The stereoselective synthesis of novel 4-octulose derivatives

Article abstract of DOI:10.1016/S0008-6215(98)00076-7

Dihydroxylation of methyl (E)-2,3-dideoxy-4,5:6,8-di-O-isopropylidene- L-xylo-oct-2-ene-4-ulofuranosonate (1) with osmium tetraoxide took place with high diastereoselectivity to give a 7:1 mixture of methyl 4,5:6,8-di-O- isopropylidene-α-L-glycero-D-galacto- (2) and -D-ido-oct-4-ulofuranosonate (3). When 1 was dihydroxylated in the presence of dihydroquinine and dihydroquinidine p-chlorobenzoate, an appreciable increase and decrease, respectively, in the 2/3 ratio was observed. Compound 2 was transformed into its 2,3-di-O-methyl derivative 4 which was deisopropylidenated to methyl 2,3- di-O-methyl-α-L-glycero-D-galacto-oct-4-ulopyranosonate (5) and subsequently degraded to dimethyl 2,3-di-O-methyl-(+)-L-tartrate (6). On the other hand, compounds 2 and 3, separately, were isopropylidenated to the corresponding 2,3:4,5:6,8-tri-O-isopropylidene derivatives 7 and 8, which were reduced with LiAlH₄ to the related 2,3:4,5:6,8-tri-Oisopropylidene-α-L-glycero-D- galacto- (9) and -D-ido-oct-4-ulofuranose (10). Finally, compounds 9 and 10 were deisopropylidenated to the corresponding L-glycero-D-galacto- (11) and L-glycero-Dido-oct-4-ulose (12).

Full text of DOI:10.1016/S0008-6215(98)00076-7

Carbohydrate Research 308 (1998) 217±221
Note
The stereoselective synthesis of novel
-octulose derivatives1
4
Isidoro Izquierdo Cubero *, Maria T. Plaza Lo
Miguel Rodrõguez Alonso, Rafael Asenjo Asenjo,
Antonio Ramõrez Fernandez
Â
pez-Espinosa,
Â
Â
Â
Department of Organic Chemistry, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain
Received 2 December 1997; accepted in revised form 17 March 1998
Abstract
Dihydroxylation of methyl (E)-2,3-dideoxy-4,5:6,8-di-O-isopropylidene-l-xylo-oct-2-ene-4-ulo-
furanosonate (1) with osmium tetraoxide took place with high diastereoselectivity to give a 7:1
mixture of methyl 4,5:6,8-di-O-isopropylidene-ꢀ-l-glycero-d-galacto- (2) and -d-ido-oct-4-ulofur-
anosonate (3). When 1 was dihydroxylated in the presence of dihydroquinine and dihydro-
quinidine p-chlorobenzoate, an appreciable increase and decrease, respectively, in the 2/3 ratio was
observed. Compound 2 was transformed into its 2,3-di-O-methyl derivative 4 which was deiso-
propylidenated to methyl 2,3-di-O-methyl-ꢀ-l-glycero-d-galacto-oct-4-ulopyranosonate (5) and
subsequently degraded to dimethyl 2,3-di-O-methyl-(+)-l-tartrate (6). On the other hand, com-
pounds 2 and 3, separately, were isopropylidenated to the corresponding 2,3:4,5:6,8-tri-O-iso-
propylidene derivatives 7 and 8, which were reduced with LiAlH to the related 2,3:4,5:6,8-tri-O-
4
isopropylidene-ꢀ-l-glycero-d-galacto- (9) and -d-ido-oct-4-ulofuranose (10). Finally, compounds 9
and 10 were deisopropylidenated to the corresponding l-glycero-d-galacto- (11) and l-glycero-d-
ido-oct-4-ulose (12). # 1998 Elsevier Science Ltd. All rights reserved
Keywords: 4-Octulose derivatives; Diastereoselective synthesis
In previous papers [1,2] we have reported on the
use as starting chiral template of a common hex-
ulose, d-fructose, in the synthesis of 4-octuloses
and 2-deoxy-4-octuloses. On the other hand,
lose derivatives from l-sorbose and their con®g-
urational assignments.
4
-octuloses could be excellent chiral intermediates
1. Results and discussion
for the synthesis of potent glycosidase inhibitors
such as polyhydroxyindolizidines [3]. We report in
the present paper on the synthesis of some 4-octu-
Dihydroxylation of 1 [4] with osmium tetraoxide
a€orded an approximate 7:1 mixture of methyl
4,5:6,8-di-O-isopropylidene-ꢀ-l-glycero-d-galacto-
(
2) and -l-glycero-d-ido-oct-4-ulofuranosonate (3)
1
(GC) which could be resolved by cautious column
chromatography.
Part III. For Part II, see ref. [1].
Corresponding author. E-mail: isidoro@platon.ugr.es
*
0008-6215/98/$19.00 # 1998 Elsevier Science Ltd. All rights reserved
PII S0008-6215(98)00076-7

218
I. Izquierdo Cubero et al./Carbohydrate Research 308 (1998) 217±221
2. Experimental
General methods.ÐSee ref. [1]. In addition, GC
analyses was performed on a Perkin-Elmer 8410
gas chromatograph equipped with a ¯ame-ionisa-
tion detector and a steel column (2 mÂ3 mm i.d.)
packed with 5% OV-17 on Chromosorb W (100±
ꢀ ꢀ
120 mesh): (A) at 190 C; (B) 5 min at 190 C,
program to 230 C, 15 C/min; (C) at 230 C; (D)
ꢀ
ꢀ
ꢀ
Con®gurational proof for the osmylation products
ꢀ
was provided by conversion of 2 into dimethyl 2,3-
di-O-methyl-(+)-l-tartrate (7) [5], involving methy-
lation of 2 (!4), hydrolysis to methyl 2,3-di-O-
methyl-ꢀ-l-glycero-d-galacto-oct-4-ulopyranosonate
160 C. The He ¯ow rate was 30 mL/min, the
injection port and the zone-detector temperatures
ꢀ
ꢀ
were (A), (B) and (C) 250 C, and (D) 200 C.
Dihydroxylation of 1: without chiral catalyst.Ð
To a stirred soln of 1 [4] (8.4 g, 27 mmol) in acet-
(5), oxidation with sodium periodate and treatment
with diazomethane. The obtention of R,R-tartrate 6
clearly indicated a 2R,3R con®guration for 2.
one (80 mL) was added a soln of KClO (3.26 g,
3
27 mmol) in water (60 mL) and aq 1% OsO4
(10 mL), and the mixture left at room temperature
for 30 h. GC (C) then revealed the presence of two
new products (tR 7.17 and 8.89 min in a ꢁ7:1
ratio). The mixture was concentrated to a residue
that was extracted with EtOAc, then concentrated.
Cautious column chromatography (2:1 ether±hex-
ane!ether) a€orded ®rst methyl 4,5:6,8-di-O- iso-
propylidene-ꢀ-l-glycero-d-galacto-oct-4-ulofur-
The pyranoid structure of 5 was assigned on the
basis of its 13C NMR spectrum, where resonance
signals for only one pyranose anomer were present,
according to the ꢁ value [4] for C-4 (105.91). In
addition, the ꢀ-con®guration was tentatively
assigned to the anomeric center, since it would be
in accordance with stabilizing stereoelectronic
(anomeric e€ect) and steric (the large substituent
adopts an equatorial disposition) e€ects.
anoso-nate as solid foam (2, 7.17 g, 52%), (t
R
2
3
ꢀ
7
3
.17 min); ‰ꢀŠ +8 (c 1.4, CHCl ); IR (KBr): ꢂ
D
526 (OH), 1740 (C=O, ester), and 1385 cm
3
� 1
1
(
CMe ); H NMR: ꢁ 4.72 (s, 1 H, H-2), 4.68 (s, 1
2
H, H-3), 4.34 (d, 1 H, J6,7 1.5 Hz, H-6), 4.30 (s, 1
H, H-5), 4.11 (d, 1 H, H-7), 4.05 (s, 2 H, H-8,8),
3.80 (s, 3 H, OMe), 1.50, 1.42, 1.41, and 1.36 (4 s,
12 H, 2 CMe2); 13C NMR: ꢁ 173.60 (C-1), 114.66
(C-4), 113.47 (CMe ), 97.75 (CMe ), 85.07 (C-5),
When dihydroxylation of 1 was carried out in
the presence of chiral catalysts [6] such as
dihydroquinine or dihydroquinidine p-chlor-
obenzoate, 2 and 3 were formed in a 9:1 and 2:1
ratio, respectively. The increase and decrease of
stereoselectivity found (the 2:3 ratio changing from
2
2
73.07 (C-6), 72.39 (C-7), 71.76 (C-3), 69.96 (C-2),
60.31 (C-8), 52.90 (OMe), 28.85 and 18.63 (CMe2),
27.77 and 26.45 (CMe ). Anal. Calcd for C H O :
7
:1 to 9:1 and 2:1) in comparison with that
2
15 24
9
observed without the presence of chiral catalysts,
indicating a clear case of matched and mismatched
pair double asymmetric induction [7].
Treatment of 2 and 3 with acetone±p-toluene
sulfonic acid±cupric sulfate a€orded crystalline
C, 51.72; H, 6.94. Found: C, 51.66; H, 7.21.
Eluted second was syrupy methyl 4,5:6,8-di-O-
isopropylidene-ꢀ-l-glycero-d-ido-oct-4-ulofurano-
2
D
5
ꢀ
sonate (3, 1.14 g, 8.2%), (t 8.89 min); ‰ꢀŠ � 18 (c
R
1.2, CHCl ); IR (neat): ꢂ 3500 (OH), 1751 (C=O,
ester), and 1385 cm (CMe ); H NMR: ꢁ 4.76 (s,
3
�
1
1
methyl
2,3:4,5:6,8-tri-O-isopropylidene-ꢀ-l-gly-
2
cero-d-galacto-oct-4-ulofuranosonate (7) and the -
l-glycero-d-ido- isomer (8), respectively. Reduction
of 7 and 8 with lithium aluminium hydride gave the
corresponding octulose derivatives 9 and 10, which
were hydrolyzed to the respective free octuloses 11
and 12.
1 H, H-2), 4.65 (s, 1 H, H-3), 4.31 (d, 1 H, J6,7
1.8 Hz, H-6), 4.24 (s, 1 H, H-5), 4.12±4.05 (m, 3 H,
H-7,8,8 ), 3.79 (s, 3 H, OMe), 1.49, 1.44, 1.39, and
0
1.38 (4 s, 12 H, 2 CMe2); 13 C NMR: ꢁ 172.48 (C-
1), 114.69 (C-4), 112.19 (CMe ), 98.26 (CMe ),
85.32 (C-5), 73.70 (C-6), 73.25 (C-7), 72.34 (C-3),
2
2
7
1
0.68 (C-2), 60.24 (C-8), 52.55 (OMe), 28.78 and
8.55 (CMe ), 27.37 and 26.62 (CMe ). Anal.
2
2
Calcd for C H O : C, 51.72; H, 6.94. Found: C,
24
15
9
51.30; H, 6.93.

I. Izquierdo Cubero et al./Carbohydrate Research 308 (1998) 217±221
219
A small quantity (0.3 g) of a mixture of 2 and 3
was also obtained.
Dihydroxylation of 1: with chiral catalyst.ÐTo a
edly co-distilled with water and the residue
chromatographed (10:1 CHCl ±MeOH) to a€ord
3
methyl 2,3-di-O-methyl-ꢀ-l-glycero-d-galacto-oct-
4-ulopyranosonate (5) as a colourless solid foam
(500 mg, 91%). 13C NMR: ꢁ 171.28 (C-1), 105.91
(C-4), 87.44, 81.20, 74.40, 69.93, and 69.01 (C-
2,3,5,6,7), 65.60 (C-8), 59.64, 59.53, and 59.14 (3
OMe). Anal. Calcd for C H O : C, 44.59; H,
ꢀ
well-stirred and cooled (0 C) soln of 1 (173 mg,
0
.55 mmol), N-methylmorpholine N-oxide mono-
hydrate (79 mg, 0.67 mmol) and dihydroquinine
p-chlorobenzoate (70 mg, 0.15 mmol) in acetone±
water (5:1 v/v, 1.6 mL), was added aq 0.04 M OsO4
11
20
9
(
0.15 mL) and the mixture left for 4 d at room
6.80. Found: C, 44.25; H, 7.02.
Compound 5 (447 mg, 1.51 mmol) was oxidized
in water (15 mL) with a soln of NaIO (1.6 g,
4
temperature. GC (C) then showed the absence of 1
and the presence of 2 and 3 in ꢁ9:1 ratio.
When dihydroxylation of 1 was performed in the
presence of dihydroquinidine p-chlorobenzoate, as
chiral catalyst, a ꢁ2:1 ratio of 2 and 3 was
obtained (GC analysis).
7.5 mmol) in the same solvent (15 mL). The reac-
tion was monitored by polarimetry to a constant
rotation. The mixture was concentrated and the
residue extracted with EtOAc. Concentration of
the extracts gave a residue that was dissolved in dry
MeOH (15 mL) and a stream of CH N was passed
Methyl
4,5:6,8-di-O-isopropylidene-2,3-di-O-
methyl-a-l-glycero-d-galacto-oct-4-ulofuranosonate
2
2
(
4).ÐTo a stirred soln of NaH (80% oil dispersion)
through the soln until a slight yellow colour
remained and the mixture left at room temperature
for 30 min. GC (D) then revealed a main product
(500 mg, 16.7 mmol) in dry Me SO (5 mL) and
imidazole (150 mg) under Ar, a soln of 2 (870 mg,
2
2
.5 mmol) in dry THF (10 mL) was added dropwise
with the same t as an authentic sample of 6. The
R
ꢀ
and the mixture heated at 60 C for 30 min. After
cooling, iodomethane (3 mL, 54.5 mmol) was
added and the mixture stirred for an additional
reaction mixture was concentrated and the residue
chromatographed (1:2!1:1 ether±hexane) to a€ord
2
D
8
ꢀ
6 (113 mg) which had ‰ꢀŠ +64 (c 1.5, MeOH)
ꢀ
3
0 min. TLC (ether) then showed a faster-running
[lit. [5] [a]D +81 (c 6.26, MeOH)] and spectral
data were identical to those of an authentic sample.
product, the excess of hydride was destroyed by
cautious addition of ether saturated with water,
then water. The organic phase was separated and
the aq phase extracted with ether. The extracts
were washed with brine and concentrated. Column
chromatography (1:3!1:1 ether±hexane) of the
residue a€orded crystalline 4 (810 mg, 86%), mp
Methyl
2,3:4,5:6,8-tri-O-isopropylidene-a-l-
glycero-d-galacto-oct-4-ulofuranosonate (7).ÐTo a
stirred soln of a mixture of 2 (5 g, 14.4 mmol)] in
dry acetone (60 mL), p-toluenesulfonic acid
(950 mg) and anhyd CuSO (6 g) were added at
4
room temperature. The stirring was continued for
48 h. TLC (ether) then revealed a faster-running
product. The mixture was neutralized (K CO ),
ꢀ
23
ꢀ
8
1
1±83 C; ‰ꢀŠ +28 (c 1, CHCl ); IR (KBr): ꢂ
D
757 (C=O, ester) and 1378 cm
3
�
1
1
(CMe ); H
2
2
3
NMR: ꢁ 4.49 (s, 1 H, H-5), 4.28 (d, 1 H, J6,7 2.3 Hz,
H-6), 4.20 (d, 1 H, J2,3 5.7 Hz, H-2), 4.10 (m, 1 H,
®ltered through a Celite pad, and then con-
centrated. Column chromatography (1:2!1:1
ether±hexane) of the residue yielded crystalline 7
H-7), 4.02 (dd, 1 H, J7 2.5, J8,8
0
0
13.4 Hz, H-8),
.91 (d, 1 H, H-8 ), 3.86 (d, 1 H, H-3), 3.78 (s, 3 H,
,8
ꢀ
26
ꢀ
3
CO Me), 3.56 and 3.48 (2 s, 6 H, 2 OMe), 1.49,
(3.6 g, 65%), mp 70±72 C; ‰ꢀŠ � 15 (c 1.5,
D
CHCl ); IR (KBr): ꢂ 1748 (C=O, ester), 1387, and
2
3
13
� 1
1378 cm (CMe ); H NMR: ꢁ 4.77 (d, 1 H, J
2 2,3
1
1
.41, 1.40, and 1.39 (4 s, 12 H, 2 CMe2);
C
NMR: ꢁ 171.38 (C-1), 114.72 (C-4), 113.16 (CMe2),
7.0 Hz, H-2), 4.55 (d, 1 H, H-3), 4.49 (s, 1 H, H-5),
4.29 (d, 1 H, J6,7 2.4 Hz, H-6), 4.10 (m, 1 H, H-7),
9
7
5
7.41 (CMe ), 85.49 (C-5), 81.61 (C-3), 81.00 (C-2),
2
3.00 (C-6), 72.86 (C-7), 60.34 (C-8), 61.30 and
8.80 (2 OMe), 51.95 (CO Me), 28.74 and 18.97
4.01 (dd, 1 H, J7 2.4, J8,8
,8
0
13.4 Hz, H-8), 3.92 (bd,
0
1 H, H-8 ), 3.77 (s, 3 H, CO Me), 1.50, 1.48, 1.46,
2
2
(CMe ), 27.86 and 26.69 (CMe ). Anal. Calcd for
C H O : C, 54.24; H, 7.50. Found: C, 54.68; H,
1.38, and 1.35 (5 s, 18 H, 3 CMe2); 13 C NMR: ꢁ
171.37 (C-1), 113.18 (C-4), 112.80 and 112.40 (2
CMe ), 97.47 (CMe ), 85.25 (C-5), 79.65 (C-3),
2
2
1
7
28
9
7.52.
Degradation of 4 to 6.ÐA soln of 4 (700 mg,
1.86 mmol) in aq 70% tri¯uoroacetic acid (7 mL)
2
2
75.88 (C-2), 73.38 (C-6), 72.90 (C-7), 68.29 (C-8),
52.38 (OMe), 28.64 and 18.90 (CMe ), 27.54, 26.60,
2
was left at room temperature overnight. TLC (10:1
CHCl ±MeOH) then revealed a nonmobile com-
pound. The mixture was concentrated and repeat-
26.52, and 26.45 (2 CMe ). Anal. Calcd for
2
C H O : C, 55.66; H, 7.27. Found: C, 55.32; H,
18 28
3
9
7.25.

220
I. Izquierdo Cubero et al./Carbohydrate Research 308 (1998) 217±221
Methyl 2,3:4,5:6,8-tri-O-isopropylidene-a-l-
glycero-d-ido-oct-4-ulofuranosonate (8).ÐCom-
pound 3 (220 mg, 0.63 mmol) in dry acetone (5 mL),
crystalline 10 (516 mg, quantitative), mp 125±
ꢀ
23
127 C (from hexane); ‰ꢀŠ +6 (c 1, CHCl ); IR
ꢀ
D
3
�
1
(KBr): ꢂ 3508 (OH), 1391, 1382, and 1375 cm
1
p-toluenesulfonic acid (90 mg) and anhyd CuSO4
(250 mg) was isopropylidenated as above, to yield
(CMe ); H NMR: ꢁ 4.57 (s, 1 H, H-5), 4.40 (ddd, 1
2
H, J1,2 3.3, J
0
4.8, J2,3 8.7 Hz, H-2), 4.24 (d, 1 H,
1 ,2
ꢀ
24
D
crystalline 8 (170 mg, 70%), mp 76±78 C; ‰ꢀŠ
J6,7 2.1 Hz, H-6), 4.21 (d, 1 H, H-3), 4.07 (dd, 1 H,
J7,8 2.3, J8,8 12.4 Hz, H-8), 4.05 (m, 1 H, H-7), 3.99
ꢀ
+
ester), 1392, 1384, and 1376 cm
13 (c 1.3, CHCl ); IR (KBr): ꢂ 1749 (C=O,
0
3
�
1
1
0
(CMe2);
H
(bd, 1 H, H-8 ), 3.93 (dd, 1 H, J
0
0
11.7 Hz, H-1),
3.77 (dd, 1 H, H-1 ), 2.05 (bs, 1 H, OH), 1.47, 1.45,
1,1
NMR data: ꢁ 4.93 (d, 1 H, J2,3 6.0 Hz, H-2), 4.78
d, 1 H, H-3), 4.51 (s, 1 H, H-5), 4.27 (d, 1 H, J6,7
(
1.43, 1.41, and 1.36 (5 s, 18 H, 3 CMe );
2
13
2
2
.5 Hz, H-6), 4.08 (m, 1 H, H-7), 4.04 (dd, 1 H, J7,8
.8, J
C NMR: ꢁ 114.75 (C-4), 111.99 and 109.28
(2 CMe ), 97.67 (CMe ), 84.80 (C-5), 77.58 (C-2),
76.71 (C-3), 73.84 (C-6), 72.01 (C-7), 63.09 (C-1),
13.1 Hz, H-8), 3.96 (dd, 1 H, J7,8 1.2 Hz,
0 0
8,8
2
2
0
H-8 ), 3.77 (s, 3 H, CO Me), 1.51, 1.48, 1.40, and
2
1
1
.36 (4 s, 18 H, 3 CMe2); 13 C NMR: ꢁ 171.57 (C-
), 114.89 (C-4), 112.35 and 112.12 (2 CMe ), 97.71
60.14 (C-8), 28.60 and 18.79 (CMe ), 27.71, 27.31,
2
27.20, and 26.81 (2 CMe ). Anal. Calcd for
2
2
(
(
CMe ), 84.95 (C-5), 78.43 (C-3), 75.61 (C-2), 73.78
2
C-6), 72.49 (C-7), 60.13 (C-8), 52.46 (OMe), 28.25
C H O : C, 56.65; H, 7.83. Found: C, 56.67; H,
17 28
7.97.
8
and 19.06 (CMe ), 27.82, 27.36, 26.88, and 25.80 (2
2
l-Glycero-d-galacto-oct-4-ulose (11).ÐA soln
of 9 (80 mg, 0.22 mmol) in aq 50% TFA (3 mL)
was left at room temperature for 4 d. TLC
(EtOAc) revealed that 9 had disappeared and that
a non-mobile substance was present. The mixture
was concentrated and residual TFA removed by
co-distillation with water. Column chromatog-
CMe ). Anal. Calcd for C H O : C, 55.66; H,
2
18 28
9
7
.27. Found: C, 55.25; H, 7.14.
,3:4,5:6,8-Tri-O-isopropylidene-ꢀ-l-glycero-d-
galacto-oct-4-ulofuranose(9).ÐTo a stirred soln of
(3.4 g, 8.75 mmol) in dry ether (50 mL), LiAlH4
340 mg, 9 mmol) was added portionwise and the
mixture left at room temperature for 15 min. TLC
ether) then showed the presence of a slower-run-
2
7
(
raphy (3:1 CHCl ±MeOH) of the residue a€orded
3
(
11 (22 mg, 42%) that was homogeneous by TLC
25
[R 0.33 (2:1 CHCl ±MeOH) and had ‰ꢀŠ � 7ꢀ,
ning product. The excess of hydride was destroyed
by cautious addition of ether saturated with water.
The organic phase was separated and the aq phase
extracted with ether. The combined extracts were
f
3
D
2
5
05
ꢀ
‰ꢀŠ � 9 (c 1, MeOH).
4
l-Glycero-d-ido-oct-4-ulose (12).ÐHydrolysis of
10 (80 mg, 0.22 mmol) in aq 50% TFA (3 mL), as
described above yielded syrupy 12 (36 mg, 68%)
washed with brine and then concentrated to crys-
ꢀ
talline 9 (3.05 g, quantitative), mp 105±107
ꢀ
C
that was homogeneous by TLC (as above) R 0.38,
f
2
D
6
25
ꢀ
25
405
ꢀ
(
from hexane); ‰ꢀŠ � 6 (c 1.4, CHCl ); IR (KBr):
and had ‰ꢀŠD � 18 , ‰ꢀŠ � 40 (c 1, MeOH).
3
�
1
1
ꢂ 3487 (OH), 1387, and 1379 cm
NMR: ꢁ 4.46 (s, 1 H, H-5), 4.35 (dt, 1 H, J1,2
J1 = 4.3, J2,3 8.3 Hz, H-2), 4.31 (d, 1 H, J6,7
(CMe ); H
2
=
0
Acknowledgement
,2
2
2
.3 Hz, H-6), 4.11 (d, 1 H, H-3), 4.09 (dd, 1 H, J7,8
.2 Hz, H-7), 4.03 (dd, 1 H, J8,8 13.5 Hz, H-8), 3.94
11.8 Hz, H-1),
0
The authors are deeply grateful to Ministerio de
Educacion y Cultura, Spain, for ®nancial support
Â
(Proposal PB95-1157).
0
(bd, 1 H, H-8 ), 3.87 (ddd, 1 H, J
0
,1
1
0
3
.81 (dt, 1 H, H-1 ), 2.33 (dd, 1 H, J1,OH 8.1, J
0
1 ,OH
5
s, 18 H, 3 CMe2);
.1 Hz, OH), 1.50, 1.43, 1.41, 1.40, 1.39, and 1.34 (6
C NMR: ꢁ 113.15 (C-4),
13
References
1
13.01 and 109.82 (2 CMe ), 97.50 (CMe ), 85.43
2 2
(
(
(
C-5), 77.72 (C-2), 77.56 (C-3), 73.25 (C-6), 72.74
C-7), 63.50 (C-1), 60.26 (C-8), 28.99 and 18.72
CMe ), 27.66, 27.52, 26.62, and 26.51 (2 CMe ).
[
1] I. Izquierdo, M.-T. Plaza, R. Robles, and C.
Rodrõguez, Tetrahedron Asymmetry, (1996)
593±3604.
2] I. Izquierdo and M.-T. Plaza, J. Carbohydr. Chem.,
5 (1996) 303±315.
Â
7
2
2
3
Anal. Calcd for C H O : C, 56.65; H, 7.83.
8
17
28
[
[
Found: C, 56.80; H, 8.03.
,3:4,5:6,8-Tri-O-isopropylidene-a-l-glycero-d-
ido-oct-4-ulofuranose (10).ÐCompound 8 (529 mg,
1
1
1
2
3] S. Picasso, Y. Chen, and P. Vogel, Carbohydr.
Lett., 1 (1994) 1±8; S.H. Kang and G.T. Kim, Tet-
rahedron Lett., 36 (1995) 5049±5052; K. Zhao and
D.R. Mootoo, J. Org. Chem., 61 (1996) 6762±6763;
.47 mmol) was reduced with LiAlH4 (60 mg,
.6 mmol) in dry ether (10 mL) as above to give

I. Izquierdo Cubero et al./Carbohydrate Research 308 (1998) 217±221
221
H.S. Overkleeft and U.K. Pandit, Tetrahedron
Lett., 37 (1996) 547±550
[6] J.S. Brimacombe, G. McDonald, and M.A. Rah-
man, Carbohydr. Res., 205 (1990) 422±427.
[
4] I. Izquierdo, M.-T. Plaza, and N. Kari, Carbohydr.
Res., 261 (1994) 231±242.
5] E.L. Hirst, J. Chem. Soc., (1926) 350±357.
[7] R.E. Gawley and J. Aube, Principles of Asymmetric
Â
Synthesis, Elsevier Science, Oxford, 1996, pp 10±
14.
[