Prearranged glycosides. Part 12. Intramolecular mannosylations of glucose derivatives via prearranged glycosides

Article abstract of DOI:10.1002/1522-2675(20001004)83:10<2655::AID-HLCA2655>3.0.CO;2-U

A series of prearranged glycosides 5, 17, 23, 28, 37, and 41, having a benzyl-protected 1-thiomannosyl donor linked through its positions 2, 3, 4, and 6 via succinate and malonate tethers, respectively, to positions 2, 3, and 6 of a benzyl glucopyranoside acceptor, were prepared by condensation of the respective mannosyl succinates and malonates with suitably protected benzyl glucopyranosides. The prearranged glycosides were intramolecularly coupled under various conditions to give the corresponding tethered (1 → 4)-linked disaccharides. The yields and anomer ratios of the products of these couplings were interpreted in terms of the thermodynamic stability of the resulting disaccharides. In the case of prearranged glycoside 17, having positions 3 of both the donor and the acceptor linked by a succinate tether, a strong dependence of the diastereoselectivity of the intramolecular glycosylation on the activation procedure was observed. All other cases did not show a significant dependence of the outcome of the anomeric configuration in intramolecular glycosylation on the activation procedure or the solvent.

Full text of DOI:10.1002/1522-2675(20001004)83:10<2655::AID-HLCA2655>3.0.CO;2-U

Helvetica Chimica Acta ± Vol. 83 ,2000)
2655
Prearranged Glycosides
Part 12
Intramolecular Mannosylations of Glucose Derivatives via Prearranged Glycosides
by Gregor Lemanski and Thomas Ziegler*
Institute of Organic Chemistry, University of Cologne, Greinstrasse 4, D-50939 Cologne
A series of prearranged glycosides 5, 17, 23, 28, 37, and 41, having a benzyl-protected 1-thiomannosyl donor
linked through its positions 2, 3, 4, and 6 via succinate and malonate tethers, respectively, to positions 2, 3, and 6
of a benzyl glucopyranoside acceptor, were prepared by condensation of the respective mannosyl succinates and
malonates with suitably protected benzyl glucopyranosides. The prearranged glycosides were intramolecularly
coupled under various conditions to give the corresponding tethered ,1 ! 4)-linked disaccharides. The yields
and anomer ratios of the products of these couplings were interpreted in terms of the thermodynamic stability of
the resulting disaccharides. In the case of prearranged glycoside 17, having positions 3 of both the donor and the
acceptor linked by a succinate tether, a strong dependence of the diastereoselectivity of the intramolecular
glycosylation on the activation procedure was observed. All other cases did not show a significant dependence of
the outcome of the anomeric configuration in intramolecular glycosylation on the activation procedure or the
solvent.
Introduction. ± Intramolecular glycosylation provides an alternative route for the
construction of O-glycosidic bonds in all those cases where classical glycosylation
procedures ,i.e., intermolecular condensation of a glycosyl donor and a glycosyl
acceptor) are less effective. Two different strategies can be envisaged for the
intramolecularization of chemical glycosylation reactions. First, the glycosyl donor
and glycosyl acceptor are connected by a suitable temporary linker, which is cleaved
during the formation of the glycosidic bond. Acetal [1 ± 11] and silylene-acetal linkers
[12 ± 16] have been among the first to have been used systematically for this purpose.
Furthermore, carbonates [17 ± 19], orthoesters [20], and cobaltcarbonyl complexes of
alkynes [21] have also been applied as temporary linkers for this approach. However,
thorough investigations of intramolecular glycosylations of this type revealed that also
intermolecular processes may be involved during the formation of the O-glycosidic
bond [19][20]. The second strategy for establishing intramolecular glycosylation
resembles Ogawaꢀs cycloglycosylation [22 ± 24] and makes use of stable persisting
tethers between donor and acceptor that are not cleaved during glycosidic-bond
formation [25± 42]. The most significant advantage of the latter strategy of intra-
molecular glycosylation via prearranged glycosides is the fact that rings are formed
during the glycosylation step. Therefore, the outcome of the configuration at the
anomeric center on glycosylation strongly depends on the size of the ring formed and,
thus, can simply be controlled by selection of an appropriate tether. Furthermore, also
the diastereoselectivity of ring formation can be controlled by the positions to which
the tether is linked in the glycosyl donor and the glycosyl acceptor, respectively. For

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Helvetica Chimica Acta ± Vol. 83 ,2000)
example, it has been demonstrated that a double diastereoselection governs the
outcome of the anomer configuration in intramolecular glycosylations in these cases
[34].
Attractive applications of the strategy of intramolecular glycosylation via pre-
arranged glycosides are b-selective l-rhamnosylations [25][26][30] and d-mannosyla-
tions [27], which are still difficult to perform with classical approaches. Recently, we
disclosed such highly diastereoselective intramolecular b-mannosylations for the
construction of the disaccharide residues b-d-Manp-,1 ! 4)-d-Glcp, b-d-Manp-,1 !
4)-d-GlcNAcp, b-d-Manp-,1 ! 4)-d-Galp, and b-d-Manp-,1 ! 4)-d-Manp [35], all of
which are important structures found in many naturally occurring oligosaccharides.
Furthermore, intramolecular b-mannosylations and b-rhamnosylations were also
shown to be well suited for the construction of tetrasaccharide fragments related to
bacterial exopolysaccharides [30][40]. Of the various factors which may influence the
diastereoselectivity of intramolecular b-mannosylations in the case of syntheses of d-
Manp-,1 ! 4)-d-Glcp fragments, we have systematically studied the influence of ring
size when a dicarboxylic tether was linked to position 6 of the mannosyl donor and to
position 3 of the glucosyl acceptor. Highest b-selectivities have been found in these
cases for succinate and malonate tethers [41]. However, to gain more insight into
additional factors which may influence the outcome of anomer configuration in
intramolecular glycosylations, it is important to study further examples.
In continuation of these systematic studies, we now extended the intramolecular
mannosylation with succinate and malonate tethers to mannosylations where the tether
is linked to different positions of the donor and of the acceptor, respectively.
Results. ± For the synthesis of d-Manp-,1 ! 4)-d-Glcp fragments from mannosyl
donors tethered with succinate and malonate, respectively, at various positions, we
followed the previously published route for prearranged 1-thioglycosides [25][41].
Treatment of phenyl ,1a) [43][44] and ethyl 3,4,6-tri-O-benzyl-1-thio-a-d-mannopyr-
anoside ,1b) [45] with succinic anhydride and a catalytic amount of N,N-dimethylpyr-
idin-4-amine ,DMAP) afforded glycosides 2a ,89%) and 2b ,99%), respectively
,Scheme 1). Next, the latter were condensed with glucoside 3 [26] in the presence of
dicyclohexylcarbodiimide ,DCC), and the benzylidene group of the intermediate
succinyl-linked glycosides 4 ,57 ± 60%) was regioselectively opened using Gareggꢀs
procedure ,NaCNBH3, HCl in THF) [46] to give the prearranged glycosides 5a ,79%)
and 5b ,87%) [34]. Both glycosides 5 were then cyclized under various conditions ,see
below, Table) to the succinyl-tethered a-d-,1 ! 4)-linked disaccharide 6, the structure
of which was unambiguously assigned by NMR spectroscopy [27]. No b-d-linked
product was obtained. The a-d-linkage in 6 was also established by deacylation ,cat.
NaOMe, MeOH) and benzoylation ,BzCl, pyridine) to give disaccharide 7 in 64%
yield. In its NMR spectrum, 7 showed a C,H-coupling constant for the anomeric
center of the mannosyl residue ,1J ˆ 175.5 Hz) that is characteristic for a-d-mannosides
[47].
To prepare prearranged glycosides having the tether attached at position 3 of the
mannosyl donor, 1-thiomannosides 8 [48 ± 50] were blocked at positions 6 with ,tert-
butyl)chlorodiphenylsilane, and the intermediates 9a ,78%) and 9b ,80%) were treated
with 2,2-dimethoxypropane ,DMP, acetone, cat. TsOH) to give 1-thiomannosides 10a

Helvetica Chimica Acta ± Vol. 83 ,2000)
2657
Scheme 1
,86%) and 10b ,87%), respectively ,Scheme 2). Next, fluoride-catalyzed desilylation
,cat. Bu4NF, THF) afforded compounds 11 ,84 ± 89%), which were benzylated ,BnBr,
NaH, DMF) at positions 4 and 6 to give intermediates 12 ,85± 94%). Final removal of
the isopropylidene group ,70% AcOH/H2O) and phase-transfer benzylation ,BnBr,
NaOH/H2O, CH2Cl2, cat. ,Bu4N)HSO4) of the axial OH group of the intermediates 13
afforded in 80% yield mannosides 14a and 14b, which were succinylated at position 3
with succinic anhydride to give 1-thiomannosides 15 in 85% yield. The latter were
condensed with glucoside 3 as described above for compounds 4, and the benzylidene
groups of the resulting intermediates 16 were regioselectively opened to give
prearranged glycosides 17. Once again, cyclization of these succinyl-tethered glycosides
under various conditions ,see below, Table) gave mixtures of the corresponding a- and
b-d-,1 ! 4)-linked disaccharides 18. Also the tethered disaccharides 18a and 18b could
be separated by chromatography, but the anomer configuration of the mannosyl
residue could not be assigned since the relevant C,H-coupling constants for 18a ,1J ˆ
168.4 Hz) and for 18b ,1J ˆ 167.1 Hz) were not significantly different. Furthermore,
rather unusual vicinal coupling constants ,3J,1,2) ˆ 5.3 Hz) were found for both
disaccharides, which may be attributed to a conformation different from the usual 4C1
conformation of glycopyranosides. Therefore, a deacylation-benzoylation sequence
similar to that described above for the conversion 6 ! 7 was performed with
compounds 18a and 18b, yielding the disaccharides 19a ,73%) and 19b ,72%), which
now allowed the assignment of the anomer configuration of the mannosyl residue by
their NMR data ,1J ˆ 164.8 Hz for 19a and 153.8 Hz for 19b). In a similar sequence

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[41], 14b was also treated with tert-butyl hydrogen malonate ,DCC, 1-hydroxy-1H-
benzotriazole) to give first ethyl 1-thiomannoside 20 ,62%), the tert-butyl group of
which was then removed with CF3COOH to afford malonate 21 ,95%). Condensation
of the latter with glucoside 3 provided 22 ,55%), which afforded the corresponding
malonyl-tethered glycoside 23 upon regioselective opening of the benzylidene ring of
the glucosyl residue. However, all attempts to cyclize compound 23 under conditions
similar to those for cyclization of 17 failed. Solely products of decomposition of the
starting material could be detected on TLC of the crude reaction mixture.
Scheme 2

Helvetica Chimica Acta ± Vol. 83 ,2000)
2659
Prearranged glycosides tethered via position 4 of the respective mannosyl residues
were prepared as follows. First, a suitably protected mannoside was needed to allow the
introduction of the succinyl tether. Thus, phenyl 1-thiomannoside 25 was first prepared
by opening of the benzylidene ring [46] of phenyl 2,3-di-O-benzyl-4,6-O-benzylidene-1-
thio-a-d-mannopyranoside ,24) [51] ,Scheme 3). Next, succinylation at position 4
afforded monosaccharide 26 ,89%), which was again condensed with glucoside 3. The
thus-obtained succinyl-tethered glycoside 27 ,74%) was converted as described above
to compound 28 ,78%) and cyclized ,see below, Table) to the tethered disaccharides 29.
As previously observed for the tethered disaccharides 18, no assignment of the anomer
configuration of saccharides 29a and 29b could be made by NMR spectroscopy ,C,1) of
1
the mannosyl residue at 100.4 ,29a) and 100.8 ppm ,28a); corresponding J ˆ 175.0
,29a) and 173.7 Hz ,29b)). Therefore, disaccharides 29 were each deacylated and
benzoylated to give saccharides 30, which now showed characteristic C,H-coupling
constants ,1J ˆ 174.1 Hz ,30a) and 156.9 Hz ,30b)). For comparison reasons, the Table
,see below) also shows the already known results of the cyclization of compound 31,
which established the formation of anomer mixtures of tethered disaccharides 32 and
33, respectively, depending on the reaction conditions [41].
Scheme 3

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The two prearranged glycosides tethered with a malonate spacer via position 6 of
the mannosyl donor to position 2 and 6, respectively, of the glucosyl acceptor were
prepared from ethyl 1-thiomannoside 34 [41]. Thus, condensation of the latter with
benzyl 3-O-benzoyl-4,6-O-benzylidene-a-d-glucopyranoside ,35) [52], followed by
regioselective opening of the benzylidene group of intermediate 36, afforded the
prearranged glycoside 37 ,Scheme 4). Cyclization of compound 37 gave exclusively the
tethered a-d-linked disaccharide 38 ,see below, Table), which was deacylated and
benzoylated to afford 39 in 73% yield. Both disaccharides showed C,H-coupling
constants typical for an a-d-linkage ,1J ˆ 168.8 ,38) and 171.8 Hz ,39)). Similarly, 34
was condensed regioselectively with benzyl 2,3-di-O-benzoyl-a-d-glucopyranoside ,40)
[53] to give the prearranged glycoside 41 ,65%), cyclization of which ,see below, Table)
and subsequent deacylation and benzoylation afforded a-d-linked disaccharides 42 and
43, respectively ,1J ˆ 172.5, 42) and 172.0 Hz ,43)).
Scheme 4
Discussion. ± The Table summarizes the results for the cyclizations of tethered
disaccharides 5, 17, 23, 28, 31, 37, and 41. All cyclizations described here were performed
in CH2Cl2 or MeCN with N-iodosuccinimide ,NIS) for phenyl and ethyl 1-thioglyco-
sides and with methyl trifluoromethanesulfonate ,MeOTf) for ethyl 1-thioglycosides,
as previously described [41]. The results of the cyclizations of prearranged glycosides 5
,Table, Entries 1 ± 3) having the succinate tether at position 2 of the mannosyl donor
and at position 3 of the glucosyl acceptor are in contrast to previously performed
glycosylations with glucosyl or galactosyl instead of mannosyl donors [31][39][42]. In
the case of 5, solely a-d-,1 ! 4)-linked disaccharides were found. It was originally
expected for compounds 5 to give at least significant amounts of the corresponding b-d-
linked disaccharides. That this was not the case may be explained by the results of force-
field calculations [54] performed for the a-d-linked product 6 and its b-d-linked

Helvetica Chimica Acta ± Vol. 83 ,2000)
2661
counterpart and their comparison with those of galactosyl-derived analogues. For
example, for disaccharides obtained from 1-thiogalactosides tethered via position 2 by
succinate to position 3 of a glucose acceptor, the corresponding a-d-,1 ! 4)-linked
saccharides are ca. 7 ± 12 kcal/mol more stable than the respective b-d-,1 ! 4)-linked
ones [39]. Contrarily, compound 6 is calculated to be ca. 36 kcal/mol more stable than
the corresponding b-d-linked disaccharide. Thus, solely 6 was formed in the cyclizations
of prearranged saccharides 5.
Table. Cyclization of Tethered Glycosides 5, 17, 23, 28, 31, and 41 under Various Conditions to Tethered
'1 ! 4)-Linked Disaccharides
Entry Starting material Tether
Tether
Ring Conditions
Products
a-d/b-d
,leaving group)
,Man ! Glc) linkage size
,yield)
1
2
3
4
5a ,PhS)
succinate
,2 ! 3) 11
NIS, CH2Cl2, À308
NIS, MeCN, À308
NIS, MeCN, À308
NIS, CH2Cl2, À308
6 ,71%)
6 ,73%)
100 : 0
100 : 0
5b ,EtS)
17a ,PhS)
succinate
succinate
,2 ! 3) 11
,3 ! 3) 12
6 ,54%)a) 100 : 0
18a ,17%),
18b ,50%)
18a ,12%),
18b ,53%)
18 ,64%)
26 : 74
18 : 82
5
NIS, MeCN, À308
6
7
17b ,EtS)
succinate
,3 ! 3) 12
NIS, CH2Cl2, À308
NIS, MeCN, À308
10 : 90b)
0 : 100
18a ,0%),
18b ,66%)
8
9
MeOTf, CH2Cl2, r.t. 18 ,64%)
MeOTf, MeCN, r.t.
17: 83b)
18a ,64%), 100 : 0
18b ,0%)
c
10
11
12
23 ,EtS)
28 ,PhS)
malonate
succinate
,3 ! 3) 11
,4 ! 3) 12
NIS, CH2Cl2, À308
À )
c
MeOTf, CH2Cl2, r.t. À )
NIS, CH2Cl2, À308
NIS, MeCN, À308
NIS, CH2Cl2, À308
29a ,73%),
94 : 6
29b ,5%)
29a ,69%),
29b ,7%)
32a ,17%),
32b ,53%)
13
14
15
16
17
18
91 : 9
31a ,EtS)
31b ,EtS)
malonate
succinate
,6 ! 3) 12
,6 ! 3) 13
24 : 76d)
12 : 88d)
MeOTf, CH2Cl2, r.t. 32a ,9%),
32b ,68%)
33a ,43%),
33b ,27%)
MeOTf, CH2Cl2, r.t. 33a ,31%),
33b ,37%)
NIS, CH2Cl2, À308
62: 38d)
d
45: 55
)
31c ,PhS)
37 ,EtS)
succinate
malonate
,6 ! 3) 13
,6 ! 2) 13
NIS, CH2Cl2, À308
33a ,53%),
33b ,21%)
38 ,69%)
38 ,69%)
71 : 29d)
19
20
21
22
23
24
25
26
NIS, CH2Cl2, À308
NIS, MeCN, À308
100 : 0
100 : 0
100 : 0
100 : 0
100 : 0
100 : 0
100 : 0
100 : 0
MeOTf, CH2Cl2, r.t. 38 ,68%)
MeOTf, MeCN, r.t.
NIS, CH2Cl2, À308
NIS, MeCN, À308
38 ,71%)
42 ,72%)
42 ,68%)
41 ,EtS)
malonate
,6 ! 6) 13
MeOTf, CH2Cl2, r.t. 42 ,62%)
MeOTf, MeCN, r.t.
42 ,66%)
a) According to [34]. b) Determined from the ratio 19a/19b. c) Decomposition of the starting material.
d) According to [41].

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Helvetica Chimica Acta ± Vol. 83 ,2000)
For the prearranged glycosides 17 having succinate tethers between positions 3 of
both donor and acceptor ,Table, Entries 4 ± 9), the outcome of the anomer config-
uration on cyclization strongly depends on the activation procedure and the solvent.
Calculations performed for both anomers 18 showed that the a-d-linked disaccharide
18a should be thermodynamically less stable by ca. 10 kcal/mol than the b-d-linked
disaccharide 18b. This is in good agreement for cyclizations of compound 17a where
18b was the major product ,Entries 4 and 5). Similarly, reaction of 17b with NIS
resulted in predominant or exclusive formation of the b-d-linked disaccharide 18b
,Entries 6 ± 8). However, when 17b was cyclized with MeOTf ,Entry9 ), a complete
inversion of this trend was observed, the a-d-,1 ! 4)-linked disaccharide 18a being
formed as the sole product. Obviously, a change in the glycosylation mechanism takes
place on changing the activator from NIS to MeOTf. Thus, the complete control of the
generated anomer configuration in either direction on intramolecular glycosylation of
17b by a simple change of the activation procedure is a useful and straightforward
application of this methodology for the future preparation of oligosaccharides
containing Man-,1 ! 4)-Glc residues.
The complete failure of the cyclizations of the malonate-tethered prearranged
glycoside 23 corresponding to 17 ,Table, Entries 10 and 11) is due to the formation of
thermodynamically unfavored 11-membered rings for both anomers. Calculations for
the potential products showed that both anomers should be less stable by ca. 90 kcal/
mol than the corresponding succinate-tethered disaccharides 18 having 12-membered
rings. Thus, solely decomposition products were observed. Indeed, when the ring was
enlarged to a 12- or 13-membered ring as for prearranged glycosides 28 ,Entries 12 and
13) or 31 ,Entries 14 ± 18) [41] having positions 4 and 6, respectively, of the mannosyl
donor connected by a succinate or malonate tether to position 3 of the glucosyl
acceptor, cyclization proceeded well and gave the corresponding disaccharides 29, 32,
and 33 in good overall yield. Once again, the calculated thermodynamic stability
reflects the outcome of the anomer configuration in these intramolecular glycosylations
[41].
When the attachment of the tether is changed from position 3 of the glucose
acceptor ,cf. compounds 31) to position 2 as in 37 ,Entries 19 ± 22) or to position 6 as in
41 ,Entries 23 ± 26), only a-d-,1 ! 4)-linked disaccharides 38 and 42 were obtained in
good yield. Calculations of these cases showed again a significantly higher thermody-
namic stability of the respective a-d-anomers. Therefore, simple force-field calcula-
tions of the thermodynamic stability of the tethered disaccharides can help to plan the
length of the tether and the positions to which the tether has to be connected in the
mannosyl donor and in the acceptor in order to find suitable conditions for preparing
selectively either of the anomers. Solely in the case where a change in the activation
procedure may result in a different glycosylation mechanism ,cf. Table, Entries 7 and
9), calculated thermodynamic stabilities of the products do not properly reflect the
reality.
Experimental Part
General. For workup, solns. in org. solvents were dried ,Na2SO4) and evaporated at <408/2 kPa. TLC:
Precoated plastic sheets, Polygram SIL UV254 ,40 Â 80 mm; Macherey-Nagel), toluene/AcOEt mixtures;
detection by UV light, where applicable, and by charring with 5% H2SO4 in EtOH. Column chromatography

Helvetica Chimica Acta ± Vol. 83 ,2000)
2663
,CC): silica gel 60 ,Macherey-Nagel), toluene/AcOEt mixtures. [a]D: at 258; Perkin-Elmer-241 automatic
polarimeter. NMR Spectra: CDCl3 solns. at 258; Bruker-AC-300F and -DRX-500 spectrometers; at 300 and
500 MHz for 1H, and at 75and 126 MHz for 13C; 1H assignments by first-order analysis and by H,H-COSY; 13
C
assignments by mutual comparison of the spectra, by DEPT, and by C,H-COSY; d in ppm rel. to Me4Si as
internal standard, J in Hz; for prearranged glycosides and disaccharides, unprimed locants refer to the glucose
and primed ones to the mannose moiety.
Phenyl 3,4,6-Tri-O-benzyl-2-O-'3-carboxypropanoyl)-1-thio-a-d-mannopyranoside ,2a). A soln. of phenyl
3,4,6-tri-O-benzyl-1-thio-a-d-mannopyranoside ,1a) [43][44] ,4.62 g, 8.51 mmol), succinic anhydride ,6.81 g,
68.08 mmol), and a cat. amount of DMAP in pyridine ,40 ml) was stirred for 24 h at 608, then cooled to r.t.,
diluted with CH2Cl2, and washed with aq. HCl and NaHCO3 soln. Evaporation afforded crude 2a ,4.84 g, 89%),
which was used without further purification in the next step.
Ethyl 3,4,6-Tri-O-benzyl-2-O-'3-carboxypropanoyl)-1-thio-a-d-mannopyranoside ,2b). As described for
2a, with ethyl 3,4,6-tri-O-benzyl-1-thio-a-d-mannopyranoside ,1b) [45] ,0.93 g, 1.9 mmol), succinic anhydride
,1.13 g, 11.3 mmol), DMAP, and pyridine ,50 ml) ,24 h at r.t.): 2b ,1.10 g, 98%). [a]D ˆ ‡75.2 ,c ˆ 1.1, CHCl3).
1H-NMR ,CDCl3): 5.43 ,dd, J,1,2) ˆ 1.3, J,2,3) ˆ 2.5, HÀC,2)); 5.30 ,d, J,1,2) ˆ 1.3, HÀC,1)); 4.13
,ddd, J,4,5) ˆ 8.4, J,5,6a) ˆ 2.0, J,5,6b) ˆ 4.4, HÀC,5)); 3.91 ± 3.88 ,m, HÀC,3), HÀC,4)); 3.82
,dd, J,6a,6b) ˆ À10.8, HaÀC,6)); 3.68 ,dd, HbÀC,6)); 2.69 ± 2.55 ,m, CH2CH2COOH, SCH2); 1.27 ,t, Me).
13C-NMR ,CDCl3): 176.6, 171.4 ,CO); 82.3 ,C,1)); 78.5,C,3)); 75.2 ,Ph CH2); 74.5,C,4)); 73.4 ,Ph CH2); 71.73
,PhCH2); 71.68 ,C,5)); 71.0 ,C,2)); 68.8 ,C,6)); 29.5, 29.1 ,COCH2CH2); 25.6 ,CH2S); 14.9 ,Me). Anal. calc.
for C33H38O8S ,594.72): C 66.56, H 6.44, S 5.39; found: C 66.56, H 6.58, S 5.09.
Benzyl 2-O-Benzoyl-4,6-O-benzylidene-3-O-[1,4-dioxo-4-'phenyl 3,4,6-tri-O-benzyl-1-thio-a-d-mannopyr-
anosid-2-O-yl)butyl]-a-d-glucopyranoside ,4a). A soln. of 2a ,4.69 g, 7.30 mmol), 3 [26] ,3.75g, 8.11 mmol),
DCC ,1.67 g, 8.11 mmol), and a cat. amount of DMAP in CH2Cl2 ,50 ml) was stirred for 24 h at r.t. The resulting
suspension was filtered through a layer of Celite, and the filtrate was washed with aq. HCl and NaHCO3 soln.,
dried, and evaporated. CC ,toluene/AcOEt 20 :1) of the residue afforded 4a ,4.55 g, 57%). [a]D ˆ ‡103.7 ,c ˆ
0.8, CHCl3). 1H-NMR ,CDCl3): 5.90 ,t, J,3,4) ˆ 9.9, HÀC,3)); 5.52 ± 5.48 ,m, HÀC,1'), HÀC,2')); 5.51
,s, PhCH); 5.30 ,s, HÀC,1)); 5.10 ,dd, J,2,3) ˆ 9.9, HÀC,2)); 4.86 ,t, J ˆ À10.8, 1 H, PhCH2); 4.78 ,d, J ˆ
À12.4, 1 H, PhCH2); 4.63 ,d, J ˆ À12.0, 1 H, PhCH2); 4.58 ,d, J ˆ À11.1, 1 H, PhCH2); 4.57 ,d, J ˆ À12.4, 1 H,
PhCH2); 4.48 ,d, J ˆ À10.7, 1 H, PhCH2); 4.47 ,s, 1 H, PhCH2); 4.45, d, J ˆ À12.2, 1 H, PhCH2); 4.35± 4.32
,m, J,5',6a') ˆ 4.8, HÀC,5')); 4.28 ,dd, J,6a,6b) ˆ À10.1, HaÀC,6)); 4.09 ,dt, J,5,6a) ˆ 4.8, J,5,6b) ˆ 9.9,
HÀC,5)); 3.92 ± 3.88 ,m, HÀC,3'), HÀC,4')); 3.83 ,dd, J,6a',6b') ˆ À10.8, HaÀC,6')); 3.74 ,t, HbÀC,6));
3.70 ,dd, HbÀC,6')); 2.69 ± 2.52 ,m, COCH2CH2CO). 13C-NMR ,CDCl3): 171.2, 171.0 ,COCH2CH2CO); 165.8
,PhCO); 101.6 ,PhCH); 95.9 ,C,1)); 85.9 ,C,1')); 79.1 ,C,4)); 78.4 ,C,3')); 75.2 ,PhCH2); 74.5,C,4 ')); 73.3
,PhCH2); 72.4 ,C,5')); 72.2 ,C,2)); 71.7 ,PhCH2); 70.5,C,2 ')); 70.0 ,PhCH2); 69.2 ,C,3)); 68.8 ,C,6)); 64.0
,C,6')); 62.8 ,C,5)); 29.0 ,2 C, COCH2CH2CO). Anal. calc. for C64H62O14S ,1087.25): C 70.70, H 5.75, S 2.95;
found: C 70.50, H 5.76, S 2.97.
Benzyl 2-O-Benzoyl-4,6-O-benzylidene-3-O-[4-'ethyl 3,4,6-tri-O-benzyl-1-thio-a-d-mannopyranosid-2-O-
yl)-1,4-dioxobutyl]-a-d-glucopyranoside ,4b). As described for 4a, with 2b ,1.1 g, 1.9 mmol), 3 [26] ,0.86 g,
1.9 mmol), DCC ,2.06 g, 2.0 mmol), 1-hydroxy-1H-benzotriazole ,126 mg, 0.93 mmol), DMAP, and CH2Cl2
,50 ml): 4b ,1.16 g, 60%). [a]D ˆ ‡88.4 ,c ˆ 1.0, CHCl3). 1H-NMR ,CDCl3): 5.93 ,t, J,3,4) ˆ 9.8, HÀC,3));
5.31 ± 5.25 ,m, HÀC,1'), HÀC,2')); 5.50 ,s, PhCH); 5.29 ,d, J,1,2) ˆ 3.8, HÀC,1)); 5.11 ,dd, J,2,3) ˆ 10.0,
HÀC,2)); 4.80 ,d, J ˆ À10.5, 1 H, PhCH2); 4.76 ,d, J ˆ À11.4, 1 H, PhCH2); 4.63 ,d, J ˆ À12.2, 1 H, PhCH2);
4.55 ,d, J ˆ À12.2, 1 H, PhCH2); 4.51 ,d, J ˆ À11.0, 1 H, PhCH2); 4.45, d, J ˆ À12.1, 1 H, PhCH2); 4.50 ,s, 1 H,
PhCH2); 4.42 ,d, J ˆ À11.4, 1 H, PhCH2); 4.37 ,d, J ˆ À11.2, 1 H, PhCH2); 4.13 ± 4.03 ,m, HÀC,5), HÀC,5'));
4.30 ,dd, J,5,6a) ˆ 4.8, J,6a,6b) ˆ À10.2, HaÀC,6)); 4.13 ± 4.03 ,m, HÀC,3'), HÀC,4), HÀC,4'), HbÀC,6),
HaÀC,6')); 3.67 ,dd, HbÀC,6')); 2.69 ± 2.50 ,m, 6 H, CH2); 1.25, t, Me). 13C-NMR ,CDCl3): 171.3, 171.1
,COCH2CH2CO); 165.8 ,PhCO); 101.6 ,PhCH); 96.0 ,C,1)); 82.3 ,C,1')); 79.2 ,C,4)); 78.5,C,3 ')); 75.1
,PhCH2); 74.5,C,4 ')); 73.3 ,PhCH2); 72.3 ,C,2)); 71.8 ,C,5')); 71.6 ,PhCH2); 70.7 ,C,2')); 70.1 ,PhCH2); 70.0
,C,6)); 69.2 ,C,3)); 68.9 ,C,6')); 62.9 ,C,5)); 29.4, 25.4, 20.0 ,CH2); 14.9 ,Me). Anal. calc. for C60H62O14S
,1039.20): C 69.35, H 6.01; found: C 69.14, H 6.04.
Benzyl 2-O-Benzoyl-6-O-benzyl-3-O-[1,4-dioxo-4-'phenyl 3,4,6-tri-O-benzyl-1-thio-a-d-mannopyranosid-
2-O-yl)butyl]-a-d-glucopyranoside ,5a). A sat. soln. of dry HCl in Et2O was added dropwise at r.t. to a
suspension of 4a ,0.80 g, 0.78 mmol), NaCNBH3 ,0.61 g, 9.75mmol) and 3-Š molecular sieves in THF ,15ml)
until the gas evolution ceased. The mixture was diluted with CH2Cl2 and filtered through a layer of Celite, and
the filtrate was washed with aq. NaHCO3 soln., dried, and evaporated. CC ,toluene/acetone 13 :1) of the residue
1
afforded 5b ,0.63 g, 79%). [a]D ˆ ‡27.6 ,c ˆ 0.7, CHCl3). H-NMR ,CDCl3): 5.68 ,dd, J,3,4) ˆ 9.2, HÀC,3));

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Helvetica Chimica Acta ± Vol. 83 ,2000)
5.61 ,br. d, HÀC,2')); 5.51 ,d, J,1,2) ˆ 1.5, HÀC,1')); 5.28 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.00 ,dd, J,2,3) ˆ 10.3,
HÀC,2)); 4.87 ,d, J ˆ À10.8, 1 H, PhCH2); 4.78 ,d, J ˆ À12.4, 1 H, PhCH2); 4.68 ,d, J ˆ À11.2, 1 H, PhCH2);
4.65± 4.63 , m, 2 H, PhCH2); 4.63 ,d, J ˆ À10.5, 1 H, PhCH2); 4.56 ,d, J ˆ À12.2, 1 H, PhCH2); 4.52 ,d, J ˆ
À11.0, 1 H, PhCH2); 4.50 ,d, J ˆ À10.8, 1 H, PhCH2); 4.43 ,d, J ˆ À11.9, 1 H, PhCH2); 4.32 ,ddd, J,5',6a') ˆ 4.3,
J,5',6b') ˆ 1.8, HÀC,5')); 4.01 ± 3.91 ,m, HÀC,3'), HÀC,4'), HÀC,5)); 3.84 ,dd, J,6a',6b') ˆ À10.8,
HaÀC,6')); 3.80 ± 3.72 ,m, HÀC,4), HaÀC,6), HbÀC,6)); 3.70 ,dd, HbÀC,6')); 3.33 ,br. s, OH); 2.81 ± 2.44
,m, COCH2CH2CO). 13C-NMR ,CDCl3): 172.2, 171.3 ,COCH2CH2CO); 165.7 ,PhCO); 95.2 ,C,1)); 85.6
,C,1')); 78.3 ,C,3')); 75.2 ,PhCH2); 74.3 ,C,4')); 73.6 ,PhCH2); 73.5,C,3)); 73.3 ,Ph CH2); 72.3 ,C,5')); 71.8
,PhCH2); 71.4 ,C,2)); 70.5,C,2 ')); 70.4 ,C,5)); 69.5 ,C,4), PhCH2); 69.2 ,C,6)); 68.6 ,C,6')); 29.3, 29.1
,COCH2CH2CO). Anal. calc. for C64H64O14S ,1089.27): C 70.57, H 5.92; found: C 70.44, H 5.98.
Benzyl 2-O-Benzoyl-6-O-benzyl-3-O-[4-'ethyl 3,4,6-tri-O-benzyl-1-thio-a-d-mannopyranosid-2-O-yl)-1,4-
dioxobutyl]-a-d-glucopyranoside ,5b). As described for 5a, with 4b ,0.52 g, 0.5 mmol) and NaCNBH3 ,0.29 g,
4.64 mmol): 5b ,0.46 g, 88%). [a]D ˆ ‡86.2 ,c ˆ 1.3, CHCl3). 1H-NMR ,CDCl3): 5.98 ,dd, J,2,3) ˆ 10.1, J,3,4) ˆ
9.2, HÀC,3)); 5.43 ,dd, J,1,2) ˆ 1.5, J,2,3) ˆ 2.4, HÀC,2')); 5.25 ± 5.21 ,m, HÀC,1), HÀC,1')); 5.00 ± 4.38
,m, 11 H, HÀC,2), PhCH2), 3.88 ,ddd, J,5',6a') ˆ 1.8, J,5',6b') ˆ 3.3, HÀC,5')); 3.89 ± 3.76 ,m, HÀC,3'),
HÀC,4'), HÀC,5)); 3.66 ,dd, J,6a',6b') ˆ À10.7, HaÀC,6')); 4.99 ,dd, J,5,6a) ˆ 3.7, J,6a,6b) ˆ À10.3,
HaÀC,6)); 3.85± 3.79 , m, HbÀC,6)); 3.74 ,dd, J,6a',6b') ˆ À10.7, HbÀC,6')); 3.45, s, OH); 2.78 ± 2.36
,m, COCH2CH2CO); 1.28 ,t, Me). 13C-NMR ,CDCl3; significant signals): 95.2 ,C,1)); 82.4 ,C,1')); 78.3
,C,3')); 74.4 ,C,4')); 71.7 ,C,5')); 70.7 ,C,2')); 69.4 ,C,2)); 69.3 ,C,6)); 68.6 ,C,6')); 29.4, 29.3 ,COCH2CH2-
CO); 25.7 ,CH2S); 14.9 ,Me). Anal. calc. for C60H64O14S ,1041.22): C69.21, H 6.20, S 3.08; found: C 69.00,
H 6.33, S 3.25.
Benzyl O-'3,4,6-Tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2-O-benzoyl-6-O-benzyl-a-d-glucopyrano-
side 2',3-Succinate ,6). a) A suspension of 5a ,0.64 g, 0.59 mmol) and 3-Š molecular sieves ,ca. 0.2 g) in
CH2Cl2 ,20 ml) was stirred under Ar for 20 min at r.t. and cooled to À308. NIS ,0.66 g, 2.94 mmol) and
Me3SiOTf ,27 ml, 0.15mmol) were added, and the mixture was stirred for 5min. The reaction was quenched by
addition of pyridine, the mixture warmed to r.t., diluted with CH2Cl2 and filtered, and the filtrate washed with
aq. NaHCO3 and Na2S2O3 soln., dried, and evaporated. CC ,toluene/acetone 18 :1) of the residue afforded 6
,0.41 g, 71%). [a]D ˆ ‡128.4 ,c ˆ 1.0, CHCl3). 1H-NMR ,CDCl3): 5.80 ,dd, J,3,4) ˆ 9.2, HÀC,3)); 5.24
,d, J,1,2) ˆ 3.7, HÀC,1)); 5.11 ,br. s, HÀC,1')); 5.04 ,dd, J,2,3) ˆ 10.5, HÀC,2)); 4.82 ,dd, J,2',3') ˆ 2.9,
HÀC,2')); 4.73 ,d, J ˆ À12.4, 1 H, PhCH2); 4.63 ,d, J ˆ À11.7, 1 H, PhCH2); 4.53 ,d, J ˆ À12.2, 1 H, PhCH2);
4.54 ± 4.51 ,m, 1 H, PhCH2); 4.46 ,d, J ˆ À10.4, 1 H, PhCH2); 4.42 ,s, 2 H, PhCH2); 4.40 ,d, J ˆ À12.3, 1 H,
PhCH2); 4.37 ,d, J ˆ À12.1, 1 H, PhCH2); 4.26 ,d, J ˆ À11.8, 1 H, PhCH2); 4.12 ,br. d, HÀC,3')); 4.05± 3.96
,m, HÀC,5)), HÀC,5')); 3.89 ,t, J,4,5) ˆ 9.4, HÀC,4)); 3.79 ± 3.69 ,m, 2 HÀC,6')); 3.77 ,br. d, HÀC,4')); 3.56
,br. d, HÀC,6)); 3.49 ,br. t, HbÀC,6)); 2.86 ± 2.37 ,m, COCH2CH2CO). 13C-NMR ,CDCl3): 172.7, 170.0
,COCH2CH2CO); 165.7 ,PhCO); 102.4 ,J,1', HÀC,1')) ˆ 170.6, C,1')); 94.9 ,C,1)); 80.0 ,C,3')); 75.6 ,C,4));
74.9 ,C,4')); 73.9 ,C,2)); 73.0 ,PhCH2); 72.9 ,PhCH2); 72.7 ,C,5')); 72.4 ,PhCH2); 71.8 ,C,5)); 71.3 ,PhCH2,
C,3)); 70.2 ,C,2')); 69.7 ,PhCH2); 69.4 ,C,6)); 68.3 ,C,6')); 31.2, 30.0 ,COCH2CH2CO). Anal. calc. for
C58H58O14 ,979.10): C 71.15, H 5.97; found: C 71.29, H 6.02.
b) Exactly as described in Exper. a, with 5a ,0.95g, 0.87 mmol), NIS ,0.99 g, 2.94 mmol), Me 3SiOTf ,40 ml,
0.22 mmol), and MeCN ,30 ml): 6 ,0.63 g, 73%).
c) Exactly as described in Exper. a, with 5b ,0.63 g, 0.62 mmol), NIS ,0.67 g, 3.0 mmol), Me3SiOTf ,27 ml,
0.15mmol), and MeCN ,100 ml): 6 ,0.33 g, 45%).
Benzyl O-'2-O-Benzoyl-3,4,6-tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2,3-di-O-benzoyl-6-O-benzyl-a-
d-glucopyranoside ,7). A soln. of 6 ,122 mg, 0.115mmol) and a cat. amount of NaOMe in MeOH ,5ml) were
‡
stirred for 24 h at r.t. Then, the mixture was neutralized with ion-exchange resin ,H form) and evaporated, the
residue dissolved in pyridine ,3 ml), BzCl ,70 ml, 0.6 mmol) added, and the mixture stirred at r.t. for 24 h, then
poured into H2O, and extracted with CH2Cl2. The extracts were washed with aq. HCl and NaHCO3 soln., dried
and evaporated. CC ,hexane/AcOEt 5:1) of the residue afforded 7 ,82 mg, 64%). [a]D ˆ ‡60.3 ,c ˆ 1.4,
1
CHCl3). H-NMR ,CDCl3): 6.10 ,t, J,3,4) ˆ 10.0, HÀC,3)); 5.60 ,t, J,2',3') ˆ 2.5, HÀC,2')); 5.50 ,d, J,1',2') ˆ
1.9, HÀC,1')); 5.13 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.07 ,dd, J,2,3) ˆ 9.9, HÀC,2)); 4.88 ,d, J ˆ À10.9, PhCH2); 4.74
,d, J ˆ À11.7, 1 H, PhCH2); 4.64 ,d, J ˆ À12.1, 1 H, PhCH2); 4.61 ,d, J ˆ À12.2, 1 H, PhCH2); 4.57 ,d, J ˆ À11.5,
1 H, PhCH2); 4.56 ,d, J ˆ À11.2, 1 H, PhCH2); 4.55 ,d, J ˆ À10.9, 1 H, PhCH2); 4.50 ± 4.47 ,m, 3 H, PhCH2);
4.21 ,t, J,4,5) ˆ 10.1, HÀC,4)); 4.07 ,dd, J,3',4') ˆ 9.5, HÀC,3')); 4.00 ± 3.93 ,m, HÀC,4'), HÀC,5'), HÀC,5));
3.73 ,br. d, 2 HÀC,6')); 3.66 ,br. t, 2 HÀC,6)). 13C-NMR ,CDCl3): 166.3, 166.1, 165.7 ,PhCO); 97.8 ,J,1'),
HÀC,1') ˆ 175.5, C,1')); 95.3 ,C,1)); 77.9 ,C,3')); 75.1 ,PhCH2); 74.6 ,C,3)); 74.2 ,C,4')); 73.9 ,C,4)); 73.4

Helvetica Chimica Acta ± Vol. 83 ,2000)
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,2 C, PhCH2); 72.4 ,C,5')); 71.6 ,PhCH2); 71.3 ,C,2)); 69.6 ,PhCH2); 69.5,C,2 ')); 69.3 ,C,5)); 69.1, 69.0 ,C,6),
C,6')). Anal. calc. for C68H64O14 ,1105.25): C 73.90, H 5.84; found: C 74.15, H 5.90.
Phenyl 6-O-['tert-Butyl)diphenylsilyl]-1-thio-a-d-mannopyranoside ,9a). A soln. of 8a [48] ,7.49 g,
27.5mmol), 1 H-imidazole ,4.86 g, 68.75mmol), and , tert-butyl)chlorodiphenylsilane ,8.6 ml, 33.0 mmol) in
DMF ,200 ml) was stirred for 24 h at r.t., poured into H2O, and extracted with CH2Cl2. The extracts were washed
with aq. NaHCO3 soln., dried, and evaporated. Traces of DMF were removed by repetitive co-evaporation of
toluene. Chromatography ,toluene/AcOEt 1 :1.5containing 1% pyridine) afforded 9a ,11.0 g, 78%). [a]D
ˆ
‡141.7 ,c ˆ 1.31, CHCl3). 1H-NMR ,CDCl3): 5.46 ,d, J,1,2) ˆ 1.2, HÀC,1)); 4.17 ,dd, J,2,3) ˆ 3.2, HÀC,2));
4.15± 4.10 , m, J,5,6a) ˆ 4.5, J,5,6b) ˆ 4.8, HÀC,5)); 3.93 ± 3.86 ,m, HÀC,4)); 3.91 ,dd, J,6a,6b) ˆ À10.8,
HaÀC,6)); 3.83 ,dd, J,3,4) ˆ 9.3, HÀC,3)); 3.78 ,dd, HbÀC,6)); 2.97 ,br. s, 3 H, OH); 1.04 ,s, tBu). 13C-NMR
,CDCl3): 87.8 ,C,1)); 72.1 ,C,3)); 71.9 ,C,2)); 71.7, 70.6 ,C,4), C,5)); 65.0 ,C,6)); 26.8 ,Me3C); 19.2 ,Me3C).
Anal. calc. for C28H34O5SSi ,510.73): C 65.85, H 6.71; found: C 66.16, H 6.80.
Ethyl 6-O-['tert-Butyl)diphenylsilyl]-1-thio-a-d-mannopyranoside ,9b). As described for 9a, with 8b
[59][50] ,6.48 g, 28.9 mmol), 1H-imidazole ,4.92 g, 72.23 mmol), ,tert-butyl)chlorodiphenylsilane ,8.9 ml,
34.7 mmol), and DMF ,130 ml): 9b ,10.71 g, 80%). [a]D ˆ ‡89.7 ,c ˆ 1.65, CHCl3). 1H-NMR ,CDCl3): 5.27
,d, J,1,2) < 1, HÀC,1)); 4.08 ± 4.02 ,m, J,5,6a)ˆ 5.0, HÀC,5)); 3.98 ,dd, J,2,3) ˆ 2.9, HÀC,2)); 3.93
,dd, J,6a,6b) ˆ À10.6, HaÀC,6)); 3.86 ,dd, J,5,6b) ˆ 5.2, HbÀC,6)); 3.82 ± 3.77 ,m, HÀC,3), HÀC,4)); 3.12
,br. s, 3 H, OH); 2.65± 2.43 , m, MeCH2S); 1.22 ,t, J ˆ 7.4, MeCH2S); 1.05, s, tBu). 13C-NMR ,CDCl3): 83.6
,C,1)); 72.2 ,C,3)); 71.8 ,C,2)); 71.1, 70.5,C,4), C,5)); 65.0 ,C,6)); 26.8 , Me3C); 24.7 ,MeCH2S); 19.1 ,Me3);
14.7 ,MeCH2S). Anal. calc. for C24H43O5SSi ,462.68): C 62.30, H 7.41, S 6.93; found: C 62.61, H 7.49, S 7.03.
Phenyl 6-O-['tert-Butyl)diphenylsilyl]-2,3-di-O-isopropylidene-1-thio-a-d-mannopyranoside ,10a).
A
soln. of 9a ,3.66 g, 7.17 mmol) and TsOH ,0.87 g, 4.56 mmol) in 2,2-dimethoxypropane ,64 ml) was stirred
for 24 h at r.t., neutralized by the addition of Et3N, diluted with CH2Cl2, washed with H2O, dried, and
evaporated. CC ,hexane/AcOEt 5:1) of the residue afforded 10a ,3.40 g, 86%). [a]D ˆ ‡108.1 ,c ˆ 1.1, CHCl3).
1H-NMR ,CDCl3): 5.75 ,d, J,1,2) < 1.0, HÀC,1)); 4.35, dd, J,2,3) ˆ 5.7, HÀC,2)); 4.19 ,dd, J,3,4) ˆ 7.3,
HÀC,3)); 4.11 ± 4.04 ,m, J,5,6a) ˆ 4.1, J,5,6b) ˆ 4.7, HÀC,5)); 3.95 ,dd, J,4,5) ˆ 10.1, HÀC,4)); 3.89
,dd, J,6a,6b) ˆ À10.9, HaÀC,6)); 3.83 ,dd, HbÀC,6)); 1.54 ,s, 3 H, Me2C); 1.38 ,s, 3 H, Me3C); 1.04 ,s, tBu).
13C-NMR ,CDCl3): 109.8 ,Me2C); 84.0 ,C,1)); 78.2 ,C,3)); 76.1 ,C,2)); 71.4 ,C,5)); 70.2 ,C,4)); 64.5 ,C,6));
28.1 ,Me2C); 26.8 ,Me3C); 26.4 ,Me2C), 19.2 ,Me3C). Anal. calc. for C31H38O5SSi ,550.79): C 67.60, H 6.95;
found: C 67.73, H 6.89.
Ethyl 6-O-['tert-Butyl)diphenylsilyl]-2,3-di-O-isopropylidene-1-thio-a-d-mannopyranoside ,10b). As de-
scribed for 10a, with 9b ,4.05g, 8.75mmol), TsOH ,1.07 g, 5.60 mmol), acetone ,60 ml), and 2,2-
dimethoxypropane ,60 ml): 10b ,3.83 g, 87%). [a]D ˆ ‡67.2 ,c ˆ 1.63, CHCl3). 1H-NMR ,CDCl3): 5.56
,s, HÀC,1)); 4.15, dd, J,2,3) ˆ 5.7, HÀC,2)); 4.13 ± 4.09 ,m, J,3,4) ˆ 7.0, HÀC,3)); 4.02 ± 3.95, m, HÀC,5));
3.90 ,m, 2 HÀC,6)); 3.83 ,ddd, J,4,5) ˆ 9.9, J,4,OH) ˆ 3.0, HÀC,4)); 2.68 ,d, OH); 2.65± 2.43 , m, MeCH2S);
1.52 ,s, 3 H, Me2C); 1.35, s, 3 H, Me2C); 1.24 ,t, J ˆ 7.4, MeCH2S); 1.06 ,s, tBu). 13C-NMR ,CDCl3): 109.6
,Me2C); 79.1 ,C,1)); 78.3 ,C,3)); 76.3 ,C,2)); 71.4 ,C,4)); 69.6 ,C,5)); 64.5 ,C,6)); 28.1 , Me2C); 26.7 ,Me3C);
26.3 ,Me2C); 24.0 ,MeCH2S); 19.2 ,Me3C); 14.4 ,MeCH2S). Anal. calc. for C27H38O5SSi ,502.74): C 64.51,
H 7.62, S 6.38; found: C 64.52, H 7.63, S 6.25.
Phenyl 2,3-Di-O-isopropylidene-1-thio-a-d-mannopyranoside ,11a). A soln. of 10a ,3.28 g, 5.96 mmol) and
Bu4NF ,5ml of a 1m soln. in THF) in THF ,15ml) was stirred for 0.5h at r.t. and evaporated. CC ,toluene/
acetone 3 :1) of the residue afforded 11a ,1.66 g, 89%). M.p. 152 ± 1548 ,hexane/acetone). [a]D ˆ ‡181.8 ,c ˆ
1.28, acetone). 1H-NMR ,,D6)acetone): 5.73 ,s, HÀC,1)); 4.50 ,d, J ˆ 5.3, OH); 4.33 ,dd, J,2,3) ˆ 5.7,
HÀC,2)); 4.11 ,dd, J,3,4) ˆ 7.4, HÀC,3)); 3.98 ± 3.92 ,m, HÀC,5)); 3.77 ± 3.64 ,m, HÀC,4), 2 HÀC,6));
3.43 ,t, J ˆ 6.2, OH); 1.42 ,s, 3 H, Me2C); 1.31 ,s, 3 H, Me2C). 13C-NMR ,,D6)acetone): 109.7 ,Me2C); 85.0
,C,1)); 79.7 ,C,3)); 77.0 ,C,2)); 73.0 ,C,5)); 70.3 ,C,4)); 62.3 ,C,6)); 28.3, 26.6, ,Me2C). Anal. calc. for
C15H20O5S ,312.38): C 57.68, H 6.45, S 10.26; found: C 57.69, H 6.89, S 10.43.
Ethyl 2,3-Di-O-isopropylidene-1-thio-a-d-mannopyranoside ,11b). As described for 11a, with 10b ,12.33 g,
24.5mmol), Bu 4NF ,14 ml of a 1m soln. in THF), and THF ,60 ml): 11b ,5.43 g, 84%). M.p. 127 ± 1298 ,hexane/
acetone). [a]D ˆ ‡173.5, c ˆ 1.36, CHCl3). 1H-NMR ,CDCl3): 5.59 ,s, HÀC,1)); 4.18 ,dd, J,2,3) ˆ 5.5,
HÀC,2)); 4.12 ,dd, J,3,4) ˆ 7.3, HÀC,3)); 3.97 ± 3.91 ,m, HÀC,5)); 3.87 ± 3.82 ,m, 2 HÀC,6)); 3.81 ± 3.76
,m, HÀC,4)); 3.42 ,d, J,4,OH) ˆ 4.2, OH); 2.73 ± 2.48 ,m, MeCH2S, OH); 1.50 ,s, 3 H, Me2C); 1.31 ,s, 3 H,
Me2C); 1.26 ,t, J ˆ 7.4, MeCH2S). 13C-NMR ,CDCl3): 109.6 ,Me2C); 79.6 ,C,1)); 78.3 ,C,3)); 76.5,C,2)); 69.8,
69.7 ,C,5)); 62.0 ,C,6)); 28.1 ,Me2C); 26.3 ,Me2C); 24.3 ,MeCH2S); 14.4 ,MeCH2S). Anal. calc. for C11H20O5S
,264.34): C 49.98, H 7.63, S 12.13; found: C 49.89, H 7.61, S 12.10.

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Helvetica Chimica Acta ± Vol. 83 ,2000)
Phenyl 4,6-Di-O-benzyl-2,3-di-O-isopropylidene-1-thio-a-d-mannopyranoside ,12a). BnBr ,2.3 ml,
18.67 mmol) was added at 08 to a suspension of 11a ,1.66 g, 5.31 mmol) and NaH ,0.42 g, 17.37 mmol) in
DMF ,30 ml), and the mixture was stirred for 1 h at r.t. The excess of NaH was hydrolyzed by careful addition of
MeOH to the suspension, and the resulting soln. was poured into H2O and extracted with CH2Cl2. The extracts
were washed with H2O, dried, and evaporated. CC ,hexane/AcOEt 8 :1) of the residue afforded 12a ,2.23 g,
85%). M.p. 848 ,EtOH). [a]D ˆ ‡183.0 ,c ˆ 1.01, CHCl3). 1H-NMR ,CDCl3): 5.80 ,s, HÀC,1)); 4.88 ,d, J ˆ
À11.4, 1 H, PhCH2); 4.56 ,dd, J ˆ À11.3, 1 H, PhCH2); 4.54 ,br. s, 1 H, PhCH2); 4.42 ,d, J ˆ À12.1, 1 H,
PhCH2); 4.38 ± 4.33 ,m, 2 HÀC,2), HÀC,3)); 4.26 ,ddd, J,5,6a) ˆ 2.7, J,5,6b) ˆ 4.2, HÀC,5)); 3.74 ± 3.66
,m, J,4,5) ˆ 10.1, HÀC,4), 2 HÀC,6)); 1.52 ,s, 3 H, Me2C); 1.38 ,s, 3 H, Me2C). 13C-NMR ,CDCl3): 109.6
,Me2C); 84.1 ,C,1)); 78.5, 76.4 ,C,2), C,3)); 76.0 ,C,4)); 73.3, 73.0 ,PhCH2); 70.0 ,C,5)); 69.1 ,C,6)); 27.9
,Me2C); 26.4 ,Me2C). Anal. calc. for C29H32O5S ,492.63): C 70.71, H 6.55; found: C 70.72, H 6.34.
Ethyl 4,6-Di-O-benzyl-2,3-di-O-isopropylidene-1-thio-a-d-mannopyranoside ,12b). As described for 12b,
with 11b ,3.19 g, 12.1 mmol), BnBr ,5.1 ml, 42.41 mmol), NaH ,0.95 g, 39.45 mmol), and DMF ,60 ml): 12b
1
,5.09 g, 94%). M.p. 55 ± 578 ,EtOH). [a]D ˆ ‡128.9 ,c ˆ 1.35, CHCl3). H-NMR ,CDCl3): 5.58 ,s, J,1,2) ˆ 1.0,
HÀC,1)); 4.86 ,d, J ˆ À11.5, 1 H, PhCH2); 4.61 ,d, J ˆ À12.1, 1 H, PhCH2); 4.54 ,d, J ˆ À11.6, 1 H, PhCH2);
4.50 ,d, J ˆ À12.1, 1 H, PhCH2); 4.31 ± 4.27 ,m, HÀC,3)); 4.17 ,dd, J,2,3) ˆ 5.7, HÀC,2)); 4.12 ,ddd, J,5,6a) ˆ
2.6, HÀC,5)); 3.74 ,dd, J,6a,6b) ˆ À10.7, HaÀC,6)); 3.70 ± 3.68 ,m, J,5,6b) ˆ 4.6, HbÀC,6)); 3.63 ,dd, J,4,5) ˆ
10.3, HÀC,4)); 2.75± 2.47 , m, 2 H, MeCH2S); 1.51 ,s, 3 H, Me2C); 1.36 ,s, 3 H, Me2C). 13C-NMR ,CDCl3):
109.4 ,Me2C); 79.5,C,1)); 78.6 ,C,3)); 76.7 ,C,2)); 76.2 ,C,4)); 73.3 ,Ph CH2); 72.9 ,PhCH2); 69.2 ,C,6)); 68.9
,C,5)); 28.0 ,Me2C); 26.4 ,Me2C); 24.1 ,MeCH2S); 14.4 ,MeCH2S). Anal. calc. for C25H32O5S ,444.59): C 67.54,
H 7.26, S 7.21; found: C 67.44, H 7.24, S 7.13.
Phenyl 4,6-Di-O-benzyl-1-thio-a-d-mannopyranoside ,13a). A soln. of 12a ,2.23 g, 4.53 mmol) in 70%
AcOH/H2O ,70 ml) was stirred for 2.5h at 70 8, evaporated, and co-evaporated several times with toluene.
Crystallization of the residue from hexane/acetone afforded 13a ,1.93 g, 94%). M.p. 118 ± 1208. [a]D ˆ ‡198.0
,c ˆ 1.33, CHCl3). 1H-NMR ,CDCl3): 5.53 ,d, J,1,2) ˆ 1.4, HÀC,1)); 4.75, d, J ˆ À11.3, 1 H, PhCH2); 4.60
,d, J ˆ À11.9, 1 H, PhCH2); 4.58 ,d, J ˆ À11.3, 1 H, PhCH2); 4.44 ,d, J ˆ À11.9, 1 H, PhCH2); 4.26
,ddd, J,5,6a) ˆ 2.0, J,5,6b) ˆ 3.9, HÀC,5)); 4.09 ,dd, J,2,3) ˆ 3.3, HÀC,2)); 3.91 ,dd, J,3,4) ˆ 9.1, HÀC,3));
3.84 ± 3.79 ,m, J,6a,6b) ˆ À10.8, HaÀC,6)); 3.80 ,t, J,4,5) ˆ 9.5, HÀC,4)); 3.67 ,dd, HbÀC,6)). 13C-NMR
,CDCl3): 87.7 ,C,1)); 75.9 ,C,4)); 74.7 ,PhCH2); 73.4 ,PhCH2); 72.4 ,C,2)); 72.3 ,C,3)); 71.8 ,C,5)); 68.8
,C,6)). Anal. calc. for C26H28O5S ,452.57): C 69.00, H 6.24; found: C 68.94, H 6.20.
Ethyl 4,6-Di-O-benzyl-1-thio-a-d-mannopyranoside ,13b). As described for 13a, with 12b ,7.09 g,
15.96 mmol) and 70% AcOH/H2O ,100 ml): 13b ,6.81 g, 96%). M.p. 76 ± 788 ,hexane/acetone). [a]D
ˆ
1
‡160.4 ,c ˆ 0.72, CHCl3). H-NMR ,CDCl3): 5.31 ,d, J,1,2) ˆ 1.1, HÀC,1)); 5.24 ,d, J ˆ À11.3, 1 H, PhCH2);
4.64 ,d, J ˆ À12.1, 1 H, PhCH2); 4.55 ,d, J ˆ À11.3, 1 H, PhCH2); 4.49 ,d, J ˆ À12.0, 1 H, PhCH2); 4.12
,ddd, J,4,5) ˆ 9.5, J ,5,6a) ˆ 3.8, J,5,6b) ˆ 2.0, HÀC,5)); 3.94 ,dd, J,2,3) ˆ 3.3, HÀC,2)); 3.86 ,dd, J,3,4) ˆ 9.1,
HÀC,3)); 3.83 ± 3.78 ,m, HaÀC,6)); 3.76 ,t, J,4,5) ˆ 9.5, HÀC,4)); 3.67 ,dd, J,6a,6b) ˆ À10.8, HbÀC,6));
2.69 ± 2.51 ,m, MeCH2S); 2.80 ,br. s, 2 OH); 1.25, t, J ˆ 7.5, MeCH2S). 13C-NMR ,CDCl3): 84.0 ,C,1)); 75.9
,C,4)); 74.5,Ph CH2); 73.5,Ph CH2); 72.4, 72.3 ,C,2), C,3)); 71.0 ,C,5)); 68.8 ,C,6)); 24.9 ,MeCH2S); 14.8
,MeCH2S). Anal. calc. for C22H28O5S ,404.52): C 65.32, H 6.98, S 7.93; found: C 65.21, H 6.96, S 7.97.
Phenyl 2,4,6-Tri-O-benzyl-1-thio-a-d-mannopyranoside ,14a). A mixture of 13a ,1.93 g, 4.24 mmol),
Bu4NHSO4 ,0.29 g, 0.85mmol), BnBr ,0.88 ml, 7.42 mmol), and 5% aq. NaOH soln. ,6.15ml) in CH 2Cl2 ,23 ml)
was refluxed for 24 h. The mixture was cooled to r.t., diluted with CH2Cl2, washed with H2O, dried, and
evaporated. CC ,hexane/AcOEt 4 :1) of the residue afforded 14a ,1.84 g, 80%). [a]D ˆ ‡108.2 ,c ˆ 2.23,
CHCl3). 1H-NMR ,CDCl3): 5.70 ,s, HÀC,1)); 4.90 ,d, J ˆ À11.1, 1 H, PhCH2); 4.79 ,d, J ˆ À11.6, 1 H, PhCH2);
4.68 ,d, J ˆ À12.0, 1 H, PhCH2); 4.58 ,d, J ˆ À11.1, 1 H, PhCH2); 4.52 ,s, 1 H, PhCH2); 4.51 ,d, J ˆ À11.9, 1 H,
PhCH2); 4.33 ± 4.29 ,m, J,5,6a)ˆ 4.8, J,5,6b)ˆ 2.0, HÀC,5)); 4.03 ± 3.99 ,m, HÀC,2), HÀC,3)); 3.87
,dd, J,6a,6b) ˆ À10.9, HaÀC,6)); 3.82 ,t, J,4,5) ˆ 9.7, HÀC,4)); 3.77 ,dd, HbÀC,6)); 2.20 ,br. s, OH).
13C-NMR ,CDCl3): 85.0 ,C,1)); 79.7 ,C,2)); 76.8 ,C,4)); 74.9 ,PhCH2); 73.3 ,PhCH2); 72.3 ,C,3)); 72.1
,PhCH2); 72.0 ,C,5)); 69.1 ,C,6)). Anal. calc. for C33H34O5S ,542.69): C 73.04, H 6.32, S 5.91; found: C 72.95,
H 6.34, S 5.84.
Ethyl 2,4,6-Tri-O-benzyl-1-thio-a-d-mannopyranoside ,14b). As described for 14a, with 13b ,3.51 g,
8.68 mmol), Bu4NHSO4 ,0.59 g, 1.74 mmol), BnBr ,1.8 ml, 15.2 mmol), 5% aq. NaOH soln. ,11.2 ml), and
1
CH2Cl2 ,42 ml): 14b ,3.43 g, 80%). [a]D ˆ ‡76.9 ,c ˆ 2.15, CHCl3). H-NMR ,CDCl3): 5.48 ,s, HÀC,1)); 4.85
,d, J ˆ À11.1, 1 H, PhCH2); 4.77 ,d, J ˆ À11.7, 1 H, PhCH2); 4.67 ,d, J ˆ À12.1, 1 H, PhCH2); 4.52 ,2d, J ˆ
À11.7, 2 H, PhCH2); 4.51 ,d, J ˆ À12.1, 1 H, PhCH2); 4.12 ,ddd, J,5,6a) ˆ 4.6, J,5,6b) ˆ 2.0, HÀC,5)); 3.95
,dd, J,3,4) ˆ 9.3, HÀC,3)); 3.83 ,dd, J,2,3) ˆ 3.8, HÀC,2)); 3.81 ± 3.78 ,m, HaÀC,6)); 3.75, t, J,4,5) ˆ 9.6,

Helvetica Chimica Acta ± Vol. 83 ,2000)
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HÀC,4)); 3.71 ,dd, J,6a,6b) ˆ À10.8, HbÀC,6)); 2.71 ± 2.51 ,m, MeCH2S); 2.38 ,d, J,3,OH) ˆ 9.5, OH); 1.26
,s, J ˆ 7.4, MeCH2S). 13C-NMR ,CDCl3): 80.9 ,C,1)); 79.8 ,C,2)); 76.8 ,C,4)); 74.8 ,PhCH2), 73.3 ,PhCH2);
72.3 ,C,3)); 72.1 ,PhCH2); 71.2 ,C,5)); 69.0 ,C,6)); 25.0 ,MeCH2S); 14.9 ,MeCH2S). Anal. calc. for C29H34O5S
,494.65): C 70.42, H 6.93, S 6.48; found: C 70.20, H 7.00, S 6.49.
Phenyl 2,4,6-Tri-O-benzyl-3-O-'3-carboxypropanoyl)-1-thio-a-d-mannopyranoside ,15a). As described for
2a, with 14a ,2.39 g, 4.40 mmol), succinic anhydride ,3.50 g, 35.2 mmol), DMAP, and pyridine ,20 ml): crude
15a ,2.39 g, 85%), which was used without further purification in the next step.
Ethyl 2,4,6-Tri-O-benzyl-3-O-'3-carboxypropanoyl)-1-thio-a-d-mannopyranoside ,15b). As described for
2a, with 14b ,4.03 g, 8.15 mmol), succinic anhydride ,6.53 g, 65.20 mmol), DMAP, and pyridine ,60 ml),
followed by chromatography ,toluene/acetone 7 :1 ! 3 :1): 15b ,4.12 g, 85%). [a]D ˆ ‡47.7 ,c ˆ 2.95, CHCl3).
1H-NMR ,CDCl3): 5.37 ,d, J,1,2) ˆ 1.6, HÀC,1)); 5.18 ,dd, J,3,4) ˆ 9.2, HÀC,3)); 4.68 ,d, J ˆ À12.0, 1 H,
PhCH2); 4.65, d, J ˆ À10.5, 1 H, PhCH2); 4.64 ± 4.51 ,m, 2 H, PhCH2); 4.52 ,d, J ˆ À12.1, 1 H, PhCH2); 4.49
,d, J ˆ À11.8, 1 H, PhCH2); 4.21 ± 4.16 ,m, J,5,6a) ˆ 4.2, J,5,6b) ˆ 1.8, HÀC,5)); 4.09 ,t, J,4,5) ˆ 9.5, HÀC,4));
3.96 ,dd, J,2,3) ˆ 3.3, HÀC,2)); 3.82 ,dd, J,6a,6b) ˆ À11.0, HaÀC,6)); 3.68 ,dd, HbÀC,6)); 2.67 ± 2.43
,m, COCH2CH2COOH, MeCH2S); 1.25, t, J ˆ 7.4, MeCH2S). 13C-NMR ,CDCl3): 177.3 ,COOH); 171.4
,COCH2CH2); 81.7 ,C,1)); 77.3 ,C,2)); 74.6 ,PhCH2); 74.5,C,3)); ,2 C, C,4), Ph CH2); 72.4 ,PhCH2); 71.7
,C,5)); 68.8 ,C,6)); 28.8, 28.5 ,COCH2CH2COOH); 25.1 ,MeCH2S); 14.8 ,MeCH2S). Anal. calc. for C33H38O7S
,578.72): C 68.49, H 6.62, S 5.54; found: C 68.61, H 6.57, S 5.60.
Benzyl 2-O-Benzoyl-4,6-O-benzylidene-3-O-[1,4-dioxo-4-'phenyl 2,4,6-tri-O-benzyl-1-thio-a-d-mannopyr-
anoside-3-O-yl)butyl]-a-d-glucopyranoside ,16a). As described for 4a, with crude 15a ,2.39 g, 3.7 mmol), 3 [26]
,1.72 g, 3.7 mmol), DCC ,0.77 g, 3.7 mmol), DMAP, and CH2Cl2 ,20 ml): 16a ,2.43 g, 65%). [a]D ˆ ‡100.0 ,c ˆ
0.81, CHCl2). 1H-NMR ,CDCl3): 5.88 ,t, J,3,4) ˆ 9.9, HÀC,3)); 5.55 ,d, J,1',2') ˆ 1.8, HÀC,1')); 5.30
,d, J,1,2) ˆ 3.5, HÀC,1)); 5.52 ,s, PhCH); 5.11 ,dd, J,3',4') ˆ 9.3, HÀC,3')); 5.09 ,dd, J,2,3) ˆ 9.9, HÀC,2));
4.76 ,d, J ˆ À12.4, 1 H, PhCH2); 4.66 ,d, J ˆ À11.9, 1 H, PhCH2); 4.63 ,d, J ˆ À12.1, 1 H, PhCH2); 4.58 ,s, 1 H,
PhCH2); 4.56 ,d, J ˆ À12.1, 1 H, PhCH2); 4.48 ,d, J ˆ À11.3, 1 H, PhCH2); 4.46 ,d, J ˆ À11.9, 1 H, PhCH2); 4.44
,d, J ˆ À12.2, 1 H, PhCH2); 4.30 ,ddd, J,5',6a') ˆ 4.6, J,5',6b') ˆ 1.9, HÀC,5')); 4.25, dd, J,5,6a)ˆ 5.0,
J,5,6b) ˆ 10.3, J,6a,6b) ˆ À10.3, HaÀC,6)); 4.16 ± 4.10 ,m, HÀC,5)); 4.09 ,t, J,4',5') ˆ 9.8, HÀC,4')); 4.04
,dd, J,2',3') ˆ 3.3, HÀC,2')); 3.82 ,dd, J,6a',6b') ˆ À11.0, HaÀC,6')); 3.78 ,t, HbÀC,6)); 3.73 ,t, J,4,5) ˆ 9.7,
HÀC,4)); 3.79 ,dd, HbÀC,6')); 2.51 ± 2.35 ,m, COCH2CH2CO). 13C-NMR ,CDCl3): 171.1, 171.0 ,COCH2CH2-
CO); 165.8 ,PhCO); 95.9 ,C,1)); 85.5 ,C,1')); 79.1 ,C,4)); 77.0 ,C,2')); 74.6 ,PhCH2); 74.2 ,C,3')); 73.6 ,C,4'));
73.3 ,2 C, PhCH2); 72.3 ,C,5'), PhCH2); 72.2 ,C,2)); 70.0 ,C,6')); 69.3 ,C,3)); 68.9 ,C,6)); 62.8 ,C,5)); 28.8
,COCH2CH2CO). Anal. calc. for C64H62O14S ,1087.25): C 70.70, H 5.75, S 2.95; found: C 70.57, H 5.78, S 3.02.
Benzyl 2-O-Benzoyl-4,6-O-benzylidene-3-O-[4-'ethyl 2,4,6-tri-O-benzyl-1-thio-a-d-mannopyranoside-3-
O-yl)-1,4-dioxobutyl]-a-d-glucopyranoside ,16b). As described for 16a, with 15b ,4.12 g, 6.93 mmol), 3 [26]
,3.21 g, 6.93 mmol), DMAP, DCC ,1.72 g, 8.92 mmol), and CH2Cl2 ,30 ml): 16b ,5.13 g, 71%). [a]D ˆ ‡83.5
,c ˆ 1.24, CHCl3). 1H-NMR ,CDCl3): 5.87 ,t, J,3,4) ˆ 9.9, HÀC,3)); 5.51 ,s, PhCH); 5.34 ,d, J,1',2') ˆ 1.8,
HÀC,1')); 5.29 ,d, J,1,2) ˆ 3.8, HÀC,1)); 5.08 ,2 dd, J,3',4') ˆ 9.4, J,2,3) ˆ 10.0, HÀC,2), HÀC,3')); 4.76
,d, J ˆ À12.4, 1 H, PhCH2); 4.69 ,d, J ˆ À12.2, 1 H, PhCH2); 4.67 ,d, J ˆ À12.0, 1 H, PhCH2); 4.55 ,d, J ˆ
À12.4, 1 H, PhCH2); 4.52 ,d, J ˆ À11.6, 1 H, PhCH2); 4.49 ,d, J ˆ À12.1, 1 H, PhCH2); 4.47 ,d, J ˆ À12.2, 1 H,
PhCH2); 4.44 ,d, J ˆ À11.4, 1 H, PhCH2); 4.27 ,dd, J,6a,6b) ˆ À10.2, HaÀC,6)); 4.16 ,ddd, J,5',6a') ˆ 1.8,
J,5',6b') ˆ 4.1, HÀC,5')); 4.13 ± 4.08 ,m, J,5,6a) ˆ 4.9, J,5,6b) ˆ 10.2, HÀC,5)); 4.04 ,t, J,4',5') ˆ 9.6, HÀC,4'));
3.88 ,dd, J,2',3') ˆ 3.3, HÀC,2')); 3.81 ± 3.77 ,m, J,6a',6b') ˆ À11.0, HaÀC,6')); 3.78 ,t, HbÀC,6)); 3.72
,t, J,4,5) ˆ 9.7, HÀC,4)); 3.67 ,dd, HbÀC,6')); 2.67 ± 2.32 ,m, COCH2CH2CO, MeCH2S); 1.25, t, J ˆ 7.4,
MeCH2S). 13C-NMR ,CDCl3): 170.0 ,COCH2CH2CO); 165.8 ,PhCO); 101.6 ,PhCH); 95.9 ,C,1)); 81.7
,C,1')); 79.1 ,C,4)); 77.1 ,C,2')); 74.5,Ph CH2); 74.4 ,C,3')); 73.6 ,C,4')); 73.4 ,2 C, PhCH2); 72.3 ,PhCH2); 72.2
,C,2)); 71.6 ,C,5')); 69.9 ,C,6')); 69.2 ,C,3)); 68.9 ,C,6)); 62.8 ,C,5)); 29.0, 28.8 ,COCH2CH2CO); 25.1
,MeCH2S); 14.9 ,MeCH2S). Anal. calc. for C60H62O14S ,1039.21): C 69.35, H 6.01; found: C 69.24, H 5.99.
Benzyl 2-O-Benzoyl-6-O-benzyl-3-O-[1,4-dioxo-4-'phenyl 2,4,6-tri-O-benzyl-1-thio-a-d-mannopyrano-
side-3-O-yl)butyl]-a-d-glucopyranoside ,17a). As described for 5a, with 16a ,2.25g, 2.1 mmol) and NaCNBH 3
,1.71 g, 27.1 mmol): 17a ,1.63 g, 76%). [a]D ˆ ‡87.7 ,c ˆ 1.58, CHCl3). 1H-NMR ,CDCl3): 5.66 ,dd, J,3,4) ˆ 9.1,
HÀC,3)); 5.57 ,d, J,1',2') ˆ 1.9, HÀC,1')); 5.28 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.17 ,dd, J,3',4') ˆ 9.3, HÀC,3'));
5.06 ,dd, J,2,3) ˆ 10.2, HÀC,2)); 4.76 ,d, J ˆ À12.4, 1 H, PhCH2); 4.67 ,d, J ˆ À11.9, 1 H, PhCH2); 4.66 ,d, J ˆ
À12.2, 1 H, PhCH2); 4.65, d, J ˆ À12.1, 1 H, PhCH2); 4.62 ,s, 3 H, PhCH2); 4.55 ,d, J ˆ À12.4, 1 H, PhCH2);
4.50 ,d, J ˆ À11.3, 1 H, PhCH2); 4.47 ,d, J ˆ À12.0, 1 H, PhCH2); 4.31 ,ddd, J,5',6a') ˆ 4.3, J,5',6b') ˆ 1.9,
HÀC,5')); 4.11 ,t, J,4',5') ˆ 9.6, HÀC,4')); 4.08 ,dd, J,2',3') ˆ 3.2, HÀC,2')); 3.98 ± 3.93 ,m, HÀC,5)); 3.91 ±
3.82 ,m, 2 HÀC,6)); 3.87 ,dd, J,6a',6b') ˆ À10.9, HaÀC,6')); 3.84 ,t, J,4,5) ˆ 9.3, HÀC,4)); 3.71

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Helvetica Chimica Acta ± Vol. 83 ,2000)
,dd, HbÀC,6')); 3.00 ,br. s, OH); 2.53 ± 2.46 ,m, COCH2CH2CO). 13C-NMR ,CDCl3): 172.3, 171.7
,COCH2CH2CO); 165.7 ,PhCO); 95.2 ,C,1)); 85.4 ,C,1')); 77.3 ,C,2')); 74.6 ,PhCH2); 73.8 ,C,3')); 73.7
,C,4')); 73.6 ,2 C, C,3), PhCH2); 73.3, 72.2 ,PhCH2); 71.8 ,C,5')); 71.4 ,C,2)); 70.4 ,C,5)); 70.2 ,C,4)); 69.4
,C,6)); 69.3 ,PhCH2); 69.0 ,C,6')); 29.1, 29.0 ,COCH2CH2CO). Anal. calc. for C64H64O14S ,1089.27): C 70.57,
H 5.92, S 2.94; found: C 70.45, H 5.98, S 3.00.
Benzyl 2-O-Benzoyl-6-O-benzyl-3-O-[4-'ethyl 2,4,6-tri-O-benzyl-1-thio-a-d-mannopyranoside-3-O-yl)-1,4-
dioxobutyl]-a-d-glucopyranoside ,17b). As described for 5a, with 16b ,3.15g, 3.03 mmol) and NaCNBH 3
1
,2.38 g, 37.9 mmol): 17b ,2.44 g, 77%). [a]D ˆ ‡67.3 ,c ˆ 1.04, CHCl3). H-NMR ,CDCl3): 5.63 ,t, J,3,4) ˆ 9.7,
HÀC,3)); 5.36 ,d, J,1',2') ˆ 1.5, HÀC,1')); 5.26 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.13 ,dd, J,3',4') ˆ 9.2, HÀC,3'));
5.04 ,dd, J,2,3) ˆ 10.2, HÀC,2)); 4.74 ,d, J ˆ À12.4, 1 H, PhCH2); 4.68 ,d, J ˆ À12.0, 1 H, PhCH2); 4.66 ,d, J ˆ
À12.2, 1 H, PhCH2); 4.62 ± 4.55 ,m, 4 H, PhCH2); 4.49 ,2d, J ˆ À12.2, 2 H, PhCH2); 4.48 ,d, J ˆ À12.0, 1 H,
PhCH2); 4.16 ,ddd, J,5',6a') ˆ 2.5, J,5',6b') ˆ 1.7, HÀC,5')); 4.06 ,t, J,4',5') ˆ 9.5, HÀC,4')); 3.95± 3.91
,m, J,2',3') ˆ 3.3, HÀC,2')); HÀC,5)); 3.85± 3.80 ,m, HÀC,4), HaÀC,6')); 3.79 ± 3.70 ,m, 2 HÀC,6)); 3.67
,dd, J,6a',6b') ˆ À11.0, HbÀC,6')); 2.95,br. d, J,4,OH) ˆ 4.2, OH); 2.66 ± 2.52 ,m, MeCH2S); 2.45
,s, COCH2CH2CO); 1.25, t, J ˆ 7.3, MeCH2S). 13C-NMR ,CDCl3): 172.3, 171.7 ,COCH2CH2CO); 165.8
,PhCO); 95.3 ,C,1)); 81.7 ,C,1')); 77.2 ,C,2')); 74.6 ,PhCH2); 73.7 ,C,3'), PhCH2); 73.6 ,C,4')); 73.5,C,3));
73.4 ,PhCH2); 72.3 ,PhCH2); 71.7 ,C,5')); 71.4 ,C,2)); 70.4 ,C,5)); 70.2 ,C,4)); 69.6 ,PhCH2); 69.4 ,C,6)); 68.9
,C,6')); 29.2, 29.0 ,COCH2CH2CO); 25.2 ,MeCH2S); 14.9 ,MeCH2S). Anal. calc. for C60H64O14S ,1041.23):
C 69.21, H 6.20, S 3.08; found: C 69.26, H 6.28, S 2.99.
Benzyl O-'2,4,6-Tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2-O-benzoyl-6-O-benzyl-a-d-glucopyrano-
side 3,3'-Succinate ,18a) and Benzyl O-'2,4,6-Tri-O-benzyl-b-d-mannopyranosyl)-'1 ! 4)-2-O-benzoyl-6-O-
benzyl-a-d-glucopyranoside 3,3'-Succinate ,18b). a) As described for 6 ,Exper. a) with 17a ,0.58 g, 0.53 mmol),
NIS ,0.62 g, 2.78 mmol), Me3SiOTf ,26 ml, 0.14 mmol), and CH2Cl2 ,15ml), followed by CC ,toluene/acetone
20 :1): 18a ,86 mg, 17%), then 18b ,257 mg, 50%).
Data of 18a: [a]D ˆ ‡105.7 ,c ˆ 1.61, CHCl3). 1H-NMR ,CDCl3): 5.96 ,t, J,3,4) ˆ 10.2, HÀC,3)); 5.80
,br. d, HÀC,3')); 5.31 ,d, J,1,2) ˆ 3.8, HÀC,1)); 5.15 ,d, J,1',2') ˆ 6.8, HÀC,1')); 5.13 ,dd, J,2,3) ˆ 10.4,
HÀC,2)); 4.78 ,d, J ˆ À12.5, PhCH2); 4.74 ,d, J ˆ À12.0, 1 H, PhCH2); 4.69 ,d, J ˆ À11.8, 1 H, PhCH2); 4.60 ±
4.51 ,m, 5 H, PhCH2); 4.46 ,d, J ˆ À12.2, 1 H, PhCH2); 4.44 ,d, J ˆ À11.7, 1 H, PhCH2); 4.08 ± 4.02
,m, HÀC,4')); 3.80 ,t, J,4,5) ˆ 9.9, HÀC,4)); 3.73 ,dd, J,5,6a)ˆ 3.0, J,6a,6b) ˆ À10.5, HaÀC,6)); 3.72
,dd, J,2',3') ˆ 2.8, HÀC,2')); 3.72 ± 3.66 ,m, J,6a',6b') ˆ À11.2, HaÀC,6')); 3.66 ± 3.61 ,m, J,5,6b)ˆ 4.8,
HÀC,5)); 3.51 ,dd, HbÀC,6')); 3.50 ,dd, HbÀC,6)); 2.50 ± 2.31 ,m, 2 H, COCH2CH2CO); 2.14 ± 2.07 ,m, 2 H,
COCH2CH2CO). 13C-NMR ,CDCl3): 171.8, 171.2 ,COCH2CH2CO); 165.5 ,PhCO); 95.2 ,C,1)); 92.1 ,J,1',
HÀC,1') ˆ 168.4, C,1')); 76.6 ,C,4)); 75.3 ,C,4')); 73.6 ,PhC H2); 73.0 ,PhCH2, C,2')); 71.7 ,PhCH2); 71.5
,C,2)); 69.8 ,PhCH2, C,5)); 68.7 ,PhCH2); 68.2 ,C,6')); 67.9 ,C,6)); 67.8, 73.4, 67.2 ,C,3), C,3'), C,5')); 30.2,
28.5,CO CH2CH2CO). Anal. calc. for C58H58O14 ,979.10): C 71.15, H 5.97; found: C 70.96, H 6.03.
Data of 18b: [a]D ˆ ‡62.1 ,c ˆ 0.96, CHCl3). 1H-NMR ,CDCl3): 5.96 ,t, J,3,4) ˆ 10.3, HÀC,3)); 5.32
,d, J,1,2) ˆ 3.8, HÀC,1)); 5.20 ,br. t, HÀC,3')); 5.15 ,dd, J,2,3) ˆ 10.6, HÀC,2)); 4.99 ,d, J,1',2') ˆ 5.3,
HÀC,1')); 4.74 ,d, J ˆ À12.4, 1 H, PhCH2); 4.70 ,d, J ˆ À11.9, 1 H, PhCH2); 4.67 ,d, J ˆ À11.9, 1 H, PhCH2);
4.56 ± 4.50 ,m, 4 H, PhCH2); 4.54 ,d, J ˆ À12.0, 1 H, PhCH2); 4.44 ,d, J ˆ À12.1, 1 H, PhCH2); 4.43 ,d, J ˆ
À12.0, 1 H, PhCH2); 4.02 ± 3.97 ,m, HÀC,4)); 3.77 ,dd, J,2',3') ˆ 2.5, HÀC,2')); 3.70 ± 3.60 ,m, 3 H, J,5,6a) ˆ
3.1, J,5,6b) ˆ 4.4, HÀC,4'), HÀC,5'), HÀC,5)); 3.52 ,dd, J,6a,6b) ˆ À10.7, HaÀC,6)); 3.43 ,dd, HbÀC,6));
3.33 ± 3.28 ,m, 1 HaÀC,6')); 3.17 ± 3.06 ,m, HbÀC,6')); 2.43 ± 2.29 ,m, 2 H, COCH2CH2CO); 2.16 ± 2.03 ,m, 2 H,
COCH2CH2CO). 13C-NMR ,CDCl3): 172.2, 171.0 ,COCH2CH2CO); 165.6 ,PhCO); 95.4 ,C,1)); 93.9 ,J,1',
HÀC,1') ˆ 167.1, C,1')); 75.2 ,C,4)); 73.4, 73.2 ,PhCH2); 72.7, 71.5,C,2 '), C,4')); 71.3 ,2 C, C,2), PhCH2); 70.6
,C,3)); 69.9, 69.8 ,C,5), C,5')); 69.7 ,C,3')); 69.6 ,PhCH2); 69.4 ,C,6'), PhCH2); 68.7 ,C,6)). Anal. calc. for
C58H58O14 ,979.10): C 71.15, H 5.97; found: C 70.91, H 6.00.
b) As described for 6 ,Exper. b), with 17a ,0.62 g, 0.57 mmol), NIS ,0.68 g, 3.0 mmol), Me3SiOTf ,29 ml,
0.16 mmol), and MeCN ,20 ml), followed by CC ,toluene/acetone 20 :1): 18a ,67 mg, 12%) and 18b ,297 mg,
53%).
c) As described for 6 ,Exper. a), with 17b ,0.47 g, 0.45mmol), NIS ,0.51 g, 2.25mmol), Me 3SiOTf ,20 ml,
0.11 mmol), and CH2Cl2 ,20 ml), followed by CC ,toluene/AcOEt 15:1): 18a/18b 1 :9 ,0.28 g, 64%).
d) As described for 6 ,Exper. b), with 17b ,0.94 g, 0.90 mmol), NIS ,1.02 g, 4.5mmol), Me 3SiOTf ,41 ml,
0.23 mmol) and MeCN ,30 ml), followed by CC ,toluene/AcOEt 15:1): 18b ,0.59 g, 66%).
e) A suspension of 17b ,0.44 g, 0.42 mmol), 4-Š molecular sieves ,1.1 g), and MeOTf ,0.23 ml, 2.12 mmol)
in CH2Cl2 ,20 ml) was stirred for 6 h at r.t. The mixture was neutralized by the addition of Et3N, diluted with

Helvetica Chimica Acta ± Vol. 83 ,2000)
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CH2Cl2, and filtered. The filtrate was washed with H2O, dried, and evaporated. CC ,toluene/acetone 20 :1) of
the residue afforded 18a/18b 17:83 ,0.26 g, 64%).
f) As described in Exper. e, with 17b ,0.55 g, 0.53 mmol), 4-Š molecular sieves ,1.32 g), MeOTf ,0.40 ml,
3.7 mmol), and MeCN ,20 ml), followed by CC ,toluene/acetone 20 :1): 18a ,0.33 g, 64%).
Benzyl O-'3-O-Benzoyl-2,4,6-tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2,3-di-O-benzoyl-6-O-benzyl-a-
d-glucopyranoside ,19a) and Benzyl O-'3-O-Benzoyl-2,4,6-tri-O-benzyl-b-d-mannopyranosyl)-'1 ! 4)-2,3-di-
O-benzoyl-6-O-benzyl-a-d-glucopyranoside ,19b). a) As described for 7, with 18a ,111 mg, 0.11 mmol),
NaOMe in MeOH ,4 ml), BzCl ,79 ml, 0.68 mmol), and pyridine ,4 ml): 19a ,92 mg, 73%). [a]D ˆ ‡43.6 ,c ˆ
1.82, CHCl3). 1H-NMR ,CDCl3): 6.10 ,dd, J,3,4) ˆ 9.2, HÀC,3)); 5.60 ,dd, J,3',4') ˆ 9.4, HÀC,3')); 5.33
,d, J,1,2) ˆ 3.8, HÀC,1)); 5.19 ,dd, J,2,3) ˆ 10.3, HÀC,2)); 5.14 ,d, J,1',2') ˆ 1.8, HÀC,1')); 4.74 ,d, J ˆ À12.5,
1 H, PhCH2); 4.75, d, J ˆ À12.5, 1 H, PhCH2); 4.65, d, J ˆ À12.7, 1 H, PhCH2); 4.62 ,d, J ˆ À12.3, 1 H, PhCH2);
4.60 ± 4.55 ,m, 2 H, PhCH2); 4.45± 4.40 , m, 2 H, PhCH2); 4.40 ,t, J,4',5') ˆ 9.5, HÀC,4')); 4.19 ,d, J ˆ À11.9,
1 H, PhCH2); 4.13 ,t, J,4,5) ˆ 9.3, HÀC,4)); 4.12 ,d, J ˆ À12.1, 1 H, PhCH2); 4.03 ± 3.98 ,m, J,5,6a) ˆ 4.1,
J,5,6b)ˆ 2.0, HÀC,5)); 3.95 ,dd, J,6a,6b) ˆ À11.2, HaÀC,6)); 3.86 ± 3.80 ,m, J,5',6b') ˆ 3.1, HÀC,5'),
HaÀC,6')); 3.84 ,dd, J,2',3') ˆ 3.0, HÀC,2')); 3.74 ,dd, J,6a',6b') ˆ À11.6, HbÀC,6')); 3.73 ,dd, HbÀC,6)).
13C-NMR ,CDCl3): 165.6, 165.5, 165.4 ,PhCO); 98.8 ,J,1', HÀC,1')) ˆ 170.9, C,1')); 95.1 ,C,1)); 77.7 ,C,2'));
76.3 ,C,4)); 75.6 ,C,4')); 74.7 ,PhCH2); 74.1 ,PhCH2); 73.9, 73.7, 73.5,1 C, 1 C, 2 C, C,5 '), C,3), C,3'), PhCH2);
72.7 ,PhCH2); 72.4 ,C,2)); 70.2 ,C,5)); 69.8 ,PhCH2); 68.8 ,C,6')); 68.5,C,6)). Anal. calc. for C 68H64O14
,1105.25): C 73.90, H 5.84; found: C 74.05, H 5.93.
b) As described for 7, with 18b ,159 mg, 0.16 mmol), NaOMe, MeOH ,4 ml), BzCl ,113 ml, 0.98 mmol), and
pyridine ,4 ml): 19b ,130 mg, 72%). [a]D ˆ À32.3 ,c ˆ 1.10, CHCl3). 1H-NMR ,CDCl3): 6.10 ,t, J,3,4) ˆ 9.8,
HÀC,3)); 5.34 ,d, J,1,2) ˆ 3.8, HÀC,1)); 5.21 ,dd, J,2,3) ˆ 10.2, HÀC,2)); 5.00 ,dd, HÀC,3')); 4.76 ,d, J ˆ
À12.6, 1 H, PhCH2); 4.75, d, J ˆ À12.5, 1 H, PhCH2); 4.71 ,d, J ˆ À12.7, 1 H, PhCH2); 4.60 ,d, J ˆ À12.9, 1 H,
PhCH2); 4.60 ± 4.52 ,m, 3 H, PhCH2); 4.44 ,s, HÀC,1')); 4.43 ,d, J ˆ À12.1, 1 H, PhCH2); 4.42 ,d, J ˆ À11.8,
1 H, PhCH2); 4.33 ,t, J,4,5) ˆ 9.8, HÀC,4)); 4.15, d, J ˆ 11.8, 1 H, PhCH2); 4.05± 3.99 , m, J,5,6a) ˆ 2.8,
J,5,6b) ˆ 1.8, HÀC,5)); 4.00 ,t, J,4',5') ˆ 9.7, HÀC,4')); 3.89 ,br. d, J,2',3') ˆ 3.1, HÀC,2')); 3.74
,dd, J,6a,6b) ˆ À11.2, HÀC,6a)); 3.66 ,dd, HbÀC,6)); 3.44 ,dd, J,6a',6b') ˆ À11.4, HaÀC,6')); 3.34
,dd, HbÀC,6')); 3.26 ± 3.21 ,m, J,5',6a') ˆ 4.5, J,5',6b') ˆ 1.8, HÀC,5')). 13C-NMR ,CDCl3): 165.7, 165.6 ,1 C,
2 C, PhCO); 100.6 ,J,1', HÀC,1')) ˆ 158.5, C,1')); 95.3 ,C,1)); 76.2, 76.0 ,1 C, 2 C, C,2'), C,3'), C,5')); 74.9
,C,4)); 74.6 ,PhCH2); 74.3 ,PhCH2); 73.7 ,PhCH2); 73.1 ,PhCH2); 73.0 ,C,4')); 72.2 ,C,2)); 70.9, 70.2 ,C,3),
C,5)); 69.8 ,PhCH2); 68.8 ,C,6')); 68.1 ,C,6)). Anal. calc. for C68H64O14 ,1105.25): C 73.90, H 5.84; found:
C 74.10, H 5.90.
c) As described for 7, with 18a/18b 1:9 ,see above, Exper. c; 0.20 g, 0.2 mmol), NaOMe in MeOH ,8 ml),
BzCl ,139 ml, 1.2 mmol), and pyridine ,8 ml), followed by CC ,hexane/AcOEt 5:1): 19a ,14 mg, 7%) and 19b
,141 mg, 64%).
d) As described for 7, with 18a/18b 17:83 ,see above, Exper. e; 0.18 g, 0.18 mmol), NaOMe in MeOH
,8 ml), BzCl ,126 ml, 1.1 mmol), and pyridine ,8 ml), followed by CC ,hexane/AcOEt 5:1): 19a ,23 mg, 12%)
and 19b ,105mg, 58%).
Ethyl 2,4,6-Tri-O-benzyl-3-O-[3-'tert-butoxy)-1,3-dioxopropyl]-1-thio-a-d-mannopyranoside ,20). A soln.
of 14b ,1.78 g, 4.54 mmol), tert-butyl hydrogen malonate ,0.61 g, 3.78 mmol), 1-hydroxy-1H-benzotriazole
,0.61 g, 4.54 mmol), and DCC ,0.78 g, 3.78 mmol) in CH2Cl2 ,30 ml) was stirred for 1 h at 08 followed by 48 h at
r.t. Workup as described for 4a and CC ,hexane/AcOEt 8 :1) afforded 20 ,1.50 g, 62%). [a]D ˆ ‡51.4 ,c ˆ 1.83,
CHCl3). 1H-NMR ,CDCl3): 5.35 ,d, J,1,2) ˆ 1.8, HÀC,1)); 5.27 ,s, PhCH); 5.22 ,dd, J,3,4) ˆ 9.1, HÀC,3));
4.68 ,d, J ˆ À12.0, 1 H, PhCH2); 4.67 ,d, J ˆ À12.0, 1 H, PhCH2); 4.66 ,d, J ˆ À11.1, 1 H, PhCH2); 4.58 ,d, J ˆ
À12.0, 1 H, PhCH2); 4.48 ,d, J ˆ À12.0, 1 H, PhCH2); 4.46 ,d, J ˆ À11.1, 1 H, PhCH2); 4.18 ,ddd, J,5,6a) ˆ 4.2,
J,5,6b) ˆ 1.9, HÀC,5)); 4.09 ,t, J,4,5) ˆ 9.5, HÀC,4)); 3.99 ,dd, J,2,3) ˆ 3.3, HÀC,2)); 3.82 ,dd, J,6a,6b) ˆ
À11.0, HaÀC,6)); 3.68 ,dd, HbÀC,6)); 3.18 ,br. d, COCH2); 2.67 ± 2.51 ,m, MeCH2S); 1.42 ,s, tBu); 1.24 ,t, J ˆ
7.4, MeCH2S). 13C-NMR ,CDCl3): 166.2 ,COCH2); 165.4 ,COCH2); 82.1 ,Me3C); 81.7 ,C,1)); 77.3 ,C,2)); 75.1
,C,3)); 74.5,Ph CH2); 73.4 ,C,4)); 73.3 ,PhCH2); 72.4 ,PhCH2); 71.7 ,C,5)); 68.8 ,PhCH2); 63.6 ,C,6)); 42.7
,COCH2); 27.9 ,Me3C); 25.1 ,MeCH2S); 14.8 ,MeCH2S). Anal. calc. for C36H44O8S ,636.80): C 67.90, H 6.96,
S 5.04; found: C 67.58, H 6.92, S 5.06.
Ethyl 2,4,6-Tri-O-benzyl-3-O-'carboxyacetyl)-1-thio-a-d-mannopyranoside ,21). A soln. of 20 ,1.25g,
1.96 mmol) and CF3COOH ,4.3 ml, 37.2 mmol) in CH2Cl2 ,40 ml) was stirred for 3 h at r.t. Evaporation afforded
crude 21 ,1.08 g, 95%), which was used without further purification in the next step.
Benzyl 2-O-Benzoyl-4,6-O-benzylidene-3-O-[3-'ethyl 2,4,6-tri-O-benzyl-1-thio-a-d-mannopyranosid-3-O-
yl)-1,3-dioxopropyl]-a-d-glucopyranoside ,22). As described for 4a, with crude 21 ,1.08 g, 1.9 mmol), 3 [26]

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Helvetica Chimica Acta ± Vol. 83 ,2000)
,0.91 g, 1.96 mmol), DCC ,0.41 g, 1.96 mmol), DMAP, and CH2Cl2 ,30 ml): 22 ,1.1 g, 55%). [a]D ˆ À81.6 ,c ˆ
0.97, CHCl3). 1H-NMR ,CDCl3): 5.86 ,t, J,3,4) ˆ 9.9, HÀC,3)); 5.44 ,s, PhCH); 5.27 ,d, J,1,2) ˆ 3.6, HÀC,1));
5.26 ,d, J,1',2') ˆ 1.7, HÀC,1')); 5.08 ,dd, J,3',4') ˆ 9.7, HÀC,3')); 5.07 ,dd, J,2,3) ˆ 10.0, HÀC,2)); 4.74 ,d, J ˆ
À12.4, 1 H, PhCH2); 4.64 ,d, J ˆ À12.0, 1 H, PhCH2); 4.54 ,d, J ˆ À12.5, 1 H, PhCH2); 4.53 ,d, J ˆ À12.1, 1 H,
PhCH2); 4.52 ,d, J ˆ À11.3, 1 H, PhCH2); 4.46 ,d, J ˆ À12.1, 1 H, PhCH2); 4.40 ,d, J ˆ À12.1, 1 H, PhCH2); 4.32
,d, J ˆ À11.3, 1 H, PhCH2); 4.24 ,dd, J,6a,6b) ˆ À10.2, HaÀC,6)); 4.14 ± 4.01 ,m, J,5,6a) ˆ 4.9, J,5',6b') ˆ 2.0,
HÀC,5), HÀC,5')); 3.94 ,t, J,4',5') ˆ 9.6, HÀC,4')); 3.84 ,dd, J,2',3') ˆ 3.3, HÀC,2')); 3.76 ± 3.61
,m, J,6a',6b') ˆ À10.8, HÀC,4), HaÀC,6'), HbÀC,6)); 3.61 ,dd, HbÀC,6')); 3.17 ,s, COCH2); 2.64 ± 2.48
,m, MeCH2S); 1.23 ,t, J ˆ 7.4, MeCH2S). 13C-NMR ,CDCl3): 165.8 ,CO); 165.3 ,CO); 165.2 ,CO); 101.5
,PhCH); 95.9 ,C,1)); 81.7 ,C,1')); 78.9 ,C,4)); 77.3 ,C,2')); 75.2 ,C,3')); 74.3 ,PhCH2); 73.4 ,C,4')); 73.3
,PhCH2); 72.5,Ph CH2); 72.0 ,C,2)); 71.5,C,5 ')); 70.1 ,C,3)); 70.0 ,C,6')); 68.8 ,C,6), PhCH2); 62.7 ,C,5));
41.0 ,COCH2); 25.1 ,MeCH2S); 14.9 ,MeCH2S). Anal. calc. for C59H60O14S ,1025.18): C 69.12, H 5.90, S 3.13;
found: C 68.76, H 5.90, S 3.21.
Benzyl 2-O-Benzoyl-6-O-benzyl-3-O-[3-'ethyl 2,4,6-tri-O-benzyl-1-thio-a-d-mannopyranosid-3-O-yl)-1,3-
dioxopropyl]-a-d-glucopyranoside ,23). As described for 5a, with 22 ,1.30 g, 1.25mmol) and NaCNBH 3 ,1.57 g,
25.0 mmol): 23 ,0.93 g, 72%). [a]D ˆ ‡83.3 ,c ˆ 1.08, CHCl3). 1H-NMR ,CDCl3): 5.64 ,t, J,3,4) ˆ 9.1, HÀC,3));
5.37 ,d, J,1',2') ˆ 1.9, HÀC,1')); 5.25 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.15 ,dd, J,3',4') ˆ 9.1, HÀC,3')); 5.04
,dd, J,2,3) ˆ 10.3, HÀC,2)); 4.75, d, J ˆ À12.4, 1 H, PhCH2); 4.67 ,d, J ˆ À12.0, 1 H, PhCH2); 4.66 ,d, J ˆ
À12.2, 1 H, PhCH2); 4.65, d, J ˆ À12.2, 1 H, PhCH2); 4.63 ,s, 1 H, PhCH2); 4.59 ,d, J ˆ À12.1, 1 H, PhCH2);
4.55 ,d, J ˆ À12.4, 1 H, PhCH2); 4.52 ,d, J ˆ À10.2, 1 H, PhCH2); 4.46 ,d, J ˆ À12.2, 1 H, PhCH2); 4.44 ,d, J ˆ
À11.0, 1 H, PhCH2); 4.17 ,ddd, J,5',6a') ˆ 4.0, J,5',6b') ˆ 1.9, HÀC,5')); 4.06 ,t, J,4',5') ˆ 9.5, HÀC,4')); 3.97 ±
3.93 ,m, HÀC,5)); 3.92 ,dd, J,2',3') ˆ 3.4, HÀC,2')); 3.80 ± 3.77 ,m, J,4,5) ˆ 9.4, HÀC,4)); 3.79
,dd, J,6a',6b') ˆ À11.0, HaÀC,6')); 3.74 ± 3.70 ,m, 2 HÀC,6)); 3.67 ,dd, HÀC,6')); 3.23 ,d, J ˆ À16.3, 1 H,
COCH2); 3.11 ,d, J ˆ À16.3, 1 H, COCH2); 2.69 ± 2.54 ,m, MeCH2S); 2.35,br. d, OH); 1.26 ,t, J ˆ 7.4,
MeCH2S). 13C-NMR ,CDCl3): 166.8 ,CO); 165.8 ,CO); 165.7 ,CO); 95.3 ,C,1)); 81.5 ,C,1')); 77.1 ,C,2')); 75.3,
74.8 ,C,3), C,3')); 74.4 ,PhCH2); 73.6 ,PhCH2); 73.5,2 C, C,4 '), PhCH2); 72.3 ,PhCH2); 71.6 ,C,5')); 71.3
,C,2)); 70.5,C,5)); 69.7 ,Ph CH2); 69.0 ,C,6)); 68.8 ,C,6')); 41.9 ,COCH2); 25.2 ,MeCH2S); 14.9 ,MeCH2S).
Anal. calc. for C59H62O14S ,1027.20): C 68.99, H 6.08; found: C 69.03, H 6.07.
Phenyl 2,3,6-Tri-O-benzyl-1-thio-a-d-mannopyranoside ,25). As described for 5a, with 24 [51] ,4.63 g,
8.56 mmol) and NaCNBH3 ,6.70 g, 107.0 mmol), followed by CC ,CCl4/acetone 15:1): 25 ,3.76 g, 80%). [a]D
ˆ
‡32.9 ,c ˆ 1.74, CHCl3). 1H-NMR ,CDCl3): 5.61 ,d, J,1,2) ˆ 1.3, HÀC,1)); 4.70 ,d, J ˆ À12.2, 1 H, PhCH2);
4.61 ,d, J ˆ À11.9, 1 H, PhCH2); 4.58 ,d, J ˆ À11.7, 1 H, PhCH2); 4.53 ,d, J ˆ À11.9, 1 H, PhCH2); 4.50 ,d, J ˆ
À11.6, 1 H, PhCH2); 4.48 ,d, J ˆ À11.9, 1 H, PhCH2); 4.32 ± 4.26 ,m, HÀC,5)); 4.13 ,dt, J,4,5) ˆ 9.6, J,4,OH) ˆ
2.1, HÀC,4)); 4.01 ,dd, J,2,3) ˆ 3.0, HÀC,2)); 3.86 ± 3.77 ,m, 2 HÀC,6)); 3.68 ,dd, J,3,4) ˆ 9.4, HÀC,3)); 2.55
,d, OH). 13C-NMR ,CDCl3): 85.5 ,C,1)); 79.6 ,C,3)); 75.5 ,C,2)); 73.4 ,PhCH2); 72.4 ,C,5)); 71.9, 71.7
,PhCH2); 70.1 ,C,6)); 67.8 ,C,4)). Anal. calc. for C33H34O5S ,542.69): C 73.04, H 6.32, S 5.91; found: C 72.91,
H 6.27, S 6.10.
Phenyl 2,3,6-Tri-O-benzyl-4-O-'3-carboxypropanoyl)-1-thio-a-d-mannopyranoside ,26). As described for
2a, with 25 ,1.78 g, 3.28 mmol), succinic anhydride ,2.62 g, 26.24 mmol), DMAP, and pyridine ,20 ml): 26
,1.72 g, 82%). [a]D ˆ ‡78.9 ,c ˆ 2.11, CHCl3). 1H-NMR ,CDCl3): 5.57 ,d, J,1,2) ˆ 1.7, HÀC,1)); 5.41
,t, J,4,5) ˆ 9.8, HÀC,4)); 4.57 ,d, J ˆ À12.3, 1 H, PhCH2); 4.56 ,d, J ˆ À12.1, 1 H, PhCH2); 4.52 ,d, J ˆ
À11.9, 1 H, PhCH2); 4.50 ,d, J ˆ À12.1, 1 H, PhCH2); 4.48 ,d, J ˆ À12.0, 1 H, PhCH2); 4.46 ,d, J ˆ À12.2,
1 H, PhCH2); 4.38 ± 4.34 ,m, J,5,6a) ˆ 5.8, J,5,6b) ˆ 3.1, HÀC,5)); 4.04 ,dd, J,2,3) ˆ 2.4, HÀC,2)); 3.84
,dd, J,3,4) ˆ 9.8, HÀC,3)); 3.61 ,dd, J,6a,6b) ˆ À10.3, HaÀC,6)); 3.54 ,dd, HbÀC,6)); 2.58 ± 2.39
,m, COCH2CH2CO). 13C-NMR ,CDCl3): 177.2 ,COOH); 171.4 ,COCH2CH2COOH); 86.3 ,C,1)); 77.5, 76.4
,C,2), C,3)); 72.5, 72.1, 70.3 ,PhCH2); 70.0 ,C,6)); 69.8, 69.7 ,C,4), C,5)); 29.3, 29.2 ,COCH2CH2CO). Anal.
calc. for C37H38O8S ,642.77): C 69.14, H 5.96, S 4.99; found: C 69.30, H 5.90, S 5.15.
Benzyl 2-O-Benzoyl-4,6-O-benzylidene-3-O-[1,4-dioxo-4-'phenyl 2,3,6-tri-O-benzyl-1-thio-a-d-mannopyr-
anosid-4-O-yl)butyl]-a-d-glucopyranoside ,27). As described for 4a, with 26 ,1.72 g, 2.68 mmol), 3 [26] ,1.36 g,
2.95mmol), DCC ,0.61 g, 2.95mmol), DMAP, and CH 2Cl2 ,20 ml): 27 ,2.15g, 74%). [ a]D ˆ ‡73.9 ,c ˆ 0.93,
CHCl3). 1H-NMR ,CDCl3): 5.87 ,t, J,3,4) ˆ 9.9, HÀC,3)); 5.54 ,d, J,1',2') ˆ 1.8, HÀC,1')); 5.53 ,s, PhCH); 5.36
,t, J,4',5') ˆ 9.7, HÀC,4')); 5.30 ,d, J,1,2) ˆ 3.8, HÀC,1)); 5.08 ,dd, J,2,3) ˆ 10.0, HÀC,2)); 4.74 ,d, J ˆ À12.4,
1 H, PhCH2); 4.68 ,d, J ˆ À12.3, 1 H, PhCH2); 4.59 ,s, 1 H, PhCH2); 4.57 ,d, J ˆ À11.8, 1 H, PhCH2); 4.54
,d, J ˆ À12.3, 1 H, PhCH2); 4.49 ,d, J ˆ À12.2, 1 H, PhCH2); 4.48 ,d, J ˆ À11.8, 1 H, PhCH2); 4.39 ,d, J ˆ
À12.3, 1 H, PhCH2); 4.35± 4.32 , m, J,5',6a') ˆ 6.0, J,5',6b') ˆ 3.3, HÀC,5')); 4.27 ,dd, J,5,6a) ˆ 4.8, HaÀC,6));
4.08 ,dt, J,5,6b) ˆ 9.8, HÀC,5)); 3.98 ± 3.94 ,m, J,2',3') ˆ 2.4, HÀC,2')); 3.85, t, J,6a,6b) ˆ À10.2, HbÀC,6));

Helvetica Chimica Acta ± Vol. 83 ,2000)
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3.78 ± 3.76 ,m, HÀC,4)); 3.73 ,dd, J,3',4') ˆ 9.7, HÀC,3')); 3.58 ,dd, J,6a',6b') ˆ À10.4, HaÀC,6')); 3.53
,dd, HbÀC,6')); 2.52 ± 2.35 ,m, 4 H, COCH2CH2CO). 13C-NMR ,CDCl3): 171.1 ,COCH2CH2CO); 170.8
,COCH2CH2CO); 165.8 ,PhCO); 101.6 ,PhCH); 96.4 ,C,1)); 86.3 ,C,1')); 79.6 ,C,4)); 77.4, 76.2 ,C,2'), C,3'));
73.7 ,PhCH2); 72.7 ,C,3)); 72.6 ,PhCH2); 72.2 ,PhCH2); 71.6 ,C,2)); 70.4 ,PhCH2); 69.9 ,C,6')); 69.7, 69.5
,C,4'), C,5')); 69.3 ,C,6)); 63.3 ,C,5)); 29.5 ,2 C, COCH2CH2CO). Anal. calc. for C64H62O14S ,1087.25):
C 70.70, H 5.75, S 2.98; found: C 70.53, H 5.80, S 3.08.
Benzyl 2-O-Benzoyl-6-O-benzyl-3-O-[1,4-dioxo-4-'phenyl 2,3,6-tri-O-benzyl-1-thio-a-d-mannopyranosid-
4-O-yl)butyl]-a-d-glucopyranoside ,28). As described for 5a, with 27 ,1.54 g, 1.42 mmol) and NaCNBH3 ,1.12 g,
17.75mmol): 28 ,1.21 g, 78%). [a]D ˆ ‡58.9 ,c ˆ 0.93, CHCl3). 1H-NMR ,CDCl3): 5.63 ,dd, J,3,4) ˆ 9.1,
HÀC,3)); 5.54 ,d, J,1',2') ˆ 1.8, HÀC,1'); 5.39 ,t, J,4',5') ˆ 9.7, HÀC,4')); 5.24 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.04
,dd, J,2,3) ˆ 10.2, HÀC,2)); 4.73 ,d, J ˆ À12.4, 1 H, PhCH2); 4.68 ,d, J ˆ À12.5, 1 H, PhCH2); 4.62 ,d, J ˆ
À10.2, 1 H, PhCH2); 4.59 ,d, J ˆ À12.1, 1 H, PhCH2); 4.58 ,d, J ˆ À10.3, 1 H, PhCH2); 4.50 ,d, J ˆ À11.7, 1 H,
PhCH2); 4.54 ± 4.43 ,m, 2 H, PhCH2); 4.39 ± 4.33 ,m, HÀC,5')); 3.97 ± 3.95, m, J,2',3') ˆ 3.0, HÀC,2')); 3.92 ±
3.81 ,m, HÀC,4), HaÀC,6)); 3.76 ,dd, J,3',4') ˆ 9.6, HÀC,3')); 3.71 ± 3.68 ,m, HÀC,5), HbÀC,6)); 3.62 ± 3.59
,m, 2 HÀC,6')); 3.13 ,d, J,4,OH) ˆ 3.6, OH); 2.59 ± 2.38 ,m, COCH2CH2CO). 13C-NMR ,CDCl3): 172.4
,COCH2CH2CO); 171.2 ,COCH2CH2CO); 165.8 ,PhCO); 94.7 ,C,1)); 85.3 ,C,1')); 76.4 ,C,3')); 75.2 ,C,2'));
73.0 ,C,3)); 72.8 ,PhCH2); 71.7 ,PhCH2); 71.2 ,PhCH2); 71.0 ,C,2)); 70.7 ,C,5')); 70.1 ,C,4)); 69.4 ,C,5)); 69.2
,C,6')); 69.1 ,PhCH2); 68.8 ,C,6)); 68.7 ,C,4')); 28.9 ,COCH2CH2CO); 28.6 ,COCH2CH2CO). Anal. calc. for
C64H64O14S ,1089.25): C 70.57, H 5.92, S 2.94; found: C 70.65, H 6.05, S 2.93.
Benzyl O-'2,3,6-Tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2-O-benzoyl-6-O-benzyl-a-d-glucopyrano-
side 3,4'-Succinate ,29a) and Benzyl O-'2,3,6-Tri-O-benzyl-b-d-mannopyranosyl)-'1 ! 4)-2-O-benzoyl-6-O-
benzyl-a-d-glucopyranoside 3,4'-Succinate ,29b). a) As described for 6 ,Exper. a), with 28 ,0.49 g, 0.45mmol),
NIS ,0.50 g, 2.24 mmol), Me3SiOTf ,20 ml, 0.11 mmol), and CH2Cl2 ,20 ml), followed by CC ,CCl4/acetone
25:1): 29a ,0.32 g, 73%), then 29b ,21.8 mg, 5%).
Data of 29a: [a]D ˆ ‡103.7 ,c ˆ 1.14, CHCl3). 1H-NMR ,CDCl3): 5.64 ,t, J,3,4) ˆ 10.0, HÀC,3)); 5.31
,m, HÀC,4')); 5.22 ,d, J,1,2) ˆ 3.8, HÀC,1)); 5.16 ,d, J,1',2') ˆ 1.7, HÀC,1')); 4.75, dd, J,2,3) ˆ 10.4, HÀC,2));
4.66 ,d, J ˆ À12.4, 1 H, PhCH2); 4.65, d, J ˆ À11.8, 1 H, PhCH2); 4.57 ± 4.53 ,m, 4 H, PhCH2); 4.49 ,d, J ˆ
À12.3, 1 H, PhCH2); 4.48 ,d, J ˆ À12.3, 1 H, PhCH2); 4.45, d, J ˆ À12.2, 1 H, PhCH2); 4.04 ,d, J ˆ À12.3, 1 H,
PhCH2); 4.00 ± 3.88 ,m, HÀC,3'), HÀC,5')); 3.98 ,t, J,4,5) ˆ 9.8, HÀC,4)); 3.79 ± 3.60 ,m, HÀC,2'), HÀC,5),
2 HÀC,6'), 2 HÀC,6)); 2.97 ± 2.86 ,m, 1 H, COCH2CH2CO); 2.41 ± 2.34 ,m, 1 H, COCH2CH2CO); 2.16 ± 2.03
,m, 2 H, COCH2CH2CO). 13C-NMR ,CDCl3): 172.0, 169.9 ,COCH2CH2CO); 166.0 ,PhCO); 100.8 ,J,1',
HÀC,1') ˆ 175.0, C,1')); 95.5 ,C,1)); 73.7, 72.3 ,C,2), C,4)); 72.0 ,C,2')); 71.1 ,C,5)); 71.0 ,C,3')); 70.6 ,C,5'));
69.7 ,C,6')); 69.5,C,4 ')); 68.8 ,C,6)); 67.3 ,C,3)); 30.7, 30.0 ,COCH2CH2CO). Anal. calc. for C58H58O14
,979.10): C 71.15, H 5.97; found: C 71.05, H 5.99.
Data of 29b: [a]D ˆ ‡11.9 ,c ˆ 0.74, CHCl3). 1H-NMR ,CDCl3): 5.46 ,t, J,3,4) ˆ 10.0, HÀC,3)); 5.45
,t, J,4',5') ˆ 9.4, HÀC,4')); 5.34 ,d, J,1,2) ˆ 3.6, HÀC,1)); 4.85, dd, J,2,3) ˆ 10.1, HÀC,2)); 4.76 ,d, J ˆ À12.5,
1 H, PhCH2); 4.74 ,d, J ˆ À11.8, 1 H, PhCH2); 4.69 ,d, J ˆ À12.1, 1 H, PhCH2); 4.64 ,d, J ˆ À11.7, 1 H,
PhCH2); 4.61 ± 4.52 ,m, 4 H, PhCH2); 4.46 ,d, J ˆ À12.1, 1 H, PhCH2); 4.45, d, J ˆ À12.0, 1 H, PhCH2); 4.44
,s, HÀC,1')); 4.00 ± 3.89 ,m, HÀC,5)); 3.92 ± 3.80 ,m, HÀC,2'), 2 HÀC,6')); 3.87 ,t, J,4,5) ˆ 9.9, HÀC,4));
3.80 ± 3.76 ,m, 2 HÀC,6)); 3.70 ± 3.66 ,m, HÀC,3')); 3.58 ± 3.50 ,m, HÀC,5')). 13C-NMR ,CDCl3): 171.8, 170.6
,COCH2CH2CO); 166.4 ,PhCO); 100.4 ,J,1', HÀC,1')) ˆ 173.7, C,1')); 95.7 ,C,1)); 77.6 ,C,4)); 74.8 ,PhCH2);
74.5,C,3 ')); 74.2 ,PhCH2); 73.4, 72.7 ,PhCH2); 72.4 ,C,5)); 72.2 ,C,5')); 72.1 ,C,3)); 71.4 ,2 C, C,2'), C,2));
69.9 ,PhCH2); 69.8 ,C,4')); 69.0 ,C,6')); 68.3 ,C,6)). Anal. calc. for C58H58O14 ,979.10): C 71.15, H 5.97; found:
C 70.98, H 6.12.
b) As described for 6 ,Exper. b), with 28 ,0.49 g, 0.45mmol), NIS ,0.51 g, 2.27 mmol), Me 3SiOTf ,21 ml,
0.12 mmol), and MeCN ,20 ml), followed by CC ,CCl4/acetone 25:1): 29a ,0.30 g, 69%) and 29b ,32.2 mg, 7%).
Benzyl O-'4-O-Benzoyl-2,3,6-tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2,3-di-O-benzoyl-6-O-benzyl-a-
d-glucopyranoside ,30a). As described for 7, with 29a ,180 mg, 0.18 mmol), NaOMe in MeOH ,5ml), BzCl
,128 ml, 1.10 mmol), and pyridine ,5ml): 30a ,147 mg, 72%). [a]D ˆ ‡42.8 ,c ˆ 0.88, CHCl3). 1H-NMR
,CDCl3): 5.94 ,t, J,3,4) ˆ 9.4, HÀC,3)); 5.61 ,t, J,4',5') ˆ 9.3, HÀC,4')); 5.40 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.20
,d, J,1',2') ˆ 1.8, HÀC,1')); 4.99 ,dd, J,2,3) ˆ 10.3, HÀC,2)); 4.70 ,d, J ˆ À12.0, 1 H, PhCH2); 4.68 ,d, J ˆ
À11.7, 1 H, PhCH2); 4.60 ± 4.53 ,m, 4 H, PhCH2); 4.50 ,d, J ˆ À12.1, 1 H, PhCH2); 4.48 ,d, J ˆ À12.3, 1 H,
PhCH2); 4.44 ,d, J ˆ À11.9, 1 H, PhCH2); 4.17 ,dd, J,3',4') ˆ 9.2, HÀC,3')); 4.10 ± 4.06 ,m, J,5,6a) ˆ 4.2,
J,5,6b)ˆ 2.1, J ˆ À12.3, 2 H, HÀC,5), PhCH2); 4.05± 4.00 , m, 2 HÀC,6')); 3.96 ,dd, J,6a,6b) ˆ À12.0,
HaÀC,6)); 3.90 ,t, J,4,5) ˆ 9.6, HÀC,4)); 3.88 ± 3.80 ,m, HÀC,5')); 3.77 ,dd, HbÀC,6)); 3.73 ± 3.68
,m, J,2',3') ˆ 2.7, HÀC,2')). 13C-NMR ,CDCl3): 166.4, 165.8, 165.6 ,PhCO); 99.9 ,J,1', HÀC,1')) ˆ 174.1,

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Helvetica Chimica Acta ± Vol. 83 ,2000)
C,1')); 95.3 ,C,1)); 74.7 ,C,4)); 74.4, 73.6 ,PhCH2); 73.1 ,C,3)); 72.4 ,2 C, C,2'), PhCH2); 72.2 ,C,2)); 72.0
,PhCH2); 71.5,C,3 ')); 71.0 ,2 C, C,4'), C,5')); 70.2 ,C,5)); 69.9 ,PhCH2); 69.1 ,C,6')); 68.8 ,C,6)). Anal. calc.
for C68H54O14 ,1105.25): C 73.90, H 5.84; found: C 74.15, H 5.94.
Benzyl O-'4-O-Benzoyl-2,3,6-tri-O-benzyl-b-d-mannopyranosyl)-'1 ! 4)-2,3-di-O-benzoyl-6-O-benzyl-a-
d-glucopyranoside ,30b). As described for 7, with 29b ,51 mg, 0.05 mmol), NaOMe in MeOH ,3 ml), BzCl
,36 ml, 0.31 mmol), and pyridine ,3 ml): 30b ,43 mg, 75%). [a]D ˆ À33.1 ,c ˆ 0.65, CHCl3). 1H-NMR ,CDCl3):
5.96 ,t, J,3,4) ˆ 9.6, HÀC,3)); 5.42 ,d, J,1,2) ˆ 3.6, HÀC,1)); 5.38 ,t, J,4',5') ˆ 9.4, HÀC,4')); 5.04 ,dd, J,2,3) ˆ
10.0, HÀC,2)); 4.78 ,d, J ˆ À12.1, 1 H, PhCH2); 4.75, d, J ˆ À11.8, 1 H, PhCH2); 4.73 ,d, J ˆ À12.5, 1 H,
PhCH2); 4.69 ,d, J ˆ À11.7, 1 H, PhCH2); 4.65± 4.55 , m, 4 H, PhCH2); 4.51 ,s, HÀC,1')); 4.49 ,d, J ˆ À12.1,
1 H, PhCH2); 4.46 ,d, J ˆ À11.7, 1 H, PhCH2); 4.13 ± 4.08 ,m, J,5,6a) ˆ 4.1, J,5,6b) ˆ 1.9, HÀC,5)); 3.81 ± 3.78
,m, 2 HÀC,6')); 3.78 ± 3.73 ,m, J,2',3') ˆ 3.0, HÀC,2')); 3.75, dd, J,6a,6b) ˆ À12.2, HaÀC,6)); 3.74
,t, 1 J,4,5) ˆ 9.5, HÀC,4)); 3.72 ,dd, HbÀC,6)); 3.68 ,dd, J,3',4') ˆ 9.3, HÀC,3')); 3.44 ± 3.40 ,m, HÀC,5')).
13C-NMR ,CDCl3): 165.8, 165.5, 165.4 ,PhCO); 100.7 ,J,1',HÀC,1') ˆ 156.9, C,1')); 95.2 ,C,1)); 75.0, 74.4
,PhCH2); 74.2 ,C,3')); 73.6 ,PhCH2); 73.2 ,C,5')); 73.1 ,C,4)); 72.8 ,PhCH2); 72.3 ,C,2)); 71.5,C,3)); 71.1
,C,2')); 70.1 ,C,5)); 69.9 ,PhCH2); 69.5,C,4 ')); 68.8 ,C,6')); 68.5,C,6)). Anal. calc. for C 68H54O14 ,1105.25):
C 73.90, H 5.84; found: C 74.15, H 5.94.
Benzyl 3-O-Benzoyl-4,6-O-benzylidene-2-O-[3-'ethyl 2,3,4-tri-O-benzyl-1-thio-a-d-mannopyranosid-6-O-
yl)-1,3-dioxopropyl]-a-d-glucopyranoside ,36). As described for 4a, with 34 [41] ,1.44 g, 2.48 mmol), 35 [52]
,1.45g, 2.48 mmol), DCC ,0.51 g, 2.48 mmol), DMAP, and CH 2Cl2 ,30 ml): 36 ,1.74 g, 70%). [a]D ˆ ‡89.2 ,c ˆ
1.31, CHCl3). 1H-NMR ,CDCl3): 5.91 ,t, J,3,4) ˆ 9.9, HÀC,3)); 5.50 ,s, 1 H, PhCH); 5.31 ,d, J,1',2') ˆ 1.0,
HÀC,1')); 5.18 ,d, J,1,2) ˆ 3.8, HÀC,1)); 4.94 ,dd, J,2,3) ˆ 10.0, HÀC,2)); 4.88 ,d, J ˆ À10.9, 1 H, PhCH2);
4.69 ,d, J ˆ À12.3, 1 H, PhCH2); 4.62 ,d, J ˆ À12.4, 1 H, PhCH2); 4.56 ± 4.50 ,m, 3 H, PhCH2); 4.49 ,d, J ˆ
À10.7, 1 H, PhCH2); 4,46 ,d, J ˆ À10.8, 1 H, PhCH2); 4.33 ± 4.27 ,m, 2 HÀC,6')); 4.26 ,dd, J,5,6a) ˆ 4.8,
J,6a,6b) ˆ À10.5, HaÀC,6)); 4.20 ± 4.08 ,m, HÀC,5')); 4.15± 4.02 , m, HÀC,5)); 3.83 ± 3.68 ,m, J,3',4') ˆ 9.7,
HÀC,2'), HÀC,3'), HÀC,4), HbÀC,6)); 3.79 ,t, J,4',5') ˆ 9.6, HÀC,4')); 3.36 ,d, J ˆ À16.0, 1 H, COCH2);
3.27 ,d, J ˆ À16.0, 1 H, COCH2); 2.57 ± 2.44 ,m, MeCH2S); 1.19 ,t, J ˆ 7.4, MeCH2S). 13C-NMR ,CDCl3): 165.4,
165.3, 165.1 ,CO); 101.5 ,PhCH); 94.9 ,C,1)); 82.0 ,C,1')); 80.2 ,C,3')); 79.3 ,C,4)); 76.0 ,C,2')); 74.8 ,PhCH2);
74.6 ,C,4')); 72.6 ,C,2)); 71.9, 71.8 ,PhCH2); 70.1 ,C,5')); 70.0 ,PhCH2); 69.6 ,C,3)); 68.8 ,C,6)); 64.4 ,C,6'));
62.7 ,C,5)); 41.2 ,COCH2); 25.1 ,MeCH2S); 15.0 ,MeCH2S). Anal. calc. for C59H60O14S ,1025.18): C 69.12,
H 5.90; found: C 69.07, H 5.94.
Benzyl 3-O-Benzoyl-6-O-benzyl-2-O-[3-'ethyl 2,3,4-tri-O-benzyl-1-thio-a-d-mannopyranosid-6-O-yl)-1,3-
dioxopropyl]-a-d-glucopyranoside ,379). As described for 5a, with 36 ,1.26 g, 1.23 mmol) and NaCNBH3
1
,0.97 g, 15.38 mmol): 37 ,1.01 g, 80%). [a]D ˆ ‡100.8 ,c ˆ 1.02, CHCl3). H-NMR ,CDCl3): 5.71 ,dd, J,3,4) ˆ
9.3, HÀC,3)); 5.32 ,d, J,1',2') ˆ 1.0, HÀC,1')); 5.10 ,d, J,1,2) ˆ 3.8, HÀC,1)); 4.92 ,d, J ˆ À11.0, 1 H, PhCH2);
4.86 ,dd, J,2,3) ˆ 10.1, HÀC,2)); 4.75, d, J ˆ À12.3, 1 H, PhCH2); 4.66 ,d, J ˆ À12.4, 1 H, PhCH2); 4.63 ± 4.56
,m, 3 H, PhCH2); 4.55 ,d, J ˆ À11.0, 1 H, PhCH2); 4.53 ,s, 2 H, PhCH2); 4.51 ,d, J ˆ À12.4, 1 H, PhCH2); 4.46 ±
4.40 ,m, 2 HÀC,6')); 4.24 ± 4.12 ,m, HÀC,5')); 4.04 ± 3.90 ,m, HÀC,5)); 3.99 ,t, J,4',5') ˆ 9.7, HÀC,4')); 3.82 ±
3.67 ,m, J,3',4') ˆ 9.6, HÀC,2'), HÀC,3'), HÀC,4), 2 HÀC,6)); 3.56 ,d, J,4,OH) ˆ 5.0, OH); 3.36 ,d, J ˆ
À16.0, 1 H, COCH2); 3.31 ,d, J ˆ À16.0, 1 H, COCH2); 2.55 ± 2.45 ,m, MeCH2S); 1.19 ,t, J ˆ 7.4, MeCH2S).
13C-NMR ,CDCl3): 165.5, 165.3, 165.1 ,CO); 94.2 ,C,1)); 82.2 ,C,1')); 80.1 ,C,3')); 75.9 ,C,2')); 74.8 ,PhCH2);
74.5,C,4 ')); 73.7 ,C,3)); 73.6 ,PhCH2); 72.0 ,2 C, PhCH2); 71.8 ,C,2)); 70.8 ,C,5')); 69.7 ,2 C, PhCH2, C,5));
69.6 ,C,4)); 69.0 ,C,6)); 64.7 ,C,6')); 41.2 ,COCH2); 25.4 ,MeCH2S); 15.0 ,MeCH2S). Anal. calc. for
C59H62O14S ,1027.20): C 68.99, H 6.08, S 3.12; found: C 69.05, H 6.05, S 3.20.
Benzyl O-'2,3,4-Tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-3-O-benzoyl-6-O-benzyl-a-d-glucopyrano-
side 2,6'-Malonate ,38). a) As described for 6 ,Exper. a), with 37 ,0.56 g, 0.45 mmol), NIS ,0.51 g, 2.25 mmol),
Me3SiOTf ,20 ml, 0.11 mmol), and CH2Cl2 ,15ml), followed by CC ,toluene/acetone 20 :1): 38 ,0.30 g, 69%).
[a]D ˆ ‡115.4 ,c ˆ 1.31, CHCl3). 1H-NMR ,CDCl3): 5.81 ,t, J,3,4) ˆ 9.8, HÀC,3)); 4.96 ,d, J,1,2) ˆ 3.8,
HÀC,1)); 4.94 ,d, J,1',2') ˆ 1.0, HÀC,1')); 4.85, d, J ˆ À11.3, 1 H, PhCH2); 4.84 ,dd, J,2,3) ˆ 10.0, HÀC,2));
4.83 ,d, J ˆ À11.2, 1 H, PhCH2); 4.82 ,d, J ˆ À10.8, 1 H, PhCH2); 4.81 ± 4.78 ,m, HaÀC,6')); 4.78 ± 4.67 ,m, 4 H,
PhCH2); 4.56 ,d, J ˆ À12.5, 1 H, PhCH2); 4.52 ,d, J ˆ À12.2, 1 H, PhCH2); 4.50 ,d, J ˆ 12.1, 1 H, PhCH2); 4.18 ±
4.06 ,m, HÀC,5')); 4.12 ,t, J,4,5) ˆ 9.8, HÀC,4)); 3.82 ± 3.73 ,m, HbÀC,6')); 3.76 ± 3.62 ,m, HÀC,5)); 3.72
,t, J,4',5') ˆ 9.4, HÀC,4')); 3.48 ± 3.38 ,m, HÀC,2'), HÀC,3'), HaÀC,6)); 3.37 ± 3.24 ,m, HbÀC,6)); 3.28
,d, J ˆ À12.7, 1 H, COCH2); 3.15, d, J ˆ À12.7, 1 H, COCH2). 13C-NMR ,CDCl3): 165.6, 165.4, 164.4 ,CO); 93.9
,C,1)); 93.3 ,J,1',HÀC,1')) ˆ 168.8, C,1')); 79.3 ,C,3')); 75.5, 75.2, 73.6 ,C,2'), C,4), C,4')); 73.4 ,C,2)); 69.0
,C,5')); 68.8 ,C,5)); 68.7 ,C,3)); 68.6 ,C,6)); 64.9 ,C,6')); 43.1 ,COCH2). Anal. calc. for C57H56O14 ,965.07):
C 70.94, H 5.85; found: C 71.13, H 5.90.

Helvetica Chimica Acta ± Vol. 83 ,2000)
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b) As described for 6 ,Exper. b), with 37 ,0.43 g, 0.42 mmol), NIS ,0.47 g, 2.10 mmol), Me3SiOTf ,20 ml,
0.11 mmol), and MeCN ,12 ml), followed by CC ,toluene/acetone 20 :1): 38 ,0.28 g, 69%).
c) As described for 18 ,Exper. e), with 37 ,0.47 g, 0.46 mmol), 4-Š molecular sieves ,1.3 g) and MeOTf
,0.40 ml, 3.7 mmol), followed by CC ,toluene/acetone 20 :1): 38 ,0.39 g, 68%).
d) As described for 18 ,Exper. f), with 37 ,0.50 g, 0.49 mmol), 4-Š molecular sieves ,1.2 g), MeOTf
,0.27 ml, 2.45mmol), and MeCN ,15ml), followed by CC ,toluene/acetone 20 :1): 38 ,0.34 g, 71%).
Benzyl O-'6-O-Benzoyl-2,3,4-tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2,3-di-O-benzoyl-6-O-benzyl-a-
d-glucopyranoside ,39). As described for 7, with 38 ,107 mg, 0.11 mmol), NaOMe in MeOH ,8 ml), BzCl ,77 ml,
0.66 mmol), and pyridine ,8 ml): 39 ,89 mg, 73%). [a]D ˆ ‡57.7 , c ˆ 0.52, CHCl3). 1H-NMR ,CDCl3): 6.07
,dd, J,3,4) ˆ 8.9, HÀC,3)); 5.32 ,d, J,1,2) ˆ 3.7, HÀC,1)); 5.16 ,dd, J,2,3) ˆ 10.3, HÀC,2)); 5.14 ,d, J,1',2') ˆ
1.7, HÀC,1')); 4.87 ,d, J ˆ À10.8, 1 H, PhCH2); 4.79 ,d, J ˆ À12.4, 1 H, PhCH2); 4.61 ,d, J ˆ À11.6, 1 H,
PhCH2); 4.59 ,s, 1 H, PhCH2); 4.58 ,d, J ˆ À10.6, 1 H, PhCH2); 4.57 ,d, J ˆ À12.1, 1 H, PhCH2); 4.55 ± 4.52
,m, 1 H, PhCH2); 4.51 ,dd, J,6a',6b') ˆ À11.8, 1 H, HaÀC,6')); 4.45± 4.41 , m, 2 H, HbÀC,6'), PhCH2); 4.13
,t, J,4',5') ˆ 9.4, HÀC,4')); 4.06 ± 4.00 ,m, 2 H, J,5,6b) ˆ 2.0, HÀC,5), PhCH2); 4.03 ,t, J,4,5) ˆ 9.5, HÀC,4));
3.96 ± 3.91 ,m, J,5',6a') ˆ 3.1, HÀC,3'), HÀC,5')); 3.89 ± 3.83 ,m, J,6a,6b) ˆ À11.1, HaÀC,6)); 3.72
,dd, HbÀC,6)); 3.60 ,t, J,2',3') ˆ 2.4, HÀC,2')). 13C-NMR ,CDCl3): 166.3, 165.6, 165.5 ,PhCO); 100.2
,J,1',HÀC,1')) ˆ 171.8, C,1')); 95.1 ,C,1)); 79.6 ,C,3')); 76.7 ,C,4')); 75.6 ,C,2')); 75.1 ,PhCH2); 73.7
,C,4)); 73.5,Ph CH2); 72.9 ,C,3)); 72.5,Ph CH2); 71.8 ,C,2)); 71.6 ,PhCH2); 71.4 ,C,5')); 70.2 ,C,5)); 69.8
,PhCH2); 68.6 ,C,6)); 63.5,C,6 ')). Anal. calc. for C68H64O14 ,1105.25): C 73.90, H 5.84; found: C 73.95, H 5.83.
Benzyl 2,3-Di-O-benzoyl-6-O-[3-'ethyl 2,3,4-tri-O-benzyl-1-thio-a-d-mannopyranosid-6-O-yl)-1,3-dioxo-
propyl]-a-d-glucopyranoside ,41). As described for 4a, with 34 [41] ,2.24 g, 3.86 mmol), 40 [53] ,2.03 g,
4.24 mmol), DCC ,0.88 g, 4.27 mmol), DMAP, and CH2Cl2 ,60 ml): 41 ,2.88 g, 65%). [a]D ˆ ‡94.5, c ˆ 1.0,
CHCl3). 1H-NMR ,CDCl3): 5.82 ,t, J,3,4) ˆ 9.3, HÀC,3)); 5.31 ,d, J,1',2') ˆ 1.0, HÀC,1')); 5.24 ,br. d,
HÀC,2)); 5.20 ,d, J,1,2) ˆ 3.7, HÀC,1)); 4.91 ,d, J ˆ À10.8, 1 H, PhCH2); 4.75, d, J ˆ À12.4, 1 H, PhCH2); 4.68
,d, J ˆ À12.5, 1 H, PhCH2); 4.62 ,d, J ˆ À12.4, 1 H, PhCH2); 4.58 ± 4.50 ,m, J,5,6a) ˆ 3.9, J,6a,6b) ˆ À12.1, 5H,
PhCH2, HaÀC,6)); 4.47 ± 4.39 ,m, J,5',6a') ˆ 5.0, J,6a',6b') ˆ À11.8, 2 HÀC,6')); 4.34 ,dd, J,5,6b)ˆ 2.4,
HbÀC,6)); 4.20 ± 4.15, m, HÀC,5')); 4.04 ,ddd, HÀC,5)); 3.90 ± 3.79 ,m, J,4,5) ˆ 9.9, HÀC,2'), HÀC,3'),
HÀC,4'), HÀC,4)); 3.47 ,br. d, COCH2); 3.36 ,d, J,4,OH) ˆ 5.1, OH); 2.62 ± 2.48 ,m, MeCH2S); 1.22 ,t, J ˆ 7.4,
MeCH2S). 13C-NMR ,CDCl3): 167.0, 166.4, 166.2, 165.7 ,CO); 95.3 ,C,1)); 81.9 ,C,1')); 80.1 ,C,3')); 76.0
,C,2')); 75.1 ,PhCH2); 74.4 ,C,4')); 73.7 ,C,3)); 72.0 ,PhCH2); 71.9 ,PhCH2); 71.2 ,C,2)); 70.0 ,C,4), C,5'));
69.8 ,PhCH2); 69.2 ,C,4)); 64.5,C,6)); 63.8 ,C,6 ')); 41.2 ,COCH2); 25.4 ,MeCH2S); 14.9 ,MeCH2S). Anal.
calc. for C59H60O15S ,1041.18): C 68.06, H 5.81, S 3.08; found: C 68.34, H 5.90, S 3.05.
Benzyl O-'2,3,4-Tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2,3-di-O-benzoyl-a-d-glucopyranoside 6,6'-
Malonate ,42). a) As described for 6 ,Exper. a), with 41 ,0.37 g, 0.36 mmol), NIS ,0.41 g, 1.80 mmol),
Me3SiOTf ,16 ml, 0.09 mmol), and CH2Cl2 ,15ml), followed by CC ,toluene/acetone 30 :1): 42 ,354 mg, 72%).
[a]D ˆ ‡91.1 ,c ˆ 1.03, CHCl3). 1H-NMR ,CDCl3): 6.13 ,t, J,3,4) ˆ 9.3, HÀC,3)); 5.30 ,d, J,1,2) ˆ 3.8,
HÀC,1)); 5.28 ,s, HÀC,1')); 5.12 ,dd, J,2,3) ˆ 10.3, HÀC,2)); 4.83 ± 4.77 ,m, J,6a',6b') ˆ À10.7, HaÀC,6'));
4.78 ,d, J ˆ À11.5, 1 H, PhCH2); 4.74 ,d, J ˆ À12.5, 1 H, PhCH2); 4.69 ± 4.62 ,m, 2 H, PhCH2, HaÀC,6)); 4.59
,d, J ˆ À12.5, 1 H, PhCH2); 4.47 ,2d, J ˆ À11.9, 1 H, PhCH2); 4.43 ,s, 1 H, PhCH2); 4.38 ,t, J,3,4) ˆ 9.6,
HÀC,4)); 4.13 ± 4.07 ,m, HbÀC,6)); 3.97 ,d, J ˆ À11.7, 1 H, PhCH2); 3.90 ,br. d, HbÀC,6')); 3.69 ± 3.59
,m, J,3',4') ˆ 6.8, HÀC,2'), HÀC,3'), HÀC,5')); 3.58 ,d, J ˆ À13.6, 1 H, COCH2); 3.48 ,dd, J,4',5') ˆ 9.3,
HÀC,4')); 3.39 ,d, J ˆ À15.6, 1 H, COCH2). 13C-NMR ,CDCl3): 166.5 ,CO); 165.6 ,2 C, CO); 165.2 ,CO); 99.7
,J,1',HÀC,1')) ˆ 172.5, C,1')); 95.4 ,C,1)); 78.4 ,C,3')); 76.6 ,C,2')); 74.7 ,C,4')); 73.9 ,PhCH2); 73.8 ,C,5'));
73.4 ,C,3)); 73.0 ,PhCH2); 72.9 ,C,4)); 72.0 ,PhCH2, C,2)); 70.3 ,PhCH2); 67.8 ,C,5)); 64.1 ,C,6')); 63.3
,C,6)); 42.5,CO CH2). Anal. calc. for C57H54O15 ,979.05): C 69.93, H 5.56; found: C 70.05, H 5.50.
b) As described for 6 ,Exper. b), with 41 ,0.42 g, 0.40 mmol), NIS ,0.45g, 2.02 mmol), Me 3SiOTf ,19 ml,
0.10 mmol) and MeCN ,15ml), followed by CC ,toluene/acetone 30 :1): 42 ,268 mg, 68%).
c) As described for 18 ,Exper. e), with 41 ,0.41 g, 0.39 mmol), 4-Š molecular sieves ,1.02 g), and MeOTf
,0.21 ml, 1.95mmol), followed by CC ,toluene/acetone 25:1): 42 ,238 mg, 62%).
d) As described for 18 ,Exper. f), with 41 ,0.55 g, 0.53 mmol), 4-Š molecular sieves ,1.38 g), MeOTf
,0.29 ml, 2.65mmol), and MeCN ,25ml), followed by CC ,toluene/acetone 25:1): 42 ,0.34 g, 66%).
Benzyl O-'6-O-Benzoyl-2,3,4-tri-O-benzyl-a-d-mannopyranosyl)-'1 ! 4)-2,3,6-tri-O-benzoyl-a-d-gluco-
pyranoside ,43). As described for 7, with 42 ,176 mg, 0.18 mmol), NaOMe in MeOH ,5ml), BzCl ,105 ml,
0.9 mmol), and pyridine ,5ml): 43 ,151 mg, 75%). [a]D ˆ ‡29.7 ,c ˆ 0.88, CHCl3). 1H-NMR ,CDCl3): 6.10
,t, J,3,4) ˆ 9.4, HÀC,3)); 5.46 ,d, J,1',2') ˆ 1.5, HÀC,1')); 5.08 ,m, J,1,2) ˆ 3.6, HÀC,1)); 5.07 ,dd, J,2,3) ˆ
10.0, HÀC,2)); 4.88 ,d, J ˆ À10.9, 1 H, PhCH2); 4.74 ± 4.69 ,m, 5 H, 2 HÀC,6'), PhCH2); 4.65,br. d, 2 H,

2674
Helvetica Chimica Acta ± Vol. 83 ,2000)
PhCH2); 4.58 ,d, J ˆ À10.9, 1 H, PhCH2); 4.52 ± 4.45 ,m, 1 H, PhCH2); 4.49 ,br. dd, J,5,6a) ˆ 4.6, J,6a,6b) ˆ
À11.7, 2 HÀC,6)); 4.13 ,t, J,4,5) ˆ 9.4, HÀC,4)); 4.12 ± 4.07 ,m, HÀC,4'), HÀC,5')); 4.09 ± 4.03 ,m, HÀC,5));
4.03 ± 3.95, m, HÀC,3')); 3.97 ± 3.92 ,m, HÀC,2')). 13C-NMR ,CDCl3): 166.5, 166.3, 166.2, 166.1 ,PhCO); 99.3
,J,1',HÀC,1')) ˆ 172.0, C,1')); 95.1 ,C,1)); 79.0 ,C,3')); 75.4 ,C,3)); 75.3 ,C,2')); 74.9 ,PhCH2); 74.7 ,C,4));
74.2 ,C,4')); 72.3, 72.2 ,PhCH2); 71.6 ,C,2)); 71.5,C,5 ')); 69.7 ,PhCH2); 68.5,C,5)); 63.8 ,C,6)); 63.2 ,C,6 ')).
Anal. calc. for C68H62O15 ,1119.24): C 72.97, H 5.58; found: C 73.05, H 5.60.
We thank Dr. H. Schmickler, I. Hoven, and C. Schmitz for performing NMR spectroscopy and elemental
analyses. This work was financially supported by the Deutsche Forschungsgemeinschaft and the Fonds der
Chemischen Industrie.
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Received April 14, 2000