3), 163 (5), 142 (20), 137 (17), 124 (58), 116
(17), 111 (10), 109 (15), 107 (15), 97 (11), 96 (24), 95 (30),
CAS 64726-91-6. ½aꢂD ¼ ꢀ61:1 (c 1.5 CHCl3); (lit.:1
26
½aꢂD ¼ ꢀ69:6 (c 5.0, CHCl3)). Spectroscopic data were
the same as for the (S)-(+)-enantiomer.
Acknowledgements
We wish to thank CNPq and DAAD for financial support.