Synthesis of a fucose hexasaccharide

Article abstract of DOI:10.1055/s-1998-1994

The facile synthesis of a homogeneously α,1 → 2 interglycosidically linked fucose hexasaccharide 17 via the disaccharide methylthio donor 10 is reported. Compound 10 in turn was synthesised from a monosaccharide thiomethyl precursor in three consecutive s

Full text of DOI:10.1055/s-1998-1994

56
Papers
SYNTHESIS
Synthesis of a Fucose Hexasaccharide
Michael Ludewig, Joachim Thiem
Institut für Organische Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany
Fax: +49(40)41234325; E-mail: thiem@chemie.uni-hamburg.de
Received 22 May 1997; revised 15 August 1997
thio-b-L-fucopyranoside (6).5 However, we observed de-
creasing yields for glycosylation of higher oligomers and
poor stereospecificity with stronger activation methods.
The facile synthesis of a homogeneously a,1 ® 2 interglycosidically
linked fucose hexasaccharide 17 via the disaccharide methylthio
donor 10 is reported. Compound 10 in turn was synthesised from a
monosaccharide thiomethyl precursor in three consecutive steps.
Glycosylation employing thioglycosides activated by copper bro-
mide/tetrabutylammonium bromide proved to be selective for the
formation of a-glycosidic linkages.
Therefore, a convergent synthesis from disaccharide
building blocks seemed to be more suitable. Toth et al.
synthesised a fucobiose thiomethyl donor as an example
for the so called “armed-disarmed” strategy,6 but have not
yet applied it in any synthesis. Since this concept required
an unfavourable protection group pattern, we synthesised
a disaccharide methylthio donor from methyl 3,4-O-iso-
propylidene-1-thio-b-L-fucopyranoside (1) by simple in-
troduction of a TBDMS protecting group at the 2 position
and treatment of the completely protected compound 2
with bromine to obtain the corresponding bromide 4. The
glycosylation of thioglycoside 15c was carried out in the
presence of tetrabutylammonium bromide. The TBDMS
Recently, results from in vitro and in vivo tests1 have
shown that adhesion of disseminated tumour cells to or-
gan-specific lectins2 could be prevented by specific sugars.
In the case of mice lung cells, the use of the sulfated fucose
polymer fucoidin was found to be advantageous compared
to fucose itself. Since the cluster effect is discussed as an
enhancing factor of lectin inhibition,3 we are investigating
several aspects, such as oligomerisation, clustering and
glycopeptide syntheses of fucose conjugates.
Linear fucose oligomers were previously obtained by protecting group was not completely stable under these
Flowers et al. using the Koenigs–Knorr reaction4 and by glycosylation conditions and cross-coupling products
Matta et al. performing a CuBr2/Bu4NBr catalysed thiogly- were obtained. Nevertheless, the disaccharide donor 10
coside glycosylation with consecutive chain elongation by could be isolated in 44% after treating deprotected 10 with
methyl 3,4-O-isopropylidene-2-O-(p-methoxybenzyl)-1- TBDMSCl.
Scheme 1

January 1998
SYNTHESIS
57
The preparation of the disaccharide acceptor was carried
out with benzyl 3,4-O-isopropylidene-a-L-fucopyrano-
side (8) and the p-methoxybenzyl protected donor 6, using
CuBr2/Bu4NBr as activator. After oxidative deprotection
of the 2¢-position with DDQ traces of the b-glycosylation
product could be removed easily by column chromatogra-
phy.
The tetrasaccharide 12 was obtained from the disaccha-
ride donor 10 and the disaccharide acceptor 9 in the pres-
ence of CuBr2/Bu4NBr in a moderate yield (54%). The
removal of 5% b-glycosylation byproduct was carried out
after deprotection of the 2¢-position. Another glycosyla-
tion step without formation of any b-glycoside led to the
hexasaccharide 15 in 33% yield. Compound 15 was quan-
titatively deprotected to give the hexafucoside 17.
By substitution of the TBDMS protecting group with a
TBDPS group the moderate yields could not be improved.
Activation of the thioglycosides with NIS led to better
overall yields, but unfavourably changed the a/b-ratio to
about 3:2.
Similar results were obtained using the trichloroacetimi-
date glycosylation method. After acetylation of 9 at the 2¢-
position the benzyl group could be removed with a large
excess of catalyst and the comparatively stable disaccha-
ride b-imidate 20 formed stereospecifically. However, in
contrast to reports about uniform a-formation employing
monosaccharide imidates,6 glycosylation with 9 as accep-
tor in the presence of TMSOTf resulted in a 1:1-mixture
of the a- and b-linked tetrasaccharides (21).
In conclusion, contrary to other methods glycosylation
employing thioglycosides activated by CuBr2/Bu4NBr
proved to be selective for the formation of a-glycosidic
linkages.
NMR spectra were recorded with a Bruker AMX-400 spectrometer,
reference TMS. Some assignments were made with support of 1H1H-
and 1H13C-COSY experiments. Optical rotations were measured with
a Perkin–Elmer polarimeter 243. TLC was performed on silica gel
Scheme 2

58
Papers
SYNTHESIS
coated foil (silica gel 60 F254 Merck, Darmstadt). Preparative column
chromatography was performed with silica gel 60 (63–200 mm,
Merck, Darmstadt). iPr denotes (CH3)2C.
Benzyl 3,4-O-Isopropylidene-2-O-p-methoxybenzyl-a-L-fucopyr-
anosyl-(1® 2)-3,4-O-isopropylidene-a-L-fucopyranoside (7):
Compounds 6 (1.0 g, 2.82 mmol) and 8 (0.7 g, 2.38 mmol) were con-
verted together with Bu4NBr (2.4 g, 7.44 mmol), CuBr2 (1.68 g, 7.52
mmol), molecular sieves (3 g) and 30 mL solvent according to the
general glycosylation procedure. Column chromatography (toluene/
EtOAc 5:1) furnished 7 (1.31 g, 2.17 mmol, 91%) as a colourless syr-
up containing 15% b-anomer.
Thioglycoside Activation with Copper Bromide/Tetrabutylam-
monium Bromide; General Procedure:
Donor and acceptor were evaporated three times with toluene and
stirred together with freshly activated molecular sieves (4Å) in DMF/
CH2Cl2 1:1 for 1h under Ar. Bu4NBr was added, and after 1 h the re-
action was started with CuBr2 and carried out for at least 1 d at r.t.
Subsequently, the solution was filtered over Celite, diluted with
EtOAc, washed with sat. NaHCO3 (same vol. 3 ´) and sat. brine
(same vol., 1 ´), dried, evaporated and purified by flash column chro-
matography.
7a: [a]D20 –144.9 (c = 1.0, CHCl3).
1H NMR (CDCl3): d = 1.28 (d, 3H, J5¢,6¢ = 6.6 Hz, H-6’), 1.31 (d, 3H,
J5,6 = 7.1 Hz, H-6), 1.34 (s, 3H, iPr), 1.35 (s, 3H, iPr), 1.38 (s, 3H, iPr),
i
1.51 (s, 3H, Pr), 3.48 (dd, 1H, J1¢,2¢ = 3.5 Hz, J2¢,3¢ = 8.2 Hz, H-2¢),
3.76 (s, 3H, OMe), 3,80 (dd, 1H, J1,2 = 3.5 Hz, J2,3 = 8,1 Hz, H-2),
4.04 (dd≈m, 1H, J3,4 = 5.6 Hz. J4,5 = 2.5 Hz, H-4), 4.07 (dd≈m, 1H,
Methyl 2-O-tert-Butyldimethylsilyl-3,4-O-isopropylidene-1-thio-
b-L-fucopyranoside (2):
J
4¢,5¢ = 2.5 Hz, H-4¢), 4.12 (dq, 1H, J4,5 = 2.5 Hz, J5,6 = 6.6 Hz, H-5),
4.32 (dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5.6 Hz, H-3), 4.40 (dd, 1H, J2¢,3¢
=
To a stirred solution of 15c (1.0g, 4.27 mmol) in anhyd DMF (6 mL)
imidazole (680 mg, 10 mmol) and TBDMSCl (1g, 6.9 mmol) was add-
ed. After 12 h DMF was evaporated in vacuo, the residue diluted with
CH2Cl2 (30 mL), washed with sat. Na2CO3 (2 ´ 50 mL) and brine
(50 mL), dried and concentrated in vacuo to give 1.48g (4.23 mmol,
99%) of white crystalline product; [a]D20 + 1.7 (c = 1.0, CHCl3).
8.2 Hz, J3¢,4¢ = 5.4 Hz, H-3¢), 4.49 (dq, 1H, J4¢,5¢ = 2.5 Hz, J5¢,6¢ = 6.6
Hz, H-5¢), 4.55 (d, 1H, JBn = 12.2 Hz, Bn), 4.61 (dd≈s, 2H, Bn), 4.68
(d, 1H, JBn = 12.2 Hz, Bn), 4.82 (d, 1H, J1¢,2¢ = 3.5 Hz, H-1¢), 4.98 (d,
1H, J1,2 = 3.5 Hz, H-1), 6.76 (m, 2H, BnOMe), 7.17 (m, 2H, BnOMe),
7.3 (m, 5H, Bn).
13C NMR (CDCl3): d = 16.16 (C-6), 16.29 (C-6), 26.47 (iPr), 26.49
(iPr), 28.34 (iPr), 28.40 (iPr), 55.26 (OMe), 63.22 (C-5¢), 63.43 (C-5),
70.05 (Bn), 71.35 (Bn), 73.76 (C-2), 74.65 (C-3), 75.31 (C-2¢), 75.81
(C-3¢), 76.22 (C-4, C-4¢), 95,01 (C-1¢), 95.25 (C-l), 108,67 (iPr),
l08.73 (iPr), 113.67 (BnOMe), 127.00-130.00 (Bn,BnOMe), 137.21
(BnOMe), 159.15 (BnOMe).
1H NMR (CDCl3): d = 0.14 (2 ´ s, 6H, SiMe2), 0.90 (s, 9H, tBu), 1.35
(s, 3H, iPr), 1.39 (d, 3H, J5,6 = 6.5 Hz, H-6), 1 .51 (s, 3H, iPr), 2.18 (s,
3H, SMe), 3.58 (dd, 1H, J1,2 = 9.1 Hz, J2,3 = 6.1 Hz, H-2), 3.82 (dq,
1H, J4,5 = 2.0 Hz, J5,6 = 6.5 Hz, H-5), 3.96 (dd ≈ t, 1H, J2,3 = J3,4 = 6.1
Hz, H-3), 4.03 (dd, 1H, J3,4 = 5.6 Hz, J4,5 = 2.0 Hz, H-4), 4.17 (d, 1H,
J1,2 = 9.2 Hz, H-l).
7b:
1H NMR (CDCl3): d = 3.37 (dd, 1H, H-2¢), 3.95 (dd, 1H, H-4), 3.99
(dd, 1H, H-2), 4.19 (dq, 1H, H-5), 4.76 (d, 1H, H-1¢).
C16H32O4SiS
(348.57)
calcd
found
C
55.13
55.00
H
9.25
9.15
C33H44O10 calcd
C
65.98
65.86
H
7.38
7.49
Methyl 2-O-tert-Butyldiphenylsilyl-3,4-O-isopropylidene-1-thio-
b-L-fucopyranoside (3):
(600.71)
found
A solution of 1 (1.0g, 4.27 mmol), imidazole (680 mg, 10 mmol) and
TBDPSCl (1.8 mL, 7.03 mmol) in anhyd DMF (6 mL) was stirred for
12 h. Then, DMF was evaporated in vacuo, the residue diluted with
CH2Cl2 (30 mL), washed with sat. Na2CO3 (2 ´ 50 mL) and brine
(50 mL), dried and concentrated in vacuo. Column chromatography
(petroleum ether/EtOAc 10:1) gave 1.95g (3.91 mmol, 92%) of a co-
lourless syrup; [a]D20 + 0.4 (c = 1.0, CHCl3).
Benzyl
3,4-O-Isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-O-
isopropylidene-a-L-fucopyranoside (9):
A stirred solution of 7 (870 mg, 1.45 mmol) in CH2Cl2/H2O (25 mL,
18:1) was treated with 2,3-dicyano-5,6-dichloro-p-benzoquinone
(DDQ, 490 mg, 2.1 mmol). After 40 min the solids were filtered off
and the solution was washed with aq Na2CO3 (2 ´ 40 mL) and brine
(40 mL). The solution was dried, the solvents evaporated and flash
chromatography (petroleum ether/EtOAc 1.75:1) led to product 9
(509 mg, 1.06 mmol, 73%), and the respective, b-linked disaccharide
(89 mg, 0.19 mmol, 13%).
1H NMR (CDCl3): d = 1.07 (s, 9H, tBu), 1.16 (s, 3H, iPr), 1.21 (s, 3H,
iPr), 1.32 (d, 3H, J5,6 = 6.6 Hz, H-6), 1.84 (s, 3H, SMe), 3.72 (dd, 1H,
J1,2 = 8.1 Hz, J2,3 = 5.8 Hz, H-2), 3.87 (dq, 1H, J4,5 = 2.0 Hz, J5,6 = 6.6
Hz, H-5), 4.01 (dd, 1H, J3,4 = 6.1 Hz, J4,5 = 2.0 Hz, H-4), 4.19 (dd ≈ t,
1H, J2,3 = J3,4 = 6.1 Hz, H-3), 4.17 (d, 1H, J1,2 = 8.1 Hz, H-l), 7.37
(m, 6H, Ph), 7.71 (m, 4H, Ph).
9a: [a]D20 –190.0 (c = 1.0. CHCl3).
1H NMR (CDCl3): d = 1.30 (d, 3H, J5¢,6¢ = 6.6 Hz, H-6¢), 1.45 (s, 3H,
iPr), 1.46 (d, 3H, H-6), 1.46 (s, 3H, iPr), 1.51 (s, 3H, iPr), 1.53 (s, 3H,
iPr), 2.20 (d, 1H, JOH,2¢ = 9.5 Hz, OH-2). 3.64 (ddd, 1H, J1¢,2¢ = 3.9 Hz,
C26H36O4SiS
(472.71)
calcd
found
C
66.06
66.94
H
7.68
7.71
J
2¢,3¢ = 7.1 Hz, JOH,2¢ = 9.5 Hz, H-2¢), 3.80 (dd, 1H, J1,2 = 3.5 Hz, J2.3
= 8.1 Hz, H-2), 4.05 (dd ≈ m, 1H, J4,5 = 2.5 Hz, H-4), 4.06 (dd ≈ m,
1H, J4¢,5¢ = 2.5 Hz, H-4¢), 4.12 (dd, 1H, H-3¢), 4.13 (dq≈m, 1H, H-5),
4.24 (dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5.4 Hz, H-3), 4.44 (dq, 1H, J4¢,5¢
Methyl 3,4-O-Isopropylidene-2-O-(p-methoxybenzyl)-1-thio-b-L-
fucopyranoside (6):
=
A solution of 1 (1.44 g, 6.14 mmol) in anhyd DMF (30 mL) under Ar
was cooled to 0 °C and NaH (0.3 g, 10 mmol, 80% in paraffin) was
added. After hydrogen formation decreased, p-methoxybenzyl chlo-
ride (1.16 g, 7.41 mmol) was added dropwise, the solution was stirred
for another 6 h and warmed up to r.t. The excess of NaH was destroyed
by MeOH (2 mL), the mixture evaporated in vacuo to dryness, diluted
with CH2Cl2, washed with sat. Na2CO3 (50 mL), H2O (50 mL) and
brine (50 mL), dried and concentrated under reduced pressure. Col-
umn chromatography (petroleum ether/EtOAc 5:1) gave 2.12 g
(5.98 mmol, 97%) of a bright yellow syrup;[a]D20–3.4 (c = 1.0, CHCl3)
1H NMR (CDCl3): d = 1.37 (s, 3H, iPr), 1.39 (d, 3H, J5,6 = 6.6 Hz, H-
6), 1.48 (s, 3H, iPr), 2.18 (s, 3H, SMe), 3.42 (dd, 1H, J1,2 = 9.7 Hz, J2,3
= 6.6 Hz, H-2), 3.79 (s≈m, 3H, OMe), 3.80 (dq≈m, 1H, J4,5 = 2.0 Hz,
J5,6 = 6.6 Hz, H-5), 4.05 (dd, 1H, J3,4 = 5.6 Hz, J4,5 = 2.0 Hz, H-4),
4.18 (dd≈t, 1H, J2,3 = J3,4 = 6.1 Hz, H-3), 4.26 (d, 1H, J1,2 = 9.7 Hz,
H-1), 4.68 (d, 1H, JBn = 11.2 Hz, Bn), 4.79 (d, 1H, JBn = 11.2 Hz, Bn),
6.87 (m, 2H, Bn), 7.35 (m, 2H, Bn).
2.0 Hz, J5¢,6¢ = 6.6 Hz, H-5¢), 4.50 (d, 1H, JBn = 11.7 Hz, Bn), 4.70 (d,
1H, JBn = 11.7 Hz, Bn), 4.80 (d, 1H, J1¢,2¢ = 3.9 Hz, H-1¢), 4.97 (d, 1H,
J1,2 = 3.5 Hz, H-1), 7.34 (m, 5H, Bn).
13C NMR (CDCl3): d = 16. 16 (C-6¢), 16.31 (C-6), 26.26 (iPr), 26.44
(iPr), 28.18 (iPr), 28.25 (iPr), 63.35 (C-5¢), 63.55 (C-5), 69.87 (Bn),
70.13 (C-2¢), 73.59 (C-2), 74.48 (C-3), 75.87 (C-4¢), 76.16 (C-4),
76.88 (C-3¢), 94.79 (C-l), 96. 18 (C-1¢), 108.99 (iPr), 109.05 (iPr),
128.20 (Bn), 128.32 (Bn), 128.63 (Bn), 136.82 (Bn).
C25H36O9
(480.56)
9b:
calcd
found
C
62.48
61.99
H
7.55
7.59
1H NMR (CDCl3): d = 1.31 (d, 3H, J5,6 = 6.5 Hz, H-6), 1.34 (s, 3H,
iPr), 1.35 (d ≈ m, 3H, H-6¢), 1.37 (s, 3H, iPr), 1.51 (s, 3H, iPr), 1.55 (s,
i
3H, Pr), 3.57 (dd≈t, 1H, J1¢,2¢ = J2¢,3¢ = 7.8 Hz, H-2¢), 3.81 (dq, 1H,
J4¢,5¢ = 2. 1 Hz, J5¢,6¢ = 6.5 Hz, H-5¢), 3.87 (dd, 1H, J1,2 = 3.5 Hz, J2,3 =
8.6 Hz, H-2), 3.98 (dd, 1H, J3¢,4¢ = 5.6 Hz, J4¢,5¢ = 2.1 Hz, H-4¢), 4.03
(dd, 1H, J4¢,5¢ = 5.1 Hz, J4,5 = 2.5 Hz, H-4), 4.07 (dd, 1H, J2¢,3¢ = 7.1
Hz, J3¢,4¢ = 5.5 Hz, H-3¢), 4.12 (dq, 1H, J4,5 = 2.5 Hz, J5,6 = 6.5 Hz, H-
C18H26O5S
(354.46)
calcd
found
C
60.99
60.99
H
7.39
7.58

January 1998
SYNTHESIS
59
raphy yielded 568 mg (0.86 mmol, 21%) of product, byproducts were
5), 4,35 (dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5.1 Hz, H-3), 4,47 (d, 1H, J1¢,2¢
8.1 Hz, H-1¢), 4.59 (d, 1H, JBn = 12.2 Hz, Bn), 4.69 (d, 1H, JBn = 12.2
Hz, Bn), 5.03 (d, 1H, J1,2 = 3,5 Hz, H-1), 7.32 (m, 5H, Bn).
13C NMR (CDCl3): d = 16.25 (C-6), 16.59 (C-6¢), 26.36 (iPr), 26.46
(iPr), 28.26 (iPr), 28.30 (iPr), 63.27 (C-5), 69.24 (C-5¢), 69.96 (Bn),
73.57 (C-2¢), 75.44 (C-3), 76.30 (C-4?), 76.34 (C-4?), 76.69 (C-2),
78.74 (C-3¢), 97.99 (C-1), 102.57 (C-1¢), 108.88 (iPr), 109.77 (iPr),
127.73 (Bn), 127.82 (Bn), 128.37 (Bn), 137.44 (Bn).
=
not isolated; [a]D20 –62.5 (c = 1.0, CHCl3).
1H NMR (CDCl3): d = 1.08 (s, 9H, tBu), 1.14 (s, 3H, iPr), 1.25 (d, 3H,
J5,6 = 6.6 Hz, H-6), 1.27 (s, 3H, iPr), 1.35 (d, 3H, J5,6 = 6.6 Hz, H-6),
1.36 (s, 3H, iPr), 1.39 (s, 3H, iPr), 1.94 (s, 3H, SMe), 3.71 (dd, 1H, J1.2
= 8.6, J2,3 = 6.1 Hz, H-2), 3.79 (dq, 1H, J4,5 = 2.0 Hz, J5,6 = 6.6 Hz,
H-5), 3.85 (dd, 1H, J1¢,2¢ = 3.5 Hz, J2¢,3¢ = 7.1 Hz, H-2¢), 4.02 (dd, 1H,
J3,4 = 6.1 Hz, J4,5 = 2.0 Hz, H-4), 4.06 (dd, 1H, J3¢,4¢ = 5.6 Hz, J4¢,5¢
2.5 Hz, H-4¢), 4.09 (d, 1H, J1,2 = 8.6 Hz, H-1), 4.16 (dd≈t, 1H, J2,3
=
=
J3,4 = 6,1 Hz, H-3), 4.30 (dd, 1H, J2¢,3¢ = 7.1 Hz, J3¢,4¢ = 5.6 Hz, H-3¢),
Methyl 2-O-tert-Butyldimethylsilyl-3,4-O-isopropylidene-a-L-fu-
copyranosyl-(1 ® 2)-3,4-O-isopropylidene-1-thio-b-L-fucopyra-
noside (10):
4.49 (dq, 1H, J4¢,5¢ = 2.5 Hz, J5¢,6¢ = 6.6 Hz, H-5¢), 5.09 (d, 1H, J1¢,2¢
3.5 Hz, H-l¢), 7.38 (m, 6H, Ph), 7.72 (m, 4H, Ph).
=
13C NMR (CDCl3): d = 12.33 (SMe), 16.20 (C-6), 16.71 (C-6), 19.61
(tBu, q), 26.22 (iPr), 26.38 (iPr). 27,00 (tBu, s), 27.72 (tPr), 27.82 (iPr),
63.12 (C-5¢), 71.71 (C-5), 71.76 (C-2¢), 73.13 (C-2), 76.03 (C-4¢),
76.11 (C-4), 76.43 (C-3¢), 78.24 (C-3), 83.52 (C-1), 96.88 (C-1¢),
108.55 (iPr), 109.43 (iPr), 127–l37 (Ph).
1 (1240 mg, 5.29 mmol) was stirred with activated molecular sieves
(4 g) in DMF/CH2Cl2 (2:1, 22 mL) for 1 h. To a solution of 2
(1470 mg, 4.22 mmol) in CH2Cl2 (20 mL) activated molecular sieves
(0.5 g) was added, and after 1 h stirring the mixture was cooled to 0 °C
and treated with abs bromine in CH2Cl2 (1:24, 5.53 mL, 4.3 mmol).
After 20 min the solvent was evaporated at 0°C under reduced pres-
sure and codistilled with CH2Cl2 until the orange colour disappeared.
The crude residue was suspended in CH2Cl2 (7 mL) and together with
Bu4NBr (3.87 g, 12 mmol) added to the solution containing 1. After
stirring for 24 h workup was performed following the genera1 gly-
cosylation procedure. Column chromatography (petroleum ether/
EtOAc 7:1) furnished 731 mg (1.37 mmol, 32%) product as well as
211 mg (0.50 mmol, 12%) of product deprotected at position 2. This
could be protected with TBDMSCl (see 3). Further starting material
(2, 37%, anomeric mixture and 1, 9%, anomeric mixture), b-linked
disaccharide (108 mg, 5%) and the corresponding trisaccharide (32l
mg, 11%) were isolated.
C35H50O8SSi calcd
(658.92) found
C
63.80
63.84
H
7.65
7.40
Benzyl 2-O-tert-Butyldimethylsilyl-3,4-O-isopropylidene-a-L-fu-
copyranosyl-(1®2)-3,4-O-isopropylidene-a-L-fucopyranosyl-
(1®2)-3,4-O-isopropylidene-a-L-fucopyranosyl-(1 ® 2)-3,4-O-
isopropylidene-a-L-fucopyranoside (12):
Compounds 9 (320 mg, 0.67 mmol) and 10 (360 mg, 0.67 mmol) were
treated according to the general glycosylation procedure with Bu4NBr
(640 mg, 2 mmol), CuBr2 (440 mg, 2 mmol), DMF/CH2Cl2 (15 mL)
and molecular sieves (1 g). After a reaction time of 8 d and standard
workup column chromatography (toluene/EtOAc 7.5:1) furnished
350 mg (0.36 mmol, 54%) of product containing 15% b-linked tetra-
saccharide. Further starting material (9, 41%) and the corresponding
disaccharide bromide (23%) and its hydrolysate (12%) were isolated.
10a: [a]D20 –94.0 (c = 1.0, CHCl3),
1H NMR (CDCl3): d = 0.11 (s, 3H, SiMe), 0.12 (s, 3H, SiMe), 0.92
(s, 9H, tBu), 1.31 (d, 3H, J5¢,6¢ = 6.6 Hz, H-6¢), 1.36 (s, 3H, iPr), 1.37
(s, 3H, iPr), 1.39 (d, 3H, J5,6 = 6.6 Hz, H-6), 1.51 (s, 3H, iPr), 1.53 (s,
3H, iPr), 2.18 (s, 3H, SMe), 3.71 (dd≈m, 1H, J1,2 = 9.2 Hz, J2,3 = 6.6
Hz, H-2), 3.73 (dd ≈ m, 1H, J1¢,2¢ = 3.5 Hz, J2¢,3¢ = 7.1 Hz, H-2¢), 3.81
(dq, 1H, J4,5 = 2.0 Hz, J5,6 = 6.6 Hz, H-5), 4.05 (dd, 1H, J3,4 = 5.6 Hz,
J4,5 = 2.0 Hz, H-4), 4.08 (dd, 1H, J3¢,4¢ = 5.6 Hz, J4¢,5¢ = 2.5 Hz, H-4¢),
12
a: [a]20 –145.8 (c = 1.0, CHCl3).
D
1H NMR (CDCl3): d = 0.10 (s, 3H, SiMe), 0.11 (s, 3H, SiMe), 0.88
(s, 9H, tBu), 1.2–1.7 (m, 36H, 4 ´ H-6, 8 ´ iPr), 3.65 (dd ≈ m, 1H, J1.2
= 3.6 Hz, J2,3 = 6.6 Hz, H-2), 3.67 (dd≈m, 1H, J1,2 = 3.5 Hz, H-2), 3.7–
3.8 (m, 3H, 2 ´ H-2, H-4), 4.0–4.1 (m, 4H, 3 ´ H-4, H-5), 4.14 (dd,
1H, J2,3 = 5,6 Hz, J3,4 = 8.1 Hz, H-3), 4.20 (dd ≈ t, 1H, J2,3 = J3,4 = 5.6
Hz, H-3), 4.26 (dd, 1H, J2,3 = 8.2 Hz, J3,4 = 5.1 Hz, H-3), 4.31 (dd,
1H, J2,3 = 8.1 Hz, J3,4 = 5.6 Hz, H-3), 4.35 (dq, 1H, J4,5 = 2.5 Hz, J5,6
= 6,6 Hz, H-5), 4.42 (dq ≈ m, 1H, J4,5 = 2.5 Hz, J5,6 = 6.6 Hz, H-5),
4.46 (dq ≈ m, 1H, J4,5 = 2.5 Hz, J5,6 = 6.6 Hz, H-5), 4.58 (d, 1H, JBn
= 11.8 Hz, Bn), 4.72 (d, 1H, JBn =11.9 Hz, Bn), 4.88 (d, 1H, J1,2 = 3.5
Hz, H-1), 4.94 (d, 1H, J1,2 = 3.1 Hz, H-1), 4.99 (d, 1H, J1,2 = 3.5 Hz,
H-l), 5.01 (d, 1H, J1,2 = 3.5 Hz, H-1), 7.3-7.4 (m, 5H, Bn).
4.11 (dd ≈ t, 1H, J2¢,3¢ = J3¢,4¢ = 6.1 Hz, H-3¢), 4.16 (dd ≈ t, 1H, J2,3
=
J3,4 = 5.8 Hz, H-3), 4.23 (d, 1H, J1,2 = 9.2 Hz, H-1), 4.55 (dq, 1H, J4¢,5¢
= 2.5 Hz, J5¢,6¢ = 6.6 Hz, H-5¢), 5.21 (d, 1H, J1¢,2¢ = 3.5 Hz, H-1¢).
13C NMR (CDCl3): d = –4.56 (SiMe). –4.42 (SiMe), 12.49 (SMe),
16.19 (C-6¢), 16.79 (C-6), 18.25 (tBu. q), 25.80 (tBu, s), 26.42 (2 ´
iPr), 28.07 (iPr), 28.44 (iPr), 62.99 (C-5¢), 71.59 (C-2¢), 71.91 (C-5),
74.14 (C-2), 76.19 (C-4¢), 76.31 (C-4), 76,66 (C-3¢), 78.58 (C-3),
84.04 (C-1), 98.13 (C-1¢), 108.50 (iPr), 109.45 (iPr).
13C NMR (CDCl3): d = -4,46 (SiMe), -4.33 (SiMe), 16.18, 16.27 (4 ´
C-6), 18,31 (tBu, q), 26.00 (tBu, s), 26.21 (iPr), 26.40 (iPr), 26.49 (iPr),
26.55 (iPr), 28.20 (iPr), 28.38 (iPr), 28.41 (2 ´ iPr), 63.15 (C-5), 63.45
(C-5), 63.54 (C-5), 63.63 (C-5), 69.59 (Bn), 71.91 (C-2), 74.44, 74.91
(C-2, 2 ´ C-3), 76.20, 76.29, 76.37, 76.70, 76.84, 77,02, 77.34 (2 ´ C-
2, 2 ´ C-3, 4 ´ C-4), 95.38 (C-1), 95.79 (C-1), 96.80 (C-1), 98.21 (C-
1), 108.45 (2 ´ iPr), 108.48 (iPr), 108.66 (iPr), 127–137 (Bn).
C25H46O8SSi calcd
C
56.15
56.98
H
8.67
8.93
S
5.99
5.49
(534.79)
found
10b:
1H NMR (CDCl3): d = 0.08 (s, 3H, SiMe), 0.12 (s, 3H, SiMe), 0.90
(s, 9H, tBu), 1.37 (m, 9H, H-6, H-6¢, 2 ´ iPr), 1.51 (s, 6H, 2 ´ iPr), 2.18
(s, 3H, SMe), 3.49 (dd, 1H, J1,2 = 8.1, J2,3 = 6.1 Hz, H-2), 3.80
(dq ≈ m, 1H, J4,5 = 2.0 Hz, J5,6 = 6.6 Hz, H-5), 3.82 (dq≈m, 1H, J4¢.5¢
= 2.0 Hz, J5¢,6¢ = 6.6 Hz, H-5¢), 3.98 (m, 3H, H-2¢, H-3, H-4), 4.02 (dd,
12
b:
1H NMR (CDCl3): d = 3.80 (H-2), 3.91 (H-2), 3.95 (H-4), 4.98 (H-l),
1H, J3,4 = 5.6 Hz, J4,5 = 2.0 Hz, H-4¢), 4.11 (dd≈t, 1H, J2¢,3¢ = J3¢,4¢
=
6.7 Hz, H-3¢), 4.27 (d, 1H, J1,2 = 8.6 Hz, H-1), 4.64 (d, 1H, J1¢,2¢ = 7.9
Hz, H-1¢).
5.40 (H-1).
C49H78O17Si calcd
(967.23) found
C
60.85
61.26
H
8.13
8.17
13C NMR (CDCl3): d = –4.59 (SiMe), –4.20 (SiMe), 11.84 (SMe),
l6.49 (C-6?), 16.72 (C-6?), 18.24 (tBu, q), 25.87 (tBu, s), 26.46 (iPr),
26.49 (iPr), 28.15 (iPr), 28.17 (iPr), 69.00 (C-5), 72.50 (C-5¢), 73.63
(C-2¢), 74.11 (C-2), 76.42 (C-4¢), 76.85 (C-4), 79.18 (C-3¢), 80.91 (C-
3), 83.27 (C-l¢), 99.75 (C-1), 109.35 (iPr), 109.48 (iPr).
Benzyl 2-O-tert-Butyldiphenylsilyl-3,4-O-isopropylidene-a-L-fu-
copyranosyl-(1®2)-3,4-O-isopropylidene-a-L-fucopyranosyl-
(1 ® 2)-3,4-O-isopropylidene-a-L-fucopyranosyl-(1 ® 2)-3,4-O-
isopropylidene-a-L-fucopyranoside (13):
13 was prepared in the same way as compound 12, using 9 (300 mg,
0.62 mmol), 11 (200 mg, 0.30 mmol), Bu4NBr (640 mg, 2 mmol),
CuBr2 (440 mg, 2 mmol), DMF/CH2Cl2 (10 mL) and molecular
sieves (0.5 g). After stirring for 14 d and standard workup column
chromatography (toluene/EtOAc 7.5:1) yielded 168 mg (0.15 mmol,
5l%) of product as a syrup, containing 15% b-linked tetrasaccharide.
Methyl 2-O-tert-Butyldiphenylsilyl-3,4-O-isopropylidene-a-L-fu-
copyranosyl-(1 ® 2)-3,4-O-isopropylidene-1-thio-b-L-fucopyra-
noside (11):
Using 3 (1.9 g, 4.02 mmol), 1 (1.0 g, 4.27 mmol), bromine in CH2Cl2
(1:24, 5.53 mL, 4.3 mmol), and Bu4NBr (3870 mg, 12 mmol) this
compound was prepared in the same way as 10. Column chromatog-

60
Papers
SYNTHESIS
13a: [a]D20 –141,8 (c = 1.0, CHCl3).
J
2,3 = 8.6 Hz, H-2), 3.72–3.82 (m, 3H, 2 ´ H-2, H-5²), 3.90 (dd, 1H,
1H NMR (CDCl3): d = 1.04 (s, 9H, tBu), 1.2–1.35 (m, 30H, 4 ´ H-6, J3²,4² = 5,1 Hz, J4²,5² = 1.5 Hz, H-4²), 3.98 (dd, 1H, J3,4 = 5.1 Hz, J4,5
i
i
i
6 ´ Pr), 1.47 (s, 3H, Pr), 1.52 (s, 3H, Pr), 3.65 (dd ≈ m, 1H. J1,2
=
= 2.5 Hz, H-4), 4.01–4.11 (m, 3H, H-3, H-4, H-5), 4.12 (dd, 1H, J3,4
3.0, J2,3 = 8.1 Hz, H-2), 3.67 (dd ≈ m, 1H, J1,2 = 3.0 Hz. H-2), 3.73 = 5.6 Hz, J4,5 = 2.5 Hz, H-4), 4.17 (dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5,6 Hz,
(dd, 1H, J1,2 = 3.5 Hz, J2,3 = 8.1 Hz, H-2), 3.85 (dd, 1H. J1,2 = 3.5 Hz, H-3), 4.22 (dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5.1 Hz, H-3), 4.41 (dd, 1H, J2.3
J2,3 = 7.1 Hz, H-2), 3.98 (dd, 1H, J3,4 = 5.6 Hz, J4,5 = 2.5 Hz, H-4), = 8.4 Hz, J3,4 = 5.6 Hz, H-3), 4.46 (m, 2H, J1²,2² = 8.1 Hz, H-1, H-5),
4.01-4.15 (m, 5H, H-3, 3 ´ H-4, H-5), 4,25–4.47 (m, 6H, 3 ´ H-3, 3 4.62 (m, 2H, JBn =11.2 Hz, H-5, Bn), 4.77 (d, 1H, JBn =11.2 Hz, Bn),
´ H-5), 4.56 (d, 1H, JBn = 12.2 Hz, Bn), 4.75 (d, 1H, JBn = 12.2, Bn), 5.08 (d, 1H, J1,2 = 3.1 Hz, H-1), 5.18 (d, 1H, J1,2 = 3.1 Hz, H-1), 5.47
4.84 (d, 1H, J1,2 = 3.5 Hz, H-1), 4.86 (d, 1H, J1,2 = 3.5 Hz, H-l), 4.96 (d, 1H, J1,2 = 3.5 Hz, H-1), 7.3–7.4 (m, 5H, Bn).
13C NMR (CDCl3): d = 16.00 (C-6), 16.14 (C-6), 16.23 (C-6), 17.09
(d, 1H, J1,2 = 3.0 Hz, H-1), 5.00 (d, 1H, J1,2 = 3.5 Hz, H-l), 7.3–7.4
(C-6), 26.19 (iPr), 26.39 (iPr), 26.46 (iPr), 26.55 (iPr), 27.31 (iPr),
(m, 15H, Bn, Ph), 7.71 (m, 5H, Ph).
13C NMR (CDCl3): d = 16.21, 16.27, 16.33 (4 ´ C-6), 19.50 (tBu, q), 28.33 (iPr), 28.47 (iPr), 28.54 (iPr), 62.46 (C-5), 62.61 (C-5), 63.29 (C-
26.14 (iPr), 26.30 (iPr), 26.50 (iPr), 27.00 (iPr), 27.14 (tBu, s), 27.47 5), 68.76 (C-5²), 70.57 (C-2), 71.75 (Bn), 74.49 (C-3), 74.51 (C-3),
(iPr), 28.19 (iPr), 28.29 (iPr), 28.43 (iPr), 63.42 (C-5), 63.49 (C-5), 75.40 (C-2, C-2²), 75.96 (C-4), 76.10 (C-3), 76.24 (C-4), 76.32 (C-4),
63.62 (C-5), 63.72 (C-5), 69.49 (Bn), 72.44 (C-2), 74.78 (C-3). 74.86 76.43 (C-4), 77.78 (C-3²), 81.25 (C-2), 96.93 (C-1), 96.94 (C-1),
(C-3), 74.93 (C-3, C-2), 75.89 (C-2), 75.96 (C-2), 76.13 (C-4), 76.27 98.22 (C-1), 105.71 (C-1²), 108.54 (iPr), 108.74 (iPr), 109.16 (iPr),
(3 ´ C-4), 76.40 (C-3), 95.74 (C-1), 95.90 (C-1), 96.81 (C-1), 98.12 109.45 (iPr), 127,60 (Bn), 128.13 (Bn), 128.57 (Bn), 137.09 (Bn).
(C-1), 108.38 (iPr), 108.44 (iPr), 108.57 (iPr), 108.71 (iPr), 127–137
(Bn).
Benzyl 2-O-tert-Butyldimethylsilyl-3,4-O-isopropylidene-a-L-fu-
13b:
copyranosyl-(1®2)-3,4-O-isopropylidene-a-L-fucopyranosyl-
(1®2)-3,4-O-isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-O-iso-
propylidene-a-L-fucopyranosyl-(1®2)-3,4-O-isopropylidene-a-
L-fucopyranosyl-(1®2)-3,4-O-isopropylidene-a-L-fucopyrano-
side (15):
1H NMR (CDCl3): d = 3.51 (H-2), 3.56 (H-2), 3.88 (H-2), 4.89 (H-1).
C59H82O17Si calcd
(1091.38) found
C
64.93
64.59
H
7.57
7.57
Applying the general glycosylation procedure 14 (200 mg, 0.24
mmol), 10 (220 mg, 0.41 mmol), Bu4NBr 450 mg (1.4 mmol), CuBr2
(310 mg, 1.4 mmol), DMF/CH2Cl2 (10 mL) and molecular sieves (1
g) were converted in a reaction time of 10 d. Standard workup and
column chromatography (toluene/EtOAc 10:1) furnished 104 mg
(0.08 mmol, 33%) of product containing less than 5% b-linked hexa-
saccharide. Furthermore starting material (14, 30%) and disaccharide
bromide (31%) were isolated; [a]D20 –193.0 (c = 1.0, CHCl3).
Benzyl 3,4-O-Isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-O-
isopropylidene-a-L-fucopyranosyl-(1 ® 2)-3,4-O-isopropylidene-
a-L-fucopyranosyl-(1®2)-3,4-O-isopropylidene-a-L-fucopyran-
oside (14):
12 (322 mg, 0.33 mmol) was treated with 1 M TBAF in THF (10 mL)
for 4 h. Subsequently, the solvent was evaporated, the syrup dissolved
in EtOAc (20 mL), washed with aq Na2CO3 (2 ´ 20 mL) and brine (20
mL) dried and again evaporated under reduced pressure. Column
chromatography (petroleum ether/EtOAc 2:1) and following prepar-
ative TLC (petroleum ether/EtOAc 1:1) gave both, 177 mg (0.20
mmol, 62%) of product and 48 mg (0.06 mmol, 17%) of b-linked tet-
rasaccharide.
1H NMR (CDCl3): d = 0.08 (s, 3H, SiMe), 0.10 (s, 3H, SiMe), 0.87
t
i
i
(s, 9H, Bu), 1.21 (s, 3H, Pr), 1.23–l.35 (m, 27H, 5 ´ H-6, 4 ´ Pr),
1.36 (d, 3H, J5,6 =6.6 Hz. H-6), 1.47 (s, 6H, 2 ´ iPr), 1.52 (s, 3H, iPr),
1.53 (s, 6H, 2 ´ iPr), 1.54 (s, 3H, iPr), 1.65 (s, 3H, iPr), 3.57 (dd, 1H,
J1,2 = 3.1 Hz, J2,3 = 8.1 Hz, H-2), 3.59–3.64 (m, 3H, 3 ´ H-2), 3.69
(dd ≈ m, 1H, J1,2 = 3.5 Hz, H-2), 3.71 (dd ≈ m, 1H, J1,2 = 3.5 Hz, H-
2), 3.82 (dd, 1H, J3,4 = 5.6 Hz, J4,5 = 3.0 Hz, H-4), 3.93–4.01 (m, 3H,
2 ´ H-3, H-4), 4.03 (dd, 1H, J3,4 = 5.1 Hz, J4,5 = 2.6 Hz, H-4), 4.07 (dd,
1H, J3,4 = 5.1 Hz, J4,5 = 3.0 Hz, H-4), 4.14 (m, 2H, H-3, H-5), 4.19 (dd,
1H, J3,4 = 5.4 Hz, J4,5 = 3.5 Hz, H-4), 4.22 (dd, 1H, J3,4 = 5.6 Hz, J4.5
= 2.5 Hz, H-4), 4.27–4.35 (m, 3H, 3 ´ H-3), 4.39–4.51 (m, 4H, 4 ´ H-
14a: [a]D20 –228.2 (c = 1.0, CHCl3).
1H NMR (CDCl3): d = 1.23 (d, 3H, J5,6 = 6.6 Hz, H-6), 1 .30 (d ≈ m,
3H, J5,6 = 6.6 Hz, H-6), 1,31 (d ≈ m, 3H, J5,6 = 6.6 Hz, H-6), 1.33 (s,
9H, 3 ´ iPr), 1.35 (s, 3H, iPr), 1.36 (d ≈ m, 3H, H-6), 1.44 (s, 3H, iPr),
1.51 (s, 3H, iPr), 1.52 (s, 3H, iPr), 1.53 (s, 3H, iPr), 3.11 (d, 1H, J2,OH
= 5.6 Hz, OH-2), 3.66 (ddd ≈ m, 1H, H-2¢¢¢), 3.77 (dd, 1H, J1,2 = 3.5
Hz, J2,3 = 8.1 Hz, H-2), 3.85 (dd, 1H, J1,2 = 3.5 Hz, J2,3 = 8.3 Hz, H-
2), 3.93 (dd, 1H, J1,2 = 3.5 Hz, J2,3 = 6.1 Hz, H-2), 4.00 (dd, 1H, J3,4
= 5.6 Hz, J4,5 = 2.5 Hz, H-4), 4.02–4.09 (m, 4H, 3 ´ H-4, H-5), 4.18
(m ≈ dd, 3H, J2,3 = 8.1 Hz, J3,4 = 5.8 Hz, 2 ´ H-3, H-5), 4.28–4.33 (m,
2H, 2 ´ H-3), 4.41–4.48 (ddd, 2H, 2 ´ H-5), 4.55 (d, 1H, JBn =12.2
Hz, Bn), 4.67 (d, 1H, JBn =12.2 Hz, Bn), 4.91 (m ≈ d, 2H, J1,2 = 3.5
Hz, 2 ´ H-l), 4.99 (d, 1H, J1,2 = 3.2 Hz, H-1), 5.38 (d, 1H, J1,2 = 3.5
Hz, H-l), 7.3–7.4 (m, 5H, Bn).
5), 4.59 (dq, 1H, J4,5 = 2.5 Hz, J5,6 = 6.6 Hz, H-5), 4.71 (d, 1H, J1,2
=
3.5 Hz, H-1), 4.73 (d, 1H, JBn = 12.2 Hz, Bn), 4.79 (d, 1H, JBn =l2.2
Hz, Bn), 4.85 (d, 1H, J1,2 = 3.1 Hz, H-1), 4.89 (d ≈ m, 1H, J1,2 = 3.5
Hz, H-l), 4.90 (d ≈ m, 1H, J1,2 = 3.5 Hz, H-1), 4.96 (d, 1H, J1,2 = 3.l
Hz, H-1), 5.10 (d, 1H, J1,2 = 3.1 Hz, H-1), 7.3–7.4 (m, 5H, Bn).
13C NMR (CDCl3): d = –4.41 (SiMe), –4.26 (SiMe), 15.93 (C-6),
l6.06 (C-6), 16.14 (C-6), 16.18 (C-6), 16.24 (C-6), 16.35 (C-6), 18.34
(tBu, q), 26.05 (tBu, s), 26.32 (iPr), 26.67 (2 ´ iPr), 26.69 (iPr), 26.72
(iPr), 27.05 (iPr), 28.50 (2 ´ iPr), 28.52 (iPr), 28.60 (iPr), 28.71 (iPr),
29.70 (iPr), 63.15, 63.19, 63.39, 63.95 (6 ´ C-5), 70.76 (Bn), 72.71
(C-2), 74.32 (C-3), 74.55 (C-3), 74.59 (C-3), 74.68 (C-3), 74.73 (C-
3), 76–80 (5 ´ C-2, C-3, 6 ´ C-4), 97.55 (3 ´ C-l), 97.92 (C-l),
100.15 (C-1), 101.27 (C-l), 108.14 (iPr), 108.35 (iPr), 108.38 (iPr),
l08.51 (iPr), 108.62 (iPr), 108.65 (iPr), 127.35 (Bn), 127.52 (Bn),
128.32 (Bn), 138.31 (Bn).
13C NMR (CDCl3): d = 16.21 (2 ´ C-6), 16.26 (C-6), 16.42 (C-6),
25.91 (iPr), 26.35 (iPr), 26.41 (2 ´ iPr), 27.52 (iPr), 28.25 (iPr), 28.27
(iPr), 28.39 (iPr), 62.80 (C-5), 63.32 (2 ´ C-5), 64.49 (C-5), 69.58
(Bn), 70.11 (C-2), 76.63 (C-2), 72.18 (C-2), 73.27 (C-2), 74.32 (C-3),
74.37 (C-3), 74.42 (C-3), 75.93 (C-4), 76.01 (2 ´ C-4), 76.20 (C-3, C-
4), 93.14 (C-1), 93.19 (C-l), 94.63 (C-1), 95.78 (C-1), 108.64 (iPr),
l08.78 (iPr), 109.04 (iPr), 109.28 (iPr), 128.01 (Bn), 128.15 (Bn),
128.57 (Bn), 137.04 (Bn).
C67H106O25Si calcd
C
60.07
59.76
H
7.98
8.09
FAB (matrix: m-nitrobenzyl alcohol m = 852.41) = 837.5 (m–l5),
853.6 (m+1) 875.6 (m+Na).
(1339.65)
found
C43H64O17 calcd
(852.97) found
C
60.55
59.95
H
7.56
7.29
Benzyl
3,4-O-Isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-O-
isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-O-isopropylidene-
a-L-fucopyranosyl-(1®2)-3,4-O-isopropylidene-a-L-fucopyrano-
syl-(1®2)-3,4-O-isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-O-
isopropylidene-a-L-fucopyranoside (16):
1 M TBAF in THF (4 mL) was added to 15 (100 mg, 0.07 mmol) and
stirred for 3 h. For workup the solvent was evaporated, EtOAc
(20 mL) was added, the solution agitated with sat. Na2CO3 (3 ´ 20 mL)
14b: [a]D20 –323.2 (c = 2.0 CHCl3).
1H NMR (CDCl3): d = 0.96 (s, 3H, iPr), 1.23 (s, 3H, iPr), 1.27 (m ≈ d,
6H, J5,6 = 7.1 Hz, 2 ´ H-6), 1.31 (d ≈ m, 3H, J5,6 = 8.1 Hz, H-6), 1.32
(s ≈ m, 3H, iPr), 1.35 (s, 3H, iPr), 1.37 (s, 3H, iPr), 1.39 (d, 3H, J5,6
=
6.6 Hz, H-6), 1.53 (s, 3H, iPr), 1.55 (s, 3H, iPr), 1.56 (s, 3H, iPr), 3.58
(dd ≈ t, 1H, J1²,2² = J2²,3² = 8,1 Hz, H-2²), 3.63 (dd, 1H, J1,2 = 3.5 Hz,

January 1998
SYNTHESIS
61
and sat. brine (20 mL), dried, evaporated and column chromatogra-
phy (petroleum ether/EtOAc 1:1.5) yielded 78 mg (0.06 mmol, 84%)
of product containing traces of TBAF; [a]D20 –168.2 (c = 0.8, CHCl3).
1H NMR 500M Hz (CDCl3): d = 1.26 (s, 3H, iPr), 1.28 (s, 3H, iPr),
1.29–l.40 (m, 30H, 6 ´ H-6, 4 ´ Pr), 1.51 (s, 6H, 2 ´ Pr), 1.53 (s,
3H, iPr), 1.54 (s, 3H, iPr), 1.55 (s, 6H, 2 ´ iPr), 2.97 (d, 1H, J2,OH = 7.0
Hz, OH-2), 3.70 (ddd, 1H, J1,2 = 3.8 Hz, J2,3 ≈ J2,OH = 7.3 Hz, H-
(dd, 1H, J1,2 = 3.6 Hz, J2,3 = 8.1 Hz, H-2), 4.92 (d, 1H, J1,2 = 3.4 Hz,
H-1), 5.10 (d, 1H, J1,2 = 3.5 Hz, H-1), 7.34 (m, 5H, Bn).
13C NMR (CDCl3): d = 16.10 (C-6), 16.24 (C-6), 20.92 (OAc), 26.45
i
(2 ´ Pr), 28.11 (iPr), 28.42 (iPr), 62.62 (C-5), 63.31 (C-5), 69.99
i
i
(Bn), 72.43, 73.25, 73.40, 74.50, 76.17 (2 ´ C-2, 2 ´ C-3, 2 ´ C-4),
93.32 (C-1), 95.27 (C-l), 108.81 (iPr), 109.20 (iPr), 127.43 (Bn),
127.83 (Bn), 128.43 (Bn), 137.33 (Bn), 170.82 (OAc).
2²²¢), 3.77 (dd ≈ m, 1H, J1,2 = 3.8 Hz, H-2), 3.79 (dd ≈ m, 1H, J1,2
=
C27H38O10
(522.59)
calcd
found
C
62.06
61.76
H
7.33
7.34
3.8 Hz, H-2), 3.86 (dd ≈ m, 1H, J1,2 = 3.8 Hz, H-2), 3.87 (dd ≈ m, 1H,
J1,2 = 3.2 Hz, H-2), 3.98–4.06 (m, 4H, H-2, 2 ´ H-4, H-5), 4.08–4.15
(m, 4H, 4 ´ H-4), 4.23 (dd, 1H, J2,3 = 7.6 Hz, J3,4 = 5.7 Hz, H-3²²¢),
4.28 (dd, 1H, J2,3 = 7.6 Hz, J3,4 = 5.7 Hz, H-3), 4.31–4.41 (m, 7H,
4 ´ H-3, 3 ´ H-5), 4.43 (dq, 1H, J4,5 = 2.2 Hz, J5,6 = 6.6 Hz, H-5), 4.47
(dq, 1H, J4,5 = 2.5 Hz, J5,6 = 6.8 Hz, H-5), 4.67 (d ≈ s, 1H, JBn = 12.0
Hz, Bn), 4.70 (d ≈ s, 1H, JBn = 12.0 Hz, Bn), 4.97 (d, 1H, J1,2 = 3.6
Hz, H-l), 5.02 (d, 1H, J1,2 = 3.8 Hz, H-1), 5.08 (d, 1H, J1,2 = 3.8 Hz,
H-1²²¢), 5.27 (d, 1H, J1,2 = 3.2 Hz, H-1), 5.36 (d, 1H, J1,2 = 3.5 Hz,
H-l), 5.41 (d, 1H, J1,2 = 3.6 Hz, H-1), 7.3–7.5 (m, 5H, Bn).
2-O-Acetyl-3,4-O-isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-
O-isopropylidene-L-fucopyranose (19):
To a stirred solution of 18 (312 mg, 0.60 mmol) in MeOH/EtOAc
(2:1, 30 mL) HCO2NH4 (200 mg) and Pd/C (50 mg, 10%) were add-
ed. The suspension was hydrogenated under 70 bar for 2 d, the solids
were replaced and hydrogenation was carried on for another 2 d. After
filtration column chromatography (petroleum ether/EtOAc 1:1)
yielded 166 mg (0.38 mmol, 64%) of the anomeric mixture (a/b 3:2)
as a solid and unchanged starting material (31%); [a]D20 –l78.3 (c =
1.0, CHCl3).
1H NMR (CDCl3): d = 1.32 (d, 3H, J5,6 = 6.6 Hz, H-6a), 1.33–1.37
(m, 18H, H-6a, H-6b, 2 ´ iPra, 2 ´ iPrb), 1.39 (d, 3H, J5,6 = 6.6 Hz,
H-6b), 1.52 (s, 3H, iPra), 1.53 (s, 6H, iPra, iPrb), 1.55 (s, 3H, iPrb),
2.11 (s, 3H, OAcb), 2.13 (s, 3H, OAca), 3.54 (dd ≈ t, 1H, J1,2 ≈ J2,3
= 7.6 Hz, H-2b), 3.81 (dd, 1H, J1,2 = 3.6 Hz, J2,3 = 6.6 Hz, H-2a), 3.89
(dq, 1H, J4,5 = 2.0 Hz, J5,6 = 6.6 Hz, H-5b), 4.00 (dd, 1H, J3,4 = 5.2
Hz, J4,5 = 2.0 Hz, H-4b), 4.05 (dd, 1H, J3,4 = 6.1 Hz J4,5 = 2.5 Hz, H-
4a), 4.08 (dd, 1H, J2,3 = 7,1 Hz, J3,4 = 5.6 Hz, H-3b), 4.12 (dd, 2H,
J3,4 = 5.6 Hz, J4,5 = 2.5 Hz, H-4a, H-4b), 4.25 (dq, 1H, J4,5 = 2.5 Hz,
J5,6 = 6.6 Hz, H-5a), 4.28–4.36 (m, 3H, 2 ´ H-3a, H-3b), 4.40 (dq,
1H, J4,5 = 2.5 Hz, J5,6 = 6.6 Hz, H-5a), 4.54 (dq ≈ m, 1H, J4,5 = 2.5
Hz, J5,6 = 6.6 Hz, H-5b), 4.56 (d ≈ m, 1H, J1,2 = 7.1 Hz, H-1b), 4.88
(dd ≈ m, 1H, J1¢,2¢ = 3.5 Hz, J2¢,3¢ = 8.2 Hz, H-2¢b), 4.91 (dd ≈ m, 1H,
13C NMR (CDCl3): d = 16.09 (C-6), 16.23 (2 ´ C-6), 16.37 (3 ´ C-6),
i
i
26.13 (iPr), 26.38 (iPr), 26.42 (2 ´ Pr), 26.54 (2 ´ Pr), 27.84 (iPr),
28.29 (iPr), 28.36 (iPr), 28.39 (iPr), 28.42 (iPr), 28.47 (iPr), 62.64 (C-
5), 62.77 (3 ´ C-5), 62.91 (C-5), 63.95 (C-5), 69.83 (Bn), 70.19 (C-
2²²¢), 71.17 (C-2), 72.08 (C-2), 72.46 (C-2), 72.90 (2 ´ C-2), 74.05
(2 ´ C-3), 74.43 (3 ´ C-3), 75.97 (2 ´ C-4), 76.09 (3 ´ C-4), 76.20
(C-4), 76.53 (C-3), 92.11 (C-1), 92,42 (2 ´ C-1), 92.83 (C-1), 94.19
(C-l), 95.31 (C-1²²¢), 108.60 (iPr), 108.73 (iPr), 108.75 (iPr), 108.78
(2 ´ iPr), 109.05 (iPr), 127.99 (Bn), 128.44 (Bn), 128.81 (Bn), 136.97
(Bn).
FAB (matrix: m-nitrobenzyl alcohol m =1224.59): 1209.6 (m–l5),
1247.8 (m+Na).
C61H92O25
(1225.39)
calcd
found
C
59.79
60.15
H
7.57
7.89
J
1¢,2¢ = 3.6 Hz, J2¢,3¢ = 8.0 Hz, H-2¢a), 5.06 (d, 1H, J1¢,2¢ = 3.6 Hz, H-
Benzyl a-L-Fucopyranosyl-(1®2)-a-L-fucopyranosyl-(1®2)-a-
L-fucopyranosyl-(1 ® 2)-a-L-fucopyranosyl-(1 ® 2)-a-L-fucopy-
ranosyl-(1 ® 2)-a-L-fucopyranoside (17):
1¢a), 5.18 (d, 1H, J1,2 = 3.5 Hz, H-1a), 5.35 (d, 1H, J1¢,2¢ = 3.5 Hz, H-
1¢b).
13C NMR (CDCl3): d = 16.17, 16.46, 16.58 (2 ´ C-6a, 2 ´ C-6b),
20.97 (OAcb), 21.01 (OAca), 26.01, 26.35, 26.45, 27.66, 27.94,
28.10 (4 ´ iPra, 4 ´ iPrb), 62.86 (C-5b), 63.42 (C-5a), 64.07 (C-5 a),
68.88 (C-5b), 71.79 (C-2¢a), 72.02 (C-2¢b), 73.13 (C-3a, C-3b),
73.89 (C-3a), 74.70 (C-2a), 75.66 (C-4a), 75.89 (C-4a), 76.23 (C-
4b), 76.51 (C-4b), 77.61 (C-3b), 77.76 (C-2b), 89.74 (C-1a), 95.55
(C-1¢a), 95.93 (C-1¢b), 96.51 (C-1b).
16 (16 mg, 13 mmol) was treated with a mixture of dioxane and l%
H2SO4 (1:1, 10ml) for 5 h. The mixture was neutralized with BaCO3
and the solvent removed under reduced pressure to yield 12 mg (12
mmol, 92%)ofcrystallinewhiteproduct;[a]D20 –251.8(c=1.3, CHCl3).
1H NMR (D2O): d = 0.76 (d, 3H, J5,6 = 6.6 Hz, H-6), 1.00–1.10 (m,
15H, 5 ´ H-6), 3.5–4.0 (m, 23H, 6 ´ H-2, 6 ´ H-3, 6 ´ H-4, 5 ´ H-5),
4.06 (dq ≈ q, 1H, J4,5 ≤ 1 Hz, J5,6 = 6.6 Hz), 4.62 (d ≈ m, 1H, Bn), 4.72
(d, 1H, JBn = 12.2 Hz, Bn), 4.97 (d, 1H, J1,2 = 3.9 Hz, H-1), 4.98 (d,
1H, J1,2 = 3.6 Hz, H-1), 5.16 (d, 1H, J1,2 = 3.2 Hz, H-1), 5.24 (d, 1H,
J1,2 = 3.3 Hz, H-1), 5.31 (d ≈ s, 1H, H-1), 5.40 (d ≈ s, 1H, H-1), 7.2–
7.4 (m, 5H, Bn).
C20H32O10
(432.47)
calcd
found
C
55.55
55.50
H
7.46
7.57
2-O-Acetyl-3,4-O-isopropylidene-a-L-fucopyranosyl-(1®2)-3,4-
O-isopropylidene-b-L-fucopyranosyl Trichloroacetimidate (20):
To a stirred solution of 19 (100 mg, 0.23 mmol) in CH2Cl2 (5 mL) un-
der Ar were added K2CO3 (120 mg, 0.87 mmol) and trichloro-
acetonitrile (0.12 mL, 1.2 mmol). After 1 d the solids were filtered
off, the solvent was evaporated and column chromatography (pe-
troleum ether/EtOAc 1.5:1) yielded 80 mg (14 mmol, 60%) product;
[a]D20 –53.0 (c = 0.5, CHCl3).
13C NMR (D2O): d = 15.29, 15.59, 15.67, 15.76, 15.82 (6 ´ C-6),
67.01, 67.14, 67.49, 67.57, 68.37, 68.58, 68.63, 68.68, 68.81, 69.79,
71.94, 72.12, 72.24 (6 ´ C-2, 6 ´ C-3, 6 ´ C-4, 6 ´ C-5), 94.91 (C-1),
l28.68, 129.04, 129.65 (Bn).
C42H66O25
(970.97)
calcd
found
C
51.95
52.33
H
6.85
6.99
1H NMR (CDCl3): d = 1.34 (s, 3H, iPr), 1.35 (d, 3H, J5,6 = 6.6 Hz, H-
6), 1.38 (s, 3H, iPr), 1.42 (d, 3H, J5,6 = 6.6 Hz, H-6), 1.53 (s, 3H, iPr),
1.59 (s, 3H, iPr), 2.01 (s, 3H, OAc), 3.92 (dd ≈ t, 1H, J1,2 ≈ J2,3 = 7.8
Hz, H-2), 4.02 (dq, 1H, J4,5 = 2.5 Hz, J5,6 = 6.6 Hz, H-5), 4.07 (dd,
1H, J3,4 = 5.2 Hz, J4,5 = 2.5 Hz, H-4), 4.12 (dd, 1H, J3¢,4¢ = 5.1 Hz, J4¢,5¢
= 2.5 Hz, H-4¢), 4.20 (dd, 1H, J2,3 = 7.1 Hz, J3,4 = 5.1 Hz, H-3), 4.28
(dd, 1H, J2¢,3¢ = 8.4 Hz, J3¢,4¢ = 5.4 Hz, H-3¢), 4.64 (dq, 1H, J4¢,5¢ = 2.5
Hz, J5¢,6¢ = 6.6 Hz, H-5¢), 5.06 (dd, 1H, J1¢,2¢ = 3.5 Hz, J2¢,3¢ = 8.6 Hz,
H-2¢), 5.25 (d, 1H, J1¢,2¢ = 3.5 Hz, H-1¢), 5.75 (d, 1H, J1,2 = 8.6 Hz, H-
1), 8.68 (s, 1H, NH).
13C NMR (CDCl3): d = 16.11 (C-6), 16.42 (C-6), 21.06 (OAc), 26.33
(iPr), 26,54 (iPr), 27.90 (iPr), 28.14 (iPr), 62.95 (C-5), 69.95, 70.62
(C-2, C-5), 73.44, 74.44, 76.23, 76.33, 78.11 (C-2, 2 ´ C-3, 2 ´ C-4),
90.64 (CCl3), 95.98 (C-1), 97.48 (C-1), 109.23 (iPr), 109.91 (iPr),
l61.38 (CNH), 170.02 (OAc).
Benzyl
2-O-Acetyl-3,4-O-isopropylidene-a-L-fucopyranosyl-
(1®2)-3,4-O-isopropylidene-a-L-fucopyranoside (18):
9 (300 mg, 0.62 mmol) was treated with Ac2O/pyridine (1:2, 30 mL)
at 0 °C and stirred overnight at r.t. Evaporation with toluene (3 ´) and
silica gel filtration (petroleum ether/EtOAc 2:1) furnished 320 mg
(0.51 mmol, 99%) of a colourless syrup; [a]D20 –203.0 (c = 1.0,
CHCl3).
1H NMR (CDCl3): d = 1.31 (d, 3H, J5,6 = 6.6 Hz, H-6), 1.33 (d, 3H,
J5,6 = 6.6 Hz, H-6), 1.35 (s, 6H, 2 ´ iPr), 1.53 (s, 6H, 2 ´ iPr), 1.93 (s,
3H, OAc), 3.81 (dd, 1H, J1,2 = 3.6 Hz, J2,3 = 8.1 Hz, H-2), 4.05 (dd,
1H, J3,4 = 5.6 Hz, J4,5 = 2.6 Hz, H-4), 4.09 (dq, 1H, J4,5 = 2.6 Hz, J5,6
= 6.6 Hz, H-5), 4.13 (dd, 1H, J3,4 = 5.1 Hz, J4,5 = 2.6 Hz, H-4), 4.29
(dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5.1 Hz, H-3), 4.40 (dd, 1H, J2,3 = 8.1 Hz,
J3,4 = 5.1 Hz, H-3), 4.48 (d, 1H, JBn = 12.2 Hz, Bn), 4.55 (dq, 1H, J4,5
= 2.5 Hz, J5,6 = 6.6 Hz, H-5), 4.71 (d, 1H, JBn = 12.2 Hz, Bn), 4.80

62
Papers
SYNTHESIS
21a: [a]D20 –159.8 (c = 1.0, CHCl3).
C22H32O10Cl3N calcd
C
45.81
45.14
H
5.59
5.48
N
2.43
2.41
1H NMR (CDCl3): d = 1.22 (s, 3H, iPr), 1.24 (d, 3H, J5,6 = 6.6 Hz, H-
6), 1.26–1.37 (m, 18H, 3 ´ H-6, 3 ´ iPr), 1.46 (s, 3H, iPr), 1.47 (s, 3H,
(576.86)
found
i
i
iPr), 1.51 (s, 3H, Pr), 1.55 (s, 6H, 2 ´ Pr), 2.15 (s, 3H, OAc), 3.59
(dd, 1H, J1,2 = 3.5 Hz, J2,3 = 8.1 Hz, H-2), 3,68 (dd ≈ m, 1H, H-2),
3.76 (dd, 1H, J1,2 = 3,5 Hz, J2,3 = 8.6 Hz, H-2), 4.00–4.15 (m, 6H, H-
3, 4 ´ H-4, H-5), 4.18–4.25 (m, 2H, H-3, H-5), 4.30 (dd, 1H, J2,3 = 8.1
Hz, J3,4 = 5.6 Hz, H-3), 4.34 (dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5.3 Hz, H-
3), 4.42–4.53 (m, 2H, 2 ´ H-5), 4.58 (d, 1H, JBn =12.2, Bn), 4.72 (d,
1H, JBn =12,2 Hz, Bn), 4.98 (d, 1H, J1,2 = 3.6 Hz, H-1), 5.01 (m, 2H,
H-1¢¢¢, H-2¢¢¢), 5.03 (d, 1H. J1,2 = 3,5 Hz, H-1), 5.07 (dd, 1H, J1,2 = 3.6
Hz, H-1), 7.3–7.4 (m, 5H, Bn).
Benzyl
2-O-Acetyl-3,4-O-isopropylidene-a-L-fucopyranosyl-
(1®2)-3,4-O-isopropylidene-a,b-L-fucopyranosyl-(1 ® 2)-3,4-O-
isopropylidene-a-Lfucopyranosyl-(1®2)-3,4-O-isopropylidene-
a-L-fucopyranoside (21):
Compounds 9 (75 mg, 156 mmol) and 20 (68 mg, 118 mmol) were dis-
solved in Et2O and stirred with molecular sieves for 1 h. The solution
was cooled to –15 °C and TMSOTf [0.5 mL, 0.2 mL in Et2O (5 mL)]
was added dropwise. After 1 h the mixture was treated with Na2CO3
(50 mg), filtered through Celite, washed with sat. Na2CO3, dried, and
column chromatography (toluene/EtOAc 3:1) furnished two frac-
tions, 28 mg (31 mmol, 27%) b-linked product and 36 mg (40 mmol,
34%) of an anomeric mixture (a/b 3:1).
13C NMR (CDCl3): d = 16.11, 16.13, 16.63 (4 ´ C-6), 21.14 (OAc),
26.26 (iPr), 26.33 (iPr), 26.42 (iPr), 26.52 (iPr), 27.99 (iPr), 28.25
(iPr), 28.35 (iPr). 28.42 (iPr), 62.82 (C-5), 62.88 (C-5), 63.36 (C-5),
63.50 (C-5), 69.75 (Bn), 69.74, 71.46, 73.31, 73.51, 74.42, 74.48,
75.14, 76.06, 76.13, 76.32, 76.86, 79.19 (4 ´ C-2, 4 ´ C-3, 4 ´ C-4),
93.85 (C-1), 94.23 (C-1), 94.49 (C-1), 95.19 (C-1), 108.60 (iPr),
108.64 (iPr), 108.69 (iPr), 109.10 (iPr), 127.61 (Bn), 128.33 (Bn),
128.49 (Bn), 128.97 (Bn), 170.91 (OAc).
21b:
1H NMR (CDCl3): d = 1.17 (d, 3H, J5¢¢¢,6¢¢¢ = 6.6 Hz, H-6²¢), 1.20 (d,
3H, J5,6 = 6.6 Hz, H-6), 1.29 (d, 3H, J5²,6² = 6.6 Hz, H-6²), 1.31 (s,
3H, iPr), 1.32 (s, 3H, iPr), 1.33 (s, 3H, iPr), 1.34 (s, 6H, 2 ´ iPr), 1.40
(d, 3H, J5,6 = 6.6 Hz, H-6), 1.49 (s, 3H, iPr), 1.51 (s, 3H, iPr), 1.56 (s,
3H, iPr), 2.16 (s, 3H, OAc), 3.66 (dd ≈ t, 1H, J1²,2² ≈ J2²,3² = 7.6 Hz,
H-2²), 3.70 (dd, 1H, J1,2 = 3.5 Hz, J2,3 = 8.6 Hz, H-2), 3.78 (ddd, 1H,
J4,5 = 2.1 Hz, J5,6 = 6.6 Hz, H-5), 3.89 (dd, 1H, J1,2 = 3.6 Hz, J2,3 = 8.1
Hz, H-2), 3.94 (ddd ≈ m, 1H, J4,5 = 2.5 Hz, J5,6 = 6.6 Hz, H-5), 3.97
(m, 2H, H-4, H-4²), 4.04 (dd, 1H, J3,4 = 5.1 Hz, J4,5 = 2.5 Hz, H-4),
4.10 (m, 2H, H-3², H-4¢¢¢), 4.21 (dd, 1H, J2,3 = 8.6 Hz, J3,4 = 5.6 Hz,
H-3), 4.27 (dd, 1H, J2,3 = 8.1 Hz, J3,4 = 5.6 Hz, H-3), 4.34 (dd, 1H,
C45H66O18 calcd
(895.01) found
C
60.39
59.95
H
7.43
7.22
(1) Pulverer, G.; Beuth, J.; Ko, H. L.; Pichlmaier, H.; Said, S.; Oette,
K.; Uhlenbruck, G. Erfahrungsheilkunde 1994, 2, 52.
(2) Goldstein, I. J.; Hayes, C. E. Adv. Carbohydr. Chem. Biochem.
1978, 35, 127.
(3) Lee, Y. C. Carbohydr. Res. 1978, 67, 509.
(4) a) Flowers, H. M.; Levy, A.; Sharon, N. Carbohydr. Res. 1967, 4,
189.
J2¢¢¢,3¢¢¢ = 8.6 Hz, J3¢¢¢,4¢¢¢ = 5.1 Hz, H-3¢¢¢), 4.54 (ddd, 1H, J4,5 = 2.5 Hz,
J5,6 = 6.6 Hz, H-5), 4.58 (d ≈ m, 1H, JBn =11.7 Hz, Bn), 4.59
(ddd ≈ m, 1H, J4¢¢¢,5¢¢¢ = 2.5 Hz, H-5¢¢¢), 4.78 (d, 1H, JBn =11.7 Hz, Bn),
4.81 (d, 1H, J1²,2² = 8.5 Hz, H-1²), 4.90 (d, 1H, J1,2 = 3.8 Hz, H-1),
4.94 (d, 1H, J1,2 = 3.2 Hz, H-l), 5.06 (dd, 1H, J1¢¢¢,2¢¢¢ = 3.6 Hz, J2¢¢¢,3¢¢¢
= 8.6 Hz, H-2¢¢¢), 5.57 (d, 1H, J1¢¢¢,2¢¢¢ = 3.6 Hz, H-1²¢), 7.3–7.4 (m, 5H,
Bn).
b) Dejter-Juszynski, M.; Flowers, H. M. Carbohydr. Res. 1974,
37, 75.
c) Dejter-Juszynski, M.; Flowers, H. M. Carbohydr. Res. 1975,
41, 308.
(5) a) Jain, R. K.; Matta, K. L. Tetrahedron Lett. 1990, 31, 4325.
b) Jain, R. K.; Matta, K. L. Carbohydr. Res, 1990, 208, 51.
c) Jain, R. K.; Matta, K. L. Carbohydr. Res. 1990, 208, 280.
d) Jain, R. K.; Vig, R.; Rampal, R.; Chandrasekaran, E. V.; Matta,
K. L.; Khushi. L. J. Am. Chem. Soc. 1994, 116, 12123.
e) Baumann, H.; Jansson, P.-E.; Kenne, L. J. Chem. Soc., Perkin
Trans. 1 1991, 2229.
13C NMR (CDCl3): d = 16.05 (C-6), 16.13 (2 ´ C-6), 16.63 (C-6),
21.21 (OAc), 26.41 (iPr), 26.53 (iPr), 26.64 (2 ´ Pr), 28.06 (iPr),
i
28.13 (iPr), 28.37 (iPr), 28.49 (iPr), 62.40 (C-5). 62.49 (C-5), 63.23
(C-5), 68.78 (C-5), 70.73 (Bn), 71.36, 73.51, 74.01, 74.42. 74.49,
74.63, 76.06, 76.28, 76.46, 78.20 (4 ´ C-2, 4 ´ C-3, 4 ´ C-4), 95.47
i
(C-1), 95.51 (C-1), 96.03 (C-1), 101.58 (C-1), 108.39 (2 ´ Pr),
108.92 (iPr), 109.41 (iPr), 128.23 (Bn), 128.36 (Bn), 128.53 (Bn),
137.91 (Bn), 170.53 (OAc).
(6) Dekany, G.; Ward, P.; Toth, I. J. Carbohydr. Chem. 1995, 14,
227.