Preparation of various C-2 branched carbohydrates using intramolecular radical reactions

Article abstract of DOI:10.1016/S0008-6215(00)00246-9

A new and efficient method for the facile synthesis of C-2 branched carbohydrates has been developed using an intramolecular radical cyclization-fragmentation reaction. The desired C-2 branched glucopyranosides were isolated in 40-84% yield. Additionally, an unexpected furanoside was obtained from a tributyltin iodide-promoted rearrangement of the radical intermediate. The C-2 formyl glycal was also isolated in good yield using tris(trimethylsilyl)silane (TTMSS) as the reducing agent. This method was extended to synthesize a β C-2 branched glucopyranoside, a C-2 branched galactoside and a C-2 cyano glucopyranoside.

Full text of DOI:10.1016/S0008-6215(00)00246-9

www.elsevier.nl/locate/carres
Carbohydrate Research 329 (2000) 731–744
Preparation of various C-2 branched carbohydrates
using intramolecular radical reactions
Sung Won Tina Choe a,*, Michael E. Jung b
aDepartment of Chemistry and Biochemistry, Loyola Marymount Uni6ersity, 7900 Loyola Boule6ard, Los Angeles,
CA 90045-8225, USA
bDepartment of Chemistry and Biochemistry, Uni6ersity of California, Los Angeles, CA 90024, USA
Received 6 July 2000; accepted 10 August 2000
Abstract
A new and efficient method for the facile synthesis of C-2 branched carbohydrates has been developed using an
intramolecular radical cyclization–fragmentation reaction. The desired C-2 branched glucopyranosides were isolated
in 40–84% yield. Additionally, an unexpected furanoside was obtained from a tributyltin iodide-promoted rearrange-
ment of the radical intermediate. The C-2 formyl glycal was also isolated in good yield using tris(trimethylsilyl)silane
(TTMSS) as the reducing agent. This method was extended to synthesize a b C-2 branched glucopyranoside, a C-2
branched galactoside and a C-2 cyano glucopyranoside. © 2000 Elsevier Science Ltd. All rights reserved.
Keywords: C-2 Branched carbohydrates; Intramolecular radical cyclization–fragmentation reaction; Formyl glycal
sired C-2 formyl glucopyranoside 4a (Scheme
1).
1. Introduction
While investigating the synthesis of the po-
tential antiviral agents cyclophellitol 1b and
1a, an efficient method was required to con-
struct a C-2 formyl glucopyranoside 4a [1].
The sequence of reactions used in the synthe-
sis of cyclophellitol was lengthy and repetitive,
although the overall yield was acceptable [2].
The sequence required a Swern oxidation of
the mannopyranoside 2, followed by a Wittig
olefination to produce 3 in 70% yield (two
steps). Hydroboration of the olefin 3 afforded
a mixture of hydroxymethylglucopyranosides
that was oxidized to give C-2 formyl adducts
4ab. The aldehydes were treated under mild
basic conditions overnight to furnish the de-
Various methods have been reported for the
preparation of C-2 branched sugars [3]. Bala-
subramanian and co-workers published a
short route to C-2 formyl glycals using the
Vilsmeier–Haack reaction [4]. The reported
reaction conditions, however, were too harsh
for acid-labile protective groups. The most
direct approach was accomplished by Kahne
and co-workers using an intermolecular radi-
cal trapping of carbon monoxide (CO). How-
ever, the reported low yields (5–37%) and the
required reaction conditions (1200–1400 psi
CO) made it less attractive as a general
method for the preparation of C-2 branched
sugars [5].
This paper describes a new method to syn-
thesize a C-2 formyl carbohydrates using com-
mercially available glucals by employing an
intramolecular cyclization–fragmentation rad-
* Corresponding author. Tel.: +1-310-3387405; fax: +1-
310-3382905.
E-mail address: tchoe@lmumail.lmu.edu (S.W.T. Choe).
0008-6215/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(00)00246-9

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S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
group upon b-scission onto the side chains of
carbohydrates.
2. Results and discussion
2-Iodo glucopyranoside 7 was prepared in
75% yield from commercially available tri-O-
acetyl-
D
-glucal (5) by addition of N-iodosuc-
cinimide
and commercially available
dimethylvinyl carbinol (Scheme 2) [8]. Ozonol-
ysis and reduction with methyl sulfide fur-
nished the desired iodoaldehyde 9 in 96%
yield. To test the feasibility of the radical
cyclization, 7 was subjected to tributyltin hy-
dride-promoted radical cyclization, which suc-
cessfully furnished the cyclized product 13 in
68% yield as a 1:1 mixture of diastereomers.
The free-radical promoted cyclization of the
aldehyde 9 produced a mixture of products in
varying yields depending on the reaction con-
ditions. The products from the radical reac-
tions were separated using flash column
chromatography. The desired formyl-transfer
product 11 was isolated in 40% yield under
optimal conditions (Table 1, Method A). In
addition to the C-2 formyl glucopyranoside
11, the bicyclic alcohols 14ab as a 1:1 mixture
of diastereomers, the C-2 formyl glycal 17,
and the directly reduced sugar 19 were iso-
lated from the reaction. An unexpected furan-
oside 16 was isolated, and the structure was
determined by careful spectroscopic analysis.
Scheme 1. Synthesis of 2-C-formyl glucoside 3a. Reagents: (i)
(a) DMSO, TFAA, TEA, (b) Wittig; (ii) (a) BH3·DMS, THF,
(b) DMSO, TFAA, TEA; (iii) TEA.
ical reaction (Scheme 2) [6]. The functionaliz-
able formyl moiety is ideal to further branch
the sugar if needed. The mechanism for the
formation of the desired C-2 formyl sugar
requires the generation of a secondary alkyl
radical from iodoaldehydes 9 and 10. The
resulting radical adds intramolecularly to the
aldehyde group at the C-1 center of the sugar
to give the highly reactive bicyclic alkoxy rad-
ical. The radical intermediate undergoes b-
scission to produce an a-isopropoxy radical,
which upon reduction affords the formyl-
transfer products 11 and 12. A conceptually
similar process was reported by Fraser-Reid
and co-workers [7]. They reported a number
of examples that transposes an aldehyde
Scheme 2. Synthesis of the radical substrates and the products from the radical reactions. Reagents: (i) NIS, dimethylvinyl
carbinol, acetonitrile; (ii) O3, DMS; (iii) Bu3SnH, AIBN, PhH.

S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
733
Table 1
Representative reaction conditions and product distribution for the radical reaction a,b
Method
[9]c
Time (h) d
[11]
[14]
[16]
[17]
[19]
23
9
A
A
A
A
A
B
B
B
B
B
0.004
0.005
0.01
0.02
0.03
0.006
0.01
0.021
0.024
0.024
0.5
2
0.5
6
5
5
1.5
3
1.5
3
60
27
42
38
42
40
16
21
20
10
17
20
13
33
13
65
17
32
11
31
20
30
41
17
a Method A: typical reaction was conducted in benzene with 1.0–1.5 equiv of Bu3SnH and 0.01–0.5 equiv of AIBN under reflux.
b Method B: typical reaction was conducted in toluene with 1.0–1.5 equiv of TTMSS and 0.01–0.5 equiv of AIBN under reflux.
c Initial concentrations (mol/L) of the deoxyiodoglucoside 9.
d Time required to deliver the reducing agent using a syringe pump.
Scheme 3. Proposed mechanism for the formation of the furanoside and NOE data.
NMR analysis of 16 indicated the absence
of large trans-diaxial coupling constants and
axial–equatorial coupling constants typical
for glucopyranosides. Instead, coupling con-
stants expected from a furanoside ring system
were observed. We propose that the furan-
oside 16 is formed from a tributyltin iodide-
catalyzed rearrangement of the radical inter-
mediate 14a (Scheme 3). The mechanism
involves the complexation of the pyran oxy-
gen with the iodostannane, followed by a
pyranoside ring opening to give 16A. The
resulting oxonium ion 16A would then be
attacked by the C-4 acetate group to afford
16B, followed by an internal (or intermolecu-
lar) acetate transfer to give the furanoside 16.
The stereochemistry of the alcohol was deter-
mined using NOE difference spectra (Scheme
3). The NOE difference spectra of H-3 (5.37
ppm) showed a strong enhancement of the
signal for H-4 (4.74 ppm) and a weak en-
hancement of the signal for H-7 (3.86 ppm),
H-2 (2.45 ppm) and OH (2.46 ppm). Irradia-
tion of H-7 (3.86 ppm) showed weak enhance-
ment of H-3 (5.37 ppm) but a strong
enhancement of the signal for H-2 (2.45 ppm)
and one of the methyl singlets (1.19 ppm).
Irradiation of the methyl singlet at 1.19 ppm
showed a strong NOE to both H-2 and H-7,
which added further evidence that this methyl
group is cis to both H-2 and H-7. Lastly,
irradiation of the methyl singlet at 1.39 ppm
showed a strong enhancement of OH (2.46
ppm) but a weak enhancement of H-7 and no
NOE enhancement of H-2. The methyl singlet
at 1.39 ppm was therefore assigned cis to OH
and trans to both H-2 and H-7.
Chatgilialoglu and co-workers reported that
tris(trimethylsilyl)silane (TTMSS) rivaled tri-

734
S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
butyltin hydride in efficiency as a reducing agent
with several advantages [9]. They found that the
silane was less reactive as a hydrogen donor than
the stannanes since the SiꢀH bond is 5 kcal
mol−1 stronger than the SnꢀH bond. In addi-
tion, removal of the byproducts from the radical
reaction using TTMSS was reported to be much
easier than with the tin reagent. To diminish the
formation of 14 and 19, the radical precursor
9 was subjected to TTMSS radical conditions.
Furthermore, the sterically bulky nature of the
intermediate tris(trimethylsilyl)silyl iodide was
expected to function as a poor catalyst for the
rearrangement needed to give the furanoside 16.
As anticipated, the radical reactions using
TTMSS (Table 1, Method B) did not form any
of the furanoside 16. However, a 65% yield of
the C-2 formyl glycal 17 was isolated. This route
to C-2 formyl glycals is more general by allow-
ing for acid-sensitive protecting groups than the
known method via the Vilsmeier–Haack reac-
tion. Along with the glycal, the bicyclic alcohols
14ab were isolated in varying yields depending
on the reaction conditions. The desired formyl-
transfer product 11 was isolated in 41% yield
under optimal conditions. Efforts towards in-
creasing the yield of 11 using in situ generation
of the reducing agent and attempts using hex-
abutyldistannane under photolytic conditions
were unsuccessful.
Conversion of the commercially available
tri-O-benzyl- -glucal (6) [8] by the same two-
D
step procedure furnished the desired radical
precursor 10 (Scheme 2). A solvent effect was
observed on the iodoetherification of 6. Namely,
a reaction using tetrahydrofuran as the solvent
afforded the diaxial a glucoside 8a exclusively
in 86% yield. However, using acetonitrile as the
solvent, the diaxial glucoside 8a and the diequa-
torial glucoside 8b were isolated as a 4:1 mixture
in 62% yield. The two diastereomers were
separated and ozonized to give an 82% yield of
the diaxial iodoaldehyde 10a and a 76% yield
of the diequatorial iodoaldehyde 10b. Easy
access to the two isomers allowed us to inves-
tigate not only the a-formyl transfer reactions
but also the feasibility of extending this process
to generate the b-branched sugars.
The formyl-transfer reaction of 10a using
tributyltin hydride gave 12 in 20% yield under
optimal conditions (Table 2). Under most ex-
perimental conditions, the alcohols 15ab were
isolated as the major product. Formyl glycal 18
was isolated in 21% yield. No furanosides and
only traces of the directly reduced product 20
were detected in the radical reactions of 10ab.
Using TTMSS on the radical substrate 10a
yielded the bicyclic alcohol 15 with only traces
of other byproducts.
Extending the formyl-transfer reaction to b
branched sugars, the iodoaldehyde 10b was
subjected to radical reaction conditions (Table
2). The reaction yielded the alcohol 21 as the
major product with yields as high as 82% with
no traces of the b C-2 formyl product.
Table 2
Product distribution for the radical reaction
[10]
Time (h)
[12]
[15]
[18]
[21]
The radical reactions for the tri-O-acetyl and
the tri-O-benzyl glucal substrates furnished
substantial amounts of the bicyclic alcohols 14,
15, and 21. Therefore, in order to increase the
yields of 11 and 12, these intermediates were
subjected to reaction conditions that regenerate
the alkoxy radical, thus allowing the b-fission
to complete the rearrangement process [10].
However, attempts at converting the alcohols to
the desired formyl-transfer products were un-
successful. In several cases the 1:1 mixture of the
alcohols 14ab epimerized to give mostly one
isomer upon reaction with mercuric oxide and
iodine under photolysis. This result indicated
the formation of the hypoiodite and the gener-
ation of the aldehyde but that the bicyclic
alcohol had reformed to give the thermody-
0.009 a
0.009 a
0.01 a
3.4
6.5
3
6.5
3
0.5
3
3
14
20
20
11
17
30
20
58
60
53
17
21
0.02 a
0.02 a
0.004 b
0.005 b
0.03 b
0.009c
67
82
67
3.5
45
a Typical reaction was conducted in benzene with 10a,
1.0–1.5 equiv of Bu3SnH and 0.01–0.5 equiv of AIBN under
reflux.
b Typical reaction was conducted in benzene with 10b,
1.0–1.5 equiv of Bu3SnH and 0.01–0.5 equiv of AIBN under
reflux.
c Radical reaction with 10a using TTMSS as the reducing
agent.

S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
735
indicated that the initial radical cyclization to
the aldehyde occurred but the subsequent frag-
mentation of the alkoxyl radical to form the
a-isopropoxy radical was problematic. There-
fore, the intermediate a-isopropoxy radical
was not stable enough to drive the reaction to
completion. With this in mind, a modified
radical substrate was synthesized to favor the
fragmentation process by increasing the stabil-
ity of the resulting radical. Initially, we tried
changing the substrate such that the resulting
radical from the fragmentation would be an
a,a-diphenyl radical. In order to synthesize the
radical substrate it was necessary to add a,a-
diphenyl allyl alcohol (easily prepared from
benzophenone and vinylmagnesium bromide)
to 5 and 6. However, many attempts at the
iodoetherification reaction were unsuccessful
presumably due to the low reactivity of the
diphenyl allyl alcohol towards electrophilic re-
actions and also its propensity to rearrange to
b-phenylcinnamyl alcohol with traces of acid.
Next, a-phenyl allyl alcohol 27 was added to 5
and 6 since these substrates would produce a
stable benzyl radical upon fragmentation
(Scheme 5). The radical substrates 30 and 31
were prepared by reacting the glucals with
a-phenyl allyl alcohol and N-iodosuccinimide
in acetonitrile. The iodoetherification reaction
furnished only the diaxial products as a 1:1
diastereomeric mixture at the allylic centers of
the glucosides. Although the mixture of
diastereomers were inseparable, the newly gen-
erated chiral center was not important since
the radical reaction would produce a benzyl
group. The mixture of diastereomers was
ozonized to afford the key aldehydes 30 and 31
in 74% yields.
Scheme 4. Synthesis of C-2 branched galactoside. Reagents
used were the same as Scheme 2.
Scheme 5. Synthesis of 2-C-formyl glucosides. Reaction con-
ditions were the same as Scheme 2.
namically stable bicyclic alcohol. The NMR of
the photolyzed product showed H-2 as an
apparent doublet of triplets with J=5.7, 11.5
Hz. Thus H-2 should be nearly trans-diaxial to
both H-3 and H-7, indicating 14b as the
epimerized product. Similar photochemically
induced inversions of configuration of alcohols
were reported by Binkley and co-workers [11].
The application of this formyl-transfer
method to commercially available tri-O-acetyl-
D-galactal was explored. The same two-step
sequence of reactions (Scheme 2) was repeated
to synthesize the radical precursor 23 (Scheme
4). Iodoetherification of the galactal gave only
the diaxial galactoside 22 in 42% yield.
Ozonolysis of 22 furnished the radical precur-
sor 23 in 84% yield. Radical reaction of the
galactoside 23 using tributyltin hydride condi-
tions successfully produced the desired formyl-
transfer product 24 in 50% yield (0.05 M, 2 h)
along with an inseparable mixture of what
appeared to be the bicyclic alcohol 25 and the
rearranged furanoside 26. The structures of
these byproducts were not confirmed since the
two compounds were inseparable.
The modified radical precursor 30 yielded
the formyl-transfer adduct 32 in 50% yield
under optimal conditions. Radical reaction of
the tri-O-benzyl iodoglucoside 31 produced
the desired glucoside 33 in 84% yield with only
traces of the glycal 18. Therefore, the driving
force of producing a benzyl radical caused the
fragmentation to occur more efficiently, lead-
ing to higher yields of the desired C-2 formyl
glucopyranosides. Thus, this simple three-step
procedure of iodoetherification, ozonolysis,
and radical cyclization–fragmentation effi-
ciently converts glucals into a C-2 formyl
pyranosides.
The collective results of the radical reactions

736
S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
3. Experimental
To further explore this radical fragmenta-
tion process, this reaction was extended to
nitrile-transfer reactions. Curran and co-work-
ers reported several examples of intramolecu-
lar nitrile-transfer reactions on non-carbo-
hydrate systems [12]. The radical substrates
were prepared from 5 and 6 using acetone
cyanohydrin and N-iodosuccinimide. This re-
action successfully furnished 34 in 82% yield
and 35 in 42% yield (Scheme 6). The
iodoetherification reaction using mandeloni-
trile as the nucleophile gave unsatisfactory
yields of the radical substrates, presumably
due to the same reasons given for a,a-diphenyl
allyl alcohol.
The iodoglucoside 34 successfully produced
the nitrile-transfer product 36, albeit in 30%
yield along with the directly reduced glucoside
37. The cyano-transfer reactions with the tri-
O-benzyl glucoside 35 led to decomposition of
the starting material.
A new method for the construction of C-2
branched sugars was developed using an in-
tramolecular formyl- and cyano-transfer reac-
tions via a radical cyclization–fragmentation
process. The desired formyl-transfer product
11 was isolated in 41% yield along with the
furanoside 16. Tris(trimethylsilyl)silane gave
good yields of the formyl glycal 17, a com-
pound otherwise difficult to synthesize di-
rectly. In addition, this study showed that the
formyl-transfer method is a viable means to
afford not only the a C-2 branched sugars but
also the b C-2 branched sugar 21. The yields
of the formyl-transfer reactions were im-
proved by changing the radical substrates to
give a benzyl radical upon fragmentation. This
method was also used to synthesize a C-2
branched galactopyranoside and a C-2 cyano
glucoside 36.
General methods.—1H NMR spectra were
recorded on a Bruker AF 200 spectrometer,
operating at 200.132 MHz, a Bruker AM 360
spectrometer, operating at 360.134 MHz, and
the Bruker ARX 400 spectrometer, operating
at 400.130 MHz, and are so indicated. 13C
NMR spectra were recorded on the AF 200,
operating at 50.323 MHz, the AM 360, oper-
ating at 90.556 MHz, the ARX 400, operating
at 100.625 MHz, and the ARX 500 spectrom-
eter, operating at 125.767 MHz, and are also
specified. IR spectra were recorded on a Nico-
let 510 FTIR as a liquid film (neat) on sodium
chloride plates, and the spectra were refer-
enced to a polystyrene standard. High-resolu-
tion mass spectra were obtained from the
Mass Spectrometry Facilities at the University
of California, Riverside and at the University
of California, Los Angeles using ZAB 7070
HP spectrometers. The chemical-impact high-
resolution mass spectra (CIHRMS) were ob-
tained using ammonia as the reagent gas. All
optical rotations were obtained from a
Perkin–Elmer 243 polarimeter at ambient
temperature and referenced to the sodium D
line (589 nm). Thin-layer chromatography
(TLC) was performed using E. Merck Silica
Gel 60 F254 0.2 mm aluminum-backed plates.
Visualization was accomplished using ultravi-
olet light or by using an anisaldehyde stain
[p-anisaldehyde (2 mL) in EtOH (85 mL),
glacial AcOH (10 mL), and concd H2SO4 (2
mL)]. Silica gel column chromatography was
conducted on E. Merck Silica Gel 60 (70–230
mesh). Concentration in vacuo refers to the
removal of solvent using a Bu¨chi rotary
evaporator.
1,1-Dimethyl-2-propenyl 3,4,6-tri-O-acetyl-
2-deoxy-2-iodo-h- -mannopyranoside (7). A
D
solution of commercially available tri-O-ace-
tyl- -glucal (3 g, 11.0 mmol) in dry MeCN (30
D
mL) was stirred for 30 min with N-iodosuc-
cinimide (2.5 g, 11.0 mmol) in the dark. To
the reaction mixture was added dropwise 2-
methyl-3-buten-2-ol (5.7 mL, 55.0 mmol), and
the mixture was stirred at rt for an additional
16 h. The reaction mixture was diluted with
EtOAc, then washed several times with aq
sodium thiosulfate until the organic layer
Scheme 6. Synthesis of 2-C-cyanoglucoside.

S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
737
in the manner described for 7 to yield 201 mg
(62% based on recovered starting material): Rf
0.61 (1:2 EtOAc–hexane); 1H NMR (360
MHz, CDCl3): l 7.29 (m, 15 H, Ph), 6.13 (dd,
1 H, J8,9 10.8, J8,9% 17.6 Hz, H-8), 5.22 (d, 1 H,
H-9), 5.13 (d, 1 H, H-9%), 4.97 (d, 1 H, J8,9 10.1
Hz, benzyl), 4.85–4.78 (m, 2 H), 4.64–4.50
(m, 3 H), 4.59 (d, 1 H, J1,2 9.2 Hz, H-1), 3.92
(t, 1 H, J1,3 9.0 Hz, H-2), 3.74–3.58 (m, 3 H),
3.55 (t, 1 H, J2,4 9.7 Hz, H-3), 3.45 (m, 1 H),
1.41, 1.38 (each s, 6 H, Me).
turned clear. The organic layer was combined,
dried over MgSO4 and concentrated in vacuo.
The resulting yellow oil was purified by flash
column chromatography (1:5 EtOAc–hexane)
to give 3 g (84% based on recovered starting
material) of the desired iodo sugar 7 as a clear
liquid along with 1 g of recovered tri-O-ace-
tyl- -glucal: [h]D +18.3° (c 12.2, CH2Cl2); Rf
D
0.73 (1:1 EtOAc–hexane); IR (neat): 2982,
2940, 1752, 1433, 1416, 1368, 1231, 1113,
1
1030, 938, 920 cm−1; H NMR (360 MHz,
CDCl3): l 5.81 (dd, 1 H, J8,9 10.7, J8,9% 17.5
Hz, H-8), 5.35 (t, 1 H, J3,5 9.6 Hz, H-4), 5.28
(bs, 1 H, H-1), 5.19 (m, 2 H, H-9, H-9%), 4.68
(dd, 1 H, J2,3 4.1, J3,4 9.5 Hz, H-3), 4.40 (dd, 1
H, J1,2 1.3, J2,3 4.1 Hz, H-2), 4.23 (m, 3 H,
H-5, H-6, H-6%), 2.09, 2.07, 2.05 (each s, 9 H,
1,1-Dimethyl-2-oxoethyl 3,4,6-tri-O-acetyl-
2-deoxy-2-iodo-h- -mannopyranoside (9). To
D
a solution 7 (1.2 g, 2.6 mmol) in dry CH2Cl2
(120 mL) at −78 °C was added a steady
stream of ozone until the clear solution turned
dark blue (15 min). The excess ozone was
purged with nitrogen (10 min) methyl sulfide
(0.94 mL, 12.8 mmol) was added and the
mixture was allowed to stir at −78 °C for an
additional hour before warming to rt. The
solvent was removed in vacuo and the result-
ing yellow residue was purified by flash
column chromatography (3:7 EtOAc–hexane)
to give 1.2 g (96%) of the desired aldehyde 9
as a clear oil: [h]D +22.2° (c 3.7, CH2Cl2); Rf
0.64 (1:1 EtOAc–hexane); IR (neat): 2986,
2940, 1748, 1435, 1370, 1231, 1161, 1115,
13
OAc), 1.35, 1.32 (each s, 6 H, Me); C NMR
(90 MHz, CDCl3): l 170.4, 169.6, 169.3,
142.0, 115.1, 96.4, 78.3, 68.9, 68.7, 67.6, 62.2,
31.4, 27.6, 24.9, 20.8, 20.6, 20.5; CIHRMS
(m/z): 485.0672 (M+). Calcd for C17H25IO8
485.0641 (M+).
1,1-Dimethyl-2-propenyl 3,4,6-tri-O-benzyl-
2-deoxy-2-iodo-h-D-mannopyranoside
(8a).
Prepared from 6 (1 g, 2.4 mmol) using dry
THF in the manner as described for 7 to yield
460 mg (86% based on recovered starting ma-
terial): [h]D +12.2° (c 0.9, CH2Cl2); Rf 0.61
(1:2 EtOAc–hexane); IR (neat): 3031, 2979,
2926, 2861, 1497, 1455, 1364, 1144, 1113,
1
1040, 1013, 968, 949, 920 cm−1; H NMR
(360 MHz, CDCl3): l 9.44 (s, 1 H, CHO), 5.28
(d, 1 H, J1,2 1.7 Hz, H-1), 5.25 (t, 1 H, J3,5 9.2
Hz, H-4), 4.60 (dd, 1 H, H-3), 4.47 (dd, 1 H,
H-2), 4.14 (m, 2 H), 3.98 (m, 1 H), 2.07, 2.06,
2.03 (each s, 9 H, OAc), 1.34, 1.33 (each s, 6
1
1053, 1028, 1000 cm−1; H NMR (360 MHz,
CDCl3): l 7.30 (m, 15 H, Ph), 5.82 (dd, 1 H,
J8,9 10.7, J8,9% 17.5 Hz, H-8), 5.36 (d, 1 H, J1,2
0.7 Hz, H-1), 5.16 (d, 1 H, H-9), 5.14 (d, 1 H,
H-9%), 4.87 4.75, 4.72, 4.56, 5.11, 4.99 (each d,
6 H, J 10.5 Hz, benzyl), 4.37 (dd, 1 H, J1,2 1.4,
J2,3 4.0 Hz, H-2), 4.07 (m, 1 H, H-5), 3.97 (dd,
1 H, J3,4 8.8, J4,5 9.7 Hz, H-4), 3.83 (dd, 1 H,
J5,6 4.2, J6,6% 10.7 Hz, H-6), 3.69 (dd, 1 H,
H-6%), 3.40 (dd, 1 H, J2,3 4.0, J3,4 8.7 Hz, H-3),
1.34, 1.28 (each s, 6 H, Me); 13C NMR (90
MHz, CDCl3): l 142.7, 138.4, 138.2, 137.8,
128.3 (2C), 128.2, 128.1, 128.0, 127.7, 127.6
(2C), 127.3, 114.6, 96.7, 77.8, 76.9, 76.1, 75.2,
73.2, 71.9, 70.9, 68.8, 35.7, 27.8, 25.1; HRMS
FAB (m/z): 627.1608 (M+−H). Calcd for
C32H36IO5 627.1581 (M+−H).
13
H, Me); C NMR (90 MHz, CDCl3): l 200.8,
170.5, 169.7, 169.3, 97.1, 82.1, 69.4, 68.7, 67.6,
62.2, 29.7, 21.5, 21.1, 20.8, 20.6, 20.5;
CIHRMS (m/z): 504.0731 (M+NH+4 ). Calcd
for C16H27INO9 504.0751 (M+NH+4 ).
1,1-Dimethyl-2-oxoethyl 3,4,6-tri-O-benzyl-
2-deoxy-2-iodo-h- -mannopyranoside (10a).
D
Prepared from 8a (690 mg, 1.09 mmol) using
the same procedure described for 9 to yield
0.60 g (86%): [h]D +13.0° (c 1.5, CH2Cl2); Rf
0.69 (1:2 EtOAc–hexane); IR (neat): 2923,
2865, 1736, 1455, 1374, 1267, 1246, 1115,
1046, 911 cm−1; 1H NMR (360 MHz, CDCl3):
l 9.54 (s, 1 H, CHO), 7.36 (m, 15 H, Ph), 5.46
(d, 1 H, J1,2 1.58 Hz, H-1), 4.87, 4.75, 4.72
(each d, 3 H, J 10.1 Hz, benzyl), 4.56 (m, 4
H), 4.09 (m, 1 H), 3.97 (dd, 1 H, J3,4 8.4, J4,5
1,1-Dimethyl-2-propenyl 3,4,6-tri-O-benzyl-
2-deoxy-2-iodo-i- -glucopyranoside (8b). Pre-
D
pared from 6 (517 mg, 24 mmol) using MeCN

738
S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
Typical radical reaction using tris-
(trimethylsilyl)silane (TTMSS). To a reflux-
ing solution of 9 (236 mg, 0.484 mmol) in
degassed toluene (15 mL) was added a solu-
tion of tris(trimethylsilyl)silane (0.15 mL,
0.484 mmol), and AIBN (0.04 g, 0.242
mmol) in toluene (5 mL) via syringe pump
over a 1.5 h period. The reaction was al-
lowed to heat at reflux for an additional 4 h
before cooling to rt. The reaction mixture
was concentrated in vacuo, then the prod-
ucts were purified by flash column chro-
matography (3:7 EtOAc–hexane). Depending
on the reaction conditions, i.e., the concen-
trations and the rate of addition of the tin
hydride, we observed different products (see
Tables 1 and 2).
8.6 Hz, H-4), 3.80 (dd, 1 H, J5,6 4.6, J6,6%
10.7 Hz, H-6), 3.69 (dd, 1 H, H-6%), 3.41
(dd, 1 H, J2,3 4.0, J3,4 8.4 Hz, H-3), 1.34,
1.33 (each s, 6 H, Me); 13C NMR (90 MHz,
CDCl3): l 201.6, 138.2, 137.9, 137.5, 128.3
(2C), 128.2, 128.0 (2C), 127.8, 127.7, 127.5,
127.4, 97.3, 81.6, 76.7, 75.8, 75.1, 73.3, 72.5,
71.0, 68.7, 33.8, 21.6, 21.1; CIHRMS (m/z):
629.1415 (M+−H). Calcd for C31H34IO6
629.1400 (M+ −H).
1,1-Dimethyl-2-oxoethyl 3,4,6-tri-O-benzyl-
2-deoxy-2-iodo-i-
D
-glucopyranoside
(10b).
Prepared from 8b (52 mg, 0.083 mmol) using
the same procedure described for 9 to yield
39.4 mg (76%): [h]D +28.2° (c 0.4, CH2Cl2);
IR (neat): 3031, 2926, 2855, 1732, 1497,
1455, 1360, 1310, 1273, 1213, 1111, 1074,
1
1045, 1028, 911 cm−1; H NMR (360 MHz,
Isopropyl 3,4,6-tri-O-acetyl-2-deoxy-2-C-
CDCl3): l 9.66 (s, 1 H, CHO), 7.32 (m, 15
H, Ph), 4.97, 4.86, 4.79, 4.60, 4.58, 4.49
(each d, 6 H, J 10.1 Hz, benzyl), 4.68 (d, 1
H, J1,2 8.9 Hz, H-1), 3.95 (dd, 1 H, J1,2 8.9,
J2,3 9.1 Hz, H-2), 3.70 (m, 4 H), 3.42 (m, 1
H), 1.39, 1.34 (each s, 6 H, Me); 13C NMR
(90 MHz, CDCl3): l 202.5, 137.9, 137.7,
137.6, 128.5, 128.4 (2C), 128.1 (2C), 127.9,
127.8 (2C), 127.7, 98.3, 87.1, 82.5, 79.2, 75.3,
75.2 (2C), 73.5, 68.7, 32.6, 22.6, 19.2;
CIHRMS (m/z): 648.1820 (M+NH+4 ).
Calcd for C31H34INO6 648.1822 (M+NH+4 ).
Typical radical reaction using tributyltin
hydride. To a refluxing solution of 9 (99.6
mg, 0.205 mmol) in degassed benzene (31
mL) was added a solution of tributyltin hy-
dride (0.055 mL, 0.205 mmol) and AIBN
(0.01 g, 0.061 mmol) over 2 h using a sy-
ringe pump. The reaction was allowed to
heat to reflux for an additional 3 h then
cooled to rt. The solvent was removed in
vacuo, and the yellow residue was diluted
with MeCN and washed with pentane sev-
eral times to remove all the tin byproducts.
The MeCN layers were combined and con-
centrated in vacuo to give a pale yellow oil.
The products of the radical reaction were
purified by flash column chromatography
(3:7 EtOAc–hexane). Depending on the re-
action conditions, i.e., the concentrations
and the rate of addition of the tin hydride,
we observed different products (see Tables 1
and 2).
formyl-h- -glucopyranoside (11): IR (neat):
D
1
2967, 1750, 1373, 1229, 1119, 1051 cm−1; H
NMR (400 MHz, CDCl3): l 9.48 (d, 1 H,
J2,CHO 2.5 Hz, CHO), 5.81 (t, 1 H, J3,5 9.3
Hz, H-4), 5.25 (d, 1 H, J1,2 4.0 Hz, H-1),
5.03 (t, 1 H, J2,4 9.7 Hz, H-3), 4.30 (dd, 1
H, J5,6 4.5, J6,6% 12.1 Hz, H-6), 4.15 (m, 1 H,
H-5), 4.08 (dd, 1 H, H-6%), 3.88 (septet, 1 H,
H-7), 2.78 (ddd, 1 H, H-2), 2.09, 2.05, 2.01
(each s, 9 H, OAc), 1.22, 1.11 (each d, 6 H,
J7,Me 6.2 Hz, Me); 13C NMR (100 MHz,
CDCl3): l 197.4, 170.6, 170.2, 169.8, 95.2,
77.1, 71.0, 68.9, 68.2, 68.1, 67.7, 61.9, 56.6,
23.0, 20.6 (2C); CIHRMS (m/z): 378.1761
(M+NH+4 ). Calcd for C16H28NO9 378.1764
(M+NH+4 ).
Isopropyl 3,4,6-tri-O-benzyl-2-deoxy-2-C-
formyl-h- -glucopyranoside (12): Rf 0.73 (1:2
D
EtOAc–hexane); 1H NMR (360 MHz,
CDCl3): l 9.47 (d, 1 H, J2,CHO 2.6 Hz,
CHO), 7.30 (m, 15 H, Ph), 5.19 (d, 1 H, J1,2
3.9 Hz, H-1), 4.90, 4.82, 4.77, 4.66, 4.56,
4.52 (each d, 6 H, J 11.0 Hz, benzyl), 4.36
(dd, 1 H, J3,4 8.9, J4,5 11.0 Hz, H-4), 3.94–
3.65 (m, 5 H), 2.71 (ddd, 1 H, H-2), 1.16,
1.05 (each d, 6 H, J7,Me 6.2 Hz, Me); 13C
NMR (100 MHz, CDCl3): l 199.8, 138.0,
137.8, 137.7, 128.4, 128.3, 128.2, 128.0, 127.8
(2C), 127.7, 127.6, 127.5, 95.4, 79.1, 74.9,
74.7, 73.5, 70.9, 69.8, 68.3, 58.5, 23.1, 21.2.
(one aliphatic carbon not resolved);
CIHRMS (m/z): 522.2832 (M+NH+4 ).
Calcd for C31H40NO6 522.2856 (M+NH+4 ).

S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
739
(m, 15 H, Ph), 5.19 (d, 1 H, J1,2 4.3 Hz, H-1),
4.63–4.32 (m, 7 H, benzyl, H-7), 4.04 (bs, 1 H,
OH), 3.94 (dt, 1 H, J2,3 1.4, J3,4 7.4 Hz, H-3),
3.80 (t, 1 H, J 7.2 Hz), 3.60 (m, 3 H), 2.64
(ddd, 1 H, J1,2 4.3, J2,7 4.3, J2,3 7.1 Hz, H-2),
1.36, 1.20 (each s, 6 H, Me); 13C NMR (90
MHz, CDCl3): l 137.6, 136.5, 128.5 (2C),
128.4, 128.3, 128.1, 128.0, 127.8 (2C), 127.7,
127.6, 100.9, 87.9, 79.0, 76.5, 73.4, 72.3, 71.9,
71.1, 71.0, 68.3, 47.9, 28.9, 23.9. Data for 15b:
Rf 0.35 (1:2 EtOAc–hexane); IR (neat): 3445,
3031, 2930, 2867, 1497, 1455, 1366, 1275,
[4R - (3hi,3ai,4i,5h,6i,7ai)] - 6 - [(Acetyl-
oxy)methyl]hexahydro - 2,2,3 - trimethyl - 4H-
furo[2,3-b]pyran-4,5-diol, diacetate (13). Pre-
pared from 7 (373 mg, 0.77 mmol) using typi-
cal radical reaction conditions described
above to yield 113 mg (68% based on recov-
ered starting material): Rf 0.44 (1:1 EtOAc–
hexane); IR (neat): 2973, 1744, 1456, 1437,
1372, 1231, 1165, 1130, 1032, 963, 916 cm−1
;
1H NMR (400 MHz, CDCl3): l 5.49–5.39 (m,
2 H), 5.30–5.29 (m, 1 H), 5.00–4.92 (m, 1 H),
4.92–5.00 (m, 1 H), 4.48–4.10 (m, 7 H), 3.15–
3.21 (m, 1 H, H-2), 2.52 (m, 1 H), 2.32 (m, 2
H), 2.10, 2.09, 2.07, 2.04, 2.03, 2.02 (each s, 18
H, OAc), 1.58, 1.52, 1.32, 1.30 (each s, 12 H,
Me), 1.26, 0.94 (each d, 6 H, J7,Me 6.8 Hz,
Me); 13C NMR (100 MHz, CDCl3): l 170.7,
169.6 (2C), 97.3, 83.1, 70.9, 68.8, 67.3, 63.2,
48.0, 43.0, 27.5, 22.3, 20.9, 20.8, 20.7, 13.3;
CIHRMS (m/z): 376.1976 (M+NH+4 ). Calcd
for C17H30NO8 376.1971 (M+NH+4 ).
1
1207, 1111, 1067, 1028 cm−1; H NMR (360
MHz, CDCl3): l 7.31 (m, 15 H, Ph), 5.50 (d,
1 H, J1,2 4.9 Hz, H-1), 4.80, 4.78, 4.68, 4.56,
4.55, 4.43 (each d, 6 H, J 11.6 Hz, benzyl),
4.19 (dd, 1 H, J3,4 7.7, J4,5 7.7 Hz, H-4), 3.94
(dd, 1 H, J2,3 8.2, J3,4 8.2 Hz, H-3), 3.86 (m, 2
H), 3.68 (m, 2 H), 2.61 (ddd, 1 H, J1,2 5.7, J2,7
5.7, J2,3 10.9 Hz, H-2), 2.60 (bs, 1 H, OH),
1.37, 1.19 (each s, 6 H, Me); 13C NMR (90
MHz, CDCl3): l 138.2, 137.7, 128.5, 128.4,
128.3, 128.0, 127.9, 127.8 (2C), 127.7, 127.6,
98.4, 84.9, 77.2, 76.8, 75.6, 73.9, 73.4, 73.0,
69.4, 49.7, 27.8, 23.4, 1. (one aromatic and
one aliphatic carbon not resolved); CIHRMS
(m/z): 522.2856 (M+NH+4 ). Calcd for
C31H40NO6 522.2867 (M+NH+4 ).
[3R-(3h,3ai,4i,5h,6i,7ai)]-6-[(Acetyloxy)-
methyl]hexahydro-2,2-dimethyl-4H-furo[2,3-b]
pyran-3,4,5-triol, 4,5-diacetate (14). Data for
14a: 1H NMR (360 MHz, CDCl3): l 5.45 (d, 1
H, J1,2 5.1 Hz, H-1), 5.39 (dd, 1 H, J3,4 8.7, J4,5
8.8 Hz, H-4), 5.15 (t, 1 H, J2,4 8.9 Hz, H-3),
4.32–4.12 (m, 3 H), 2.34 (ddd, 1 H, H-2),
2.06, 2.05, 2.04 (each s, 9 H, OAc), 1.41, 1.21
[3R - (3h,3ai,4i,5i(R*),6ai)] - 5 - [1,2 - Bis-
(acetyloxy)ethyl]hexahydro-2,2-dimethyl-furo-
[2,3-b]furan-3,4-diol, 4-acetate (16). [h]D
−18.8° (c 0.8, CH2Cl2); Rf 0.36 (2:3 EtOAc–
hexane); IR (neat): 3567, 2975, 2938, 1744,
1435, 1372, 1233, 1154, 1125, 1098, 1049, 984,
1
(each s, 6 H, Me). Data for 14b: H NMR
(360 MHz, CDCl3): l 5.51 (d, 1 H, J1,2 5.5 Hz,
H-1), 5.14 (t, 1 H, J3,5 6.4 Hz, H-4), 5.02 (dd,
1 H, J2,3 6.5, J3,4 9.2 Hz, H-3), 4.29 (dd, 1 H,
J5,6 5.1, J6,6% 12.2 Hz, H-6), 4.13–3.99 (m, 3 H,
H-5, H-6%, H-7), 2.34 (ddd, 1 H, J1,2 5.7, J2,7
5.7, J2,3 11.5 Hz, H-2), 2.08, 2.07, 2.06 (each s,
9 H, OAc), 1.44, 1.21 (each s, 6 H, Me). Data
for the mixture of isomers 14ab: IR (neat):
3480, 2977, 2938, 1748, 1435, 1370, 1237,
1
953 cm−1; H NMR (360 MHz, CDCl3): l
5.37 (bd, 1 H, H-3), 5.19 (d, 1 H, J1,2 4.1 Hz,
H-1), 4.74 (dd, 1 H, J3,4 1.9, J4,5 2.1 Hz, H-4),
4.08 (m, 2 H, H-6, H-6%), 4.05 (m, 1 H, H-5),
3.86 (dd, 1 H, J2,7 6.1, J7,OH 12.0 Hz, H-7),
2.46 (d, 1 H, OH), 2.45 (m, 1 H, H-2), 2.11,
2.10, 2.05 (each s, 9 H, OAc), 1.39, 1.19 (each
s, 6 H, Me); 13C NMR (90 MHz, CDCl3): l
170.6, 169.3, 169.1, 101.1, 87.7, 76.5, 70.2,
68.3, 66.5, 62.1, 47.2, 28.3, 23.5, 20.9, 20.8,
20.7; CIHRMS (m/z): 361.1488 (M+H+).
Calcd for C16H25O9 361.1498 (M+H+).
1161, 1113, 1036, 916 cm−1 13C NMR (90
;
MHz, CDCl3): l 171.1, 170.8, 169.8, 169.5,
97.5, 97.4, 83.3, 82.1, 78.5, 76.6, 71.3, 69.8,
69.3, 68.5, 68.3, 68.2, 62.6, 62.4, 50.5, 48.2,
27.8, 27.7, 23.0, 22.1, 20.9, 20.7 (2C);
CIHRMS (m/z): 378.1773 (M+NH+4 ). Calcd
for C16H28NO9 378.1764 (M+NH+4 ).
4R-(3hi,3ai,4i,5h,6i,7ai) Hexahydro-2,2-
dimethyl - 4,5 - bis(phenylmethoxy) - 6 - [(phenyl-
methoxy)methyl] - 4H - furo[2,3 - b]pyran - 3 - ol
(15ab). Data for 15a: Rf 0.50 (1:2 EtOAc–
1,5-Anhydro-3,4,6-tri-O-acetyl-2-deoxy-2-
C-formyl-h- -arabino-hex-1-enitol (17). [h]D
D
34.7° (c 0.5, CH2Cl2); Rf 0.30 (1:1 EtOAc–
1
hexane); H NMR (360 MHz, CDCl3); l 7.34
hexane); IR (neat): 2963, 2924, 2853, 1748,

740
S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
137.7, 128.7, 128.5, 128.3, 128.1, 127.9, 127.8
(2C), 127.6, 127.5, 99.4, 80.7, 77.2, 76.1, 74.9,
74.1, 73.5 (2C), 68.8, 50.0, 29.5, 23.2. (one
aliphatic carbon not resolved); CIHRMS (m/
z): 522.2850 (M+NH+4 ). Calcd for
C31H40NO6 522.2856 (M+NH+4 ).
1682, 1634, 1424, 1372, 1032, 1229, 1194,
1125, 1032 cm−1 1H NMR (360 MHz,
;
CDCl3): l 9.36 (bs, 1 H, CHO), 7.46 (s, 1 H,
H-1), 5.68 (bd, 1 H, H-3), 5.18 (t, 1 H, J3,5 3.5
Hz, H-4), 4.62 (m, 1 H, H-5), 4.47 (dd, 1 H,
J5,6 7.7, J6,6% 12.2 Hz, H-6), 4.17 (dd, 1 H,
13
1,1-Dimethyl-2-propenyl 3,4,6-tri-O-acetyl-
H-6%), 2.09, 2.06, 2.04 (each s, 9 H, OAc); C
2-deoxy-2-iodo-h-
Prepared from commercially available tri-O-
acetyl- -galactal (1 mL, 4.52 mmol) in the
D
-galactopyranoside
(22).
NMR (90 MHz, CDCl3): l 188.1, 170.3,
169.4, 169.2, 163.6, 115.7, 76.3, 65.6, 60.8,
60.6, 20.6; CIHRMS (m/z): 301.0931 (MH+).
Calcd for C13H17O8 301.0923 (MH+).
D
same manner described for 7 to give 488 mg
(42% based on recovered starting material):
[h]D +46.1° (c 1.7, CH2Cl2); Rf 0.82 (2:3
EtOAc–hexane); IR (neat): 2978, 2928, 1750,
1497, 1455, 1370, 1231, 1105, 1028, 988, 930
1,5-Anhydro-3,4,6-tri-O-benzyl-2-deoxy-2-
C-formyl-h- -arabino-hex-1-enitol (18) [4a].
D
1
Rf 0.12 (1:2 EtOAc–hexane); H NMR (360
MHz, CDCl3): l 9.41 (s, 1 H, CHO), 7.29 (m,
15 H, Ph), 4.75–4.41 (m, 9 H), 3.84–3.77 (m,
2 H), 3.62 (dd, 1 H, J5,6 4.6, J6,6% 10.8 Hz,
H-6); CIHRMS (m/z): 445.2006 (MH+).
Calcd for C28H29O5 445.2015 (MH+).
1
cm−1; H NMR (360 MHz, CDCl3): l 5.81
(dd, 1 H, J7,8 10.7, J7,8% 17.5 Hz, H-7), 5.41 (bs,
1 H, H-1), 5.35 (m, 1 H), 5.20 (d, 1 H, H-8),
5.18 (d, 1 H, H-8%), 4.93 (dd, 1 H, J2,3 3.6, J3,4
4.2 Hz, H-3), 4.47 (ddd, 1 H, J 1.8, 6.5, 13.2
Hz), 4.12 (m, 3 H), 2.16, 2.05, 2.02 (each s, 9
H, OAc); 13C NMR (90 MHz, CDCl3): l
170.4, 170.1, 169.6, 142.3, 115.1, 98.1, 78.4,
66.4, 65.5, 65.3, 62.1, 27.8, 25.1, 23.4, 21.0,
20.9, 20.6; CIHRMS (m/z): 502.0938 (M+
NH+4 ). Calcd for C17H29INO8 502.0957 (M+
NH+4 ).
1,1-Dimethyl-2-oxoethyl 3,4,6-tri-O-acetyl-
2-deoxy-h- -mannopyranoside (19). IR (neat):
D
2978, 1746, 1437, 1370, 1231, 1152, 1123,
1
1090, 1047, 1005, 924 cm−1; H NMR (360
MHz, CDCl3): l 9.53 (s, 1 H, CHO), 5.37 (m,
1 H, H-3), 5.19 (bd, 1 H, J1,2 3.3 Hz, H-1),
4.96 (t, 1 H, J3,5 9.7 Hz, H-4), 4.27 (dd, 1 H,
J5,6 5.4, J6,6% 12.0 Hz, H-6), 4.16 (m, 1 H, H-5),
3.98 (dd, 1 H, H-6%), 2.22 (dd, 1 H, J1,2% 5.3,
J2,2% 12.8 Hz, H-2%), 2.08, 2.04, 2.01 (each s, 9
H, OAc), 1.87 (td, 1 H, J1,2 3.8, J2,2% 12.8 Hz,
1,1-Dimethyl-2-oxoethyl 3,4,6-tri-O-acetyl-
2-deoxy-2-iodo-h-
D
-galactopyranoside
(23).
Prepared from 22 (218 mg, 0.45 mmol) using
the same procedure described for 9 to give 184
mg (84%): [h]D +61.3° (c 1.5, CH2Cl2); Rf
0.60 (2:3 EtOAc–hexane); IR (neat): 2982,
1752, 1464, 1435, 1373, 1231, 1169, 1109,
13
H-2), 1.33 (s, 6 H, 2Me); C NMR (90 MHz,
CDCl3): l 201.8, 170.7, 170.3, 169.9, 92.6,
81.2, 69.5, 68.7, 68.2, 62.4, 35.6, 21.8, 20.9,
20.8, 20.7 (2C); CIHRMS (m/z): 378.1768
(M+NH+4 ). Calcd for C16H28NO9 378.1764
(M+NH+4 ).
1
1040, 992, 955, 914 cm−1; H NMR (360
MHz, CDCl3): l 9.44 (s, 1 H, CHO), 5.38 (d,
1 H, J1,2 1.9 Hz, H-1), 5.30 (dd, 1 H, J2,3 2.8,
J3,4 3.0 Hz, H-3), 4.92 (t, 1 H, J3,5 4.0 Hz,
H-4), 4.39 (m, 1 H), 4.22 (m, 1 H), 4.11 (dd, 1
H, J5,6 7.7, J6,6% 11.6 Hz, H-6), 4.01 (dd, 1 H,
H-6%), 2.07, 1.99, 1.96 (each s, 9 H, OAc),
1.26, 1.25 (each s, 6 H, Me); 13C NMR (50
MHz, CDCl3): l 201.1, 170.5, 170.0, 169.6,
98.2, 82.0, 67.5, 65.5, 61.9, 22.2, 21.8, 21.0,
20.9, 20.7. (Two aliphatic carbons not re-
solved); CIHRMS(m/z): 504.0731(M+NH+4 ).
Calcd for C16H27INO9 504.0749 (M+NH+4 ).
Isopropyl 3,4,6-tri-O-acetyl-2-deoxy-2-C-
4R-(3hi,3ah,4i,5h,6i,7ai) Hexahydro-2,2-
dimethyl - 4,5 - bis(phenylmethoxy) - 6 - [(phenyl-
methoxy)methyl] - 4H - furo[2,3 - b]pyran - 3 - ol
(21). Data for one diastereomer: Rf 0.52 (1:2
EtOAc–hexane); IR (neat): 3463, 3032, 2924,
1
1497, 1455, 1366, 1321, 1076, 1028 cm−1; H
NMR (360 MHz, CDCl3): l 7.30 (m, 15 H,
Ph), 4.99 (d, 1 H, J1,2 3.4 Hz, H-1), 4.84, 4.78,
4.73, 4.69, 4.67, 4.54 (each d, 6 H, benzyl),
4.40 (d, 1 H, J3,4 9.8 Hz, H-3), 3.98 (m, 2 H),
3.81 (dd, 1 H, J5,6 3.6, J6,6% 11.0 Hz), 3.71 (dd,
1 H, H-6), 3.28 (m, 1 H), 2.71 (m, 1 H), 2.62
(bs, 1 H), 1.49, 1.19 (each s, 6 H, Me); 13C
NMR (90 MHz, CDCl3): l 138.4, 138.2,
formyl-h-
D
-galactopyranoside (24). Prepared
from 23 (59 mg, 0.12 mmol) using Bu3SnH

S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
741
H-31), 5.12 (bd, 1 H, H-1), 2.23 (bs, 1 H,
OH).
radical reaction conditions (0.01 M, 3 h) to
give 18.5 mg (43%) of 24 and 14 mg (32%) of
a mixture of 25 and 26: [h]D +154.5° (c 0.62,
CH2Cl2); IR (neat): 2977, 2930, 1750, 1437,
1372, 1233, 1163, 1125, 1071, 1017, 950, 928
cm−1; 1H NMR (400 MHz, CDCl3): l 9.48 (d,
1 H, J2,CHO 2.7 Hz, CHO), 5.70 (dd, 1 H, J3,4
3.1, J2,3 11.8 Hz, H-3), 5.43 (bd, 1 H, H-4),
5.29 (d, 1 H, J1,2 3.9 Hz, H-1), 4.31 (t, 1 H, J
6.9 Hz), 4.09 (m, 2 H), 3.87 (septet, 1 H, H-7),
2.95 (ddd, 1 H, H-2), 2.13, 2.04, 1.98 (each s,
9 H, OAc), 1.20, 0.92 (each d, 6 H, J7,Me 6.1
Hz, Me); 13C NMR (90 MHz, CDCl3): l
198.9, 170.4, 170.2, 170.0, 95.8, 71.1, 66.9,
66.2, 66.0, 62.1, 51.4, 23.0, 21.4, 22.7, 20.6
(2C); CIHRMS (m/z): 378.1758 (M+NH+4 ).
Calcd for C16H28NO9 378.1764 (M+NH+4 ).
1-Phenyl-2-propenyl
3,4,6-tri-O-acetyl-2-
deoxy-2-iodo-h- -mannopyranoside (28). Pre-
D
pared from 5 (28.8 g, 10.2 mmol) and 27 (1.5
g, 11.2 mmol) in the manner described for 7 to
give 2.92 g (80% based on recovered starting
material). Data for the mixture of
diastereomers: Rf 0.36 (2:3 EtOAc–hexane);
IR (neat): 3031, 2986, 2940, 1748, 1493, 1456,
1431, 1370, 1296, 1231, 1175, 1119, 1038, 945,
1
916 cm−1; H NMR (360 MHz, CDCl3): l
7.30 (m, 10 H, Ph), 5.97 (m, 1 H), 5.94 (m, 1
H), 5.42–5.16 (m, 11 H), 4.71 (dd, 1 H, J2,3
4.2, J3,4 9.4 Hz, H-3), 4.61 (m, 1 H), 4.47 (dd,
1 H, J1,2 1.1, J2,3 4.4 Hz, H-2), 4.25–4.05 (m,
4 H), 3.89 (m, 12 H), 3.82 (m, 1 H), 2.12, 2.08,
13
2.06, 2.05, 2.02, 1.99 (each s, 18 H, OAc); C
4R - (3hi,3ai,4i,5h,6i)] - 6 - [(Acetyloxy)-
6
NMR (100 MHz, CDCl3): l 170.9, 170.5 (2C),
169.7, 169.4, 169.3, 139.6, 138.5, 137.7, 136.3,
128.7, 128.5, 128.4, 127.9, 127.2, 126.5, 118.6,
115.9, 99.0, 98.4, 80.3, 79.5, 69.3 (2C), 69.1,
69.0, 67.4, 67.2, 62.1, 61.8, 29.7, 29.6, 20.9,
20.8, 20.7, 20.6 (2C), 20.5; CIHRMS (m/z):
550.0920 (M+NH+4 ). Calcd for C21H29INO8
550.0938 (M+NH+4 ).
methyl]hexahydro-2,2-dimethyl-4H-furo[2,3-b]
pyran-3,4,5-triol, 4,5-diacetate (25), 4R-(3hi,
3ai,4i,5h(R*),6ai)] - 5 - [1,2 - bis(acetyloxy)-
ethyl]-hexahydro-2,2-dimethylfuro[2,3-b]furan-
3,4-diol, 4-acetate (26). Data for the mixture
of 25 and 26: IR (neat): 3470, 2926, 1748,
1
1462, 1433, 1372, 1231, 1047 cm−1; H NMR
(360 MHz, CDCl3): l 5.66 (t, 1 H, J 3.7 Hz),
5.56 (d, 1 H, J 4.3 Hz), 5.35–3.31 (m, 3 H),
5.05 (dd, 1 H, J 3.0, 9.8 Hz), 4.65–3.92 (m),
2.74 (m, 1 H), 2.58 (m, 1 H), 2.11, 2.08, 2.07,
2.05, 2.04, 2.03 (each s, 18 H, OAc), 1.42,
1.27, 1.25, 1.23 (s, 12 H, Me); CIHRMS (m/
z): 378.1766 (M+NH+4 ). Calcd for
C16H28NO9 378.1764 (M+NH+4 ).
1-Phenyl-2-propenyl 3,4,6-tri-O-benzyl-2-
deoxy-2-iodo-h- -mannopyranoside (29). Pre-
D
pared from 6 (2.1 g, 4.9 mmol) and 27 (0.73 g,
5.42 mmol) in the manner described for 7 to
yield 2 g (60%). Data for the mixture of
diastereomers: Rf 0.68 (1:6 EtOAc–hexane);
IR (neat): 3088, 3063, 3031, 2865, 1605, 1497,
1455, 1362, 1308, 1291, 1265, 1208, 1113,
1
1028, 932, 912 cm−1; H NMR (360 MHz,
1-Phenyl-2-propen-1-ol (27). To a stirred
solution of benzaldehyde (1 g, 9.42 mmol) in
dry tetrahydrofuran (50 mL) was added drop-
wise vinylmagnesium bromide (1.0 M in THF,
1.9 ml, 14.3 mmol) at 0 °C. The reaction
mixture was allowed to warm to rt and stirred
for an additional hour before quenching with
aq NH4Cl. The reaction mixture was concen-
trated, diluted with ether and washed with
brine several times. The organic layer was
combined, dried over MgSO4 and concen-
trated in vacuo. Flash column chromatogra-
phy (1:9 EtOAc–hexane) of the resulting oil
gave 0.82 g (65%) of the desired alcohol 90 as
CDCl3): l 7.36 (m, 40 H, Ph), 5.98 (dd, 1 H,
J 6.1, 10.4 Hz), 5.95 (dd, 1 H, J 6.2, 10.3 Hz),
5.84 (dd, 1 H, J 7.7, 10.1 Hz), 5.79 (dd, 1 H,
J 7.7, 9.9 Hz), 5.48–4.47 (m, 19 H), 3.98 (m, 4
H), 3.87–3.58 (m, 5 H), 3.46 (dd, 1 H, J 4.1,
8.2 Hz), 3.36 (dd, 1 H, J 4.1, 8.7 Hz); 13C
NMR (90 MHz, CDCl3): l 140.2, 139.3,
138.5, 138.3, 138.2, 137.9, 137.8, 136.7, 128.5
(2C), 128.4 (2C), 128.3 (2C), 128.2 (2C), 127.9
(2C), 127.8, 127.7, 127.6, 127.5, 126.8, 126.7,
118.8, 115.8, 99.3, 99.0, 98.8, 85.9, 80.4, 79.5,
78.9, 77.6, 77.2, 76.2, 75.5 (2C), 75.4, 75.3,
74.9, 73.5, 73.4 (2C), 72.6 (2C), 71.1 (2C),
68.9, 68.8, 68.6, 60.4, 34.0, 33.9, 21.1, 14.3.
(Several carbons not resolved); CIHRMS (m/
z): 675.1627 (M−H). Calcd for C36H36IO5
675.1608 (M−H).
1
a clear oil: Rf 0.52 (1:2 EtOAc–hexane); H
NMR (360 MHz, CDCl3): l 7.27 (m, 5 H,
Ph), 5.99 (ddd, 1 H, J1,2 6.0, J2,3 10.3, J2,3% 16.8
Hz, H-2), 5.27 (d, 1 H, H-3), 5.13 (d, 1 H,

742
S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
13
1497, 1455, 1362, 1267, 1101, 1028 cm−1; C
NMR (90 MHz, CDCl3): l 197.0, 196.4,
138.2, 138.0, 137.9, 137.5, 132.6, 129.3, 129.2,
129.1 (2C), 128.4 (3C), 128.3(2C), 128.2, 128.1
(2C), 128.0, 127.8 (2C), 127.6 (2C), 127.5 (2C),
101.1, 99.6, 83.2, 82.7, 76.8, 76.5, 75.8, 75.7,
75.4, 75.3, 73.4, 73.3, 73.0, 72.8, 71.2, 71.0,
68.6, 68.5, 32.5, 29.7. (Several carbons not
resolved); CIHRMS (m/z): 696.1805 (M+
NH+4 ). Calcd for C35H39INO6 696.1822 (M+
NH+4 ).
1-Phenyl-2-oxoethyl
3,4,6-tri-O-acetyl-2-
deoxy-2-iodo-h-
D
-mannopyranoside (30). Pre-
pared from 28 (0.10 g, 0.19 mmol) using the
same procedure described for 9 to yield 76 mg
(74%): IR of mixture (neat): 2937, 1746, 1494,
1455, 1370, 1232, 1124, 1061, 913 cm−1; Data
1
for one of the diastereomers: H NMR (360
MHz, CDCl3): l 9.61 (bs, 1 H, CHO), 7.42
(m, 5 H, Ph), 5.46 (bs, 1 H, H-1), 5.38 (t, 1 H,
J3,5 9.8 Hz, H-4), 5.11 (bs, 1 H, H-7), 4.81 (dd,
1 H, J1,2 1.2, J2,3 4.4 Hz, H-2), 4.65 (dd, 1 H,
J2,3 4.4, J3,4 9.6 Hz, H-3), 4.06 (dd, 1 H, H-6),
3.89 (dd, 1 H, H-6%), 3.77 (ddd, 1 H, H-5),
Benzyl 3,4,6-tri-O-acetyl-2-deoxy-2-C-for-
myl-h- -glucopyranoside (32). Prepared from
D
13
30 (75 mg, 0.14 mmol) using Bu3SnH (0.046
mL, 0.17 mmol) radical reaction conditions
(0.60 M, 3 h) to yield 28.5 mg (50%): [h]D
+141.9° (c 0.0016, CH2Cl2); IR (neat): 3034,
2957, 1748, 1455, 1433, 1370, 1229, 1125,
1024, 922 cm−1; 1H NMR (400 MHz, CDCl3):
l 9.51 (d, 1 H, J2,CHO 2.4 Hz, CHO), 7.33 (m,
5 H, Ph), 5.81 (t, 1 H, J3,5 9.7 Hz, H-4), 5.23
(d, 1 H, J1,2 3.9 Hz, H-1), 5.05 (t, 1 H, J2,4 9.7
Hz, H-3), 4.68, 4.52 (each d, 2 H, J 11.9 Hz,
benzyl), 4.30 (dd, 1 H, J5,6 4.2, J6,6% 12.1 Hz,
H-6), 4.06 (m, 2 H, H-5, H-6%), 2.84 (ddd, 1 H,
J2,CHO 2.7, J1,2 3.6, J2,3 8.4 Hz, H-2), 2.11,
2.09, 2.07, 2.00 (each s, 9 H, OAc); C NMR
(90 MHz, CDCl3): l 196.3, 170.5, 169.8,
169.4, 132.7, 129.4, 129.3, 127.7, 101.3, 83.6,
70.0, 68.7, 67.3, 61.8, 28.5, 20.9, 20.7, 20.6.
1
Data for one of the diastereomers: H NMR
(360 MHz, CDCl3): l 9.64 (d, 1 H, J 1.7 Hz,
CHO), 7.42 (m, 5 H, Ph), 5.40 (t, 1 H, J3,5 9.4
Hz, H-4), 5.20 (d, 1 H, J 1.4 Hz, H-1 or H-7),
4.99 (d, 1 H, J 1.4 Hz, H-1 or H-7), 4.77 (dd,
1 H, J2,3 4.4, J3,4 9.3 Hz, H-3), 4.62 (dd, 1 H,
J1,2 1.5, J2,3 4.3 Hz, H-2), 4.21 (m, 3 H, H-5,
H-6, H-6%), 2.13, 2.10, 2.09 (each s, 9 H, OAc);
13C NMR (90 MHz, CDCl3): l 195.8, 170.6,
169.8, 169.5, 132.3, 129.6, 129.4, 127.7, 99.6,
83.8, 70.0, 69.0, 67.3, 62.1, 28.4, 20.9, 20.7,
20.6; CIHRMS (m/z): 552.0720 (M+NH+4 ).
Calcd for C20H27INO9 552.0731 (M+NH+4 ).
1-Phenyl-2-oxoethyl 3,4,6-tri-O-benzyl-2-
13
2.04, 2.00 (each s, 9 H, OAc); C NMR (125
MHz, CDCl3): l 196.8, 170.5, 170.1, 169.7,
135.9, 128.5, 128.2, 128.0, 95.7, 69.8, 68.7,
67.9, 61.8, 56.6, 30.8, 20.6 (2C), 20.5;
CIHRMS (m/z): 426.1752 (M+NH+4 ). Calcd
for C20H28NO9 426.1764 (M+NH+4 ).
deoxy-2-iodo-h- -mannopyranoside (31). Pre-
D
Benzyl 3,4,6-tri-O-benzyl-2-deoxy-2-C-for-
myl-h- -glucopyranoside (33). Prepared from
pared from 29 (570 mg, 0.84 mmol) using the
same procedure described for 9 to yield 425
mg (74%). Data for one of the diastereomers:
1H NMR (360 MHz, CDCl3): l 9.60 (s, 1 H,
CHO), 7.36 (m, 20 H, Ph), 5.54 (bs, 1 H), 5.21
(s, 1 H), 4.85, 4.78, 4.68, 4.58, 4.50, 4.49 (each
d, 6 H, J 10.6 Hz, benzyl), 4.82 (dd, 1 H, J
1.2, 4.2 Hz), 3.95 (t, 1 H, J 9.4 Hz), 3.73 (m,
2 H), 3.58 (m, 1 H), 3.37 (dd, 1 H, J 4.1, 8.7
D
31 (76.5 mg, 0.112 mmol) using Bu3SnH (0.03
mL, 0.112 mmol) radical reaction conditions
(0.01 M, 3 h) to yield 26 mg (84% based on
recovered starting material): [h]D +96.6° (c
0.4, CH2Cl2); Rf 0.52 (1:2 EtOAc–hexane); IR
(neat): 3032, 2924, 2853, 1727, 1497, 1455,
1360, 1273, 1125, 1059, 1026 cm−1; H NMR
1
(360 MHz, CDCl3): l 9.51 (d, 1 H, J2,CHO 2.6
Hz, CHO), 7.35–7.17 (m, 20 H, Ph), 5.20 (d,
1 H, J1,2 3.9 Hz, H-1), 4.90–4.45 (m, 8 H,
benzyl), 4.39 (dd, 1 H, J3,4 8.8, J4,5 8.9 Hz,
H-4), 3.90–3.87 (m, 1 H), 3.78 (m, 2 H), 3.66
(dd, 1 H, J 1.9, 10.6 Hz), 2.78 (ddd, 1 H,
J2,CHO 2.6, J1,2 3.8, J2,3 6.5 Hz, H-2); 13C NMR
(90 MHz, CDCl3): l 199.4, 138.2, 138.0,
137.8, 136.9, 128.5 (2C), 128.4 (2C), 127.9,
127.8 (3C), 96.5, 79.1, 76.5, 75.0, 74.9, 73.6,
71.2, 69.3, 68.3, 58.6. (Several aromatic car-
1
Hz). Data for one of the diastereomers: H
NMR (360 MHz, CDCl3): l 9.60 (d, 1 H, J
1.4 Hz, CHO), 7.36 (m, 20 H, Ph), 5.26 (d, 1
H, J 1.1 Hz), 5.04 (d, 1 H, J 1.5 Hz), 4.89,
4.76, 4.74, 4.61, 4.56, 4.52 (each d, 6 H, J 10.7
Hz, benzyl), 4.58 (d, 1 H, J 1.6 Hz), 4.02 (m,
2 H), 3.82 (dd, 1 H, J5,6 4.5, J6,6% 10.9 Hz,
H-6), 3.75 (dd, 1 H, J 1.5, 10.9 Hz), 3.51 (dd,
1 H, J 4.1, 8.2 Hz). Data of the mixture of
diastereomers: IR (neat): 3031, 2924, 1734,

S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
743
and 26 mg (30%) of 37: [h]D +187.5° (c 0.08,
bons not resolved); CIHRMS (m/z): 551.2448
(M+−H). Calcd for C35H35O6 551.2434 (M+
−H).
CH2Cl2); IR (neat): 2977, 2932, 2255, 1752,
1456, 1372, 1227, 1119, 1047, 959, 924 cm−1
;
1H NMR (400 MHz, CDCl3): l 5.58 (t, 1 H,
J2,4 9.3 Hz, H-3), 5.20 (d, 1 H, J1,2 3.3 Hz,
H-1), 4.93 (t, 1 H, J3,5 9.8 Hz, H-4), 4.27 (dd,
1 H, J5,6 4.5, J6,6% 12.3 Hz, H-6), 4.13 (ddd, 1
H, J 2.2, 4.4, 10.2 Hz), 4.06 (m, 1 H), 3.98
(septet, 1 H, H-7), 3.07 (dd, 1 H, J1,2 3.4, J2,3
11.3 Hz, H-2), 2.04, 2.03, 2.01 (each s, 9 H,
OAc), 1.27, 1.25 (each d, 6 H, J7,Me 6.1 Hz,
Me); 13C NMR (100 MHz, CDCl3): l 170.4,
169.6, 169.4, 115.1, 94.0, 77.1, 72.3, 68.3 (2C),
67.8, 61.6, 38.8, 30.8, 22.9, 21.3, 20.5;
CIHRMS (m/z): 375.1763 (M+NH+4 ). Calcd
for C16H27N2O8 375.1767 (M+NH+4 ).
1-Cyano-1-methylethyl 3,4,6-tri-O-acetyl-2-
deoxy-2-iodo-h- -mannopyranoside (34). Pre-
D
pared from 5 (2 g, 7.35 mmol) and acetone
cyanohydrin (2.68 mL, 29.4 mmol) in the
manner described for 7 to yield 1.4 g (82%
based on recovered starting material): [h]D
+4.26° (c 10.8, CH2Cl2); Rf 0.48 (1:1 EtOAc–
hexane); IR (neat): 2994, 2963, 2942, 2200,
1748, 1435, 1372, 1221, 1167, 1119, 1084,
1
1032, 1007, 916 cm−1; H NMR (360 MHz,
CDCl3): l 5.55 (d, 1 H, J1,2 1.2 Hz, H-1), 5.37
(t, 1 H, J3,5 9.6 Hz, H-4), 4.56 (dd, 1 H, J2,3
4.3, J3,4 9.3 Hz, H-3), 4.46 (dd, 1 H, J1,2 1.5,
J2,3 4.3 Hz, H-2), 4.23–4.10 (m, 3 H, H-5,
H-6, H-6%), 2.07, 2.06, 2.03 (each s, 9 H, OAc),
1.64, 1.63 (each s, 6 H, Me); 13C NMR (90
MHz, CDCl3): l 170.5, 169.8, 169.3, 120.0,
98.5, 70.5, 70.1, 68.6, 67.2, 61.8, 28.8, 27.9,
26.6, 20.9, 20.6 (2C); CIHRMS (m/z):
501.0716 (M+NH+4 ). Calcd for C16H26IN2O8
501.0734 (M+NH+4 ).
1-Cyano-1-methylethyl 3,4,6-tri-O-acetyl-2-
deoxy-h- -glucopyranoside (37). IR (neat):
D
2994, 2963, 1746, 1441, 1370, 1304, 1233,
1173, 1154, 1123, 1088, 1049, 1017, 1003
1
cm−1; H NMR (360 MHz, CDCl3): l 5.42
(bd, 1 H, J1,2 2.2 Hz, H-1), 5.30 (m, 1 H, H-3),
5.02 (t, 1 H, J3,5 9.8 Hz, H-4), 4.34 (dd, 1 H,
J5,6 4.2, J6,6% 12.2 Hz, H-6), 4.13–4.04 (m, 2 H,
H-5, H-6%), 2.19 (m, 1 H, H-2), 2.07, 2.04, 2.01
(each s, 9 H, OAc), 1.91 (m, 1 H, H-2%), 1.65,
1.64 (each s, 6 H, Me); 13C NMR (90 MHz,
CDCl3): l 170.6, 170.2, 169.8, 120.5, 94.2,
70.0, 69.0, 68.9, 68.5, 61.9, 35.4, 28.1, 26.7,
20.9, 20.7 (2C); CIHRMS (m/z): 375.1758
(M+NH+4 ). Calcd for C16H27N2O8 375.1767
(M+NH+4 ).
1-Cyano-1-methylethyl 3,4,6-tri-O-benzyl-
2-deoxy-2-iodo-h-D-mannopyranoside
(35).
Prepared from 6 (1.22 g, 2.93 mmol) and
acetone cyanohydrin (1.5 mL, 14.7 mmol) in
the manner described for 7 to yield 0.78 g
(42%): [h]D +20.0° (c 1.0, CH2Cl2); Rf 0.43
(1:2 EtOAc–hexane); IR (neat): 3088, 3063,
3031, 2992, 2919, 2867, 1497, 1455, 1364,
1293, 1267, 1208, 1171, 1113, 1028, 999 cm−1
;
1H NMR (360 MHz, CDCl3): l 7.43–7.15 (m,
15 H, Ph), 5.65 (bs, 1 H, H-1), 4.85 (d, 1 H, J
10.5 Hz, benzyl), 4.76–4.70 (m, 2 H), 4.55–
4.44 (m, 4 H), 4.04–3.95 (m, 1 H), 3.82 (dd, 1
H, J2,3 3.4, J3,4 10.8 Hz, H-3), 3.73 (dd, 1 H, J
1.5, 11.0 Hz), 3.28 (dd, 1 H, J 4.1, 7.6 Hz),
1.63, 1.60 (each s, 6 H, Me); 13C NMR (90
MHz, CDCl3): l 138.2, 138.0, 137.5, 128.4
(2C), 128.3, 128.1, 128.0, 127.9, 127.8, 127.6,
127.5, 120.4, 98.9, 76.5, 75.6, 75.3, 73.4, 73.2,
71.0, 70.4, 68.3, 32.8, 27.7, 27.2; CIHRMS
(m/z): 645.1841 (M+NH+4 ). Calcd for
C31H38IN2O5 645.1826 (M+NH+4 ).
Acknowledgements
This work was supported in part by the
Camille and Henry Dreyfus Faculty Start-up
Grant for Undergraduate Institutions.
S.W.T.C. would like to thank B.S. Safina and
J.N. Bashara for their contributions to the
work with mandelonitrile.
References
[1] (a) D.H.R. Barton, P. Dalko, S.D. Gero, Tetrahedron
Lett., 32 (1991) 2471–2474. (b) K. Tatsuta, Y. Niwata,
K. Umezawa, K. Toshima, M. Nakata, Tetrahedron
Lett., 31 (1990) 1171–1172. (c) S. Atsumi, H. Iinuma, C.
Nosaka, K. Umezawa, J. Antibiot., (1990) 1579–1585.
[2] M.E. Jung, S.W.T. Choe, J. Org. Chem., 60 (1995) 3280–
3281.
1-Methylethyl 3,4,6-tri-O-acetyl-C-cyano-2-
deoxy-2-h- -glucopyranoside (36). Prepared
D
from 34 (122 mg, 0.25 mmol) using Bu3SnH
(0.08 mL, 0.28 mmol) radical reaction condi-
tions (0.13 M, 2 h) to yield 26 mg (30%) of 36

744
S.W.T. Choe, M.E. Jung / Carbohydrate Research 329 (2000) 731–744
[3] (a) B. Giese, Angew. Chem., Int. Ed. Engl., 22 (1983)
[8] (a) S.H. Chen, R.F. Horvath, J. Joglar, M.J. Fisher, S.J.
Danishefsky, J. Org. Chem., 56 (1991) 5834–5845. (b) J.
Thiem, H. Karl, J. Schwentner, Synthesis, (1978) 696–698.
[9] (a) C. Chatgilialoglu, M. Ballestri, K.B. Clark, D. Griller,
B. Giese, B. Kopping, J. Org. Chem., 56 (1991) 678–683.
(b) C. Chatgilialoglu, D. Griller, M. Lesage, J. Org. Chem.,
54 (1989) 2492–2494. (c) B. Giese, B. Kopping, Tetrahedron
Lett., 30 (1989) 681–684.
[10] H. Suginome, S. Yamada, Tetrahedron, 43 (1987) 3371–
3386.
[11] R.W. Binkley, D.J. Kolohic, J. Org. Chem., 44 (1979)
2047–2048.
753–764. (b) B. Giese, Pure Appl. Chem., 60 (1988)
1655–1658. (c) D.P. Curran, J. Tamine, J. Org. Chem., 56
(1991) 2746–2750.
[4] (a) N.G. Ramesh, K.K. Balasubramanian, Tetrahedron
Lett., 32 (1991) 3875–3878. (b) J.C. Lopez, E. Lameignere,
G. Lukacs, J. Chem. Soc., Chem. Commun., (1988)514–515.
[5] V. Gupta, D. Kahne, Tetrahedron Lett., 34 (1993) 591–593.
[6] M.E. Jung, S.W.T. Choe, Tetrahedron Lett., 34 (1993)
6247–6250.
[7] (a) R. Tsang, J.K. Dickson, H. Pak, R. Walton, B.
Fraser-Reid, J. Am. Chem. Soc., 109 (1987) 3484–3486. (b)
R. Tsang, B. Fraser-Reid, J. Am. Chem. Soc., 108 (1986)
2116–2117. (c) B. Fraser-Reid, G.D. Vite, B.W.A. Yeung,
R. Tsang, Tetrahedron Lett., 29 (1988) 1645–1648.
[12] D.P. Curran, C.M. Seong, Tetrahedron, 48 (1992) 2175–
2190.
.