E. Paz-Morales et al. / Carbohydrate Research 344 (2009) 1123–1126
1125
br = broad. IR spectra were recorded on a Nicolet 380 FT-IR spec-
trometer and values are reported in cm units. Optical rotations
were recorded on a Perkin Elmer 341 polarimeter.
sphere until TLC analysis indicates the disappearance of starting
material (approx 2 h). The benzene was removed on a rotary evap-
orator to obtain a residue which was filtered and evaporated. The
residue purified by flash silica gel chromatography (first hexane
then a mixture of hexane–EtOAc 4:1) afforded deoxygenated com-
pounds 7 and 8 in high yields.
À1
1
.2. General procedure for Grignard reaction11
To a solution of copper iodide (2.0 mmol) in dry THF (10 mL)
under N
kyl magnesium chloride (2.0 mmol). The reaction mixture was stir-
red for 30 min, and 1,2-O-isopropylidene-5-O-p-toluensulfonyl-
2
atmosphere at À10 °C was added the corresponding n-al-
1.6. (3aR,5R,6aR)-5-Butyl-dihydro-2,2-dimethyl-5H-furo[2,3-
d][1,3]dioxole (7)
a
-
1
0
D
-xylofuranose 4 (1.0 mmol dissolved in 5 mL of dry THF) was
Yield 88% as colorless syrup; [
(CH Cl ) 2959, 2925, 2855, 1097, 1031 cm ; H NMR (400 MHz,
CDCl ) d: 0.83 (t, 3H, J = 6.8 Hz) 1.18–1.39 (m, 6H), 1.24 (s, 3H),
a
]
D
À12.6 (c 1, CHCl
3 max
); IR m
À1
1
slowly added. The reaction mixture was allowed to react for 4 h
at 0 °C. When the consumption of starting material was complete
2
2
3
(
monitored by TLC), the reaction mixture was quenched by the
1.44 (s, 3H), 1.59 (m, 1H), 2.02 (dd, 1H, J = 13.2, 4.0 Hz), 4.09 (m,
addition of ammonium chloride (5 mL of a saturated aqueous solu-
tion), and was extracted with diethyl ether (3 Â 30 mL). The com-
bined ethereal layers were washed with water (50 mL), dried with
1H), 4.64 (t, 1H, J = 4.0 Hz), 5.73 (d, 1H, J = 4.0 Hz); 13C NMR
(100 MHz, CDCl
80.5, 105.2, 110.6; EI-MS m/z (rel intensity) 185 ([MÀCH
3
) d: 13.9, 22.7, 26.0, 26.5, 28.1, 33.9, 38.9, 77.9,
+
3
] , 6);
21 3
H 0 : 201.2829.
+
Na
2
SO
4
, filtered, and concentrated. The residue purified by flash sil-
FAB-HRMS m/z 201.2829 [M+H] . Calcd for C11
ica gel chromatography (hexane–EtOAc 7:1) afforded 5 or 6 in high
yields.
1
.7. (3aR,5R,6aR)-5-Hexyl-dihydro-2,2-dimethyl-5H-furo[2,3-
d][1,3]dioxole (8)
1
.3. 1,2-O-Isopropylidene-5-deoxy-5-C-(n-propyl)-
a
-D
-
1
0
xylofuranose (5)
Yield 86% as colorless syrup; [
a
]
D
À15.5 (c 1, CHCl
3 max
), IR m
H NMR
À1
1
(
2
CH Cl
2
) 2925, 2855, 1376, 1164, 1070, 731 cm
;
Yield 85% as a crystalline solid; Mp = 72–73 °C; [
CHCl ); lit: –13.6 (c 1.0, CHCl ); IR Cl
458, 1372, 1070 cm ; H NMR (400 MHz, CDCl
J = 6.8 Hz), 1.24 (s, 3H), 1.31 (m, 2H), 1.42 (s, 3H), 1.47–1.67 (m,
H), 3.97 (b, 1H), 4.04 (td, 1H, J = 6.8, 2.4 Hz), 4.40 (d, 1H,
a
]
D
À13.5 (c 1,
(400 MHz, CDCl
3
) d: 0.87 (t, 3H, J = 6.8 Hz), 1.28 (m, 7H), 1.31 (s,
3H), 1.42 (m, 3H), 1.51 (s, 3H), 1.65 (m, 1H), 2.09 (dd, 1H,
3
3
m
max (CH
2
2
) 3403, 2917, 2851,
À1
1
1
3
) d: 0.81 (t, 3H,
J = 13.2, 4.0 Hz), 4.16 (m, 1H), 4.71 (t, 1H, J = 4.4 Hz), 5.80 (d, 1H,
1
3
J = 3.6 Hz); C NMR (100 MHz, CDCl
3
) d: 14.0, 22.5, 26.0, 26.1,
4
26.5, 29.3, 31.7, 34.2, 38.9, 77.9, 80.5, 105.2, 110.6; EI-MS m/z
13
+
J = 5.2 Hz), 5.82 (d, 1H, J = 5.2 Hz); C NMR (100 MHz, CDCl
3
) d:
(rel intensity) 213 ([MÀCH
3
] , 10); FAB-HRMS m/z 229.1796
+
1
3.9, 22.7, 26.1, 26.5, 27.2, 28.1, 75.3, 80.2, 85.2, 104.1, 111.3; EI-
[M+H] . Calcd for C13H 0 : 229.1804.
25 3
+
MS m/z (rel intensity) 201 ([M+HÀCH
3
] , 23); FAB-HRMS m/z
+
1.8. General procedure for the sequential allylation–
dihydroxylation–dehomologation–oxidation reaction
2
17.1440 [M+H] . Calcd for C11
21
H O
4
: 217.1442.
1
.4. 1,2-O-Isopropylidene-5-deoxy-5-C-(n-pentyl)-a-D-
xylofuranose (6)
To a solution of corresponding deoxygenated compounds 7 or 8
(
1.0 mmol) and allyltrimethylsilane (6.0 mmol) in dry CH
(10 mL) was added dropwise BF (6.0 mmol) at 0 °C. The
ÁOEt
resulting solution was vigorously stirred for 4 h and then quenched
by the addition of a satd aq NaHCO (10 mL). The aqueous layer
was extracted three times with CH Cl (30 mL), dried over Na SO
2 2
Cl
Yield 86% as crystalline solid; Mp = 75 °C; [
a
]
D
À16.4 (c 1,
3
2
CHCl
3
); IR
m
max (CH
2
Cl
2
)
3399, 2925, 2851, 1380, 1160,
074 cm ; 1H NMR (400 MHz, CDCl
.24 (s, 3H), 1.22-1.31 (m, 6H), 1.48–1.56 (m, 4H), 1.52 (m, 2H),
.63 (m, 2H), 3.97 (d, 1H, J = 2.4 Hz), 4.04 (td, 1H, J = 6.8, 2.4 Hz),
.4 (d, 1H, J = 4.0 Hz), 5.8 (d, 1H, J = 4.0 Hz); 13C NMR (100 MHz,
À1
3
1
1
1
4
3
) d: 0.81 (t, 3H, J = 6.8 Hz),
2
2
2
4
,
and concentrated under reduced pressure to give a diastereoiso-
meric mixture of tetrahydrofurans 9a and 9b in a ratio of 78:22,
or 10a and 10b in a ratio of 80:20. The mixture of tetrahydrofurans
3
CDCl ) d: 14.0, 22.5, 25.9, 26.1, 26.5, 27.5, 29.3, 31.6, 75.3, 80.2,
+
8
3
2
5.1, 104.1, 111.3; EI-MS m/z (rel intensity) 229 ([M+HÀCH
3
] ,
(9a/9b or 10a/10b) was dissolved in a mixture of acetone–H
10:1 (10 mL), and N-methylmorpholine oxide (2.0 mmol) and
OsO (0.08 mmol) were added. The resulting solution was stirred
at room temperature for 6 h, then an aqueous solution of NaIO
2
O
+
5); FAB-HRMS m/z 245.1787 [M+H] . Calcd for
13 25 4
C H O :
45.1753.
4
4
1
.5. General procedure for Barton–McCombie reduction with
(2 mmol in 2 mL of water) was added dropwise and the resulting
suspension was allowed to react at room temperature for 1 h.
The solution was filtered to remove solids (washed with EtOAc)
and the organic phase was extracted with EtOAc, and dried over
Na SO . Then the solution is evaporated to dryness and redissolved
silane
A suspension of the corresponding secondary alcohol 5 or 6
(
1.0 mmol) and sodium hydride (3.0 mol) in dry THF (40 mL) under
2
4
argon atmosphere was allowed to react for 30 min at room tem-
perature. Then, CS was added all at once, and the reaction mixture
was stirred for 30 min before to add CH I (2.0 mol) in a single por-
tion. The reaction mixture was stirred for another 25 min. When
the consumption of starting material was complete (monitored
by TLC), the reaction mixture was quenched by the addition of gla-
cial acetic acid (0.5 mL). The solution was filtered and the filtrate
was concentrated under reduced pressure. A combined mixture
2 2
in dry CH Cl (10 mL), and PCC (2 mmol) was added. The resulting
2
solution was allowed to react for 5 h at room temperature, and
then the reaction was quenched by the addition of water (30 mL)
and the organic phase was extracted with CH Cl (3 Â 40 mL),
3
2
2
dried over Na SO , filtered, and concentrated under reduced pres-
2
4
sure. The residue purified by flash chromatography (hexane–EtOAc
4:1) gave the corresponding Hagen’s lactones 1 or 2 in good yields.
of H
phase was extracted with EtOAc (three 30 mL portions), dried with
Na SO , and concentrated under reduced pressure. The residue was
purged with argon and dissolved in dry benzene (5 mL), and
tris(trimethylsilyl)silane (1.8 mmol) and AIBN (0.1 mmol) were
added. The reaction mixture was heated at reflux in an argon atmo-
2
O–EtOAc (50 mL of a 1:1 mixture) was added, and organic
1.9. Hage n´ s gland lactones
2
4
1.9.1. (3aR,5R,6aR)-5-n-Butyl-tetrahydrofuro-[3,2b]furan-
2(3H)-one (1)
3,4c
Yield 49% as a colorless oil; [
a
] +50.9 (c 1, CHCl ); lit:
D
3
+49.9
1
(c 1.0, CHCl ); H NMR (400 MHz, CDCl ) d: 0.88 (t, 3H, J = 6.8 Hz),
3
3