Synthesis of inositol glycan cyclic phosphates

Article abstract of DOI:10.1016/S0008-6215(01)00047-7

An efficient synthesis of tri-, tetra-, and pentasaccharide cyclic phosphates 1-5, structurally related to natural inositol phosphate glycans, is reported. The title compounds were assembled by PhSeOTf-promoted glycosylation of the known glucosamine precu

Full text of DOI:10.1016/S0008-6215(01)00047-7

www.elsevier.nl/locate/carres
Carbohydrate Research 331 (2001) 375–391
Synthesis of inositol glycan cyclic phosphates
Christine H. Jaworek, Sarah Iacobucci, Pericles Calias, Marc d’Alarcao*
Michael Chemistry Laboratory, Department of Chemistry, Tufts Uni6ersity, Medford, MA 02155, USA
Received 7 November 2000; accepted 26 January 2001
Abstract
An efficient synthesis of tri-, tetra-, and pentasaccharide cyclic phosphates 1–5, structurally related to natural
inositol phosphate glycans, is reported. The title compounds were assembled by PhSeOTf-promoted glycosylation of
the known glucosamine precursor, t-butyldimethylsilyl 2-azido-3,6-di-O-benzyl-2-deoxy-b- -glucopyranoside (8) with
D
protected 1-methylthio mono-, di-, and trimannosides 7a–c, and, after conversion into glycosyl fluorides, Cp2ZrCl2–
AgOTf-promoted glycosylation of differentially protected optically pure 1D-myo-inositol 11. The syntheses were
completed by installing the cyclic phosphate moieties with methylpyridinium dichlorophosphate and finally, removal
of all protecting groups by dissolving-metal reduction. © 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Inositol phosphate glycans; Cyclic phosphates; 1D-myo-inositol derivatives
1. Introduction
PI-PLC and Pronase release of the variant
surface glycoprotein (VSG) GPI anchor from
variant clone 118 of Trypanosoma bruceii
strain 427, presumed to have structure 6, is
insulin mimetic.3,14
In the US, approximately 16 million people
suffer from diabetes mellitus. Ninety to
ninety-five percent of these are afflicted by
non-insulin dependent diabetes mellitus
(NIDDM), a condition characterized by in-
sulin resistance. Diminished binding of insulin
to its receptor usually does not adequately
account for the decreased responsiveness on
the cellular level. Therefore, NIDDM may be
However, due to the miniscule amounts of
biological material available and the hetero-
geneity of many isolates, the precise chemical
structures of these putative insulin mediators
are not known. At least two general classes of
compounds have been identified. One class,
referred to by Larner’s group4 as the pH 1.3
mediator because of the pH of an eluting
solvent during purification, inhibits cAMP-de-
pendent protein kinase and contains myo-
inositol and glucosamine.5 The other,
so-called pH 2 mediator, stimulates pyruvate
dehydrogenase phosphatase and contains
chiro-inositol and galactosamine.6
considered
a
disease of insulin signal
transduction.1
During the past 15 years, small inositol-con-
taining oligosaccharides have been implicated
as signaling molecules in the insulin signal
transduction pathway.2 These oligosaccharides
are believed to be structurally similar to the
glycosylphosphatidyl-inositol (GPI) mem-
brane anchors. This idea is supported by the
observation that the compound obtained by
The lack of complete structural characteri-
zation has led to intense synthetic efforts by
several groups7–11 in the hope of determining
the structural features necessary for mimick-
ing insulin action. Herein, we report the syn-
* Corresponding author. Fax: +1-617-6273443.
E-mail address: mdalarca@tufts.edu (M. d’Alarcao).
0008-6215/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(01)00047-7

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C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
Fig. 1. Synthetic compounds 1–5, and natural VSG membrane anchor fragment 6.
thesis of oligosaccharides 1–5.12,13†‡ Com-
pounds 1, 3, and 5 constitute the terminal tri-,
tetra-, and pentasaccharide portion of 6, the
presumed structure of the VSG anchor frag-
ment from T. bruceii variant 118. Compounds
2 and 4 differ from the truncated VSG anchor
in that there is a b linkage between the inositol
and the glucosamine residues (Fig. 1).
would be attached to a suitably protected
linking glucosamine unit. To minimize the
number of manipulations, all protecting
groups remaining after final assembly of the
oligosaccharides were chosen to be removable
in a single deprotection step.
The known glucosamine precursor t-
butyldimethylsilyl 2-azido-3,6-di-O-benzyl-2-
deoxy-b-
-glucopyranoside (8)15 satisfied these
D
criteria. We envisioned glycosylating the 4-po-
sition of 8 with mono-, di-, and trimannoses
7a,16 7b, or 7c to provide the corresponding
di-, tri-, and tetrasaccharides 9a–c. The
methyl 1-thio-a-glycosides 7a–c were selected
to utilize Ogawa’s a-selective phenylselenyl
triflate-promoted glycosylation procedure.22
After desilylation and conversion into the gly-
cosyl fluorides 10a–c, zirconocene dichloride-
promoted coupling17 to myo-inositol 11 would
produce fully protected tri-, tetra-, and pen-
tasaccharides 12a–c, respectively. This glyco-
sylation method was chosen since both the a
and b anomers of the oligosaccharides were
desired. Recent work by Mu¨ller’s group8 has
2. Results and discussion
Synthetic strategy.—The syntheses of com-
pounds 1–5 were designed to be modular so
that assembly of a variety of oligosaccharides
could be achieved rapidly (Scheme 1). The two
terminal portions of each target compound,
an oligomannose unit and an inositol unit,
† Our synthesis of 1 has been communicated previously,
without experimental details (Ref. 11) and has been synthe-
sized independently (Ref. 10).
‡ A report on the synthesis of 5 by a different procedure
appeared at the time of submission of this manuscript.13

C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
377
demonstrated that some IPGs with b-
tol linkages are insulin mimetic.
D
inosi-
tive deprotection step would produce targets
1–5.
Inositol 11 was chosen to allow selec-
tive removal of the carbonate moiety of
12a–c, thereby freeing the hydroxyl groups
to be esterified in the cyclic phosphate moiety
of the targets. Cyclic phosphorylation
could then be accomplished in one step by
addition of methylpyridinium dichloro-
phosphate (31).18 Finally, removal of the
benzyl protecting groups and reduction of
the azido functionality in a single reduc-
Synthesis of mannose methyl 1-thioglycosides
7a–c.—Selective dimethoxytritylation of the
C-6 hydroxyl of the known mannose glycoside
1319,20 (Scheme 2) with 4,4%-dimethoxytrityl
tetrafluoroborate21 yielded triol 14. Exhaustive
benzylation under standard conditions ((i)
NaH, DMF, 0 °C; (ii) BnBr) yielded fully
protected 15. Removal of the DMT protecting
group with 50% HOAc provided alcohol 16 in
64% overall yield from 13.
Scheme 1. Overview of the syntheses of compounds 1–5.
Scheme 2. (i) DMTBF, DBMP, CH3CN, reflux (92%); (ii) (a) NaH, DMF; (b) BnBr; (iii) CHCl3, 50% CH3CO2H, 80 °C (70%,
from 14).

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C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
,
Scheme 3. (i) PhSeCl, AgOTf, toluene, 4 A molecular sieves, −40 °C (56–71%); (ii) NH3, MeOH, 20 °C (78%); (iii) (a) NaH,
DMF; (b) BnBr (85%); (iv) CH3CN–H2O, +1.55 V, 0.1 M Bu4NPF6, 20 °C (74%); (v) DAST, THF (86%); (vi) Bu3SnSMe,
SnCl4, ClCH2CH2Cl (85%).
Coupling of 16 to the known methyl 1-
thiomannoside 1716 (Scheme 3) using Ogawa’s
protocol22 yielded the differentially protected
mannose disaccharide 18. The a configuration
of the glycosidic linkage in the product was
confirmed by the 13C–1H coupling constant
(171 Hz) at the anomeric position according
to the observation of Bock and Pedersen23
lation with Bu3SnSMe16,26 produced the glyco-
syl donor 7b, ready to couple with acceptor 8.
For the synthesis of trisaccharide 7c
(Scheme 4), the common intermediate 19 was
glycosylated with methyl 1-thiomannoside 17
to produce trisaccharide 23. Elaboration of 23
to 7c proceeded in direct analogy to the syn-
thesis of 7b, producing 7c in 24% overall yield
from the common intermediate 19.
Synthesis of myo-inositol 11.—The differen-
tially protected inositol 11 (Scheme 5), ready
for coupling, was prepared from known, opti-
cally pure diol 2827 by protection of the two
free hydroxyl groups as the cyclic carbonate
(N,N%-carbonyldiimidazole, benzene) followed
by removal of the triisopropylsilyl (TIPS) pro-
tecting group. Use of acetyl groups to protect
the 1- and 2-positions of the inositol ring
proved unsuitable because of acetyl group mi-
grations upon fluoride-induced removal of the
TIPS group at position 6. The cyclic carbon-
ate did not suffer migration, presumably be-
cause the more rigid structure prevents
intramolecular attack of the intermediate C-6
alkoxide on the carbonyl group.
that a-mannosides exhibit anomeric JC,H
ꢀ
170 Hz while b-mannosides exhibit anomeric
JC,Hꢀ160 Hz. In every case in our work
where a glycosidic bond was formed from
mannose, the anomeric configuration of the
product(s) was confirmed by this method.
Deacetylation of 18 with methanolic ammo-
nia produced alcohol 19, which was a com-
mon intermediate in the synthesis of methyl
1-thioglycoside donors 7b and 7c (Schemes 3
and 4).
The synthesis of 7b was easily realized as
shown in Scheme 3. Compound 19 was benzy-
lated to produce 20 and this was subjected to
electrochemical
oxidation
in
aqueous
acetonitrile24 to remove the p-methoxyphenyl
(PMP) protecting group providing an
anomeric mixture of alcohols 21. This mixture
was readily converted into a mixture of
anomeric fluorides 22 by treatment with
DAST.25 Finally, SnCl4-promoted thiomethy-
Synthesis of oligosaccharides 1–5.—With
the necessary precursors in hand, each final
oligosaccharide could be synthesized in seven
steps (Scheme 6). The mannose mono-, di-,

C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
379
,
Scheme 4. (i) PhSeCl, AgOTf, toluene, 4 A molecular sieves, −40 °C (88%); (ii) NH3, MeOH, 20 °C (85%); (iii) (a) NaH, DMF;
(b) BnBr (81%); (iv) CH3CN–H2O, +1.55 V, 0.1 M Bu4NPF6, 20 °C (78%); (v) DAST, THF (90%); (vi) Bu3SnSMe, SnCl4,
ClCH2CH2Cl (52%).
and trisaccharides 7a–c were coupled with
glucosamine derivative 8 utilizing Ogawa’s
method16 resulting in a-linked disaccharide 9a,
trisaccharide 9b, and tetrasaccharide 9c in 56,
36, and 37% yield, respectively. Fluoride-pro-
moted desilylation of each, followed by con-
version into the anomeric fluorides with
DAST yielded glycosyl donors suitable for
coupling with the inositol. Silver triflate and
Cp2ZrCl2-promoted coupling of 11 with 10a–c
yielded the corresponding trisaccharide 12a,
tetrasaccharide 12b, and pentasaccharide 12c.
In each case, a mixture of a and b anomers
was obtained. These were separated chro-
matographically and each was carried forward
independently.
the protected oligosaccharide cyclic phos-
phates. Finally, dissolving-metal reduction
(Na (s), NH3 (l), −78 °C, 15 min) followed by
careful quenching at −78 °C with NH4Cl (s),
then MeOH, resulted in removal of all benzyl
protecting groups and reduction of the azido
group to provide compounds 1–5 contami-
nated with NaCl. Pure products were obtained
by desalting with Sephadex G-10 (56–85%
yield).
The biological activity of these compounds
is currently being evaluated and will be re-
ported elsewhere.
Removal of the cyclic carbonate moiety by
alkaline hydrolysis yielded diols ready for in-
stallation of the cyclic phosphate moiety. Ad-
dition of methylpyridinium dichlorophosphate
(31), prepared according to the literature
procedure18 from methyl phosphorodichlori-
date and pyridine, to diols 30aa, 30ab, 30ba,
30bb, and 30ca resulted in the formation of
Scheme 5. (i) N,N%-Carbonyldiimidazole, benzene, 20 °C; (ii)
TBAF, THF, 0 °C, 3 min (84%, from 28).

380
C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
,
Scheme 6. (i) PhSeCl, AgOTf, toluene, 4 A molecular sieves, −42 °C; (ii) TBAF, HOAc, THF, 20 °C; (iii) DAST, THF, −42
,
to 20 °C; (iv) Cp2ZrCl2, AgOTf, 11, toluene, 4 A molecular sieves, −42 to 20 °C; (v) LiOH, THF, 12 h, 20 °C; (vi) 31, pyridine;
(vii) (a) Na, NH3 (l), THF, −78 °C, 15 min; (b) NH4Cl (s), −78 °C; (c) MeOH, −78 °C.
3. Experimental
nm fluorescent indicator. Chromatograms
were visualized by one or more of the follow-
ing techniques: (a) ultraviolet illumination; (b)
dipping in an ethanolic solution of 2.5% p-an-
isaldehyde, 3.5% H2SO4 and 1% AcOH fol-
lowed by heating; (c) dipping in an ethanolic
solution of Hanes–Isherwood stain (ammo-
nium molybdate–HCl–perchloric acid–ace-
tone);28 (d) dipping in a 2-propanol solution
of ninhydrin–AcOH–pyridine.28 Purifications
were performed by flash chromatography on
Baker silica gel (40 mm), by preparative TLC,
or by gel-filtration utilizing Sephadex G-10.
Nuclear magnetic resonance (NMR) data
were obtained on a Bruker AM-300 FT NMR
General methods.—All nonaqueous reac-
tions were performed under an Ar atmo-
sphere. Organic extracts were dried with
anhyd MgSO4 unless otherwise noted. Sol-
vents were removed in vacuo on a Bu¨chi
rotary evaporator. Solvents and reagents ob-
tained from commercial sources were used
without further purification with the following
exceptions. Tetrahydrofuran (THF) and ben-
zene were distilled from Na and benzophe-
none. Acetonitrile, CH2Cl2, pyridine, and
toluene were distilled from CaH2. Benzyl bro-
mide was fractionally distilled. N,N%-
Dimethylformamide (DMF) was dried with
MgSO4, filtered, and then distilled. 1,2-
Dichloroethane was dried with MgSO4,
filtered, and distilled from P2O5. Silver triflate
was dried in vacuo (0.1 mmHg) for 24 h.
Reactions were monitored by thin-layer chro-
matography (TLC) on Baker glass-backed sil-
ica gel plates (0.25 mm thickness) with a 254
1
spectrometer operating at 300 MHz for H.
Tetramethylsilane (Me4Si, 0.03%) was used as
1
the internal standard for most H and 13C
NMR spectra. CFCl3 and H3PO4 (85% in
D2O) were used as the external standards for
the 19F and 31P NMR spectra, respectively.
High-resolution and low-resolution mass spec-
trometry data were obtained on a JEOL AX-

C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
381
was added and the mixture was extracted with
ether (4×1 mL). The ether layer was washed
with NaHCO3 (1 M, 4×1 mL), dried, and
concentrated. The crude sample was used di-
rectly in the next step. A small portion of the
crude product was purified for analysis using
flash silica gel chromatography with step gra-
dient elution. To prevent hydrolysis, the
column was first treated with 1% triethylamine
in hexane. Compound 15 was purified via
flash-column chromatography utilizing step
gradient elution: hexane to remove excess
BnBr followed by 2:1 hexane–ether to obtain
a pure sample of 15; Rf 15 0.40 (2:1 hexanes–
505 or JEOL SX-102 mass spectrometer using
FAB or electrospray as the ionization method
at the Harvard University Department of
Chemistry and Chemical Biology Mass Spec-
trometry Facility. An EG&G model 174A po-
larographic analyzer was used as the
potentiostat for the electrochemical oxidations
and the Pt (98 cm2) electrodes were rinsed
with concd HNO3 followed by water prior to
use.
p - Methoxyphenyl 6 - O - (4,4% - dimethoxy-
trityl)-h-
D
-mannopyranoside
(14).—To
a
flame-dried flask was added 4,4%-dime-
thoxytrityl tetrafluoroborate (DMTBF4, 3.4 g,
8.8 mmol) and 2,6-di-t-butyl-4-methylpyridine
(DBMP, 1.8 g, 8.8 mmol, both were dried by
coevaporation with toluene). Acetonitrile (5
mL) was added followed by glycoside 13,19,20
(1.6 g, 5.9 mmol, previously dried by coevapo-
ration with toluene). The reaction mixture was
warmed at reflux. After 12 h and several addi-
tions of more reagent (DMTBF4 and DBMP,
3× ꢀ200 mg), though the reaction had not
gone to completion, the reaction was stopped
by addition of NaHCO3 (1 M, 10 mL), the
mixture extracted with ether (3×30 mL), and
the ethereal extracts were dried, filtered, and
concentrated. Purification of the resulting oil
via flash-column chromatography utilizing
step gradient elution, CHCl3 to remove excess
DMTBF4 followed by 9:1 CHCl3–MeOH,
produced 3.2 g of 14 (92% yield); Rf 14 0.37
(ether); 1H NMR (CDCl3): l 2.61 (d, J 4.0 Hz,
OH-2), 2.83 (d, J 5.0 Hz, OH-3), 2.89 (d,
Jꢀ3.0 Hz, OH-4), 3.37 (pseudo-t, 1 H, J 4.0
Hz), 3.69 (m, 1 H), 3.77 (s, 9 H, OCH3), 3.83
(m, 1 H), 4.00 (m, 1 H, H-3), 4.11 (m, 1 H,
H-2), 5.42 (s, 1 H, H-1), 6.70–6.85 (pseudo-t,
6 H, J 7.0 Hz), 7.01 (d, 2 H, J 7.0 Hz),
7.15–7.35 (m, 7 H), 7.39 (d, 2 H, J 8.0 Hz).
1
ether); H NMR (CDCl3): l 3.24 (dd, 1 H, J
5.0 Hz), 3.45 (d, 1 H, J 10.0 Hz), 3.76 (s, 9 H,
OCH3), 3.8–4.1 (m, 4 H), 4.3 (d, 1 H, J 11.0
Hz), 4.68–4.73 (m, 4 H), 4.88 (d, 1 H, J 11.0
Hz), 5.5 (s, 1 H, H-1), 6.74–6.82 (m, 5 H), 6.9
(d, 2 H, J 9.0 Hz), 7.02 (d, 2 H, J 9.0 Hz),
7.17–7.48 (m, aryl H’s, 21 H).
p-Methoxyphenyl
2,3,4-tri-O-benzyl-h- -
D
mannopyranoside (16).—To a solution of 15
(1.0 g, 1.0 mmol) in CHCl3 (8 mL) was added
a solution of 4 mL of 1:1 AcOH–water and
the mixture was stirred for 2 h at 80 °C. When
the reaction was complete, ether (25 mL) was
added and the solution was neutralized with
NaHCO3 (1 M, 20 mL). The layers were sepa-
rated and the aqueous layer was extracted
with ether (3×50 mL). The combined organic
extracts were dried, filtered, and concentrated.
Compound 16 was purified via flash-column
chromatography utilizing step gradient elu-
tion: 2:1 hexane–ether was first used to
remove nonpolar side-products followed by
1:1 hexane–ether to obtain pure 16 (454 mg,
1
70% yield); Rf 16 0.20 (1:1 hexanes–ether); H
NMR (CDCl3): l 1.9 (bs, 1 H, OH), 3.75 (s, 3
H, OCH3), 3.77 (m, 2 H), 3.92 (m, 1 H),
4.05–4.15 (m, 2 H), 4.69–4.77 (m, 5 H, H-2, 4
H, CH2Ph), 4.82 (d, 1 H, J 10.0 Hz, CH2Ph),
4.93 (d, 1 H, J 10.0 Hz, CH2Ph), 5.40 (s, 1 H,
H-1), 6.78 (d, 2 H, J 9.0 Hz, PMP), 6.88 (d, 2
H, J 9.0 Hz, PMP), 7.35–7.45 (m, 15 H,
phenyl H’s); HRMS: Calcd for C34H36O7Na+:
579.2359; Found: 579.2352.
p-Methoxyphenyl
2,3,4-tri-O-benzyl-6-O-
- mannopyranoside
(4,4 - dimethoxytrityl) - h -
D
(15).—To a solution of 14 (3.0 g, 5.0 mmol)
in DMF (18.3 mL) at 0 °C was added NaH
(0.9 g, 50% dispersion in mineral oil). The
mixture was allowed to warm to 20 °C and
stirred at that temperature for 25 min. The
suspension was again cooled to 0 °C and BnBr
(3.0 mL, 0.025 mol) was added and the mix-
ture was stirred in the dark for 2 h. After the
reaction was complete, NaHCO3 (1 M, 1 mL)
p-Methoxyphenyl
benzyl-h-
O-benzyl-h-
flame-dried flask was added 4 A molecular
sieves (ꢀ100 mg), phenylselenium chloride
2-O-acetyl-3,4,6-tri-O-
D
-mannopyranosyl-(1“6)-2,3,4-tri-
D
-mannopyranoside (18).—To a
,

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C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
Methanol (5 mL) was added and the mixture
was cooled to 0 °C. Ammonia (g) was bubbled
through the solution for 5 min then the flask
was tightly stoppered. The solution was stirred
for 12 h at 20 °C, cooled again to 0 °C and
additional NH3 (g) was added. The reaction
was then stirred for 24 h at 20 °C. The solu-
tion was then transferred to a round-bottom
flask and concentrated. Purification via silica
gel-flash chromatography (1:1 hexane–ether)
produced 19 (412 mg, 78% yield). Crude 19
was not usually purified and was used directly
in the production of 20; Rf 18 0.76, Rf 19 0.40
(0.258 g, 1.349 mmol) and toluene (2 mL).
The mixture was cooled to −30 °C [CH3CN–
CO2(s)] and silver trifluoromethanesulfonate
(462 mg, 1.798 mmol) was added. Slowly a
solution of 16 (500 mg, 0.899 mmol) and 1716
(704 mg, 1.349 mmol) in toluene (2 mL) was
added to the vigorously stirred mixture. After
ꢀ30 min, NaHCO3 (1 M, ꢀ5 mL) and
bleach (ꢀ5 mL) were added to the reaction
mixture. The mixture was stirred until the
solution was no longer orange (pale yellow)
and extractions were done with ether (3×5
mL). The combined organic layers were dried,
filtered and concentrated. Compound 18 was
purified via flash-column chromatography uti-
lizing step gradient elution: hexane was first
used to remove nonpolar side-products fol-
lowed by 3:2 hexane–ether to obtain pure 18
(56–71% yield); Rf 17 0.63, Rf 18 0.49, Rf 16
1
(1:2 hexane–ether); H NMR (CDCl3): l 2.28
(s, 1 H, OH), 3.48 (s, 3 H, CH3O), 3.50 (s, 1
H), 3.54–3.57 (m, 2 H), 3.63–3.76 (m, 5 H),
3.81–3.82 (m, 2 H), 3.85–3.86 (m, 1 H), 3.95
(dd, 1 H, J 3, J 11 Hz), 4.30 (d, 2 H, J 11 Hz),
4.36 (d, 2 H, J 11 Hz), 4.37 (s, 1 H), 4.46 (d,
1 H, J 11 Hz), 4.54 (s, 2 H), 4.58 (d, 2 H), 4.64
(d, 1 H, J 11 Hz), 4.75 (d, 1 H, J 11 Hz), 4.81
(s, 1 H, H-1), 5.22 (s, 1 H, H-1), 6.53 (d, 2 H,
J 9 Hz, PMP), 6.68 (d, 2 H, J 9 Hz, PMP),
6.91–7.15 (m, 30 H, phenyl H’s).
1
0.14 (1:1 hexane–ether); H NMR (CDCl3): l
2.14 (s, 3 H, CH3CO), 3.58 (s, 3 H, CH3O),
3.62 (2pseudo-t, 2 H, H-4 mannose-1, H-4
mannose-2), 3.73 (dd, 1 H, J 3.7, J 10 Hz, H-3
mannose-1), 3.82–3.89 (m, 6 H), 3.96 (dd, 1
H, H-2 mannose-1), 4.12 (dd, 1 H, J 8.9, J 3
Hz, H-3 mannose-2), 4.37 (d, 1 H, J 11 Hz,
CH2Ph), 4.42 (d, 1 H, J 11 Hz, CH2Ph), 4.45
(d, 1 H, J 11 Hz, CH2Ph), 4.51 (d, 1 H, J 11
Hz, CH2Ph), 4.59 (d, 1 H, J 11 Hz, CH2Ph),
4.66 (d, 1 H, J 11 Hz, CH2Ph), 4.68 (s, 2 H,
CH2Ph), 4.77 (s, 2 H, CH2Ph), 4.86 (d, 1 H, J
11 Hz, CH2Ph), 4.90 (d, 1 H, J 1.8 Hz, H-2
mannose-2), 4.93 (d, 1 H, J 11 Hz, CH2Ph),
5.40 (s, 1 H, H-1 mannose-1), 5.42 (d, J 1.8
Hz, H-1 mannose-2), 6.78 (d, 2 H, J 9 Hz,
PMP), 6.98 (d, 2 H, J 9 Hz, PMP), 7.15–7.42
p-Methoxyphenyl 2,3,4,6-tetra-O-benzyl-h-
D
-mannopyranosyl-(1“6)-2,3,4-tri-O-benzyl-
h- -mannopyranoside (20).—Compound 19
D
(400 mg, 0.405 mmol) was dried by coevapo-
ration with toluene, then dissolved in DMF
(0.4 mL). The solution was cooled to 0 °C and
NaH (40 mg of a 50% dispersion in mineral
oil, 0.81 mmol) was added. The mixture was
stirred for 30 min, and then BnBr (136 mg,
0.096 mL, 0.81 mmol) was added. The mix-
ture was stirred in the dark at 20 °C and
monitored by TLC. When the reaction was
complete (ꢀ1 h), 5.0 mL of ether was added
and the mixture was washed with NaHCO3 to
remove the DMF. The ether layer was dried
with MgSO4, filtered, and concentrated. Com-
pound 20 was purified via flash-column chro-
matography. The crude evaporate was applied
to a hexane-equilibrated column as a solution
in hexane with a few drops of CH2Cl2 added
to enhance solubility. The column was eluted
with a step gradient: hexane was first used to
remove excess BnBr followed by 1.5:1 hex-
ane–ether to obtain pure 20 (370 mg, 85%
yield); Rf 20 0.80, Rf 19 0.30 (1:1 hexanes–
13
(m, 30 H, phenyl H); C NMR (CDCl3): l 21
(H3CCO), 55 (CH3O), 66.4 (CH2), 68.4 (CH),
68.6 (CH), 71.2 (CH), 71.4 (CH2), 71.6 (CH),
72.2 (CH2), 72.7 (CH2), 73.2 (CH2), 74.1 (CH),
74.5 (CH), 75.0 (CH2), 77.0 (t, CDCl3), 77.8
(CH), 80.0 (CH), 96.6 (d, J 171 Hz, C-1), 97.8
(d, J 171 Hz, C-1), 114.5 (CH, PMP), 117.4
(CH, PMP, 127.6–128.3 (phenyl Cs), 137.9–
138.6 (phenyl Cs), 150.1 (CꢀO, PMP), 154.8
(CꢀO, PMP), 170.1 (CꢁO).
p-Methoxyphenyl 3,4,6-Tri-O-benzyl-h-
mannopyranosyl-(1“6)-2,3,4-tri-O-benzyl-h-
-mannopyranoside (19).—Compound 18 (550
D
-
1
D
ether); H NMR (CDCl3): l 3.60 (s, 3 H,
mg, 0.534 mmol) was dissolved in CH2Cl2 (5
mL) and transferred to a pressure vessel.
CH3O), 3.65–4.15 (m, 12 H, mannose), 4.45–
4.55 (m, 4 H), 4.65–4.82 (m, 8 H), 4.88–4.95

C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
383
ane–ether) was used to obtain 22 (75 mg, 86%
(m, 2 H), 5.15 (d, 1 H, J 1 Hz, H-1 mannose-
2), 5.45 (d, 1 H, J 1 Hz, H-1 mannose-1), 6.78
(d, 2 H, J 9 Hz, PMP), 6.92 (d, 2 H, J 9 Hz,
PMP), 7.15–7.40 (m, 35 H, phenyl H’s).
1
yield), Rf 22 0.63 (1:1 hexanes–ether); H
NMR (CDCl3): l 3.60–3.78, 3.80–4.00 (2m,
12 H, mannose), 4.45–4.75, 4.80–5.20 (2m, 14
H, CH2Ph), 5.52 (d, 1 H, J 50 Hz, H-1),
7.10–7.40 (m, 35 H, phenyl H’s).
2,3,4,6-Tetra-O-benzyl-h-
D
-mannopyran-
-manno-
osyl-(1“6)-2,3,4-tri-O-benzyl-h,i-
D
Methyl 2,3,4,6-tetra-O-benzyl-h-
pyranosyl-(1“6)-2,3,4-tri-O-benzyl-1-thio-h-
-mannopyranoside (7b).—To pre-dried 22
D
-manno-
pyranose (21).—The reaction vessel used was
simply a beaker equipped with an Ag ꢀ AgCl
reference electrode and two Pt (98 cm2) elec-
trodes separated by a porous glass plate.
Compound 20 (150 mg, 0.139 mmol) was dis-
solved in 6:1 MeCN–water (140 mL) with
D
(140 mg, 0.144 mmol) cooled to 0 °C was
added Bu3SnSMe in CH2ClCH2Cl (97 mg,
0.288 mmol, 1.3 mL of a 74 mg/mL stock
solution). After stirring for 5 min, SnCl4 in
CH2ClCH2Cl (75 mg, 0.29 mmol, 1.3 mL of a
57 mg/mL stock solution) was added. The
yellowish solution was stirred at 0 °C for 15
min. When the reaction was complete, NaF (1
M, 15 mL) and EtOAc were added and the
reaction was stirred for 1 h. The resulting
white precipitate was removed by filtration
through Celite. The organic layer was sepa-
rated, washed with NaHCO3 (1 M, 3×15
mL), dried, filtered and concentrated. To ob-
tain pure product, two flash chromatography
separations were required. After the first sepa-
ration (8:1 toluene–EtOAc, Rf a,b RSMeꢀ
0.80), the mixture of anomers was collected
and applied to a second column (1:1 hexanes–
ether) to produce pure 7b (122 mg, 85% yield).
tetrabutylammonium
hexafluorophosphate
(Bu4NPF6, 0.1 M, 2.32 g) as the electrolyte.
The solution was stirred for 72 h at 25 °C as a
voltage of +1.55 V was applied. When the
reaction was complete, the solution was trans-
ferred to a round-bottom flask and concen-
trated; water (30 mL) was added, and the
mixture was extracted with ether (3×30 mL).
The white precipitate, Bu4NPF6, was collected
by filtration for future reuse. The combined
ether layers were dried, filtered, and concen-
trated. Compounds 21 were purified via flash-
column
chromatography
utilizing
step
gradient elution: 2.5:1 hexane–ether was first
used to remove nonpolar side-products fol-
lowed by 1:2.5 hexane–ether to obtain 21 (100
mg, 74% yield); Rf 21 0.20 (1:1 hexane–ether);
1H NMR (CDCl3): l 1.65 (bs, 1 H, OH),
3.28–3.40, 3.55–4.0 (2m, 12 H, mannose),
4.20–4.75, 4.82–4.90 (2m, 14 H, CH2Ph), 5.05
(s, 1 H, H-1 mannose), 5.15 (s, 1 H, H-1
mannose), 7.10–7.40 (m, 35 H, phenyl H’s).
1
For 7b: Rf 0.56 (1:1 hexanes–ether); H NMR
(CDCl3): l 2.05 (s, 3 H, CH3S), 3.62–4.05 (m,
12 H, mannose), 4.55–4.70 (m, 13 H, CH2Ph),
4.88 (d, J 12 Hz, CH2Ph), 5.10 (s, 1 H, H-1),
5.20 (s, 1 H, H-1), 7.10–7.38 (m, 35 H, phenyl
H’s).
2,3,4,6-Tetra-O-benzyl-h-
D
-mannopyran-
-manno-
osyl-(1“6)-2,3,4-tri-O-benzyl-h,i-
D
For the b anomer: Rf 0.33; 1H NMR
(CDCl3): l 2.18 (s, 3 H, CH3S), 3.35, 3.58–
4.05 (2m, mannose), 4.39–4.98 (m, CH2Ph
and mannose), 5.15 (d, 1 H, J 1.5 Hz, H-1
mannose-2), 7.15–7.48 (m, phenyl H’s).
p-Methoxyphenyl 2-O-acetyl-3,4,6-tri-O-
pyranosyl fluoride (22).—Compounds 21 (87
mg, 0.089 mmol) were azeotropically dried
with toluene then dissolved in THF (0.25 mL)
and cooled to −30 °C. Diethylaminosulfur
trifluoride (DAST, 18 mL, 0.135 mmol) was
added and the reaction mixture was slowly
brought to 20 °C over 30 min. When the
reaction was complete, the mixture was cooled
to −30 °C and MeOH was added to quench
any unreacted DAST. After warming the mix-
ture to 20 °C, NaHCO3 (1 M, ꢀ1 mL) was
added and the mixture was extracted with
ether (3×5 mL). The combined ether layers
were dried, filtered, and concentrated. Flash
silica gel-column chromatography (3:1 hex-
benzyl-h-
O-benzyl-h-
tri-O-benzyl-h-
D
-mannopyranosyl-(1“2)-3,4,6-tri-
-mannopyranosyl-(1“6)-2,3,4-
-mannopyranosidee (23).—
D
D
Compound 23 was synthesized in a manner
analogous to the synthesis of compound 18
except that 19 was used as the glycosyl accep-
tor in place of 16. The trisaccharide pro-
duct 23 was purified via flash chromato-
graphy utilizing step gradient elution:
hexane was first used to remove nonpolar

384
C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
CH2Ph), 4.82 (d, 1 H, J 12 Hz, CH2Ph), 4.88
(d, J 12 Hz, CH2Ph), 4.92 (d, 1 H, J 12 Hz,
CH2Ph), 5.1 (pseudo-s, 1 H, H-1 mannose),
5.2 (pseudo-s, 1 H, H-1 mannose), 5.5
(pseudo-s, 1 H, H-1 mannose), 6.78 (d, 2 H, J
9 Hz, PMP), 7.00 (d, 2 H, J 9 Hz, PMP),
7.15–7.45 (m, 45 H, phenyl H’s).
side-products followed by 3:1 hexane–ether to
obtain pure 23 (88% yield); Rf 23 0.47 (1:1
1
hexanes–ether); H NMR (CDCl3): l 2.12 (s,
3 H, CH3CO), 3.58 (s, 3 H, CH3O), 3.50–4.20
(m, 17 H, mannose), 4.10 (dd, 1 H, J 3, J 11
Hz), 4.34 (d, 1 H, J 12 Hz, CH2Ph), 4.43 (d, 1
H, J 12 Hz, CH2Ph), 4.48 (d, 1 H, J 12 Hz,
CH2Ph), 4.52 (s, 2 H, CH2Ph), 4.56 (d, 1 H, J
12 Hz, CH2Ph), 4.62 (d, 1 H, J 12 Hz,
CH2Ph), 4.63 (d, 1 H, J 12 Hz, CH2Ph), 4.67
(s, 2 H, CH2Ph), 4.75 (s, 2 H, CH2Ph), 4.82 (d,
1 H, J 12 Hz, CH2Ph), 4.86 (d, J 12 Hz,
CH2Ph), 4.91 (d, 1 H, J 12 Hz, CH2Ph), 4.93
(pseudo-t, 1 H, J 1 Hz, H-1 mannose-2), 5.03
(d, 1 H, J 1 Hz, H-1 mannose-3), 5.41 (d, 1 H,
J 1 Hz, H-1 mannose-1), 5.52 (pseudo-t, 1 H,
J 1 Hz, H-2 mannose-3), 6.70 (d, 2 H, J 9 Hz,
PMP), 6.93 (d, 2 H, J 9 Hz, PMP), 7.10–7.42
(m, 45 H, phenyl H’s); 13C NMR (CDCl3): l
21 (CH3CO), 53.45, 55.44 (CH3O), 66.49,
68.83, 71.88, 72.30, 72.34, 73.30, 74.62, 75.02,
77.04 (t, CDCl3) 78.18, 79.32, 80.15, 96.94 (d,
J 170 Hz, CꢀH, C-1), 98.81 (d, J 171 Hz,
CꢀH, C-1), 99.57 (d, J 173 Hz, CꢀH, C-1),
114.64 (CH, PMP), 117.52 (CH, PMP),
127.55–133.58 (phenyl Cs), 137.9–140.0 (aro-
matic), 151 (CꢀO, PMP), 156 (CꢀO, PMP),
171 (CꢁO); HRMS: Calcd for C90H94O18+
Na: 1485.6337; Found: 1485.4656.
p-Methoxyphenyl 2,3,4,6-tetra-O-benzyl-h-
D
-mannopyranosyl-(1“2)-3,4,6-tri-O-benzyl-
h-
zyl-h-
D
-mannopyranosyl-(1“6)-2,3,4-tri-O-ben-
-mannopyranoside (25).—Compound
D
25 was synthesized in a manner analogous to
synthesis of compound 20 except that alcohol
24 was benzylated instead of alcohol 19. After
work-up, product 25 was purified via flash-
column chromatography utilizing step gradi-
ent elution: hexane was used first to remove
nonpolar side-products followed by 2:1 hex-
ane–ether to obtain pure 25 (81% yield); Rf 25
0.49 (1:1 hexanes–ether); 1H NMR (CDCl3): l
3.55 (s, 3 H, CH3O), 3.60–4.12 (m, 18 H,
mannose), 4.42–4.90 (m, 20 H, CH2Ph), 4.93
(m, 1 H, H-1), 5.13 (d, 1 H, J 1 Hz, H-1), 5.42
(d, 1 H, J 2 Hz, H-1), 6.75 (d, 2 H, J 9 Hz,
PMP), 6.95 (d, 2 H, J 9 Hz, PMP), 7.15–7.45
(m, 50 H, aromatic).
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“2)-3,4,6-tri-O-benzyl-h-
pyranosyl-(1“6)-2,3,4-tri-O-benzyl-h,i-
D
-mannopyran-
D
-manno-
D
-
p-Methoxyphenyl 3,4,6-tri-O-benzyl-h-
mannopyranosyl-(1“2)-3,4,6-tri-O-benzyl-h-
-mannopyranosyl-(1“6)-2,3,4-tri-O-benzyl-
h- -mannopyranoside (24).—Compound 24
D
-
mannopyranose (26).—Compound 26 were
synthesized by a procedure analogous to that
utilized for the synthesis of compounds 21
except that trisaccharide 25 was oxidized in-
stead of disaccharide 20. After work-up,
product 26 was purified via flash-column chro-
matography utilizing step gradient elution: 2:1
hexane–ether was used first to remove nonpo-
lar side-products followed by 1:2 hexane–
ether to obtain 26 (78% yield); Rf 26 0.18 (1:1
D
D
was synthesized in a manner analogous to
compound 19 except that compound 23 was
deacetylated instead of compound 18. After
work-up, silica gel-flash chromatography (1:1
hexane–ether) was used to obtain pure
product 24 (554 mg, 85% yield); Rf 24 0.20
(1:1 hexanes–ether); 1H NMR (CDCl3): l 2.45
(s, 1 H, OH), 3.58 (s, 3 H, CH3O), 3.52–3.98
(m, 24 H, mannose), 4.05 (m, 1 H, H-2 man-
nose-3), 4.09 (d, 1 H, J 2 Hz), 4.11 (d, 1 H, J
1 Hz), 4.34 (d, 1 H, J 12 Hz, CH2Ph), 4.45 (d,
1 H, J 12 Hz, CH2Ph), 4.47 (d, 1 H, J 12 Hz,
CH2Ph), 4.50 (d, 1 H, J 12 Hz, CH2Ph), 4.52
(d, 1 H, J 12 Hz, CH2Ph), 4.54 (d, 1 H, J 12
Hz, CH2Ph), 4.56 (d, 1 H, J 12 Hz, CH2Ph),
4.58 (d, 1 H, J 12 Hz, CH2Ph), 4.63 (d, 1 H,
J 12 Hz, CH2Ph), 4.68 (d, 1 H, J 12 Hz,
CH2Ph), 4.70 (s, 2 H, CH2Ph), 4.77 (s, 2 H,
1
hexanes–ether); H NMR (CDCl3): l 3.60–
4.00 (m, 17 H, mannose), 4.18 (m, 1 H),
4.45–4.90 (m, 20 H, CH2Ph), 4.92 (m, 1 H,
H-1), 4.96 (d, 1 H, J 2 Hz, H-1), 5.16 (d, 1 H,
J 1 Hz, H-1), 7.15–7.40 (m, 50 H, aromatic).
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“2)-3,4,6-tri-O-benzyl-h-
pyranosyl-(1“6)-2,3,4-tri-O-benzyl-h,i-
D
-mannopyran-
D
-manno-
D
-
mannopyranosyl fluoride (27).—Compound 27
were synthesized in a manner analogous to the
synthesis of compound 22 except that tri-
saccharide 26 were fluorinated instead of di-

C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
385
was cooled to 0 °C and 5.5 mL of 1 M t-buty-
lammonium fluoride (TBAF) in THF was
added. The reaction was stirred at 0 °C for 3
min and quenched by addition of 12 mL of
water at 0 °C. The mixture was extracted with
CH2Cl2 (4×12 mL). The combined organic
extracts were washed with water (2×10 mL)
and then satd NaCl (10 mL), dried, and con-
centrated. Purification via flash silica-column
chromatography yielded 262 mg of 11 (84%).
[h]D +22.7° (c 0.0075, CH2Cl2); Rf 11 0.29
saccharide 21. After work-up, flash silica gel-
column chromatography (2:1 hexanes–ether)
was used to obtain pure 27 (as an anomeric
mixture), 90% yield; Rf 27 0.62 (1:1 hexanes–
1
ether); H NMR (CDCl3): l 3.55–4.03 (m, 17
H, mannose), 4.15 (pseudo-t, 1 H, J 2 Hz),
4.40–4.89 (m, 20 H, CH2Ph), 4.96 (d, 1 H, J 1
Hz, H-1), 5.15 (d, 1 H, J 1 Hz, H-1), 5.56 (d,
1 H, J 51 Hz, H-1 mannose-1), 7.10–7.36 (m,
50 H, phenyl H’s); 19F NMR (CDCl3) l −
138.5 (d, JFH 51 Hz).
1
(7:3 hexanes–EtOAc); H NMR (CDCl3): l
Methyl 2,3,4,6-tetra-O-benzyl-h-
pyranosyl - (1“2) - 3,4,6 - tri - O - benzyl - h -
mannopyranosyl-(1“6)-2,3,4-tri-O-benzyl-1-
thio - h,i - - mannopyranoside (7c).—Com-
D
-manno-
2.7 (bs, 1 H, OH), 3.38 (dd, 1 H, J 4.5, 10.7
Hz), 3.79 (dd, 1 H, J 2.5, 4.5 Hz), 3.90
(pseudo-t, 1 H, J 2.8 Hz), 4.31 (d, 1 H, J 11.5
Hz, HCHPh), 4.38 (d, 1 H, J 11.5 Hz,
HCHPh), 4.45 (dd, 1 H, J 7.0, 10.7 Hz), 4.56
(d, 1 H, J 11.4 Hz, HCHPh), 4.58 (d, 1 H, J
11.9 Hz, HCHPh), 4.62–2.67 (m, 2 H), 4.71
(d, 1 H, J 11.9 Hz, HCHPh), 4.86 (dd, 1 H, J
D
-
D
pound 7c was synthesized in a manner
analogous to the synthesis of compound 7b
except that trisaccharides 27 were thiomethy-
lated instead of disaccharides 22. To obtain
the pure a anomer, two flash chromatography
column separations were required. After the
first column (8:1 toluene–EtOAc, Rf a,b
RSMeꢀ0.80), the mixture of anomers were
collected and applied to a second column (3:2
hexanes–ether) providing 80 mg (52% yield)
of 7c (a anomer) and 7 mg (5% yield) of the
corresponding b anomer; Rf 7c 0.50 (1:1 hex-
anes–ether); 1H NMR 7c (CDCl3): l 2.05 (s, 3
H, CH3S), 3.55–3.95, 4.05–4.10 (2m, man-
nose), 4.15 (pseudo-t, 1 H, J 2 Hz), 4.45–4.95
(m, 20 H, CH2Ph), 4.95 (d, 1 H, J 1.5 Hz,
H-1), 5.18 (d, 1 H, J 1.5 Hz, H-1), 7.15–7.42
(m, 50 H, phenyl H’s); Rf (b anomer) 0.25 (1:1
13
3.3, 8.7 Hz), 7–7.5 (m, 15 H, phenyl H’s); C
NMR (CDCl3): l 70.57 (CꢀO), 72.02 (CꢀO),
73.34 (CꢀO), 73.43 (CꢀO), 73.72 (CꢀO), 74.34
(CꢀO), 79.26 (CꢀO), 80.07 (CꢀO), 80.92
(CꢀO), 127.89 (phenyl C), 128.15 (phenyl C),
128.52 (phenyl C), 136.76 (phenyl C), 137.46
(phenyl C), 154.46 (CꢁO). HRMS-FAB+:
Calcd for C28H28O7+Na 499.1733; Found
499.1744.
t-Butyldimethylsilyl 2,3,4,6-tetra-O-benzyl-
h -
D
- mannopyranosyl - (1“4) - 2 - azido - 2 - de-
oxy - 3,6 - di - O - benzyl - i -
D
- glucopyranoside
(9a).—To a flame-dried flask containing a stir
bar was added PhSeCl (60 mg, 0.313 mmol), 4
1
hexanes–ether); H NMR (b anomer, CDCl3):
,
A molecular sieves, and 2.4 mL of toluene.
l 3.40, 3.55–4.05 (2m, mannose), 4.10
(pseudo-t, 1 H, J 1 Hz), 4.40–4.95 (m, CH2Ph
and mannose), 5.20 (d, 1 H, J 1 Hz, H-1), 5.30
(d, 1 H, J 1 Hz, H-1), 5.30 (CH2Cl2), 7.10–
7.40 (m, 50 H, phenyl H’s).
The reaction mixture was cooled to 0 °C and
AgOTf (80 mg, 0.311 mmol) was added. After
stirring at 0 °C for 10 min, the mixture was
cooled to −42 °C and a solution containing
7a (120 mg, 0.206 mmol) and 815 (86 mg, 0.171
mmol), pre-dried by coevaporation with tolu-
ene, in 7.5 mL of toluene was added. The
reaction was stirred at −42 °C for 30 min,
then quenched by addition of 1 M NaHCO3
(5 mL) followed by filtration through Celite.
The layers were separated, the filtrate was
diluted with CHCl3 (5 mL) and the organic
layer was washed with water (3×5 mL),
dried, and concentrated. Purification via silica
gel chromatography with 4:1 hexane–ether
provided 99 mg of 9a as an oil (56% yield); Rf
9a 0.26 (4:1 hexane–ether); 1H NMR
3,4,5 - Tri - O - benzyl - 1D - myo - inositol 1,2-
cyclic carbonate (11).—To 335 mg of diol 2827
(0.55 mmol) in 27.5 mL of benzene was added
275 mg of 1,1%-carbonyldiimidazole (1.7
mmol). The reaction was stirred at 20 °C for
17 h and quenched by the addition of water
(20 mL). The layers were separated and the
aqueous layer was extracted with CH2Cl2 (4×
20 mL). The combined organic extracts were
washed with satd NaCl (20 mL), dried, con-
centrated by co-evaporation with toluene, and
dissolved in 24 mL of dry THF. The reaction

386
C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
glycosyl donor instead of monosaccharide 7a.
After work-up, purification via column chro-
matography 4:1 hexanes–ether yielded 9c
(37% yield); Rf 9c 0.65 (1:1 hexanes–ether); 1H
NMR (CDCl3): l 0.15 (s, 6 H, 2 CH3), 0.96 (s,
9 H, t-butyl), 3.21–3.33 (m, 2 H), 3.37–3.60
(m), 3.64–3.92 (m), 4.02 (t, 1 H, J 9.5 Hz),
4.11 (t, 1 H, J 2.1 Hz), 4.25 (d, 1 H, J 12.3 Hz,
HCHPh), 4.30 (d, 1 H, J 12.3 Hz, HCHPh),
4.37–4.57 (m), 4.58 (d, 1 H, J 12.3 Hz,
HCHPh), 4.65 (d, J 12.3 Hz, HCHPh), 4.79
(d, 1 H, J 11.1 Hz, HCHPh), 4.84 (d, 1 H, J
10.9 Hz, HCHPh), 4.85 (d, 1 H, J 11.3 Hz,
HCHPh), 4.91 (d, 1 H, J 11.4 Hz, HCHPh),
4.92 (d, 1 H, J 1.6 Hz, H-1 mannose), 5.14 (d,
1 H, J 1.6 Hz, H-1 mannose), 5.28 (d, 1 H, J
1.9 Hz, H-1 mannose), 7.12–7.36 (m, phenyl
H’s); 13C NMR (CDCl3): l 97.12 (d, J 155 Hz,
C-1 glucosamine), 99.27 (d, J 168.3 Hz, 2×C-
1 mannose), 99.83 (d, J 169.7 Hz, C-1 man-
nose).
(CDCl3): l 0.19 (s, 3 H, CH3), 0.20 (s, 3 H,
CH3), 0.94 (s, 9 H, t-butyl), 3.25 (dd, 1 H, J
8.6, 9.9 Hz, H-3 glucosamine), 3.36–3.42 (m,
2 H, H-5 and H-2 of glucosamine), 3.58 (dd, 1
H, J 1.5, 9.1 Hz, H-3 mannose), 3.64–3.83 (m,
7 H), 3.98 (pseudo-t, 1 H, J 9.3 Hz, H-4
mannose), 4.25 (d, 1 H, J 12.2 Hz, HCHPh),
4.35 (d, 1 H, J 12.2 Hz, HCHPh), 4.43–4.63
(m, 9 H), 4.82 (d, 1 H, J 10.8 Hz, HCHPh),
4.94 (d, 1 H, J 11.4 Hz, HCHPh), 5.30 (d, 1
H, J 2.0 Hz, H-1 mannose), 7.14–7.40 (m,
phenyl H’s); 13C NMR (CDCl3): l 100.15 (d, J
169 Hz, C-1 mannose), 97.15 (d, J 160 Hz,
C-1 glucosamine).
t-Butyldimethyl 2,3,4,6-tetra-O-benzyl-h-
mannopyranosyl-(1“6)-2,3,4-tri-O-benzyl-h-
-mannopyranosyl-(1“4)-2-azido-2-deoxy-
3,6 - di - O - benzyl - silyl - i - - glucopyranoside
D
-
D
D
(9b).—Compound 9b was synthesized accord-
ing to the procedure outlined for compound
9a except that disaccharide 7b was used as the
glycosyl donor instead of monosaccharide 7a.
After work-up, purification via silica gel chro-
matography with 2.5:1 hexane–ether provided
9b as an oil (36% yield); Rf 9b 0.43 (2.5:1
2,3,4,6-Tetra-O-benzyl-h-
(1“4)-2-azido-2-deoxy-3,6-di-O-benzyl-h,i-
-glucopyranose (29a).—To 360 mg (0.348
D-mannopyranosyl-
D
mmol) of 9a in 11 mL of THF was added 700
mL of glacial AcOH followed by 5.3 mL of
t-butylammonium fluoride (TBAF, 5.32 mmol
in THF). The reaction was stirred at 20 °C for
14 h. The mixture was quenched with 1 mL of
1 M NaHCO3 and extracted with CHCl3 (2×
1 mL). The organic phase was washed sequen-
tially with water (2×5 mL), satd NaCl (5
mL), dried, and concentrated. Purification via
silica gel chromatography yielded 270 mg of
29a (84% yield); Rf 29a 0.29 (1:1 hexanes–
1
hexane–ether); H NMR (CDCl3): l 0.18 (s, 3
H, CH3), 0.19 (s, 3 H, CH3), 0.96 (s, 9 H,
t-butyl), 3.26 (dd, 1 H, J 8.6, 9.9 Hz, H-3
glucosamine), 3.32–3.40 (m, 2 H), 3.54–3.75
(m), 3.78–3.90 (m, 4 H), 3.92–4.01 (m, 2 H),
4.20 (d, 1 H, J 12.1 Hz, HCHPh), 4.33 (d, 1
H, J 12.2 Hz, HCHPh), 4.39–4.55 (m, 14 H),
4.61 (d, 1 H, J 12.1 Hz, HCHPh), 4.83 (d, 1
H, J 11.0 Hz, HCHPh), 4.86 (d, 1 H, J 10.8
Hz, HCHPh), 4.95 (d, 1 H, J 11.5 Hz,
HCHPh), 5.07 (d, 1 H, J 1.03 Hz, H-1 mann-
ose), 5.26 (d, 1 H, J 1.8 Hz, H-1 mannose),
7.09–7.38 (m, phenyl H’s); 13C NMR
(CDCl3): l 99.86 (d, J 171.5 Hz, C-1 mann-
ose), 98.20 (d, J 171.3 Hz, C-1 mannose),
97.15 (d, J 155.6 Hz, C-1 glucosamine).
LRMS (electrospray): Calcd for C87H99N3-
O15Si: 1453.7; Found: 1454.
1
ether); H NMR (CDCl3): l 2.36–3.40 (m, 4
H), 3.48–4.05 (m, 22 H), 4.21 (d, 1 H, J 12.1
Hz), 4.24 (d, 1 H, J 12.1 Hz), 4.35 (d, 2 H, J
12.0 Hz), 4.41–4.46 (m, 17 H), 4.80 (d, 1 H, J
10.8 Hz), 4.82 (d, 1 H, J 10.8 Hz), 4.90 (d, 1
H, J 10.8 Hz), 4.93 (d, 1 H, J 10.8 Hz), 5.25
(d, 1 H, J 2.4 Hz, H-1 mannose of b anomer),
5.27 (d, 1 H, J 1.8 Hz, H-1 mannose of a
anomer), 5.33 (d, 1 H, J 3.4 Hz, H-1 glu-
cosamine of a anomer), 7.16–7.39 (m, phenyl
H’s).
t-Butyldimethylsilyl 2,3,4,6-tetra-O-benzyl-
h-
zyl-h-
benzyl-h-
2-deoxy-3,6-di-O-benzyl-i-
D
-mannopyranosyl-(1“2)-3,4,5-tri-O-ben-
-mannopyranosyl-(1“6)-2,3,4-tri-O-
-mannopyranosyl-(1“4)-2-azido-
-glucopyranoside
D
D
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“6)-2,3,4-tri-O-benzyl-h-
pyranosyl-(1“4)-2-azido-2-deoxy-3,6-di-O-
benzyl-h,i- -glucopyranoside (29b).—Com-
pounds 29b were synthesized according to the
D
-mannopyran-
D
D
-manno-
(9c).—Compound 9c was synthesized accord-
ing to the procedure outlined for compound
9a except that trisaccharide 7c was used as the
D

C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
387
H, CH2Ph), 5.03 (pseudo-s, 1 H, H-1 mannose
2), 5.07 (dd, 0.5 H, J 7.1, J 52.7 Hz, H-1
glucosamine of b anomer), 5.22 (d, 0.5 H, J
1.92 Hz, H-1 mannose 1), 5.27 (d, 0.5 H, J 2.1
Hz, H-1 mannose 1), 5.60 (dd, 0.5 H, J 2.4, J
53 Hz, H-1 glucosamine of a anomer), 7.1–7.5
(m, 45 H, phenyl H’s).
procedure outlined for compound 29a except
that trisaccharide 9b was desilylated instead of
disaccharide 9a. After work-up, purification
via preparative TLC (1:1 hexanes–ether)
yielded 1:1 anomeric mixture of alcohols (85%
1
yield); Rf 29b 0.34 (1:1 hexanes–ether); H
NMR (CDCl3): l 2.43 (bs, 1 H, OH), 3.28–
3.56 (m, 4 H), 3.61–4.02 (m, 14 H), 4.16 (d, 1
H, J 12.1 Hz, HCHPh), 4.31 (d, 1 H, J 12 Hz,
HCHPh), 4.32 (d, 1 H, J 12 Hz, HCHPh),
4.39–4.63 (m, 13.5 H), 4.80–4.91 (m, 3 H),
5.04 (pseudo-s, 1 H, H-1 mannose 2), 5.21 (d,
0.5 H, J 1.92 Hz, H-1 mannose 1), 5.23 (d, 0.5
H, J 2.01 Hz, H-1 mannose 1), 5.26 (d, 0.5 H,
J 3.32 Hz, H-1 glucosamine of a anomer),
7.2–7.5 (m, phenyl H’s).
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“4)-2-azido-2-deoxy-3,6-di-O-ben-
zyl-h,i- -glucopyranosyl-(1“6)-3,4,5-tri-O-
benzyl-1- -myo-inositol 1,2-cyclic carbonate
D
-mannopyran-
D
D
(12a,a,b).—To a pre-dried mixture of donors
10a (45 mg, 0.049 mmol) and acceptor 11 (47
,
mg, 0.099 mmol) was added 4 A molecular
sieves, toluene (3.7 mL), and ZrCp2Cl2 (72
mg, 0.25 mmol). The mixture was cooled to
−42 °C and AgOTf (127 mg, 0.49 mmol) was
added. The reaction was stirred briefly at
−42 °C (ꢀ5 min) and then allowed to warm to
20 °C. The reaction was stirred for 5 h, and
then quenched by addition of 1 M NaHCO3
(6 mL), diluted with 6 mL of CH2Cl2, and
filtered through Celite. The layers were sepa-
rated and the aqueous layer was extracted
with CH2Cl2 (4×4 mL). The combined or-
ganic extracts were washed with satd NaCl (4
mL), dried, and concentrated. Purification via
preparative TLC (7:3 hexanes–EtOAc)
yielded 18.6 mg of a product and 17.8 mg of
b product (54% combined yield); Rf 12a,a
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“4)-2-azido-2-deoxy-3,6-di-O-ben-
zyl-h,i- -glucopyranosyl fluoride (10a).—
D
-mannopyran-
D
Compounds 10a were synthesized according
to the procedure outlined for compound 22
except that 29a was fluorinated instead of 21.
After work-up, the crude products were chro-
matographed on silica gel with 3:1 hexane–
ether yielding a 1:2 a,b mixture of anomeric
fluorides (84% yield); Rf 10a 0.18 (3:1 hex-
anes–ether); 1H NMR (CDCl3): l 3.31–
3.41(m), 3.42–3.88 (m), 3.8–4.03 (m), 4.27 (d,
1 H, J 10.2 Hz), 4.31 (d, 1 H, J 10.1 Hz),
4.39–4.66 (m), 4.81 (d, 1 H, J 10.8 Hz), 4.83
(d, 1 H, J 10.9 Hz), 4.87 (d, 1 H, J 11.2 Hz),
4.88 (d, 1 H, J 11.1 Hz), 5.09 (dd, 1 H, J 7.1,
J 52.7 Hz, H-1 glucosamine of b anomer),
5.26 (d, 1 H, J 2.2 Hz, H-1 mannose), 5.30 (d,
1 H, J 2.3 Hz, H-1 mannose), 5.66 (dd, 1 H, J
2.6, J 52.9 Hz, H-1 glucosamine of a anomer),
7.14–7.39 (m, phenyl H’s).
1
0.37, Rf 12a,b 0.45 (7:3 hexanes–EtOAc); H
NMR (CDCl3) 12a,a: l 3.39 (dd, 1 H, J 3.6,
9.7 Hz, H-2 glucosamine), 3.51–3.90 (m, 12
H), 4.02 (pseudo-t, 2 H, 9.3 Hz), 4.20–4.66
(m, 17 H), 4.79–5.02 (m, 4 H), 5.27 (d, 1 H, J
1.9 Hz, H-1 mannose), 5.34 (d, 1 H, J 3.6 Hz,
H-1 glucosamine), 7–7.5 (m, 45 H, phenyl
H’s); 1H NMR (CDCl3) 12a,b: l 3.23 (pseudo-
t, 1 H, J 9.3 Hz, H-2 glucosamine), 3.37 (m, 1
H), 3.44 (dd, 1 H, J 8.1, 9.8 Hz), 3.57–3.83
(m, 10 H), 3.88 (pseudo-s, 1 H), 4.00 (pseudo-
t, 1 H, J 9.2 Hz), 4.30 (m, 2 H), 4.37–4.63 (m,
14 H), 4.70 (d, 1 H, J 10.6 Hz, HCHPh), 4.82
(d, 1 H, J 10 Hz, HCHPh), 4.82 (pseudo-s, 2
H, CH2Ph), 4.88 (d, 1 H, J 11.3 Hz, HCHPh),
5.31 (d, 1 H, J 2.0 Hz, H-1 mannose), 7–7.5
(m, 45 H, phenyl H’s). LRMS 12a,a: Calcd
for C82H83N3O16+Na: 1388.57; Found: 1388.
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“6)-2,3,4-tri-O-benzyl-h-
pyranosyl-(1“4)-2-azido-2-deoxy-3,6-di-O-
benzyl-h,i- -glucopyranosyl fluoride (10b).—
D
-mannopyran-
D
-manno-
D
Compounds 10b were synthesized according
to the procedure outlined for compound 22
except that 29b was fluorinated instead of 21.
After work-up, purification via preparative
TLC (1:1 hexanes–ether) yielded a 1:1 (a,b)
mixture of fluorides (86% yield); Rf 10b 0.42
1
(1:1 hexanes–ether); H NMR (CDCl3): l
2,3,4,6-Tetra-O-benzyl-h-
(1“6)-2,3,4-tri-O-benzyl-h-
osyl-(1“4)-2-azido-2-deoxy-3,6-di-O-ben-
zyl - h,i - - glucopyranosyl - (1“6) - 3,4,5 - tri-
D
-mannopyranosyl-
3.31–4.02 (m, 18 H), 4.24 (d, 1 H, J 12.4 Hz,
HCHPh), 4.25 (d, 1 H, 12.1 Hz, HCHPh),
4.35–4.67 (m, 13 H, CH2Ph), 4.81–4.89 (m, 3
D
-mannopyran-
D

388
C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
was stirred at 20 °C for 17 h and quenched by
O-benzyl-1- -myo-inositol 1,2 cyclic carbonate
D
addition of 1 M NH4Cl (3 mL). The mixture
was extracted with CH2Cl2 (4×3 mL). The
combined organic extracts were washed with
satd NaCl (3 mL), dried, and concentrated.
Purification via preparative TLC (1:1 CHCl3–
ether) yielded 13.8 mg of diol 30a,a (80%
(12b,a,b).—Compounds 12b,a,b were synthe-
sized in a manner analogous to that for com-
pounds 12a,a,b except that trisaccharides 10b
were used as glycosyl donor instead of disac-
charides 10a. After work-up, purification via
preparative TLC (7:3 hexanes–EtOAc)
yielded 17.5 mg of 12b,a and 6.6 mg of
slightly impure 12b,b (57% combined yield);
Rf 12b,a 0.38, Rf 12b,b 0.46 (7:3 hexanes–
1
yield); Rf 30a,a 0.57 (1:1 CHCl3 –ether); H
NMR (CDCl3): l 2.51 (bs, OH), 3.29–3.56
(m), 3.58–3.63 (m), 3.65–4.06 (m), 4.16
(pseudo-t, 1 H, J 2.7 Hz, H-2 inositol), 4.23
(d, 1 H, J 12.2 Hz, HCHPh), 4.26–4.38 (m),
4.44–4.68 (m), 4.72–4.94 (m), 5.23 (d, 1 H, J
2.1 Hz, H-1 mannose), 5.45 (d, 1 H, J 3.6 Hz,
H-1 glucosamine), 7.10–7.39 (m, phenyl H’s).
1
EtOAc); H NMR (CDCl3) 12b,a: l 3.37 (dd,
1 H, J 3.6, 9.6 Hz, H-2 glucosamine), 3.49–3.7
(m, 11 H), 3.75–3.88 (m, 8 H), 3.94–4.0 (m, 3
H), 4.16 (d, 1 H, J 12.0 Hz, HCHPh), 4.27–
4.65 (m, 19 H), 4.80–4.91 (m, 5 H), 5.04
(pseudo-s, 1 H, H-1 mannose), 5.23 (pseudo-s,
1 H, H-1 mannose), 5.32 (d, 1 H, J 3.6 Hz,
H-1 glucosamine), 7.0–7.5 (m, 60 H, phenyl
H’s); 13C NMR (CDCl3) 12b,a: l 96.21
(anomeric C), 98.10 (anomeric C), 100.40
(anomeric C), 153.97 (carbonate carbon);
LRMS: Calcd for C109H111N3O21+NH4:
1815.8; Found: 1816.
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“4)-2-azido-2-deoxy-3,6-di-O-ben-
zyl-i- -glucopyranosyl-(1“6)-3,4,5-tri-O-
benzyl-1- -myo-inositol (30a,b).—Compound
D
-mannopyran-
D
D
30a,b was synthesized in a manner analogous
to that for compound 30a,a except that 12a,b
was hydrolyzed instead of 12a,a. After work-
up, purification via preparative TLC (1:1
CHCl3–ether) yielded 12.3 mg of diol 30a,b
(75% yield); Rf 30a,b 0.80 (1:1 CHCl3–ether);
1H NMR (CDCl3): l 3.26 (pseudo-t, 1 H, J 10
Hz, H-2 glucosamine), 3.4–4.1 (m, 15 H), 4.2
(pseudo-t, 1 H, J 2.7, H-2 inositol), 4.25–5.1
(m, 20 H), 5.26 (pseudo-s, 1 H, H-1 mannose),
7.0–7.5 (m, 45 H, phenyl H’s).
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“2)-3,4,6-tri-O-benzyl-h-
pyranosyl - (1“6) - 2,3,4 - tri - O - benzyl - h -
mannopyranosyl-(1“4)-2-azido-2-deoxy-3,6-
di - O - benzyl - h,i - - glucopyranosyl - (1“6)-
3,4,5-tri-O-benzyl-1- -myo-inositol 1,2-cyclic
D
-mannopyran-
D
-manno-
D
-
D
D
carbonate (12c,a,b).—Compounds 12c,a,b
were synthesized in a manner analogous to
that for compounds 12a,a,b except that tetra-
saccharides 10c were used as the glycosyl
donor instead of disaccharides 10a. After
work-up, purification via preparative TLC
(7:3 hexanes–EtOAc) yielded 5.2 mg of 12c,a
and 2.0 mg of 12c,b (53% combined yield); Rf
12c,a 0.44, Rf 12c,b 0.52 (7:3 hexanes–
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“6)-2,3,4-tri-O-benzyl-h-
pyranosyl-(1“4)-2-azido-2-deoxy-3,6-di-O-
benzyl-h- -glucopyranosyl-(1“6)-3,4,5-tri-
O-benzyl-1- -myo-inositol (30b,a).—Com-
D
-mannopyran-
D
-manno-
D
D
pound 30b,a was synthesized in a manner
analogous to that for compound 30a,a except
that 12b,a was hydrolyzed instead of 12a,a.
After work-up, purification via preparative
TLC (1:1 CHCl3–ether) yielded 14 mg of diol
(86% yield); Rf 30b,a 0.61 (1:1 CHCl3–ether);
1H NMR (CDCl3) l 2.6 (s, 1 H, OH), 3.25–
3.66 (m, 11 H), 3.71 (pseudo-t, 1 H, J 2.3 Hz),
3.79–3.85 (m, 6 H), 3.87–4.02 (m, 5 H), 4.14–
4.18 (m, 2 H), 4.21–4.50 (m, 12 H), 4.54 (d, 1
H, J 11.9 Hz, HCHPh), 4.58 (d, 1 H, J 12.0
Hz, HCHPh), 4.64 (d, 1 H, J 11.3 Hz,
HCHPh), 4.70–4.76 (m, 4 H), 4.82–4.90 (m, 4
H), 4.94 (d, 1 H, J 11.0 Hz, HCHPh), 5.03
(pseudo-s, 1 H, H-1 mannose), 5.22 (d, 1 H, J
1.7 Hz, H-1 mannose), 5.44 (d, 1 H, J 3.6 Hz,
1
EtOAc); H NMR (CDCl3) 12c,a: l 3.28 (dd,
1 H, J 3.5, J 9.7 Hz, H-2 glucosamine), 3.38–
3.94 (m, 24 H), 3.98–4.09 (m, 3 H), 4.23–4.67
(m, 27 H), 4.76–4.89 (m, 6 H), 5.13 (s, 1 H,
H-1 mannose), 5.27 (m, 2 H, H-1 mannose,
H-1 glucosamine), 7.2–7.4 (m, 75 H, phenyl
H’s).
2,3,4,6-Tetra-O-benzyl-h-
osyl-(1“4)-2-azido-2-deoxy-3,6-di-O-ben-
zyl - h - - glucopyranosyl - (1“6) - 3,4,5 - tri-
O-benzyl-1-
D
-mannopyran-
D
D
-myo-inositol (30a,a).—To 17.5
mg of 12a,a (0.0128 mmol) in 1.4 mL of THF
was added 192 mL of 1 M LiOH. The reaction

C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
389
quenched by addition of 1 mL of satd
NaHCO3 and concentrated by coevaporation
with heptane. The solid was dissolved in 3 mL
of water followed by dropwise acidification
with 2 M HCl to pH 1 (ꢀ20 drops). The
suspension was extracted with EtOAc (5×3
mL) and the combined organic extracts were
dried (Na2SO4), concentrated, dried by co-
evaporation with toluene, and dissolved in dry
THF (2.5 mL). In a separate flask, NH3 (5
mL) was condensed at −78 °C and Na (45
mg, 1.94 mmol) was added. Once the blue
color persisted, the THF solution was added
dropwise. The reaction mixture was stirred at
−78 °C for 15 min (blue color persisted) and
then carefully quenched by addition of 167 mg
(3.12 mmol) of NH4Cl (s) at −78 °C. The
suspension was stirred vigorously at −78 °C
until the blue color had completely disap-
peared. Methanol (6.0 mL) was added at
−78 °C, the cooling bath and the septum
covering the flask were removed, and the reac-
tion mixture was allowed to thaw and evapo-
rate for 12 h at 20 °C. The resulting white
powder was dissolved in water (4 mL) and
filtered through Celite. The filtrate was evapo-
rated to dryness, dissolved in water (1.0 mL),
and desalted by passing over 12 g of Sephadex
G-10, eluting with water (12 mL). Evapora-
tion of the eluate yielded 3.1 mg of 1 (56%
H-1 glucosamine), 7.2–7.5 (m, 60 H, phenyl
H’s).
2,3,4,6-Tetra-O-benzyl-h-
D
-mannopyranosyl-
-mannopyran-
(1“6)-2,3,4-tri-O-benzyl-h-
D
osyl-(1“4)-2-azido-2-deoxy-3,6-di-O-ben-
zyl-i-D - glucopyranosyl-(1“6)-3,4,5-tri-O-
benzyl-1- -myo-inositol (30b,b).—Compound
D
30b,b was synthesized in a manner analogous
to that for compound 30a,a except that 12b,b
was hydrolyzed instead of 12a,a. After work-
up, purification via preparative TLC (1:1
CHCl3–ether) yielded 4.3 mg of diol (66%
1
yield); H NMR (CDCl3): l 2.50 (bs, 1 H,
OH), 3.28 (pseudo-t, 1 H, J 9.3 Hz), 3.35–4.07
(m, 26 H), 4.17–4.22 (m, 2 H), 4.32–4.62 (m,
13 H), 4.68–5.03 (m, 9 H), 5.24 (pseudo-s, 1
H, H-1 mannose), 7.0–7.4 (m, 60 H, phenyl
Hs).
2,3,4,6 -Tetra- O-benzyl- h -
osyl-(1“2)-3,4,6-tri-O-benzyl-h-
pyranosyl - (1“6) - 2,3,4 - tri - O - benzyl - h -
mannopyranosyl-(1“4)-2-azido-2-deoxy-3,6-
di - O - benzyl - h - - glucopyranosyl - (1“6)-
3,4,5-tri-O-benzyl-1- -myo-inositol (30c,a).—
D
- mannopyran-
D
-manno-
D
-
D
D
Compound 30c,a was synthesized in a manner
analogous to that for compound 30a,a except
that 12c,a was hydrolyzed instead of 12a,a.
After work-up, purification via preparative
TLC (1:1 CHCl3–ether) yielded 5.1 mg of diol
1
30c,a (97% yield); H NMR (CDCl3): l 2.50
1
(bs, 1 H, OH), 3.28–4.95 (m, 60 H), 5.02
(pseudo-s, 1 H, H-1 mannose), 5.14 (pseudo-s,
1 H, H-1 mannose), 5.25 (pseudo-s, 1 H, H-1
mannose), 5.40 (pseudo-s, 1 H, H-1 glu-
cosamine) 7.0–7.4 (m, 75 H, phenyl H’s).
Preparation of phosphorylating reagent
3118.—Methyl dichlorophosphoridate (PCl2-
O2Me, 500 mL) was added slowly to 5.0 mL of
freshly-distilled pyridine. The reaction was
stirred at 20 °C for 30 min prior to use.
yield over two steps). H NMR (D2O): l 3–4
(m, 16 H), 4.35 (ddd, 1 H, H-1 inositol), 4.5
(pseudo-t, 1 H, H-2 inositol), 5.1 (pseudo-s, 1
H, H-1 mannose), 5.3 (pseudo-s, 1 H, H-1
glucosamine); 31P NMR (D2O): l 3.62 (trace
of acyclic phosphate), 17.14 (cyclic phos-
phate); HRMS (FAB, negative ion mode):
Calcd for C18H31NO17P: 564.1329; Found:
564.1354.
h -
D
- Mannopyranosyl - (1“4) - 2 - amino - 2-
-glucopyranosyl-(1“6)-1- -myo-
h-D-Mannopyranosyl-(1“4)-2-amino-2-de-
deoxy-i-
D
D
oxy - h -
D
- glucopyranosyl - (1“6) - 1 -
D
- myo-
inositol 1:2-(cyclic) phosphate (2).—Com-
pound 2 was synthesized in a manner
analogous to that for compound 1 except that
b anomer 30a,b was phosphorylated and de-
protected instead of the a anomer 30a,a. After
work-up, desalting with Sephadex G-10
yielded 8.0 mg of 2 (84% yield over two steps);
1H NMR (D2O): l 2.9 (m, 1 H), 3.3–4 (m, 15
H), 4.4 (ddd, 1 H, H-1 inositol), 4.55 (pseudo-
s, 1 H, H-2 inositol), 4.85 (pseudo-s, 1 H, H-1
inositol 1:2-(cyclic) phosphate (1).—To a solu-
tion of 30a,a (13.0 mg, 9.70 mmol) in pyridine
(230 mL) was added freshly prepared phospho-
rylating reagent 31 (518 mL). The reaction was
stirred at 20 °C until judged complete (30 min)
by TLC analysis (1:1:1, CHCl3 –ether–MeOH,
Rf diol 1.0, Rf cyclic phosphate 0.73, Rf acyclic
0; 1:1, CHCl3–ether, Rf diol 0.57, Rf cyclic
and acyclic phosphate 0). The reaction was

390
C.H. Jaworek et al. / Carbohydrate Research 331 (2001) 375–391
inositol), 4.84 (pseudo-s, 1 H, H-1 mannose),
4.95 (pseudo-s, 1 H, H-1 mannose), 5.04
(pseudo-s, 1 H, H-1 mannose), 5.13 (d, 1 H, J
glucosamine), 5.1 (pseudo-s, 1 H, H-1 man-
nose); 31P NMR (D2O): l 16.79.
h-
pyranosyl-(1“4)-2-amino-2-deoxy-h-
copyranosyl-(1“6)-1- -myo-inositol
D
-Mannopyranosyl-(1“6)-h- -manno-
D
31
3.1 Hz, H-1 glucosamine); P NMR (D2O): l
D
-glu-
17.12; HRMS (FAB, negative ion mode):
Calcd for C30H51NO27P: 888.2385; Found:
888.2415.
D
1:2-
(cyclic) phosphate (3).—Compound 3 was syn-
thesized in a manner analogous to that for
compound 1 except that tetrasaccharide 30b,a
was phosphorylated and deprotected instead
of trisaccharide 30a,a. After work-up, desalt-
ing with Sephadex G-10 yielded 3.1 mg of 3
Acknowledgements
1
(75% yield over two steps). H NMR (D2O): l
We are grateful to the National Institutes of
Health (grant no. DK44589) for financial
support.
3.1–4.0 (m, 22 H), 4.35 (ddd, 1 H, J 4, 12, 20
Hz, H-1 inositol), 4.5 (pseudo-t, 1 H, J 4 Hz,
H-2 inositol), 4.7 (pseudo-s, 1 H, H-1-
mannose), 5.05 (pseudo-s, 1 H, H-1 mann-
ose), 5.33 (d, 1 H, H-1 glucosamine); 31P
NMR (D2O): l 17.13; HRMS (electrospray):
Calcd for [C24H42NO22P+H]+ 728.2014;
Found: 728.1996.
References
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h-
pyranosyl-(1“4)-2-amino-2-deoxy-i-
copyranosyl - (1“6) - 1 - - myo - inositol 1:2-
D
-Mannopyranosyl-(1“6)-h-
D
-manno-
D
-glu-
D
(cyclic) phosphate (4).—Compound 4 was syn-
thesized in a manner analogous to that for
compound 1 except that b-tetrasaccharide
30b,b was phosphorylated and deprotected in-
stead of a-trisaccharide 30a,a. After work-up,
desalting with Sephadex G-10 yielded 3.1 mg
1
of 4 (83% yield over two steps). H NMR
(D2O): l 2.97 (m, 1 H), 3.33 (pseudo-t, 1 H),
3.44–4.14 (m, 20 H), 4.29 (ddd, 1 H, J 4.7,
8.1, 20 Hz, H-1 inositol), 4.5 (pseudo-t, 1 H,
H-2 inositol), 4.73 (pseudo-s, 1 H, H-1 mann-
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h- -Mannopyranosyl-(1“2)-h-
pyranosyl-(1“6)-h-
2-amino-2-deoxy-h-
1-
1
H, H-1
D
D
-manno-
D
-mannopyranosyl-(1“4)-
-glucopyranosyl-(1“6)-
-myo-inositol 1:2-(cyclic) phosphate (5).—
D
D
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