Stereoselective O-glycosylation reactions using glycosyl donors with diphenylphosphinate and propane-1,3-diyl phosphate leaving groups

Article abstract of DOI:10.1016/S0957-4166(01)00227-0

Glycosyl donors having a diphenylphosphinate and a propane-1,3-diyl phosphate leaving group were easily prepared by the addition of the anomeric hydroxyl group of 2,3,4,6-tetra-O-benzyl-α,β-D-glucopyranose to diphenylphosphinic and propane-1,3- diyldioxyphosphoryl chlorides. These glycosyl donors were selectively glycosylated with a number of primary and secondary oxygen nucleophiles in the presence of trimethylsilyl triflate (TMSOTf). The use of 1,3-diyl phosphate resulted in the stereoselective formation of β-O-linked glycosides.

Full text of DOI:10.1016/S0957-4166(01)00227-0

TETRAHEDRON:
ASYMMETRY
Pergamon
Tetrahedron: Asymmetry 12 (2001) 1373–1381
Stereoselective O-glycosylation reactions using glycosyl donors
with diphenylphosphinate and propane-1,3-diyl phosphate leaving
groups
Hariprasad Vankayalapati, Gurdial Singh* and Isabelle Tranoy
Department of Chemistry, University of Sunderland, Sunderland SR1 3SD, UK
Received 1 May 2001; accepted 16 May 2001
Abstract—Glycosyl donors having a diphenylphosphinate and a propane-1,3-diyl phosphate leaving group were easily prepared by
the addition of the anomeric hydroxyl group of 2,3,4,6-tetra-O-benzyl-a,b-D-glucopyranose to diphenylphosphinic and propane-
1,3-diyldioxyphosphoryl chlorides. These glycosyl donors were selectively glycosylated with a number of primary and secondary
oxygen nucleophiles in the presence of trimethylsilyl triflate (TMSOTf). The use of 1,3-diyl phosphate resulted in the
stereoselective formation of b-O-linked glycosides. © 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
We have studied a series of glycosylation reactions and
we recently reported part of this work concerning the
stereoselective O-glycosylation reactions using 2,3,4,6-
The involvement of oligosaccharide structures in bio-
logical processes such as neuronal development, fertili-
sation, proliferation of cells, metastasis1 and in
inducing the antibody response which is responsible for
the protection of the organism during infection2a has
markedly increased the interest in synthetic oligosac-
charides.2b Thus, efforts to develop new methods for
the synthesis of oligosaccharides, glycoconjugates,
either chemically or chemoenzymatically have increased
greatly over the past decade.3 Of the many O-glycosyla-
tion reactions4 available for oligosaccharide synthesis,
the most efficient are those where the stereochemical
outcome of the reaction is facilitated by neighbouring
group participation. Whereas this method works very
satisfactorily to synthesise trans-1,2-glycosides/oligosac-
charides,5 the synthesis of cis-1,2-glycosides can be
problematic. S-Glycosyl phosphoroimidothioates have
been reported to afford 1,2-cis-glycosides.6 There have
been a number of reports regarding glycosyl donors
that contain a phosphorus atom in the leaving group at
the anomeric centre and the coupling reactions of gly-
cosyl diphenylphosphates, glycosyl diphenylphosphin-
tetra-O-benzyl-a,b-
D
-glucopyranosyl phosphinate and
-fuco- and -galactopyran-
phosphates,9
D
-manno-,
L
D
osyl phosphates10 in the presence of catalytic
trimethylsilyl triflate (TMSOTf) as an activator. We
report herein a synthesis of glycosyl donors having
diphenylphosphinyl and propane-1,3-diyl phosphate
leaving groups and their use in glycosylation. The use
of the diphenylphosphinate function for N-protection
and coupling of amino acids has been elegantly demon-
strated by Kenner and Ramage11 in their studies
encompassing the synthesis of lysozyme. We reasoned
that employment of the diphenylphosphinate function
for the activation of the anomeric centre of
D-glucopy-
ranose should provide access to O-glycosides. In addi-
tion to these studies we chose to investigate the
chemistry of propane-1,3-diyl phosphate as the leaving
group as this would provide a comparison of the effect
of pKa on the leaving group ability and also allow
predictions of the influence that steric factors may have
in subsequent coupling reactions at the anomeric
centre.
imidates,
glycosyl
phosphoramidates
and
dimethylphosphinothioates as glycosyl donors have
been investigated.7,8
2. Results and discussion
With these considerations in mind we commenced an
investigation of the coupling at the anomeric centre of
2,3,4,6-tetra-O-benzyl-a,b-
D-glucopyranose. The choice
of this derivative was influenced by the prime consider-
* Corresponding author. E-mail: gurdial.singh@sunderland.ac.uk
0957-4166/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(01)00227-0

1374
H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
ation that there would be no participation in the
coupling reaction of the C(2) substituent. An addi-
tional factor was that a successful outcome to this
chemistry would provide access to O-glycopyranosides.
of the phosphate 5 the resonance for the C(1)H at lH
5.85 exhibited couplings of J1,2=3.3 Hz and JH-P=10.6
Hz, whilst in the case of the phosphate 6 the anomeric
resonance was observed at lH 5.24 as an apparent
triplet with J1,2,=7.3 and JH-P=13.2 Hz. We were
pleased to observe that like the diphenylphosphinate
derivatives 2 and 3 the propane-1,3-diyl phosphates 5
and 6 did not display any appreciable decomposition
upon storage at −20°C for a similar period of time.
The 2,3,4,6-tetra-O-benzyl-a,b- -glucopyranose 1 was
D
prepared as reported by Fletcher.12 Treatment of 1 with
diphenylphosphinic chloride and N-methylimidazole
resulted in the formation of the phosphinates 2 and 3
(Scheme 1), which were separable by flash column
chromatography in a ratio of 10:1, respectively, in
combined yield of 95%. The stereochemical assignment
of the anomeric centre in compounds 2 and 3 was based
With these phosphinates and phosphates in hand we
examined their reactions with a range of primary/sec-
ondary amino acid- and carbohydrate-based nucleo-
philes (Fig. 1). In the first instance we chose to examine
the reaction of 2 with n-butanol, without the addition
of a Lewis acid, which resulted in the isolation of the
corresponding phosphinate ester and recovery of
1
upon the H NMR coupling constants for C(1); in the
case of compound 2 the resonance was observed as a
doublet at lH 5.99 with a J1,2 of 3.3 Hz and JH-P of 11.9
Hz, whilst for compound 3 a doublet at lH 5.32 with
J1,2 of 7.9 Hz and JH-P of 11.9 Hz was seen. For
convenience we conducted all of the studies with an
anomeric mixture of 2 and 3. We were pleased to find
that these phosphinates could be stored at −20°C for
four months without any significant decomposition, as
evidenced by TLC and 1H NMR analysis. Similar
treatment of 1 with propane-1,3-diyldioxyphosphoryl
chloride 4 resulted in the formation of the phosphates 5
and 6, which proved to be inseparable by chromatogra-
2,3,4,6-tetra-O-benzyl-a,b-D-glucopyranose. However,
adding one equivalent of TMSOTf in the reaction at
−78°C resulted in the desired displacement of the
diphenylphosphinate function and formation a glyco-
sidic linkage at the anomeric centre (Scheme 2). Flash
column chromatographic purification on silica enabled
separation of the two stereoisomers in a combined
isolated yield of 90% (Table 1). As a result of this
finding we investigated the reaction of the mixture of
phosphinates 2 and 3 with n-butanol in the presence of
a stoichiometric amount of TMSOTf and we found
1
phy, in a yield of 65% and a ratio of 10:1 based on H
NMR analysis, as a mixture of colourless crystalline
diastereoisomers with an mp of 101–103°C. In the case
Scheme 1. Reagents and conditions: (i) Ph2POCl, MeNIm, CH2Cl2, rt, 16 h.
Scheme 2. Reagents and conditions: (i) 1 equiv. of nucleophile, 1 equiv. TMSOTf, −78°C, 25 min.

H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
1375
Figure 1.
Table 1. Reactions of phosphinate donors 2 and 3 con-
subsequent studies we employed this mixture of
anomeric phosphinates 2 and 3. In all reactions the
yields were excellent; however, the observed stereoselec-
tivity in these cases was invariably poor, being in the
order of 3:1 in favour of the desired b-isomer. The
ducted in dichloromethane
Product
% Yield
Ratio (a:b)
9, 10
94
93
90
88
94
92
84
85
1:4
1:3.5
1:2
1:2.5
2:1
1:2
1
stereochemistry of the products was established by H
11, 12
13, 14
15, 16
17, 18
19, 20
21, 22
23, 24
and 13C NMR analysis. In this respect 13C NMR data
proved particularly useful in that the b-isomers had
chemical shifts above l 100 ppm, whilst the a-isomer
had resonances at ca. l 96 ppm,13 thus allowing facile
assignment of the newly formed stereocentre.
1:3
1:2
We next investigated the chemistry of the propane-1,3-
diyl phosphates 5 and 6 as the glycosyl donors. In all
reactions studied, the displacement reaction proceeded
little difference in the stereochemical outcome of the
reaction employing this anomeric mixture. In all of our

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H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
smoothly and resulted in isolation of O-glycosides in
good yields after chromatographic purification (Scheme
2). In all cases we were able to isolate both the a- and
b-isomers in pure form. To our surprise the employ-
ment of serine and threonine as acceptors resulted in
the formation of products wherein the a-isomer was
dominant (Table 2); this may be a result of a hydrogen
bonding interaction with the N–H, resulting in delivery
from the a-face of the glucose.
[number of protons, multiplicity, coupling constants J
(Hz), and assignment]. Residual protic solvent CHCl3
(lH 7.26 ppm) was used as the internal reference. 13C
NMR spectra were recorded in CDCl3 at 67.8 MHz on
a JEOL GSX 270 NMR spectrometer using central
resonance of CDCl3 (lC 77.0 ppm) as the internal
reference. 31P NMR spectra were recorded in CDCl3 at
109.25 MHz using a JEOL GSX 270 NMR spectrome-
ter, using trimethyl phosphate as the external reference.
IR spectra were recorded on a UNICAM series FTIR
spectrometer. Mass spectra were obtained on an AEI
MS 902 or VG ZAB-E spectrometer. Microanalyses
were performed by MEDAC Ltd, Surrey, UK. Mps
were determined on a GallenKamp capillary melting
point apparatus and are uncorrected. Optical rotations
were measured in CHCl3 solution using a Bellingham &
Stanley ADP 220 polarimeter. Flash chromatography
was carried out using Fluka silica gel 60 (230–400
mesh) unless otherwise indicated. Analytical TLC was
performed using pre-coated aluminium plates (Merck
Kiselgel 60 F254) and visualised by UV, phosphomolyb-
dic acid or basic aqueous potassium permanganate
solutions. ‘Petrol’ refers to petroleum spirit (distillation
range 40–60°C), which was distilled prior to use, and
ether refers to diethyl ether (Et2O).
In the case of acceptors that were carbohydrate based
we observed improved stereoselectivity, in that only the
b-anomers were isolated in good yield. Glycosylation of
the C(6)–OH of the acceptor with propane-1,3-diyl
phosphates 5 and 6 gave the disaccharides 22 and 25 in
good yield with complete b-selectivity. In the case of
secondary alcohol acceptor C(3)OH with phosphates 5
and 6 gave the disaccharides 27 and 28 in 67% yield
with high b-selectivity (a:b=1:12). This was particu-
larly encouraging as at C(2) we have a 2-O-benzyl
function that is non-participating in glycosylation reac-
tions and would be expected to result in the formation
of a-glycosides. Based upon these findings one could in
principle use O-benzyl protected sugars as starting
materials and by changing the activating group of the
glycosyl donor either diastereoisomer can be obtained,
removing the need for differentially protected glycoside
precursors.
All reactions were carried out under an argon or nitro-
gen atmosphere in oven-dried glassware unless other-
wise stated. The sole solvent used for the glycosylation
reaction was CH2Cl2, which was distilled from calcium
hydride. Aqueous solutions are saturated unless other-
wise specified.
In these studies we have established that 2,3,4,6-tetra-
O-benzyl-a,b-D-glucopyranose can provide access to
O-linked glycosides with good stereoselectivity in the
cases where propane-1,3-diyl phosphate functions as
the anomeric leaving group, adding to the methodology
available for the synthesis of complex carbohydrates.
3.2. General procedure for the synthesis of 2,3,4,6-
tetra-O-benzyl-1-O-diphenylphosphinyl-a,b-D-gluco-
pyranosyl-2-oxides 2 and 3
3. Experimental
2,3,4,6-Tetra-O-benzyl-a,b- -glucopyranose 1 (2.5 g,
D
4.63 mmol) was dissolved in CH2Cl2 (20 mL) and the
solution was cooled to 0°C. Diphenylphosphinic chlo-
ride (1.36 g, 5.74 mmol) and 1-methylimidazole (0.76 g,
9.25 mmol) were added dropwise over 15 min to the
above solution and stirring was continued for 16 h,
with gradual warming to room temperature. The sol-
3.1. General methods
1H NMR spectra were recorded in CDCl3 (unless stated
otherwise) on a JEOL GSX 270 NMR spectrometer
and are reported as follows: chemical shifts l (ppm)
Table 2. Reactions of phosphate donors 5 and 6 conducted in dichloromethane
a
Product
% Yield
Ratio (a:b)
Chemical shift for anomeric C(1) proton lppm
9, 10
11, 12
13, 14
15, 16
17, 18
19, 20
21, 22
23, 24
25
96
98
99
91
83
68
72
88
73
79
67
3:7
3:7
4.80, 4.29
4.87, 4.45
4.76, 4.39
5.08, 4.34
4.88, 4.30
4.78, 4.22
5.45, 4.38
4.92, 4.49
4.58
b-onlya
2:1
2:1
b-onlya
b-onlya
1:4
b-onlyb
b-onlyb
1:12b
26
27, 28
4.51
4.63
a In these cases the a-isomer chemical shifts were recorded for the compounds obtained using diphenylphosphinate activation of the anomeric
centre (Table 1).
b Reactions carried out only with phosphate donors 5 and 6.

H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
1377
vent was removed, and the oily residue dissolved in
CH2Cl2 (20 mL) and evaporated a second time to
remove traces of 1-methylimidazole. A solution of
residue in CH2Cl2 (20 mL) was washed with ice-water
(25 mL), saturated aq. NaHCO3 solution (2×25 mL)
and water (25 mL). The organic layer was dried over
Na2SO4 and solvent removed in vacuo. The oily residue
was purified by column chromatography over silica
(Et2O–petrol 3:1) to afford phosphinates 2 and 3 (ratio
10:1) (3.2 g, 95%), [h]2D4mix=+83.3 (c 4.3, CHCl3).
68.86 (d, J 7.01), 72.58, 73.06, 73.54, 75.24, 75.51,
76.94, 79.03, 81.09, 94.78 (C-1), 127.60, 127.68, 127.76,
127.81, 127.86, 127.88, 129.95, 128.25, 128.32 (2C),
128.38 (2C), 137.50, 137.84, 137.90, 138.47; lP (109.25
MHz; CDCl3) −10.99; microanalysis: found: C, 67.4; H,
6.3; P, 4.7. C37H41O9P requires: C, 67.3; H, 6.3; P 4.7%.
For isomer 6, lH 5.24 (1H, dd, J1,2 13.2, 7.3); lC 98.44;
lP −10.60; m/zmix (EI) [found (M+), 660.6993.
C37H41O9P requires m/z 660.6993].
For isomer 2, IR (film) wmax 1592, 1210 cm−1; lH
3.62–3.77 (4H, m), 3.86–4.07 (2H, m), 4.36 (1H, d, J
11.9), 4.47 (1H, d, J 10.5), 4.51 (1H, d, J 11.9), 4.60
(1H, d, J 11.2), 4.73 (1H, d, J 11.2), 4.80 (1H, d, J
10.6), 4.85 (1H, d, J 10.6), 4.96 (1H, d, J 11.2), 5.99
(1H, dd, J1,2 11.9, 3.3), 7.10–7.84 (30H, m); lC 68.08,
72.10, 73.21, 74.64, 76.67, 79.14, 79.20, 81.13, 84.28,
92.79 (C-1), 127.41, 127.45, 127.48, 127.53, 127.67,
127.77, 127.81, 127.90, 128.04, 128.11, 128.14, 128.19,
128.24, 130.31, 131.05, 131.21, 131.44, 131.48, 131.55,
131.59, 131.69, 131.88, 131.97, 131.99, 132.02, 132.40,
137.57, 137.70, 137.86, 138.01, 138.22, 138.40; lP
(161.70 MHz; CDCl3) 32.50; m/z (CI, NH3) [found:
(M+NH4), 758.3246. C46H49NO7P requires m/z
758.3247].
3.4. General procedure for the synthesis of 2,3,4,6-
tetra-O-benzyl-a,b-D-glucopyranosides 7 and 8
To a stirred solution of glycosyl donor (0.25 g, 0.37
mmol) in CH2Cl2 (5 mL) at −78°C was added TMSOTf
(0.084 g, 0.37 mmol). After a period of 2 min a solution
of the glycosyl acceptor (0.37 mmol) in CH2Cl2 (2 mL)
was added to this mixture. The resultant mixture was
stirred for a further 3 min and then allowed to warm to
0°C (ca. 20 min). The mixture was diluted by the
addition of CH2Cl2 (10 mL) and washed with saturated
aq. NaHCO3 (10 mL). The aqueous layer was extracted
with CH2Cl2 (10 mL). The combined organic layer was
dried over anhydrous Na2SO4, concentrated in vacuo
and the residue was purified by column chromatogra-
phy to give compounds 7 and 8.
For isomer 3, lH 3.60–3.80 (4H, m), 3.85–4.07 (2H, m),
4.36 (1H, d, J 11.8), 4.45 (1H, d, J 10.5), 4.50 (1H, d,
J 11.9), 4.60 (1H, d, J 11.2), 4.73 (1H, d, J 11.2), 4.80
(1H, d, J 10.5), 4.85 (1H, d, J 10.5), 5.01 (1H, d, J
11.2), 5.32 (1H, dd, J1,2 11.9, 7.9), 7.10–7.84 (30H, m);
lC 96.0 (C-1); lP 32.72; m/z (EI) [found: (M+H),
741.2971. C46H46PO7 requires m/z 741.2981].
3.5. Methyl-O-2,3,4,6-tetra-O-benzyl-a-
D
-glucopyranose
914
[h]D22=+36.2 (c 1.2, CHCl3) {lit.14e [h]D=+40.0 (c 1.0,
CHCl3); lit.14d [h]D=+21.2 (c 1.0, CHCl3)}; IR (film)
wmax 1606 cm−1; lH 3.37 (3H, s), 3.46 (1H, d, J 7.3), 3.53
(1H, dd, J 9.9, 4.0), 3.61–3.65 (2H, m), 3.68–3.72 (1H,
m), 3.94 (1H, t, J 9.2), 4.44 (1H, d, J 11.9), 4.49 (1H,
unresolved), 4.57, (1H, J 12.5), 4.63 (1H, d, J 11.9),
4.77 (1H, d, J 9.9), 4.79 (1H, d, J 10.6), 4.80 (1H, d, J1,2
3.3), 4.84 (1H, d, J 10.6), 4.95 (1H, d, J 10.6), 7.11–7.33
(20H, m); lC 55.18, 68.58, 70.13, 73.41, 73.52, 75.03,
75.77, 76.58, 79.92, 82.19, 98.25 (C-1), 127.50, 127.61,
127.69, 127.89 (2C), 127.93 (2C), 138.02, 138.25 (2C),
138.89; m/z (CI, NH3) [found: (M+NH4), 572.3012.
C35H42NO6 requires m/z 572.3012].
3.3. 2,3,4,6-Tetra-O-benzyl-a,b-D-glucopyranosyl-1,3-
diyl phosphates 5 and 6
To a mixture of 2,3,4,6-tetra-O-benzyl-a,b-D-glucopy-
ranose 1 (2 g, 3.69 mmol), at 0°C, was added a solution
of propane-1,3-diyldioxyphosphoryl chloride10 4 (1.16
g, 7.39 mmol) in CH2Cl2 (20 mL) followed by 1-
methylimidazole (0.60 g, 7.39 mmol), under N2. The
above reaction mixture was allowed to warm to rt and
stirring was continued for a total of 16 h. The solvent
was removed under reduced pressure and the resulting
residue was dissolved in CH2Cl2 (25 mL), washed with
saturated aq. NaHCO3 (10 mL) and water (10 mL).
The organic layer was dried over anhydrous Na2SO4
and in vacuo. The residue was purified by column
chromatography on silica gel (Et2O–petrol 5:1) to
afford inseparable a- and b-anomers 5 and 6 (1.62 g,
65%), mp 101–103°C; [h]2D4mix=+65.7 (c 1.4, CHCl3).
3.6. Methyl-O-2,3,4,6-tetra-O-benzyl-b-D-glucopyranose
1014
[h]D22=+11.4 (c 2.0, CHCl3) {lit.14b [h]D=+12.2 (c 3.0,
CHCl3); lit.14c [h]D=+12.6 (c 3.0, CHCl3); lit.14f [h]D=
+11.0 (c 5.3, dioxan)}; IR (film) wmax 1610 cm−1; lH
3.42–3.48 (2H, m), 3.55 (3H, s), 3.60 (1H, dd, J 7.3,
4.6), 3.63 (1H, d, J 9.2), 3.69–3.73 (2H, m), 4.29 (1H, d,
J1,2 7.9), 4.50 (1H, d, J 10.6), 4.54 (1H, unresolved),
4.58 (1H, d, J 10.6), 4.62 (1H, d, J 11.9), 4.68 (1H, d,
J 11.2), 4.76 (1H, d, J 10.6), 4.79 (1H, d, J 10.6), 4.91
(1H, d, J 10.6), 7.12–7.32 (20H, m); lC 56.84, 68.81,
73.32, 74.54, 74.76 (2C), 75.46, 77.77, 82.20, 84.54,
104.59 (C-1), 127.46 (2C), 127.61 (2C), 127.70 (2C),
127.80, 127.93, 128.21 (2C), 138.10 (2C), 138.48, 138.55;
m/z (CI, NH3) [found: (M+NH4), 572.3012. C35H42NO6
requires m/z 572.3012].
For isomer 5, IR (KBr) wmax 1600, 1214 cm−1; lH
1.55–1.63 (1H, m, JPH 15.2), 2.14–2.28 (1H, m, JPH
15.2), 3.61–3.78 (4H, m), 3.89–3.99 (2H, m), 4.15–4.41
(4H, m), 4.44 (1H, d, J 11.9), 4.52 (1H, d, J 11.9), 4.56
(1H, d, J 11.9), 4.63 (1H, d, J 11.2), 4.71 (1H, d, J
11.9), 4.80 (1H, d, J 10.6), 4.84 (1H, d, J 11.2), 4.94
(1H, d, J 11.2), 5.85 (1H, dd, J1,2 10.6, 3.3), 7.13–7.37
(20H, m); lC 25.84 (d, J 7.01), 68.14, 68.65 (d, J 7.01),

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H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
3.7. Isopropyl-O-2,3,4,6-tetra-O-benzyl-a-
D
-
69.02, 69.78, 73.45, 74.85, 74.98, 75.66, 77.96, 82.29,
84.72, 103.60 (C-1), 127.58, 127.64, 127.76, 127.89,
127.99, 128.19, 128.37, 138.23, 138.32, 138.61, 138.74;
m/z (HRMS, EI) [found: (M+), 596.3138. C38H44O6
requires m/z 596.3138].
glucopyranose 1115
[h]D21=+48.6 (c 4.4, CHCl3) {lit.15c [h]D=+28.0 (c 0.4,
CHCl3)}; IR (film) wmax 1592 cm−1; lH 1.16 (3H, d, J
5.9), 1.21 (3H, d, J 5.9), 3.43–3.60 (2H, m), 3.64 (1H, d,
J 9.2), 3.71 (1H, dd, J 10.6, 4.0), 3.82–3.86 (1H, m),
3.89 (1H, d, J 5.9) 3.96 (1H, t, J 9.2), 4.45 (1H, d, J
9.2), 4.59 (1H, d, J 9.2), 4.63 (1H, d, J 9.9), 4.74 (1H,
d, J 11.9), 4.81 (1H, d, J 10.6), 4.83 (1H, d, J 10.6), 4.85
(1H, d, J 9.9), 4.87 (1H, d, J1,2 3.9), 4.98 (1H, d, J 10.6),
7.11–7.33 (20H, m); lC 21.22, 23.20, 68.64, 69.13, 70.11,
73.17, 73.50, 75.15, 75.69, 76.59, 80.02, 82.19, 94.86
(C-1), 127.56, 127.73, 127.93 (2C), 128.02 (2C), 128.19,
128.41 (2C), 138.08, 138.36 (2C), 139.06; m/z (CI, NH3)
[found: (M+NH4), 600.3325. C37H46NO6 requires m/z
600.3376].
3.11. N-Benzyloxycarbonyl-O-(2,3,4,6-tetra-O-benzyl-a-
D
-glucopyranosyl)-L-serine methyl ester 15
[h]2D3=+28.8 (c 9.2, CHCl3); IR (film) wmax 3424, 1722,
1214, 1070 cm−1; lH 3.50–3.55 (2H, m), 3.54 (1H, dd, J
9.2, 3.3), 3.71 (3H, s), 3.73 (2H, s), 3.88 (1H, d, J 9.2),
4.13 (1H, d, J 7.9), 4.41 (1H, d, J 11.9), 4.47 (1H, d, J
12.5), 4.49 (1H, d, J 10.6), 4.52 (2H, appt. d, J 9.2),
4.74 (1H, d, J 8.6), 4.80 (1H, d, J 10.6+1H, unresolved),
4.91 (1H, d, J 10.6), 4.93 (1H, unresolved), 5.08 (1H, d,
J1,2 3.3), 5.10 (2H, s), 6.02 (1H, d, J 7.9), 7.10–7.31
(25H, m); lC 52.53, 54.52, 67.02, 68.23, 69.68, 70.02,
73.00, 75.08, 75.60, 76.58, 79.88, 81.65, 81.80, 98.65
(C-1), 127.41, 127.58, 127.67, 127.79, 127.90, 128.10,
128.34 (2C), 136.23, 137.85, 138.03, 138.16, 138.51,
138.74, 155.99, 170.48; m/z (CI, NH3) [found: (M+
NH4), 779.36697. C46H53N2O10 requires m/z 779.3670].
3.8. Isopropyl-O-2,3,4,6-tetra-O-benzyl-b-D-
glucopyranose 1215
[h]D21=+22.5 (c 4.0, CHCl3) {lit.15b [h]D=+11.0 (c 1.0,
CHCl3)}; IR (film) wmax 1600 cm−1; lH 1.22 (3H, d, J
5.6), 1.30 (3H, d, J 5.9), 3.41–3.47 (2H, m), 3.53 (1H, d,
J 9.2), 3.59–3.68 (3H, m), 3.72 (1H, d, J 8.6), 3.99 (1H,
t, J 5.9), 4.45 (1H, d, J1,2 7.3), 4.52 (1H, d, J 11.2), 4.58
(1H, d, J 12.5), 4.69 (1H, d, J 11.2), 4.76 (1H, d, J
10.6), 4.80 (1H, d, J 10.6), 4.91 (1H, d, J 11.2), 4.95
(1H, d, J 11.2), 7.12–7.32 (20H, m); lC 22.16, 23.68,
69.13, 72.22, 73.35, 74.73, 74.79, 74.86, 75.57, 76.58,
82.28, 84.81, 102.16 (C-1), 127.47, 127.56, 127.63 (2C),
127.79, 127.90, 128.11, 128.27 (2C), 138.17, 138.28,
138.55, 138.68; m/z (CI, NH3) [found: (M+NH4),
600.3325. C37H46NO6 requires m/z 600.3336].
3.12. N-Benzyloxycarbonyl-O-(2,3,4,6-tetra-O-benzyl-b-
D
-glucopyranosyl)-L-serine methyl ester 16
[h]2D3=−8.6 (c 3.7, CHCl3); IR (film) wmax 3432, 1742,
1216, 1070 cm−1; lH 3.39 (2H, m), 3.50 (1H, dd, J 9.9,
4.0), 3.67 (3H, s), 3.73 (2H, s), 3.81 (1H, d, J 9.2), 4.10
(1H, d, J 7.9), 4.34 (1H, bs, H-1), 4.37 (1H, d, J 11.9),
4.43 (1H, d, J 10.6), 4.52 (2H, unresolved), 4.67 (1H, d,
J 11.9), 4.70 (1H, d, J 8.6), 4.77 (2H, unresolved), 4.85
(1H, d, J 8.6), 4.89 (1H, d, J 11.2), 5.10 (2H, s), 5.73
(1H, d, J 7.9), 7.10–7.31 (25H, m); lC 52.53, 54.52,
67.02, 68.54, 70.83, 73.41, 74.91 (2C), 75.60, 76.58,
79.88, 81.65, 84.52, 103.86 (C-1), 127.58, 127.67, 127.79,
127.90, 128.10, 128.34, 136.23, 137.85 (2C), 138.03,
138.16, 138.51, 138.74, 155.99, 170.48.
3.9. Butyl-O-2,3,4,6-tetra-O-benzyl-a-D-glucopyranose
1316
[h]2D2=+42.5 (c 1.2, CHCl3); IR (film) wmax 1600 cm−1;
lH 0.89 (3H, t, J 7.3), 1.33–1.42 (2H, m), 1.56–1.65 (2H,
m), 3.38–346 (1H, m), 3.53–3.66 (4H, m), 3.68 (1H, dd,
J 10.6, 8.6), 3.75–3.80 (1H, m), 3.96 (1H, t, J 9.2), 4.43
(1H, d, J 11.9), 4.45 (1H, d, J 11.2), 4.58 (1H, d, J
10.6), 4.62 (1H, d, J 9.9), 4.75 (1H, d, J 11.9), 4.76 (1H,
d, J1,2 4.0), 4.79 (1H, d, J 10.6), 4.81 (1H, d, J 10.6),
4.97 (1H, d, J 11.2), 7.11–7.36 (20H, m); lC 13.82,
19.34, 31.44, 67.83, 68.55, 70.07, 73.05, 73.41, 75.02,
75.60, 76.58, 80.14, 82.09, 96.86 (C-1), 127.47, 127.61,
127.75, 127.87 (2C), 137.97, 138.28, 138.36, 138.94; m/z
(CI, NH3) [found: (M+NH4), 614.3482. C38H48NO6
requires m/z 614.3482].
3.13. N-Benzyloxycarbonyl-O-(2,3,4,6-tetra-O-benzyl-a-
D
-glucopyranosyl)-L-threonine methyl ester 17
[h]2D3=+35.5 (c 1.7, CHCl3); IR (film) wmax 3428, 1724,
1216, 1070 cm−1; lH 1.32 (3H, d, J 6.6), 3.34–3.37 (3H,
m), 3.46–3.50 (4H, m), 3.66 (3H, s), 3.75 (1H, d, J 10.6,
3.3), 3.84 (1H, d, J 9.24), 4.41 (1H, d, J 11.9), 4.45 (1H,
d, J 8.6), 4.46 (1H, d, J 11.9+1H, unresolved), 4.65 (1H,
d, J 11.9), 4.78 (1H, d, J 11.2), 4.86 (1H, d, J 11.9), 4.88
(1H, d, J1,2 4.0), 4.93 (1H, d, J 10.6), 5.12 (1H, s), 5.88
(1H, d, J 8.6), 7.09–7.33 (25H, m); lC 18.98, 52.31,
58.71, 67.02, 68.27, 70.94, 73.02, 74.65, 75.10 (2C),
76.68, 79.52, 81.62, 84.58, 97.91 (C-1), 127.49, 127.81,
127.90, 128.00. 128.29 (2C), 128.43, 137.79, 138.02,
138.14, 138.52, 138.62, 156.72, 170.70; m/z (CI, NH3)
[found: (M+NH4), 807.3857. C47H55N2O10 requires m/z
807.3857].
3.10. Butyl-O-2,3,4,6-tetra-O-benzyl-b-
D
-glucopyranose
14
Mp 69–71°C; [h]2D2=+16.5 (c 1.3, CHCl3); IR (KBr)
wmax 1592 cm−1; lH 0.91 (3H, t, J 7.3), 1.35–1.71 (4H,
m), 3.41–3.50 (2H, m), 3.52–3.69 (4H, m), 3.73 (1H, dd,
J 10.6, 2.0), 3.97 (1H, dt, J 12.5, 5.9), 4.39 (1H, d, J1,2
7.9), 4.51 (1H, d, J 11.2), 4.55 (1H, d, J 11.9), 4.61 (1H,
d, J 12.5), 4.71 (1H, d, J 10.6), 4.76 (1H, d, J 11.2), 4.80
(1H, d, J 10.6), 4.91 (1H, d, J 10.6), 4.93 (1H, d, J
10.6), 7.10–7.31 (20H, m); lC 13.85, 19.29, 31.82, 67.88,
3.14. N-Benzyloxycarbonyl-O-(2,3,4,6-tetra-O-benzyl-b-
D
-glucopyranosyl)-L-threonine methyl ester 18
[h]2D3=−12.0 (c 2.2, CHCl3); IR (film) wmax 3438, 1725,
1267, 1070 cm−1; lH 1.30 (3H, d, J 6.6), 3.34–3.37 (3H,
m), 3.45–3.50 (4H, m), 3.60 (3H, s), 3.70 (1H, dd, J

H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
1379
10.6, 3.3), 3.80 (1H, d, J 9.2), 4.30 (1H, d, J1,2 8.6), 4.36
(1H, d, J 11.9), 4.41 (1H, d, J 12.5), 4.42 (1H, d, J 9.9),
4.50 (1H, d, J 11.2), 4.76 (1H, d, J 11.2), 4.82 (2H,
unresolved), 4.89 (1H, d, J 11.2), 5.12 (1H, s), 5.78 (1H,
d, J 8.6), 7.09–7.33 (25H, m); lC 17.67, 52.37, 58.85,
67.05 (2C), 68.62, 73.44, 74.70, 74.94, 75.48, 77.55,
81.78 (2C), 84.48, 101.52 (C-1), 127.67, 127.83, 127.94
(2C), 128.04, 128.31, 136.24, 137.92, 138.02, 138.14,
138.52, 138.62, 156.72, 171.08; m/z (CI, NH3) [found:
(M+NH4), 807.3861. C47H55N2O10 requires m/z
807.3857].
(20H, m); lC 20.65 (2C), 20.90, 55.13, 62.71, 68.49,
70.72, 71.03, 71.58, 73.40, 73.64, 74.80, 75.45, 75.58,
80.21, 81.25, 84.71, 96.51 (C-1), 99.00 (C-1%), 127.50,
127.63, 127.72, 127.79, 127.92, 128.18, 128.28, 128.31
(2C), 128.45, 137.82, 138.03, 138.23, 138.48, 138.66,
169.72, 170.22, 170.31.
3.18. Methyl 2,3,4-tri-O-acetyl-6-O-(2%,3%,4%,6%-tetra-O-
benzyl-b-D-glucopyranosyl)-(1-6)-a-D
-glucopyranose 2217
[h]2D1=+65.5 (c 3.3, CHCl3); IR (thin film) wmax 3011,
1748, 1370, 1221, 1051 cm−1; lH (270 MHz; CDCl3)
1.99 (3H, s), 2.02 (3H, s), 2.08 (3H, s), 3.29 (3H, s),
3.41–3.55 (3H, m), 3.64–3.80 (2H, m), 3.84–3.97 (4H,
m), 4.38 (1H, d, J1%,2% 8.6, H-1%), 4.46 (1H, d, J 11.9),
4.49 (1H, d, J 11.9), 4.56 (1H, d, J 11.9), 4.58 (1H, d,
J 10.6), 4.64 (1H, d, J 11.2), 4.74 (1H, d, J 11.2),
4.81–4.85 (3H, m), 4.89 (1H, d, J 10.6), 4.91 (1H, d, J
11.2), 5.36 (1H, app t, J1,2 4.6, H-1), 7.03–7.27 (20H,
m); lC 20.68, 20.70, 29.59, 66.83, 68.43, 69.51, 70.24,
70.82, 73.15, 74.67, 74.82, 75.12, 75.47, 80.21, 81.27,
82.49, 84.71, 96.61 (C-1), 102.93 (C-1%), 127.52, 127.65,
127.68, 127.72, 127.77, 127.87, 127.92, 127.99, 128.18,
128.32, 128.34, 128.51, 137.72, 138.06, 138.34, 138.50,
170.10, 170.29, 170.40; m/z (CI, NH3) [found: (M+
NH4), 860.3867. C47H58NO14 requires m/z 860.3857].
3.15. Methyl 2,3-O-isopropylidene-(2%,3%,4%,6%-tetra-O-
benzyl-a-D-glucopyranosyl)-b-D-ribofuranoside 19
[h]2D5=+33.3 (c 1.3, CHCl3); IR (film) wmax 1604 cm−1;
lH 1.30 (3H, s), 1.46 (3H, s), 3.27 (3H, s), 3.43–3.59
(2H, m), 3.62–3.66 (2H, m), 3.68–3.70 (3H, m), 3.76
(1H, d, J 9.9), 3.96 (1H, t, J 9.2), 4.35 (1H, t, J1,2 5.9,
H-1), 4.39 (1H, d, J 11.2), 4.43 (1H, d, J 11.9), 4.55
(1H, d, J 11.9), 4.58 (1H, d, J 11.9), 4.75 (1H, d, J
11.9), 4.78 (1H, d, J1%,2% 3.3, H-1%), 4.81 (1H, d, J 11.2),
4.83 (1H, d, J 5.3), 4.94 (1H, d, J 11.2), 4.95 (1H, d, J
11.2), 4.98 (1H, s), 7.11–7.33 (20H, m); lC 25.07, 26.46,
54.83, 69.71, 70.52, 73.05, 73.47, 74.99, 75.60, 80.21,
81.86, 82.03, 82.19, 84.63, 84.84, 85.12, 98.07 (C-1%),
109.27 (C-1), 112.33, 127.49, 127.63, 127.70, 127.75,
127.81 (2C), 128.31 (2C), 137.97, 138.34, 138.42, 138.91;
m/z (CI, NH3) [found: (M+NH4), 744.3752.
C43H54NO10 requires m/z 744.3748].
3.19. Cholesteryl-O-2,3,4,6-tetra-O-benzyl-a-D-glucopy-
ranose 2318
[h]D24=+44.8 (c 2.2, CHCl3) {lit.18b [h]D=+48.0 (c 2.0,
CHCl3)}; IR (film) wmax 1596 cm−1; lH 0.68 (3H, s), 0.85
(3H, s), 0.88 (3H,s), 1.01 (3H, s), 1.07–1.23 (4H, m),
1.25 (3H, s), 1.28–2.43 (21H, m), 3.47 (1H, s), 3.53 (1H,
dd, J 9.9, 4.0), 3.56 (1H, dd, J 9.2, 3.3), 3.60–3.67 (3H,
m), 3.72–3.86 (2H, m), 3.97 (1H, t, J 9.3), 4.10 (1H, d,
J 7.26), 4.42 (1H, d, J 12.5), 4.44 (1H, d, J 10.6), 4.59
(1H, d, J 12.5), 4.63 (1H, d, J 11.9), 4.75 (1H, d, J
12.5), 4.80 (1H, d, J 10.6), 4.83 (1H, d, J 10.6), 4.92
(1H, d, J1,2 4.0), 4.99 (1H, d, J 10.6), 5.28 (1H, s),
7.11–7.35 (20H, m); lC 11.84, 18.72, 19.36, 21.07, 22.53,
22.77, 23.83, 24.28, 27.58, 27.99, 28.21, 29.62, 29.66,
31.92, 35.73, 35.76, 36.21, 36.79, 37.15, 39.53, 39.82,
39.83, 42.35, 50.18, 56.22, 56.82, 68.78, 70.16, 73.01,
73.44, 75.07, 75.61, 76.77, 78.02, 80.07, 82.14, 94.75
(C-1), 121.70, 127.48, 127.59, 127.65, 127.81, 127.88
(2C), 127.94, 128.10, 128.32 (2C), 128.34 (2C), 128.35,
128.40, 138.10, 138.36, 139.07, 140.88.
3.16. Methyl 2,3-O-isopropylidene-(2%,3%,4%,6%-tetra-O-
benzyl-b-D-glucopyranosyl)-b-D-ribofuranoside 20
[h]2D5=−5.5 (c 0.7, CHCl3); IR (film) wmax 1600 cm−1; lH
1.24 (3H, s), 1.36 (3H, s), 3.34–3.49 (2H, m), 3.51 (3H,
s), 3.52–3.55 (2H, s), 3.58 (1H, d, J 6.6, 2.0), 3.63–3.66
(2H, m), 3.68 (1H, dd, J 5.9, 2.0), 4.22 (1H, d, J1%,2% 7.92,
H-1%), 4.42 (1H, d, J1,2 5.9, H-1), 4.43 (1H, d, J 11.2),
4.45 (1H, d, J 12.5), 4.50 (1H, d, J 8.6), 4.53 (1H, d, J
12.5), 4.61 (1H, d, J 10.6), 4.69 (1H, d, J 11.2), 4.72
(1H, d, J 10.6), 4.73 (1H, d, J 2.6), 4.83 (1H, d, J 11.2),
4.87 (1H, d, J 10.6), 4.98 (1H, s), 7.18–7.30 (20H, m);
lC 24.82, 26.41, 57.07, 68.97, 73.50, 74.73, 74.88, 74.99,
75.64, 77.47, 77.91, 82.34, 84.67, 84.73, 86.50, 87.69,
104.72 (C-1%), 106.75 (C-1), 112.35, 127.59, 127.61,
127.74, 127.77, 127.87, 127.93, 127.96, 128.09, 128.35
(2C), 138.16, 138.22, 138.58, 138.65; m/z (CI, NH3)
[found: (M+NH4), 744.3748. C43H54NO10 requires m/z
744.3748].
3.20. Cholesteryl-O-2,3,4,6-tetra-O-benzyl-b-D-glucopy-
ranose 2418
[h]D24=−0.7 (c 1.4, CHCl3) {lit.18c [h]D=−0.5 (c 1.6,
CHCl3)}; IR (film) wmax 1600 cm−1; lH 0.68 (3H, s), 0.85
(3H, s), 0.88 (3H, s), 0.91–0.96 (4H, m), 1.03 (3H, s),
1.08–1.22 (4H, m), 1.25 (3H, s), 1.33–2.38 (21H, m),
3.41–3.47 (2H, m), 3.51 (1H, t, J 9.2), 3.60–3.67 (2H,
m), 3.72 (1H, d, J 8.6), 4.49 (1H, bs, H-1), 4.51 (1H, d,
J 10.6), 4.52 (1H, d, J 11.9), 4.59 (1H, d, J 11.9), 4.70
(1H, d, J 11.2), 4.76 (1H, d, J 10.6), 4.80 (1H, d, J
10.6), 4.90 (1H, d, J 11.2), 4.96 (1H, d, J 10.6), 5.35
(1H, s), 7.15–7.33 (20H, m); lC 11.90, 18.79, 19.44,
21.14, 22.58, 22.82 (2C), 23.89, 24.33, 28.05, 28.26,
29.73 (2C), 30.05, 31.99 (2C), 35.83, 36.27, 36.82, 37.40,
3.17. Methyl 2,3,4-tri-O-acetyl-6-O-(2%,3%,4%,6%-tetra-O-
benzyl-a-D-glucopyranosyl)-(1-6)-a-D
-glucopyranose 2117
[h]2D1=+ 59.2 (c 1.5, CHCl3); IR (film) wmax 3019, 1745,
1369, 1216, 1041 cm−1; lH 1.94 (3H, s), 2.01 (3H, s),
2.07 (3H, s), 3.36 (3H, s), 3.42–3.50 (4H, m), 3.57–3.65
(2H, m), 3.70–3.74 (1H, m), 3.80 (1H, d, J 8.6), 3.88
(1H, t, J 9.2), 4.30 (1H, d, J 12.5), 4.41 (1H, d, J 12.5),
4.42 (1H, d, J 11.2), 4.54 (1H, d, J 11.9), 4.59 (1H,
unresolved), 4.70 (1H, d, J 12.5), 4.78 (1H, d, J 10.6),
4.82 (1H, unresolved), 4.83–4.89 (3H, m), 5.45 (1H, d,
J1%,2% 1.3, H-1%), 5.57 (1H, d, J1,2 4.6, H-1), 7.10–7.35

1380
H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
39.19, 39.59, 39.89, 42.42, 50.32, 56.28, 56.86, 69.33,
73.47, 74.93 (2C), 75.67, 78.15, 79.74, 82.48, 84.95,
102.33 (C-1), 121.96, 127.56, 127.72, 127.92, 128.01,
128.21, 128.39 (2C), 138.32, 138.46, 138.69, 138.83,
140.72; m/z (CI, NH3) [found: (M+NH4), 926.6298.
C61H84NO6 requires m/z 926.6299].
22.66, 23.95, 26.54, 27.15, 65.54, 66.92, 69.12, 70.94,
71.78, 72.17, 72.46, 73.21, 74.66, 74.84, 74.94, 79.27,
79.85, 83.98, 97.53, 100.87, 106.36, 112.20, 127.46,
127.53, 127.68, 127.76, 127.82, 127.89, 127.97, 128.10,
128.24, 128.30, 128.32, 128.37, 128.41, 128.83, 138.40,
138.48, 138.53, 138.63; m/z (CI, NH3) [found: (M+
NH4), 800.4019. C46H58NO11 requires m/z 800.4010].
3.21. 6-O-(2%,3%,4%,6%-Tetra-O-benzyl-b-
D
-glucopyran-
osyl)-(1-6)-1,2:3,4-di-isopropylidene-a-
D-galactopyranose
25
Acknowledgements
[h]2D3=−8.6 (c 0.7, CHCl3); IR (film) wmax 1605 cm−1; lH
1.27 (6H, s), 1.46 (3H, s), 1.51 (3H, s), 3.44 (1H, dd, J
8.57, 4.0), 3.57–3.81 (4H, m), 3.96 (1H, dd, J 9.2, 5.9),
4.07 (1H, d, J 3.3, 1.3), 4.41 (1H, dd, J 4.0, 4.0),
4.23–4.38 (2H, m), 4.45 (1H, d, J 11.9), 4.46 (1H, dd, J
5.9, 3.3), 4.49 (1H, dd, J 5.3, 4.0), 4.58 (1H, bs), 4.70
(1H, d, J 11.2), 4.71 (1H, d, J 11.2), 4.75 (1H, d, J
11.2), 4.81 (1H, d, J 11.2), 4.81 (1H, d, J 11.2), 4.95
(1H, d, J 10.6), 5.04 (1H, d, J 11.2), 5.56 (1H, d, J1,2
5.3), 7.13–7.71 (20H, m); lC 24.41, 25.00, 25.97, 26.00,
65.67, 67.34, 70.63, 70.65, 70.78, 73.48, 74.75, 74.93,
74.97, 75.63, 77.73, 81.62, 81.96, 84.55, 96.36, 104.38,
108.56, 109.36, 127.46, 127.51, 127.59, 127.62, 127.69,
127.81, 127.87, 127.93, 128.19, 128.34 (2C), 128.63,
138.16, 138.18, 138.37, 138.72; m/z (CI, NH3) [found:
(M+NH4), 800.4017 C46H58NO11 requires m/z
800.4010].
We thank Professor R. Ramage (Edinburgh University)
for his interest in this work. We also thank the EPSRC
for access to the mass spectrometry service at the
University of Wales, Swansea (Director, Professor D.
E. Games).
References
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Esterl, W. Eur. J. Biochem. 1986, 154, 471; (b) Hakomori,
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Carbohydr. Chem. Biochem. 1980, 37, 157.
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3.22. Methyl 2,4,6-tri-O-benzyl-3-O-(2%,3%,4%,6%-tetra-O-
benzyl-b-D-glucopyranosyl)-(1-3)-a-D-mannopyranose 26
[h]2D1=+21.9 (c 0.6, CHCl3); IR (film) wmax 1602 cm−1;
lH 3.36 (3H, s), 3.72–3.78 (4H, m), 3.92 (1H, d, J 4.62),
3.94 (1H, d, J 2.6), 4.01–4.05 (4H, m), 4.19 (1H, d, J
3.3, 2.6), 4.51 (1H, bs+1H, d, J 10.6), 4.54 (1H, d, J
11.9+1H, unresolved); 4.55 (1H, d, J 9.9 +1H, unre-
solved), 4.57 (2H, dd, J 11.2, 9.2), 4.59 (1H, d, J 9.2),
4.62 (1H, d, J 12.5), 4.67 (1H, d, J 10.6), 4.69 (1H, d,
J 11.9), 4.73 (1H, d, J 11.9), 4.74 (1H, d, J 12.5), 4.78
(1H, d, J 1.3), 4.95 (1H, d, J 11.2), 5.31 (1H, d, J 1.3),
7.20–7.41 (35H, m); lC 54.75, 69.12, 69.67, 71.78, 72.12,
72.15, 72.25, 72.61, 73.31, 73.33, 74.39, 74.72, 75.00,
75.11, 75.58, 77.47, 78.47, 79.86, 98.49, 99.93, 126.89,
126.95, 127.27, 127.34, 127.37, 127.40, 127.45, 127.54,
127.61, 127.63 (2C), 128.06, 128.12, 128.14, 128.22,
128.24, 128.29, 128.31, 138.31, 138.35 (2C), 138.43,
138.47, 138.50, 138.78; m/z (CI, NH3) [found: (M+Na),
1009.4502. C62H66NaO11 requires m/z 1009.4503].
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3.23. 3-O-(2%,3%,4%,6%-Tetra-O-benzyl-b-
D
-glucopyran-
osyl)-(1-3)-1,2:5,6-di-isopropylidene-a-
D-glucofuranose
28
[h]2D5=+20.0 (c 0.8, CHCl3); IR (film) wmax 1605 cm−1;
lH 1.27 (6H, s), 1.30 (3H, s), 1.33 (3H, s), 3.63–3.85
(4H, m), 3.87 (1H, dd, J 9.2, 2.6), 3.99–4.06 (2H, m),
4.16 (1H, d, J 3.3), 4.26 (1H, d, J 4.0), 4.29 (1H, d, J
2.6), 4.32 (1H, d, J 6.6), 4.50 (1H, d, J 11.2), 4.54 (1H,
d, J 9.9), 4.55 (1H, d, J 11.9), 4.56 (1H, d, J 3.3), 4.63
(1H, bs), 4.64 (1H, d, J 9.9), 4.66 (1H, d, J 11.9), 4.69
(1H, d, J 11.2), 4.86 (1H, d, J 10.6), 4.87 (1H, d, J
10.6), 5.98 (1H, d, J1,2 3.3), 7.26–7.36 (20H, m); lC

H. Vankayalapati et al. / Tetrahedron: Asymmetry 12 (2001) 1373–1381
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