Multifunctionalized α,β-cyclopentenones from C-2 and C-4-ulopyranosyl compounds: A stereospecific rearrangement initiated by base

Article abstract of DOI:10.1016/S0008-6215(01)00187-2

Base treatment of O-benzyl protected C-2- or C-4-ulopyranosyl compounds (4α, 4β, and 11) by either 10% Et₃N or 1% K₂CO₃ in MeOH initiated a β elimination to afford α,β-unsaturated C-ulopyranosyl compounds (5α, 5β, and 12), which further rearranged in a stereocontrolled manner to multifunctionalized α,β-cyclopentenones (6 and 14) in 70-80% yield. Both C-α- and C-β-2-ulosides (5α and 5β) produced the same cyclopentenone 6, indicating that a 1,2-enolate is formed prior to the cleavage of the C-5-O bond. Because 6 is racemic, it was probably formed by the intramolecular cycloaldolization of two equally populated enantiomeric intermediates. When treated with 90% Et₃N in MeOH, 5α yielded almost exclusively 15 (isomer of 6), which was formed by a migration of the double bond in 5α during the previously described rearrangement. Thus either 6 or 15 was the major product, depending on the base used.

Full text of DOI:10.1016/S0008-6215(01)00187-2

www.elsevier.com/locate/carres
Carbohydrate Research 334 (2001) 223–231
Multifunctionalized a,b-cyclopentenones from C-2 and
C-4-ulopyranosyl compounds: a stereospecific
rearrangement initiated by base
Wei Zou,a,* Zerong Wang,a Edith Lacroix,a Shih-Hsiung Wu,b Harold J. Jenningsa
aInstitute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6
bInstitute of Biological Chemistry, Academy Sinica, Taipei 115, Taiwan, ROC
Received 16 April 2001; accepted 27 June 2001
Abstract
Base treatment of O-benzyl protected C-2- or C-4-ulopyranosyl compounds (4a, 4b, and 11) by either 10% Et3N
or 1% K2CO3 in MeOH initiated a b elimination to afford a,b-unsaturated C-ulopyranosyl compounds (5a, 5b, and
12), which further rearranged in a stereocontrolled manner to multifuctionalized a,b-cyclopentenones (6 and 14) in
70–80% yield. Both C-a- and C-b-2-ulosides (5a and 5b) produced the same cyclopentenone 6, indicating that a
1,2-enolate is formed prior to the cleavage of the C-5ꢀO bond. Because 6 is racemic, it was probably formed by the
intramolecular cycloaldolization of two equally populated enantiomeric intermediates. When treated with 90% Et3N
in MeOH, 5a yielded almost exclusively 15 (isomer of 6), which was formed by a migration of the double bond in
5a during the previously described rearrangement. Thus either 6 or 15 was the major product, depending on the base
used. © 2001 Elsevier Science Ltd. All rights reserved.
Keywords: C-Ulosyl compound; Cyclopentenone; Synthesis; Rearrangement
1. Introduction
pounds.7 We report herein a convenient syn-
thesis of multifuctionalized a,b-cyclopen-
tenones from a base-initiated rearrangement
of C-2- or C-4-ulopyranosyl compounds. The
reaction has led to the formation of a new
carbonꢀcarbon bond between C-1 and C-5 of
the ulopyranosyl moiety in a stereocontrolled
manner.
Cyclopentenones are important structural
elements found in prostaglandins1 and many
other natural products, and these compounds
serve as intermediates for the synthesis of
carbocyclic nucleosides.2 The synthetic
methodology for producing cyclopentenones
has been well developed and includes cycliza-
tion of 1,4-dicarbonyl functions,3 Khand–
Pauson and modified reactions,4 other [2+3]
annulations,5 photo and radical reactions,6 as
well as approaches from carbohydrate com-
2. Results and discussion
In order to convert C-a-glycosylic com-
pounds (‘a-C-glycosides’) to C-b-glycosylic
compounds (‘b-C-glycosides’) we had thought
that epimerization at C-1 of an a-C-2-ulosyl
compound might be achievable via 1,2-enolate
* Corresponding author. Tel.: +1-613-9910855; fax: +1-
613-99529092.
E-mail address: wei.zou@nrc.ca (W. Zou).
0008-6215/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(01)00187-2

224
W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
ration, which is consistent with the observa-
tion of a strong NOE between CH2ꢀCHꢁCH2
and 6-CH2, but not H-5. However, we could
not detect a significant optical rotation for 6,
and the 13C NMR experiments also excluded
the existence of dimeric 6, which would have
created a symmetric center. Therefore, 6 must
be a mixture of enantiomers, (1S,5S) and
(1R,5R).
formation, and that this reaction could be a
route to a facile synthesis of C-b-mannosyl
compounds. Therefore, we prepared allyl C-a-
glucoside (2a) from glucose derivative 18 by a
procedure described previously,9 which gave a
mixture of both anomers (2a/2b 8:1, 85%) in
which 2a was the major product. O-Deacety-
lation of 2a/2b with 0.1% NaOMe in MeOH
gave 3a/3b (\90%), which when followed by
Moffatt oxidation,10 afforded the respective
allyl C-2-ulosides, 4a and 4b, in 80–90% yield
(Scheme 1). No hydrated form of the ketone
was observed by NMR spectroscopic analysis.
Compound 4a on treatment with base (10%
Et3N or 1% K2CO3 in MeOH) was rapidly
converted to a slower moving compound as
shown by TLC. However, when the com-
pound was isolated (ꢀ90%) and character-
ized, it was found to be an a,b-unsaturated
C-2-uloside (5a) instead of epimerized product
(4b). Under prolonged reaction times, using
either of the above bases, 5a slowly underwent
a further transformation to afford ring-con-
tracted compound 6 (70–80% from 4a, see
Scheme 1). It is noteworthy that the skeleton
of 6 is also found in mongolicains,11 a type of
tannin isolated from plants.
When we treated b-isomer 5b with 1:9
Et3N–MeOH, compound 6 was isolated in
70–80% yield. Therefore, a plausible reaction
mechanism for the formation of 6 is proposed
in Fig. 1. The b elimination product (5a or 5b)
on further treatment with base forms the same
1,2-enolate. This in turn facilitates the break-
down of the C-5ꢀO bond with the formation
of a species having a carbon anion at C-5,
which then rearranges to a more stable eno-
late. The presence of two cis-ene enantiomeric
conformers of the enolate is critical to the
outcome of stereochemistry. Both right- (pro-
R,R) and left-turn (pro-S,S) conformers are
equally populated which on intramolecular cy-
cloaldolization, would then form of both 6
(1S,5S) and 6 (1R,5R) in equal amounts.
In order to study whether the rearrange-
ment can be carried out using different sub-
stituents, another C-4-uloside (11) was
prepared in multiple steps from 2a (Scheme
2). The catalytic hydrogenation of 2a fur-
nished 7 (90%) by removal of O-benzyl groups
and converting 1-C-allyl into 1-C-propyl. O-
Deacetylation (0.1% NaOMe in MeOH) of 7,
followed by benzylidenation [PhCH(OMe)2–
H+], afforded 8, which was further converted
to 9 (99%) by O-benzylation (BnBr–NaH).
Reductive ring opening of the benzylidene
function (NaCNBH3–HCl)12 gave 10 in 49%
Compound 6, an a,b-unsaturated cyclopen-
tenone, must have been derived from 5a in a
rearrangement involving the breakdown of the
C-5ꢀO bond and the formation of a C-1ꢀC-5
bond. The stereochemistry of the newly
formed C-1ꢀC-5 bond in 6 has the cis configu-
yield, together with 1-(2,3-di-O-benzyl-a-
D
-
glucopyranosyl)propane (40%). Moffatt
oxidation10 of 10 afforded 11 in 90% yield.
When 11 was treated with 10% Et3N–MeOH,
the same b elimination as described above
produced 12, which further rearranged to
racemic a,b-cyclopentenone 14 in 68% yield,
based on the consumed starting material.
Again, the cis configuration at C-4 and C-5
(cyclopent-2-enone numbering) was estab-
lished by a NOESY experiment. Besides the
recovery of 12 (13%), we also isolated, from
Scheme 1. Reagents and conditions: (a) Allyl-TMS–TMSOTf
in MeCN, −40 °C to rt 8 h; (b) 0.1% NaOMe in MeOH, 2
h at rt; (c) 2:1 Me2SO–Ac2O, overnight at rt; (d) 10% Et3N or
1% K2CO3 in MeOH, 1 h; (e) 10% Et3N or 1% K2CO3 in
MeOH, 1–3 days.

W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
225
Fig. 1. A proposed mechanism of the rearrangement initiated by base.
migration of the double bond must take place
after the cleavage of the C-5ꢀO bond occurs in
both intermediates (pro-S,S and pro-R,R) in
the base treatment of 11, a C-5 (ulopyranosyl
numbering) epimerized derivative 13 (27%). A
strong NOE between H-1 and H-5, which was
not observed in 12, confirmed the epimeriza-
tion. This result further supports the mecha-
nism as illustrated in Fig. 1.
We also investigated the effect of different
bases on the rearrangement of 5a. Both 1%
K2CO3 and 10% Et3N in MeOH produced
good yields of 6 (see Table 1). Using 0.1%
NaOMe and LiOMe, 5a decomposed, and 6
was isolated in poor yield. The addition of
LiOBz to 10% Et3N in MeOH had no effect
on the stereoselectivity of the reaction. How-
ever, when 10% DBU–CH2Cl2 and 30%
Et3N–MeOH were used as bases, we isolated
a chromatographically inseparable mixture of
6 and its isomer 15 (see Scheme 3). The chem-
ical shift (lH) of the propenyl methyl group
showed a doublet at 1.680 ppm (J 6.5 Hz),
and another set of protons appeared at 5.408
(d, 1 H, CHꢁCHꢀCH3, Jtrans 15.5) and 5.778
(m, 1 H, CHꢁCHꢀCH3) ppm. Therefore, the
propenyl double bond in 15 is in the E-form
as indicated by a large coupling constant. The
Scheme 2. Reagents and conditions: (a) H2/Pd–C in MeOH,
4 h; (b) (i) 0.1% NaOMe in MeOH, 2 h at rt; (ii) Ph-
CH(OMe)2–H+ in CH3CN, 2 h at rt; (iii) BnBr–NaH in
DMF, overnight at rt; (c) NaCNBH3–H+ in THF, 2 h at
0 °C; (d) 2:1 Me2SO–Ac2O, overnight at rt; (e) 10% Et3N in
MeOH, 1–3 days.

226
W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
Table 1
The effect of base to the rearrangement products
Entry
Base
Solvent
Time (h)
Ratio (6:15) a
Total yield (%) b
1
2
3
4
5
6
7
8
9
10% Et3N
30% Et3N
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH2Cl2
CH3OH
72
72
72
4
16
16
7
40:1
2:1
35:1
4.2:1
6 only
6 only
6 only
1:1.6
1:25
70–80
81
76
B10
20
81
19
22
73
10% Et3N–1% LiOBz
1% LiOMe
0.1% LiOMe
1% K2CO3
1% NaOMe
10% DBU
16
72
90% Et3N
a Isomers 6 and 15 were inseparable by silica gel chromatography. The ratio of products was determined by 1H NMR
spectroscopy.
b Isolated yield.
order to form stable a,b-unsaturated conju-
gates (see Fig. 1). Thus migration and the
intramolecular cycloaldolation compete with
each other to produce a mixture of 6 and 15.
However, using 90% Et3N–MeOH, 5a was
converted to 15 in 73% yield, and only very
minor quantities of 6 were obtained.
In summary, a base-initiated rearrangement
from C-2 or -4-ulopyranosyl compounds is
described, a reaction that could be very useful
for the synthesis of densely functionalized cy-
clopentenones with various substituents. The
starting material is readily prepared, and the
reaction conditions are very mild and conve-
nient. Unfortunately, the reaction only affords
the racemic products.
column using following solvents: solvent A:
5:1 petroleum ether (35–60 °C)–EtOAc; sol-
vent B: 4:1 petroleum ether (35–60 °C)–
EtOAc; solvent C: 3:1 hexane–EtOAc; and
solvent D: 2:1 hexane–EtOAc.
3-C-(2-O-Acetyl-3,4,6-tri-O-benzyl-h,i- -
D
glucopyranosyl)propene (2a and 2b).—To a
solution of compound 1 (3.4 g, 6.37 mmol)
and allyltrimethylsilane (5.0 mL) in dry
MeCN (35 mL) was added TMSOTf (0.7 mL)
at −40 °C. The mixture was stirred for 8 h
while the temperature was slowly raised to rt.
The mixture was diluted by the addition of
EtOAc (100 mL) and aq NaHCO3 (50 mL).
The organic phase was subsequently washed
with aq NaHCO3 and water, dried, and con-
centrated to a residue. Purification of the
crude product by chromatography (solvent A)
gave crystalline 2a (2.5 g, 76%). Recrystalliza-
tion from MeOH gave mp 109–110 °C; [h]D
3. Experimental
1
+63.0° (c 1.05, EtOAc). H NMR (CDCl3):
General methods.—1H and 13C NMR spec-
tra were recorded in CDCl3 at 500 and 125
MHz, respectively, with an INOVA-500 in-
strument at 293 K unless otherwise noted.
Chemical shifts are given in ppm relative to
the signal of internal Me4Si in CDCl3 for both
lH (CDCl3) 1.987 (s, 3 H, 2-OAc), 2.258 and
2.477 (m and m, 1 H each, CH2CHꢁCH2),
3.631–3.815 (m, 4 H, H-4,5,6,6%), 3.831 (dd, 1
H, H-3, J2,3=J3,4 8.0 Hz), 4.202 (ddd, 1 H,
H-1, J1,2 5.0, J 5.0, J 10.0 Hz), 4.487–4.780
(m, 6 H, 3×CH2Ph), 5.046 (dd, 1 H, H-2, J2,3
8.5 Hz), 5.044 and 5.096 (d and d, 1 H each,
1
1H and 13C NMR spectra. The H and 13C
resonances were assigned on the basis of 2D
1
1H-COSY and H–13C chemical-shift corre-
lated experiments. Mass analysis was per-
formed with
a
JEOL JMS-AX505H
spectrometer. Optical rotations were recorded
at rt. All chemicals were Aldrich products and
were used without further purification. Chro-
matography was performed on a silica gel
Scheme 3.

W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
227
134.71 (CH2CHꢁCH2), 137.41, 137.92, 138.18
(3×Ph) ppm. HRFABMS: Anal. Calcd for
CH2CHꢁCH2, Jcis 10.0, Jtrans 16.5 Hz), 5.755
(m, 1 H, CH2CHꢁCH2), 7.178–7.365 (m, 15
H, 3×Ph) ppm. FABMS: Anal. Calcd for
C32H36O6 [M]: 517.6. Found: 517.4.
C30H33O5
[M−H]:
473.2328.
Found:
473.2332; Anal. Calcd for C30H35O5 [M+H]:
475.2484. Found: 475.2518.
Minor product 2b, which was eluted faster,
was also obtained (0.3 g, 9%) as a semicrys-
Compound 3b was obtained in the same
way from 2b (91%): mp 70–71 °C; [h]D
1
talline solid: [h]D +15.5° (c 0.42, EtOAc). H
1
+11.1° (c 0.46, EtOAc). H NMR (CDCl3):
NMR (CDCl3): lH 1.923 (s, 3 H, 2-OAc),
2.275 (dd, 2 H, CH2CHꢁCH2, J 6.5, J 6.0 Hz),
3.357 (ddd, 1 H, H-1, J 4.5, J 6.0, J1,2 9.5 Hz),
3.445 (m, 1 H, H-5), 3.615–3.684 (m, 3 H,
H-4,6,6%), 3.721 (dd, 1 H, H-3, J2,3=J3,4 9.5
Hz), 4.548–4.826 (m, 6 H, 3×CH2Ph), 4.914
(dd, 1 H, H-2), 5.045 and 5.069 (d and d, 1 H
each, CH2CHꢁCH2, Jcis 9.0, Jtrans 15.5), 5.846
(m, 1 H, CH2CHꢁCH2), 7.172–7.345 (m, 15
lH 2.040 (d, 1 H, 2-OH, J 2.5 Hz), 2.312 and
2.560 (m and m, 1 H each, CH2CHꢁCH2),
3.253 (ddd, 1 H, H-1, J 3.5 Hz, 7.5, J1,2 9.5
Hz), 3.369 (ddd, 1 H, H-2, J2,3 8.5 Hz), 3.427
(m, 1 H, H-5), 3.477 (dd, 1 H, H-3, J3,4 9.0
Hz), 3.602 (dd, 1 H, H-4, J4,5 9.5 Hz), 3.698
and 3.717 (dd and dd, 1 H each, H-6,6%, J6,6%
11.0, J5,6 4.5, J5,6% 2.0 Hz), 4.561–4.971 (m, 6
H, 3×CH2Ph), 5.070 and 5.126 (d and d, 1 H
each, CH2CHꢁCH2, Jcis 10.0, Jtrans 17.0 Hz),
5.929 (m, 1 H, CH2CHꢁCH2), 7.203–7.357
(m, 15 H, 3×Ph) ppm. HRFABMS: Anal.
Calcd for C30H33O5 [M−H]: 473.2328.
Found: 473.2324; Anal. Calcd for C30H35O5
[M+H]: 475.2484. Found: 475.2549.
13
H, 3×Ph) ppm; C NMR (CDCl3): lC 20.95
(CH3CO), 36.18 (CH2CHꢁCH2), 68.83 (C-6),
73.70 (C-2), 73.41, 74.97, 75.12 (3×CH2Ph),
77.37 (C-1), 78.35 (C-4), 79.19 (C-5), 84.55
(C-3), 117.01 (CH2CHꢁCH2), 127.52–128.38
(3×Ph), 133.93 (CH2CHꢁCH2), 137.96,
138.21, 138.34 (3×Ph), 169.78 (CꢁO) ppm.
FABMS: Anal. Calcd for C32H36O6 [M]:
517.6. Found: 517.4.
3-C-(3,4,6-Tri-O-benzyl-h,i- -arabino-hex-
D
2-ulopyranosyl)propene (4a and 4b).—A solu-
tion of compound 3a (1.8 g, 3.80 mmol) in 2:1
Me2SO–Ac2O (12 mL) was stirred at rt for 24
h. The mixture was diluted with EtOAc (150
mL) and washed with aq NaHCO3 and water,
dried and concentrated. Purification by chro-
matography (solvent A) gave 4a (1.6 g, 89%)
3-C-(3,4,6-Tri-O-benzyl-h,i- -glucopyran-
D
osyl)propene (3a and 3b).—To a suspension of
2a (2.3 g, 4.46 mmol) in MeOH (20 mL) was
added 1% NaOMe (2.0 mL). The mixture was
stirred at rt for 2 h. The clear solution was
neutralized by the addition of AcOH (three
drops) and then concentrated. Purification by
chromatography (solvent B) gave crystalline
3a (1.9 g, 90%). Recrystallization from
petroleum ether (35–60 °C) gave mp 76–
1
as a syrup: [h]D +31.4° (c 0.21, EtOAc). H
NMR (CDCl3): lH 2.477 (dd,
2
H,
CH2CHꢁCH2, J1=J2 7.0 Hz), 3.590 and 3.630
(dd and dd, 1 H each, H-6,6%, J6,6% 10.0, J5,6
4.0, J5,6% 2.0 Hz), 3.909 (dd, 1 H, H-4, J3,4 =
J4,5 8.5 Hz), 4.038 (m, 1 H, H-5), 4.268 (t, 1 H,
H-1, J 7.0 Hz), 4.395 (d, 1 H, H-3), 4.424–
4.972 (m, 6 H, 3×CH2Ph), 5.096 and 5.116 (d
and d, 1 H each, CH2CHꢁCH2, Jcis 10.0, Jtrans
19.5 Hz), 5.767 (m, 1 H, CH2CHꢁCH2),
7.197–7.409 (m, 15 H, 3×Ph) ppm; 13C
NMR (CDCl3): lC 34.74 (CH2CHꢁCH2),
69.50 (C-6), 73.38, 73.80, 74.31 (3×CH2Ph),
75.29 (C-5), 78.18 (C-4), 79.82 (C-1), 84.37
(C-3), 118.35 (CH2CHꢁCH2), 127.69–128.35
(3×Ph), 132.26 (CH2CHꢁCH2), 137.46,
137.66, 137.78 (3×Ph), 207.74 (C-2) ppm.
HRFABMS: Anal. Calcd for C30H31O5 [M−
H]: 471.2171. Found: 471.2194; Anal. Calcd
for C30H33O5 [M+H]: 473.6. Found: 473.3.
1
77 °C; [h]D +44.2° (c 0.33, EtOAc). H NMR
(CDCl3): lH 2.402 (m, 2 H, CH2CHꢁCH2),
2.899 (d, 1 H, 2-OH, J 8.0 Hz), 3.630–3.667
(m, 2 H, H-2,4), 3.696 and 3.817 (dd and dd,
1 H each, H-6,6%, J6,6% 10.0, J5,6 5.5, J5,6% 6.0
Hz), 3.754 (dd, 1 H, H-3, J2,3 =J3,4 5.5 Hz),
3.935 (m, 1 H, H-1), 4.056 (m, 1 H, H-5),
4.490–4.659 (m, 6 H, 3×CH2Ph), 5.063 and
5.132 (d and d, 1 H each, CH2CHꢁCH2, Jcis
10.0, Jtrans 17.0 Hz), 5.834 (m, 1 H,
CH2CHꢁCH2), 7.233–7.342 (m, 15 H, 3×Ph)
ppm; 13C NMR (CDCl3): lC 33.27
(CH2CHꢁCH2), 68.03 (C-6), 69.06 (C-2),
71.00 (C-1) 72.77, 73.27(2) (3×CH2Ph), 73.50
(C-5), 74.75 (C-4), 77.60 (C-3), 116.98
(CH2CHꢁCH2),
127.58–128.55
(3×Ph),

228
W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
6.0, J5,6% 5.0 Hz), 4.066 (m, 1 H, H-1), 4.592 (s,
Compound 4b was obtained in the same
2 H, CH2Ph), 4.612 (m, 1 H, H-5), 4.825 and
4.885 (d and d, 1 H each, CH2Ph, J 11.5 Hz),
5.086 and 5.163 (d and d, 1 H each,
CH2CHꢁCH2, Jcis 10.5, Jtrans 17.0 Hz), 5.902
(m, 1 H, CH2CHꢁCH2), 5.944 (d, 1 H, H-4,
J4,5 1.5 Hz), 7.298–7.376 (m, 10 H, 2×Ph)
ppm; 13C NMR (CDCl3): lC 34.33
(CH2CHꢁCH2), 69.83 (6-CH2Ph), 71.91 (C-6),
73.27 (C-5), 73.55 (3-CH2Ph), 80.80 (C-1),
116.69 (C-4), 117.58 (CH2CHꢁCH2), 127.38–
128.60 (2×Ph), 133.77 (CH2CHꢁCH2),
135.63, 137.81 (2×Ph), 148.84 (C-3), 191.29
(C-2) ppm. HRFABMS: Anal. Calcd for
way from 3b as crystals (87%): mp 72–73 °C
1
(MeOH); [h]D −51.7° (c 0.29, EtOAc). H
NMR (CDCl3): lH 2.410 and 2.624 (m and m,
1 H each, CH2CHꢁCH2), 3.703 (dd, 1 H, H-6,
J6,6% 10.0, J5,6 4.0 Hz), 3.753–3.822 (m, 3 H,
H-1,5,6%), 3.870 (dd, 1 H, H-4, J3,4 9.0, J4,5
10.0 Hz), 4.179 (d, 1 H, H-3), 4.535–5.007 (m,
6 H, 3×CH2Ph), 5.089 and 5.161 (d and d, 1
H each, CH2CHꢁCH2, Jcis 10.0, Jtrans 19.5 Hz),
5.875 (m, 1 H, CH2CHꢁCH2), 7.171–7.412
(m, 15 H, 3×Ph) ppm; 13C NMR (CDCl3): lC
32.91 (CH2CHꢁCH2), 68.85 (C-6), 73.50,
73.73, 74.98 (3×CH2Ph), 79.32 (C-5), 80.25
(C-4), 80.52 (C-1), 86.65 (C-3), 117.56
C23H23O4
363.1595.
[M−H]:
363.1596.
Found:
(CH2CHꢁCH2),
127.63–128.45
(3×Ph),
133.73 (CH2CHꢁCH2), 137.54, 137.79, 138.07
(3×Ph), 201.92 (C-2) ppm. HRFABMS:
Anal. Calcd for C30H31O5 [M−H]: 471.2171.
Found: 471.2194; Anal. Calcd for C30H33O5
[M+H]: 473.2328. Found: 473.2404.
(9) - c - 5 - Allyl - 2 - benzyloxy - r - 4 - benzyl-
oxymethyl-5-hydroxycyclopent-2-enone (6).—
A solution of compound 4a or 4b (0.25 g,
0.687 mmol) in 10% Et3N–MeOH (5 mL) was
stirred at rt for 3 days. The solvent was evap-
orated to a residue. Purification by chro-
matography (solvent A) gave 6 (0.19 g, 78%)
as a syrup: [h]D 0° (c 0.76, EtOAc or CHCl3).
1H NMR (CDCl3): lH 2.380 (d, 2 H,
CH2CHꢁCH2, J 7.0 Hz), 2.702 (s, 1 H, 1-OH),
3.090 (ddd, 1 H, H-5, J4,5 2.0, J5,6 6.5, J5,6% 7.0
Hz), 3.532 and 3.693 (dd and dd, 1 H each,
H-6,6%, J6,6% 9.0 Hz), 4.544 (s, 2 H, 6-CH2Ph),
4.976 and 4.978 (d and d, 1 H each, 3-CH2Ph,
J 12.0 Hz), 5.136 and 5.194 (d and d, 1 H
each, CH2CHꢁCH2, Jcis 10.0, Jtrans 17.5 Hz),
5.831 (m, 1 H, CH2CHꢁCH2), 6.302 (d, 1 H,
H-4) ppm; 13C NMR (CDCl3): lC 38.96
(CH2CHꢁCH2), 47.19 (C-5), 68.59 (C-6),
71.79 (3-CH2Ph), 73.59 (6-CH2Ph), 77.66 (C-
1), 120.82 (CH2CHꢁCH2), 127.17 (C-4),
127.85–128.87 (2×Ph), 131.56 (CH2CHꢁ
CH2), 135.66, 138.04 (2×Ph), 153.68 (C-3),
202.69 (C-2) ppm. HRFABMS: Anal. Calcd
for C23H25O4 [M+H]: 365.1753. Found:
365.1759.
3-C-(3,6-Di-O-benzyl-4-deoxy-h,i- -glyc-
D
ero-2-ulopyranosyl)propene (5a and 5b).—A
solution of compound 4a (0.25 g, 0.53 mmol)
in 10% Et3N–MeOH (5 mL) was stirred at rt
for 1 h. The solvent was evaporated to a
residue. Purification by chromatography (sol-
vent A) gave 5a (0.18 g, 93%) as a syrup: [h]D
1
−26.2° (c 0.65, EtOAc). H NMR (CDCl3):
lH 2.551 (m, 2 H, CH2CHꢁCH2), 3.541 and
3.655 (dd and dd, 1 H each, H-6,6%, J6,6% 10.0,
J5,6 6.0, J5,6% 5.0 Hz), 4.413 (dd, 1 H, H-1, J
5.0, J 9.0 Hz), 4.554 (s, 2 H, 6-CH2Ph), 4.742
(m, 1 H, H-5), 4.834 (s, 2 H, 3-CH2Ph), 5.127
and 5.173 (d and d, 1 H each, CH2CHꢁCH2,
Jcis 11.0, Jtrans 16.5 Hz), 5.847 (m, 1 H,
CH2CHꢁCH2), 5.877 (d, 1 H, H-4, J4,5 2.0
13
Hz), 7.280–7.381 (m, 10 H, 2×Ph) ppm; C
NMR (CDCl3): lC 34.01 (CH2CHꢁCH2),
69.47 (C-5), 69.77 (6-CH2Ph), 71.28 (C-6),
73.47 (3-CH2Ph), 78.48 (C-1), 116.24 (C-4),
117.98 (CH2CHꢁCH2), 127.35–128.59 (Ph),
133.35 (CH2CHꢁCH2), 135.63, 137.67 (2×
Ph), 147.44 (C-3), 191.35 (C-2) ppm. HR-
FABMS: Anal. Calcd for C23H23O4 [M−H]:
363.1596. Found: 363.1668.
(9)-2-Benzyloxy-r-4-benzyloxymethyl-t-5-
hydroxy-5-propenylcyclopent-2-eneone (15).—
A solution of compound 5b (30 mg, 0.082
mmol) in 90% Et3N–MeOH (1 mL) was
stirred at rt for 72 h. Workup following the
same procedures as described above for 6 gave
15 (22 mg, 73%) as a syrup: [h]D 0° (c 2.1,
Compound 5b was obtained as a syrup
from 4b (78%): [h]D −16.8o (c 0.24, EtOAc).
1H NMR (CDCl3): lH 2.489 and 2.792 (m and
m, 1 H each, CH2CHꢁCH2), 3.517 and 3.665
(dd and dd, 1 H each, H-6,6%, J6,6% 10.0, J5,6
1
EtOAc). H NMR (CDCl3): lH 1.680 (d, 3 H,
CHꢁCHꢀCH3, J 6.5 Hz), 2.669 (s, 1 H, 1-

W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
229
orating the solvent, the residue was purified by
column chromatography (solvent C) to afford
8 (0.706 g, 97%) as crystals: mp 187 °C
(EtOAc–hexane); [h]D +28° (c 0.44, EtOAc).
1H NMR (CDCl3): lH 0.967 (t, 3 H,
CH2CH2CH3, J 7.5 Hz), 1.340 and 1.492 (m
and m, 1 H each, CH2CH2CH3), 1.649–1.708
(m, 2 H, CH2CH2CH3), 2.565 (s, 1 H, OH),
2.832 (s, 1 H, OH), 3.435 (dd, 1 H, H-4, J4,5
9.5, J3,4 8.5 Hz), 3.583 (ddd, 1 H, H-5, J5,6
10.0, J5,6% 5.0 Hz), 3.685 (dd, 1 H, H-6, J6,6%
10.5 Hz), 3.820–3.853 (m, 2 H, H-2, H-3),
4.043 (m, 1 H, H-1), 4.256 (dd, 1 H, H-6%),
5.519 (s, 1 H, PhCH), 7.370–7.501 (m, 15 H,
3×Ph) ppm; 13C NMR (CDCl3): lC 13.85
(CH2CH2CH3), 18.58 (CH2CH2CH3), 26.568
(CH2CH2CH3), 63.28 (C-5), 69.45 (C-6), 71.64
(C-2), 72.32 (C-3), 76.37 (C-1), 82.14 (C-4),
101.95 (PhCH), 126.24, 128.38, 129.31, 137.08
(Ph) ppm. HRFABMS: Anal. Calcd for
C16H23O5 [M]: 295.1546. Found: 295.1573.
1-C-(2,3-Di-O-benzyl-4,6-O-benzylidene-h-
OH), 3.073 (bdd, 1 H, H-5, J5,6 7.0, J5,6% 8.0
Hz), 3.394 and 3.590 (dd and dd, 1 H each,
H-6,6%, J6,6% 8.0 Hz), 4.512 (s, 2 H, 6-CH2Ph),
4.971 and 4.975 (d and d, 1 H each, 3-CH2Ph,
J 11.5 Hz), 5.408 (d, 1 H, CHꢁCHꢀCH3, Jtrans
15.5 Hz), 5.778 (m, 1 H, CHꢁCHꢀCH3), 6.381
(d, 1 H, H-4), 7.303–7.366 (m, 10 H, 2×Ph)
ppm; lC 17.82 (CHꢁCHꢀCH3), 47.87 (C-5),
69.27 (C-6), 71.57 (3-CH2Ph), 73.31 (6-
CH2Ph), 79.31 (C-1), 120.82 (CHꢁCHꢀCH3),
127.67 (C-4), 127.61–128.58 (2×Ph), 127.97
(CHꢁCHꢀCH3), 135.34, 137.92 (2×Ph),
153.86 (C-3), 201.75 (C-2) ppm. FABMS:
Anal. Calcd for C23H25O4 [M+H]: 365.5.
Found: 365.2.
1-C-(2-O-Acetyl-h- -glucopyranosyl)pro-
D
pane (7).—To a solution of 2a (1.60 g, 3.10
mmol) in MeOH (10 mL) was added 10%
Pd–C (0.5 g, 50% water). The mixture was
subjected to hydrogenation (50 psi H2)
overnight. Removal of solvent gave 7 (0.704 g,
90%) as a solid. Recrystalization from EtOAc
gave mp 109–110 °C; [h]D +119° (c 0.38,
D
-glucopyranosyl)propane (9).—To a solution
1
EtOAc). H NMR (CDCl3): lH 0.945 (t, 3 H,
of 8 (0.705 g, 2.39 mmol) in DMF (6 mL) was
added 60% NaH (0.23 g). After 0.5 h BnBr
(1.14 mL) was added to the mixture, and the
mixture was stirred overnight and diluted by
the addition of EtOAc (150 mL), and subse-
quently washed with 1 N HCl, aq NaHCO3,
water, dried, and concentrated. Purification by
chromatography (solvent A) afforded 9 (1.130
g, 99%) as a solid. [h]D −0.9° (c 0.44,
CH2CH2CH3, J 7.5 Hz), 1.287 and 1.402 (m
and m, 1 H each, CH2CH2CH3), 1.486 and
1.708 (m and m, 1 H each, CH2CH2CH3),
2.129 (s, 3 H, CH3CO), 3.498 (m, 1 H, H-5),
3.581 (dd, 1 H, H-4, J3,4 9.5, J4,5 9.0 Hz), 3.781
(m, 1 H, H-6), 3.822–3.855 (m, 2 H, H-3,6%),
4.129 (dd, 1 H, H-1, J1,2 5.5, J 7.0 Hz), 4.849
(dd, 1 H, H-2, J2,3 9.3 Hz) ppm; 13C NMR
(CDCl3): lC 13.78 (CH2CH2CH3), 18.43
(CH2CH2CH3), 20.94 (CH3CO), 27.06
(CH2CH2CH3), 61.60 (C-6), 70.41 (C-4), 71.73
(C-5), 72.11 (C-3), 72.79 (C-1), 73.28 (C-2),
170.93 (CH3CO) ppm. HRFABMS: Anal.
Calcd for C11H21O6 [M+H]: 249.1338.
Found: 249.1325.
1
EtOAc); H NMR (CDCl3): lH 0.941 (t, 3 H,
CH2CH2CH3, J 7.5 Hz), 1.291 and 1.454 (m
and m, 1 H each, CH2CH2CH3), 1.677 and
1.762 (m and m, 1 H each, CH2CH2CH3),
3.601 (ddd, 1 H, H-5, J4,5 8.5, J5,6 9.5, J5,6% 4.5
Hz), 3.637 (dd, 1 H, H-4, J3,4 8.5 Hz), 3.675
(dd, 1 H, H-6, J6,6% 10.5 Hz), 3.729 (dd, 1 H,
H-2, J2,3 9.0, J1,2 5.5 Hz), 3.866 (dd, 1 H, H-3),
3.975–4.027 (m, 1 H, H-1), 4.255 (dd, 1 H,
H-6%), 4.635 and 4.764 (d and d, 1 H each,
CH2Ph, J 12.0 Hz), 4.809 and 4.913 (d and d,
1 H each, CH2Ph, J 11.0 Hz), 5.563 (s, 1 H,
PhCH), 7.264–7.493 (m, 15 H, 3×Ph) ppm;
13C NMR (CDCl3): lC 13.85 (CH2CH2CH3),
18.47 (CH2CH2CH3), 27.50 (CH2CH2CH3),
63.36 (C-5), 69.56 (C-6), 73.51 (CH2Ph), 74.87
(CH2Ph), 75.12 (C-1), 78.87 (C-3), 79.70 (C-
2), 82.89 (C-4), 101.15 (PhCH), 125.97–
128.85, 137.47, 138.28, 138.73 (3×Ph) ppm.
1-C-(4,6-O-benzylidene-h- -glucopyranosyl)-
D
propane (8).—A solution of 7 (0.614 g, 2.47
mmol) in 0.1% NaOMe–MeOH (15 mL) was
kept at rt for 2 h. The solution was neutral-
ized by Dowex-50W×8 (100 mesh, H+) resin,
and the filtrate was concentrated to a residue.
To a solution of above residue in CH3CN (30
mL) was added PhCH(OMe)2 (0.85 mL) and
TsOH (20 mg). The mixture was stirred for 3
h at the end of which time the reaction was
judged completed, and it was then neutralized
by the addition of Et3N (0.5 mL). After evap-

230
W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
4.074 (m, 1 H, H-1), 4.190 (d, 1 H, H-3, J2,3
6.0 Hz), 4.281 (m, 1 H, H-5), 4.524–4.842 (m,
6 H, 3×CH2Ph), 7.266–7.373 (m, 15 H, 3×
Ph) ppm; 13C NMR (CDCl3): lC 13.93
(CH2CH2CH3), 18.85 (CH2CH2CH3), 29.69
(CH2CH2CH3), 68.42 (C-6), 73.11 (CH2Ph),
73.26 (CH2Ph), 73.50 (CH2Ph), 74.15 (C-1),
77.72 (C-5), 81.05 (C-2), 82.30 (C-3), 127.61–
128.43, 137.34, 137.82, 137.91 (3×Ph), 205.01
(C-4) ppm. HRFABMS: Anal. Calcd for
C30H34O5 [M]: 474.2406. Found: 474.2442.
HRFABMS: Anal. Calcd for C30H33O5 [M−
H]: 473.2328. Found: 473.2345; Anal. Calcd
for C30H35O5 [M+H]: 475.2485. Found:
475.2458.
1-C-(2,3,6-Tri-O-benzyl-h- -glucopyran-
D
osyl)propane (10).—To a solution of 9 (0.56 g,
,
1.18 mmol), NaCNBH3 (1.1 g) and 3 A molec-
ular sieves (5 g) in THF (20 mL) was added
satd HCl–Et2O solution at 0 °C until pH 3
was attained. The mixture was stirred for 2 h,
at the end of which time the reaction was
complete. The filtrate was diluted with EtOAc
(150 mL), subsequently washed with aq
NaHCO3, water, dried, and concentrated.
Purification on column chromatography (sol-
vent D) afforded the debenzylidenated
product (0.193 g, 42%) and 10 (0.274 g, 49%)
1-C-(3,6-Di-O-benzyl-2-deoxy-h-
hex-2-eno-4-ulopyranosyl)propane (12) and 1-
C-(3,6-di-O-benzyl-2-deoxy-i- -glycero-hex-
D
-glycero-
L
2-eno-4-ulopyranosyl)propane (13).—A solu-
tion of 11 (18 mg) in 10% Et3N–MeOH (2
mL) was kept at rt for 4 h. The solvent was
removed, and the residue was purified by
preparative TLC (solvent D). Compounds 12
(3 mg, 17%) and 13 (8 mg, 44%) were ob-
tained as major products. Small amounts of
starting material 11 and ring-contraction
product 14 were also obtained.
1
as a syrup: [h]D +33° (c 0.45, EtOAc). H
NMR (CDCl3): lH 0.934 (t,
3
H,
CH2CH2CH3, J 7.0 Hz), 1.280 and 1.477 (m
and m, 1 H each, CH2CH2CH3), 1.574 and
1.712 (m and m, 1 H each, CH2CH2CH3),
2.698 (d, 1 H, 4-OH, J 2.0 Hz), 3.633–3.714
(m, 6 H, H-2,3,4,5,6,6%), 3.990 (m, 1 H, H-1),
4.562–4.878 (m, 6 H, 3×CH2Ph), 7.368–
7.267 (m, 15 H, 3×Ph) ppm; 13C NMR
(CDCl3): lC 13.94 (CH2CH2CH3), 18.63
(CH2CH2CH3), 27.73 (CH2CH2CH3), 70.03
(C-6), 71.09 (C-4), 71.55 (C-5), 72.83
(CH2Ph), 72.93 (C-1), 73.50 (CH2Ph), 74.67
(CH2Ph), 79.18 (C-2), 80.42 (C-3), 127.58–
128.51, 138.05, 138.66 (3×Ph) ppm. HR-
FABMS: Anal. Calcd for C30H36O5 [M]:
476.2563. Found: 476.2526.
Data for 12: Rf 0.62 (solvent D); [h]D
1
+7.4° (c 0.24, EtOAc). H NMR (CDCl3): lH
0.935 (t, 3 H, CH2CH2CH3, J 7.0 Hz), 1.344
and 1.438 (m and m, 1 H each, CH2CH2CH3),
1.528 and 1.697 (m and m, 1 H each,
CH2CH2CH3), 3.794 and 3.908 (dd and dd, 1
H each, H-6,6%, J6,6% 11.0, J5,6 6.0, J5,6% 2.5 Hz),
4.474 (dd, 1 H, H-5), 4.560 (s, 2 H, CH2Ph),
4.699 (m, 1 H, H-1), 5.846 (d, 1 H, H-2, J1,2
2.5 Hz), 4.877 (s, 2 H, CH2Ph), 7.353–7.274
(m, 10 H, 2×Ph) ppm; 13C NMR (CDCl3): lC
13.90 (CH2CH2CH3), 18.68 (CH2CH2CH3),
36.59 (CH2CH2CH3), 69.50 (C-6), 69.77
(CH2Ph), 71.02 (C-1), 73.50 (CH2Ph), 77.96
(C-5), 120.83 (C-2) 127.33–129.90, 135.83,
138.54 (2×Ph), 147.39 (C-3), 190.35 (C-4)
ppm. HRFABMS: Anal. Calcd for C23H25O4
[M−H]: 365.1753. Found: 365.1835.
1-C-(2,3,6-Tri-O-benzyl-h- -xylo-hex-4-
D
ulopyranosyl)propane (11).—A solution of 10
(0.255 g, 0.536 mmol) in 2:1 Me2SO–Ac2O
(4.5 mL) was kept at rt for 8 h. The solution
was diluted with EtOAc (150 mL) and subse-
quently washed with aq NaHCO3, water,
dried, and concentrated. The residue was
purified by chromatography (solvent D) to
obtain 11 (0.23 g 90%) as a solid. Recrystal-
lization from MeOH gave mp 91–92 °C, [h]D
Data for 13: Rf 0.59 (solvent D); [h]D
1
+9.7° (c 0.29, EtOAc). H NMR (CDCl3): lH
0.945 (t, 3 H, CH2CH2CH3, J 7.0 Hz), 1.397–
1.484 (m, 2 H, CH2CH2CH3), 1.610 and 1.686
(m and m, 1 H each, CH2CH2CH3), 3.800 and
4.046 (dd and dd, 1 H each, H-6,6%, J6,6% 11.2,
J5,6 7.0, J5,6% 2.0 Hz), 4.213 (d, 1 H, H-5), 4.449
(dd, 1 H, H-1), 4.600–4.906 (m, 4 H, 2×
CH2Ph), 5.828 (s, 1 H, H-2), 7.273–7.361 (m,
1
+67° (c 0.15, EtOAc). H NMR (CDCl3): lH
0.923 (t, 3 H, CH2CH2CH3, J 7.0 Hz), 1.322
and 1.487 (m and m, 1 H each, CH2CH2CH3),
1.616 and 1.745 (m and m, 1 H each,
CH2CH2CH3), 3.775 (dd, 1 H, H-6, J6,6% 10.0,
J5,6 6.5 Hz), 3.803–3.850 (m, 2 H, H-2, 6%),

W. Zou et al. / Carbohydrate Research 334 (2001) 223–231
231
10 H, 2×Ph) ppm; 13C NMR (CDCl3): lC
13.96 (CH2CH2CH3), 18.15 (CH2CH2CH3),
37.91 (CH2CH2CH3), 68.99 (C-6), 69.82
(CH2Ph), 73.46 (C-1), 73.63 (CH2Ph), 81.19
(C-5), 120.34 (C-2), 127.33–128.62, 135.82,
138.16 (2×Ph), 148.34 (C-3), 190.21 (C-4)
ppm. HRFABMS: Anal. Calcd for C23H25O4
[M−H]: 365.1753. Found: 365.1778.
(9)-2-Benzyloxy-c-5-benzyloxymethyl-5-
hydroxy-r-4-propylcyclopent-2-enone (14).—A
solution of 11 (19 mg) in 10% Et3N–MeOH (2
mL) was kept at rt for 4 days. The solvent was
evaporated, and separation on preparative
TLC (solvent D) furnished three compounds,
12 (2.4 mg, 13%), 13 (5.3 mg, 27%), and 14
(10.8 mg, 55%).
References
1. Collins, P.; Djuric, S. W. Chem. Re6. 1993, 93, 1533–1564.
2. (a) Borthwick, A. D.; Biggadike, K. Tetrahedron 1992, 48,
571–623;
(b) Marien, C. L.; Esmans, E. L.; Lemiere, F.; Dommisse,
R. A. Synth. Commun. 1997, 27, 205–224.
3. (a) McCurry, P. M.; Singh, R. K. J. J. Org. Chem. 1974,
39, 2316–2317;
(b) Ong, C. W.; Chen, C. M.; Juang, S. H. J. Org. Chem.
1994, 59, 7915–7916;
(c) Denmark, S. E.; Jones, T. K. J. Am. Chem. Soc. 1982,
104, 2642–2645.
4. (a) Schore, N. E. Org. React. 1991, 40, 1–90;
(b) Cadierno, V.; Pilar Gamasa, M.; Gimeno, J.; Moreto,
J. M.; Ricart, S.; Roig, A.; Molins, E. Organometallics
1998, 17, 697–706;
(c) Belanger, D. B.; O’Mahony, D. J. R.; Livinghouse, T.
Tetrahedron Lett. 1998, 39, 7637–7640;
(d) Hanzawa, Y.; Kakuuchi, A.; Yabe, M.; Narita, K.;
Tabuchi, N.; Taguchi, T. Tetrahedron Lett. 2001, 42,
1737–1740;
(e) Takahashi, T.; Huo, S.; Hara, R.; Noguchi, Y.; Naka-
Jima, K.; Sun, W.-H. J. Am. Chem. Soc. 1999, 121,
1094–1095;
(f) Kondo, T.; Nakamura, A.; Okada, T.; Suzuki, N.;
Wada, K.; Mitsudo, T. J. Am. Chem. Soc. 2000, 122,
6319–6320;
(g) Trost, B. M.; Pinkerton, A. B. Org. Lett. 2000, 2,
1601–1603;
Data for 14: Rf 0.41 (solvent D); [h]D 0° (c
1
0.4, EtOAc). H NMR (CDCl3): lH 0.939 (t, 3
H, CH2CH2CH3, J 7.0 Hz), 1.314 and 1.399
(m, 2 H, CH2CH2CH3), 1.654–1.721 (m, 2 H,
CH2CH2CH3), 2.722 (dt, 1 H, H-1, J 7.5, J1,2
2.0 Hz,), 3.063 (s, OH), 3.521 (s, 2 H, H-6),
4.490 (s, 2 H, CH2Ph), 4.944 and 4.981 (d and
d, 1 H each, CH2Ph, J 12.0 Hz), 6.282 (d, 1 H,
(h) Morisaki, Y.; Kondo, T.; Mitsudo, T. Org. Lett. 2000,
2, 949–952;
13
(i) Molins, E. Organometallics 1998, 17, 697–706;
(j) Periasamy, M. Organometallics 1996, 15, 442–445.
5. (a) Takahashi, T.; Li, Y.; Tsai, F.-Y.; NakaJima, K.
Organometallics 2001, 20, 595–597;
H-2), 7.352–7.275 (m, 10 H, 2×Ph) ppm; C
NMR (CDCl3): lC 14.11 (CH2CH2CH3),
21.08 (CH2CH2CH3), 30.67 (CH2CH2CH3),
45.76 (C-1), 71.38 (CH2Ph), 71.93 (C-6), 73.60
(CH2Ph), 78.71 (C-5), 127.54–128.57, 129.80
(C-2), 135.54 (Ph), 137.52 (Ph), 153.67 (C-3),
202.26 (C-4) ppm. HRFABMS: Anal. Calcd
for C23H27O4 [M+H]: 367.1910. Found:
367.1964.
(b) Takeda, K.; Ohtani, Y.; Ando, E.; FuJimoto, K.;
Yoshii, E.; Koizumi, T. Chem. Lett. 1998, 11, 1157–1158;
(c) Takeda, K.; Nakayama, I.; Yoshii, E. Synlett 1994, 3,
178.
6. (a) Paquette, L. A.; Gallou, F.; Zhao, Z.; Young, D. G.;
Liu, J.; Yang, J.; Friedrich, D. J. Am. Chem. Soc. 2000,
122, 9610–9620;
(b) Toru, T. J. Org. Chem. 1998, 63, 3899–3904.
7. (a) Armstrong, A.; Hayter, B. R. Tetrahedron: Asymmetry
1997, 8, 1677–1684;
(b) Kuhn, C.; Florent, J.-C. Tetrahedron Lett. 1998, 39,
4247–4250.
8. Pozsgay, V.; Jennings, H. J. Synthesis 1990, 724–726.
9. (a) Bombard, S.; Maillet, M.; Capmau, M.-L. Carbohydr.
Res. 1995, 275, 433–440;
Acknowledgements
(b) Marron, T. G.; Woltering, T. J.; Weitz-Schmidt, G.;
Wong, C.-H. Tetrahedron Lett. 1996, 37, 9037–9040;
(c) McDevitt, J. P.; Lansbury, P. T. J. Am. Chem. Soc.
1996, 118, 3818–3828.
This is NRCC publication No. 42442. We
acknowledge the financial support provided,
in part, by the National Research Council of
Canada (to W.Z.) and the National Science
Council of Taiwan (to H.W.). We also thank
Dr J.-R. Brisson, S. Larocque and K. Chan
for assistance in recording the NMR and MS
spectra, respectively.
10. Jones, G. H.; Moffatt, J. G. Methods Carbohydr. Chem.
1972, 6, 315–322.
11. Nonaka, C.-I.; Ishimaru, K.; Mihashi, K.; Iwase, Y.;
Ageta, M.; Nishioka, I. Chem. Pharm. Bull. 1988, 36,
857–869.
12. Garegg, P. J.; Hultberg, H.; Wallin, S. Carbohydr. Res.
1982, 108, 97–101.
.