Synthesis of Selectively Labeled D-Fructose and D-Fructose Phosphate Analogues Locked in the Cyclic Furanose Form

Article abstract of DOI:10.1021/jo0003908

2,5-Anhydroglucitol and 2,5-anhydromannitol and their 6-phosphate and 1,6-diphosphate derivatives are cyclic analogues of the α and β anomers of D-fructofuranose, D-fructofuranose-6-phosphate, and D-fructofuranose-1,6-diphosphate. They were synthesized from protected D-mannose or D-glucose. The synthetic method was developed with emphasis on selective ²H labeling of these compounds, as a model for ³H incorporation, which will be used for further biochemical studies. A key cyclization step, based on a benzyl ether nucleophilic attack on an activated alcohol, constructed the ring system. The stereochemistry at C₂ (α/β anomers) and at C₅ (D sugar) was controlled by selective epimerizations. Mono- and diphosphate analogues were obtained from the same intermediate by changing the sequence of deprotection and phosphorylation steps.

Full text of DOI:10.1021/jo0003908

5632
J . Org. Chem. 2000, 65, 5632-5638
Syn th esis of Selectively La beled D-F r u ctose a n d D-F r u ctose
P h osp h a te An a logu es Lock ed in th e Cyclic F u r a n ose F or m
Rachel Persky and Amnon Albeck*
The J ulius Spokojny Bioorganic Chemistry Laboratory, Department of Chemistry, Bar Ilan University,
Ramat Gan 52900, Israel
albecka@mail.biu.ac.il
Received March 17, 2000
2,5-Anhydroglucitol and 2,5-anhydromannitol and their 6-phosphate and 1,6-diphosphate derivatives
are cyclic analogues of the R and â anomers of D-fructofuranose, D-fructofuranose-6-phosphate, and
D-fructofuranose-1,6-diphosphate. They were synthesized from protected D-mannose or D-glucose.
2
The synthetic method was developed with emphasis on selective H labeling of these compounds,
3
as a model for H incorporation, which will be used for further biochemical studies. A key cyclization
step, based on a benzyl ether nucleophilic attack on an activated alcohol, constructed the ring system.
The stereochemistry at C2 (R/â anomers) and at C5 (D sugar) was controlled by selective
epimerizations. Mono- and diphosphate analogues were obtained from the same intermediate by
changing the sequence of deprotection and phosphorylation steps.
In tr od u ction
al structure (mainly the furanose form) and the open
ketone form. 2,5-Anhydroglucitol 5a and 2,5-anhydro-
mannitol 5b (Chart 1) are cyclic fructose analogues
lacking the anomeric C2 hydroxy substituent, and there-
fore, they are locked either in the R (the former) or in
the â (the latter) anomeric form of the cyclic fructofura-
nose. Therefore, they (and their phosphorylated deriva-
tives 8 and 9, Chart 1) can be used as mechanistic tools
to study the anomeric specificity of enzymes, the impor-
tance of the anomeric hydroxy group, isolation of reaction
intermediates, etc. One approach is to utilize their
selectively labeled form. They can help follow and identify
the catalytic products, obtain mechanistic information or,
in the case of affinity labeling, provide a means to follow
the inactivated enzyme. Such labeling has the distinct
advantage of strictly maintaining the stereoelectronic
character of the unlabeled compound. Alas, it may
require special synthetic methodologies, different from
those utilized in the synthesis of its unlabeled equivalent.
2,5-Anhydroglucitol 5a 4,5 and 2,5-anhydromannitol
5b4,6 and their corresponding 6-phosphate and 1,6-
diphosphate derivatives 8 and 94 were previously syn-
thesized by various methods.7 Construction of the anhy-
dro ring system in these and related compounds was
achieved by diazotation of glucosamine,6,8 acid-catalyzed
dehydration,5,9 silicon-directed cyclization,10 silylation
and reductive cleavage,11 and an intramolecular displace-
ment of a mesylated hydroxyl group.12 Phosphorylation
Substrate analogues are useful tools in the study of
enzyme reaction mechanisms. Such analogues could help
in the identification of the active substrate conformation
or configuration or in the stabilization of reaction inter-
mediates. Thus, discrete changes, at the molecular level,
of the substrate during the catalytic reaction could be
detected and characterized. This approach was found to
be useful in the study of a few sugar metabolizing
enzymes.1
D-Fructose and its phosphorylated derivatives, D-fruc-
tose-1-phosphate, D-fructose-6-phosphate, and D-fructose-
1,6-diphosphate, are substrates and products of a few key
enzymes, such as phosphoglucoisomerase, phosphofruc-
tokinase and aldolase (of the glycolytic pathway), inver-
tase and sucrose synthetase, fructokinase and ketose-1-
phosphate aldolase (in the liver), and transaldolase and
transketolase.2 D-Fructose-6-phosphate is also suggested
as a possible substrate for the initial step in the biosyn-
thesis of neplanocin A and aristeromycin, two biologically
active secondary metabolites of some streptomyces.3
Therefore, analogues of fructose derivatives, with specif-
ically tailored features, are of interest in the mechanistic
study of these and other enzymes.
For fructose and its 6-phosphate and 1,6-diphosphate
derivatives in aqueous solution there is a dynamic
equilibrium between the R and â anomers of the hemiket-
* To whom correspondence should be addressed. Tel: 972-3-
5318862. Fax: 972-3-5351250.
(4) Benkovic, S. J .; Kleinschuster, J . J .; deMaine, M. M.; Siewers,
I. J . Biochemistry 1971, 10, 4881-4887.
(1) For a few recent examples, see: (a) Shoucheng, D.; Faiger, H.;
Belakhov, V.; Baasov, T. Bioorg. Med. Chem. 1999, 7, 2671-2682. (b)
Baasov, T.; Belakhov, V. Recent Res. Devel. Org. Chem. 1999, 3, 195-
206. (c) Lauhon, C. T.; Bartlett, P. A. Biochemistry 1994, 33, 14100-
14108. (d) Bender, S. L.; Widlanski, T.; Knowles, J . R. Biochemistry
1989, 28, 7560-7572. (e) Widlanski, T.; Bender, S. L.; Knowles, J . R.
Biochemistry 1989, 28, 7572-7582.
(5) Hockett, R. C.; Zief, M.; Goepp, M., J r. J . Am. Chem. Soc. 1946,
68, 935-937.
(6) Bera, B. C.; Foster, A. B.; Stacey, M. J . Chem. Soc. 1956, 4531-
4535.
(7) 2,5-Anhydromannitol is now commercially available.
(8) (a)Horton, D.; Phillips, K. D. Carbohydr. Res. 1973, 30, 367-
374. (b) Otero, D. A.; Simpson, R. Carbohydr. Res. 1984, 128, 79-86.
(9) Bock, K.; Federsen, C.; Thogersen, N. Acta Chem. Scand. 1981,
35, 441-449.
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Tetrahedron Lett. 1994, 35, 1091-1094.
(11) Bennek, J . A.; Gray, G. R. J . Org. Chem. 1987, 52, 892-897.
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(2) (a) Voet, D.; Voet. J . G. Biochemistry, 2nd ed.; Wiley: New York,
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10.1021/jo0003908 CCC: $19.00 © 2000 American Chemical Society
Published on Web 08/16/2000

D-Fructose Analogues Locked in the Cyclic Furanose Form
J . Org. Chem., Vol. 65, No. 18, 2000 5633
Ch a r t 1. F r u ctose Der iva tives Lock ed in th e
Cyclic F u r a n ose F or m
Schemes 1-3. It is based on a key regio- and stereose-
lective cyclization step (yielding cyclic olefins 2), previ-
ously described by Martin et al.17 Oxidation of the olefin
functionality of 2, yielding aldehyde 3, was carried out
by a variety of methods: ozonolysis under various condi-
tions,18,19 m-CPBA epoxidation followed by periodate
oxidation,20 one-pot OsO4/HIO4 oxidation,21 and two-step
OsO4/4-methylmorpholine N-oxide and HIO4 oxidation.22
The latter proved to be the most effective in our hands.
NaBH4 reduction of the aldehyde to the corresponding
alcohol 4 completed the construction of the cyclic system.
The C2 symmetry of the cyclic systems 4, in respect to
the C3 and C4 substitution pattern, allowed us to “rotate”
the compounds, transforming the C2 position of the
starting material into the C5 position of the final fructo-
furanose analogues and C5 of the starting material into
the C2 of the products (Schemes 1 and 3). This simplified
the following phosphorylation steps (for the production
of the monophosphate analogues), circumventing labori-
ous protection and deprotection steps, and enabled
introduction of selective labeling at the C5 and C6
positions of the analogues (see below).
Starting from 2,3,4,6-tetra-O-benzyl mannose, this
procedure provided cyclic alcohol 4a , which bears the
correct stereochemistry of R-D-fructofuranose at all its
chiral centers (Scheme 1). Aldehyde 3a could also be
prepared from 2,3,4,6-tetra-O-benzyl-D-glucose by a simi-
lar procedure (Scheme 2). Thus, cyclic olefin 2c was
oxidized to the cyclic aldehyde 3c, bearing an opposite
absolute configuration at C2, in comparison with aldehyde
3a , derived from the mannose derivative starting mate-
rial. This chiral center was inverted under basic condi-
tions (Et3N, DMF), yielding the desired epimer 3a as the
major constituent (3a /3c 4:1).
Comparison of the synthetic efficiency toward 3a from
protected glucose and mannose shows comparable total
yields, despite a step longer procedure from the glucose
derivative. Considering the price difference of the starting
materials (the 2,3,4,6-tetra-O-benzyl mannose is 2.5-fold
more expensive than the corresponding glucose deriva-
tive) and the possibility of introduction of selective
labeling at the epimerization step (see below) makes the
glucose route more attractive.
The chiral center at C5 of the sugar starting material
should be epimerized in order to obtain the â-fructofura-
nose analogues. Therefore, the linear olefin 1a , derived
from protected mannose and bearing a free hydroxy
group at C5, underwent a Mitsunobu reaction23,24 to yield
its isomer 1b. The new olefin was subject to a set of
reactions similar to those described for 1a , yielding the
involved either chemical13,14 or enzymatic14 procedures.
These and related compounds were utilized in enzymatic
studies of aldolase,13a phosphofructokinase,14,15 and fruc-
tose-1,6-diphosphatase.4,16 However, these synthetic meth-
ods could not be applied in a straightforward manner for
efficient selective radiolabeling.
In the present study, we describe an alternative
synthetic method for the above six compounds (R- and
â-fructofuranose analogues, 5a and 5b, and their 6-phos-
phate and 1,6-diphosphate derivatives, Chart 1). This
synthetic approach was developed specifically in order
to enable efficient selective incorporation of labeling
(tritium or deuterium) into as many as four positions of
the sugar skeleton (C1, C2, C5, and C6). Furthermore, this
approach can also be applied to the synthesis of other
ketohexose analogues.
Resu lts a n d Discu ssion
Syn th esis. The synthesis of the R and â anomers of
the cyclic analogues proceeds in parallel lines. The
starting material was either protected D-mannose or
protected D-glucose. These have the desired stereochem-
istry of the hydroxy substitutions at C3 and C4. The other
two chiral centers, at C2 and C5, could be manipulated
to control the family of D sugars (C2 of the starting
material, see below) and the R/â anomerism (C5 of the
starting material). While the R anomer is prepared
directly from protected D-mannose or D-glucose, the â
anomer requires epimerization at the C5 position of the
starting material (L sugar) followed by the same protocol
of the R anomer. All three fructose derivatives (the “free
sugar” and its mono- and diphosphates) are obtained
from a common key intermediate by changing the se-
quence of deprotection and phosphorylation steps.
Rin g Con str u ction . The construction of the locked
cyclic skeleton of the sugar analogues is described in
(17) Martin, O. R.; Yang, F.; Xie, F. Tetrahedron Lett. 1995, 36, 47-
50.
(18) Bailey, P. S. Ozonation in Organic Chemistry; Academic
Press: New York, 1978; p 131.
(19) (a) Wang, Y. F.; Takaoka, Y.; Wong, C.-H. Angew. Chem., Int.
Ed. Engl. 1994, 33, 1242-1244. (b) Barrett, A. G. M.; Edmunds, J . J .;
Horita, K.; Parkinson, C. J . J . Chem. Soc., Chem. Commun. 1992,
1236-1238. (c) Gupta, D.; Soman, R.; Dev, S. Tetrahedron 1982, 38,
3013-3018. (d) Pappas, J . J .; Keaveney, W. P.; Gancher, E.; Berger,
M. Tetrahedron Lett. 1966, 4273-4278.
(20) Paquette, L. A.; Ku¨nzer, H.; Green, K. E. J . Am. Chem. Soc.
1985, 107, 4788-4790.
(21) Ellison, R. A.; Lukenbach, E. R.; Chiu, C. Tetrahedron Lett.
1975, 499-502.
(22) Barrett, A. G. M.; Edmunds, J . J .; Hendrix, J . A.; Malecha, J .
W.; Parkinson, C. J . J . Chem. Soc., Chem. Commun. 1992, 1240-1242.
(23) Campbell, D. A.; Bermak, J . C. J . Org. Chem. 1994, 59, 658-
660.
(13) (a) Hartman, F. C.; Barker, R. Biochemistry 1965, 4, 1068-
1075. (b) Koerner, T. A. W., J r.; Voll, R. J .; Younathan, E. S. Carbohydr.
Res. 1979, 70, 165-168.
(14) Bar-Tana, J .; Cleland, W. W. J . Biol. Chem. 1974, 249, 1263-
1270.
(15) Bertagnolli, B. L.; Younathan, E. S.; Voll, R. J .; Pittman, C. E.;
Cook, P. F. Biochemistry 1986, 25, 4674-4681.
(16) (a) Villeret, V.; Huang, S.; Zhang, Y.; Lipscomb, W. N. Bio-
chemistry 1995, 34, 4307-4315. (b) Zhang, Y.; J iin, Y.; Huang, S.; Ke,
H.; Lipscomb, W. N. Biochemistry 1993, 32, 1844-1857. (c) Maryanoff,
B. E.; Reitz, A. B.; Nortey, S. O. Tetrahedron 1988, 44, 3093-3106.
(24) Persky, R.; Albeck, A. J . Org. Chem. 2000, 65, 3775-3780.

5634 J . Org. Chem., Vol. 65, No. 18, 2000
Persky and Albeck
Sch em e 1. Con str u ction of th e r-F u r a n ose An a logu e Rin g System fr om P r otected Ma n n osea
a
Key: (a) Ph3P+CH3Br-, BuLi, (CH3OCH2)2; (b) Tf2O, py; (c) (i) OsO4, NMO, (ii) NaIO4, THF-H2O; (d) NaBH4, EtOH.
Sch em e 2. Con str u ction of th e r-F u r a n ose
of 4a were removed by catalytic hydrogenation, yielding
2,5-anhydroglucitol (the R-D-fructofuranose analog) 5a .
Selective phosphorylation of the two primary alcohols,25
followed by deprotection (catalytic hydrogenation) af-
forded the R-D-fructofuranose-1,6-diphosphate analogue
9a (Scheme 5).13,14 9b can be similarly prepared from 5b.
It should be noted that compounds 5b, 7b, and 9b
could be easily distinguished from their corresponding R
analogues 5a , 7a , and 9a by NMR spectroscopy. The
formers have C2 symmetry. Therefore, they exhibit very
simplified NMR spectra.26 This is especially evident in
their 13C NMR spectra, exhibiting only three peaks
(besides the phenyl carbons of the phosphate esters of
7b). In contrast, the R-fructofuranose analogues 5a , 7a ,
and 9a exhibit much more complex NMR spectra, due to
the lack of symmetry.
Selective La belin g. To probe the possibilities of
introducing 3H labeling into the fructofuranose analogues
5, 8, and 9, we studied the incorporation of its stable
isotope deuterium into various positions by two methods.
Incorporation of the deuterium atom was confirmed by
1H and 13C NMR and by mass spectroscopy.
2H-La belin g a t C1/C6. Aldehyde 3d was reduced with
NaB2H4, yielding a diastereomeric mixture of (6-R,S)-[6-
2H]-4d (an analogue of protected [1-2H]-R-D-mannopyra-
nose).
This approach can be used for the synthesis of a variety
of selectively labeled derivatives. NaB3H4 reduction of
aldehyde 3a to alcohol 4a will further lead to [6-3H]-R-
fructofuranose-6-phosphate and [6-3H]-R-fructofuranose-
1,6-diphosphate analogues. The same procedure applied
to aldehyde 3d will provide, in addition to the [1-3H]-R-
fructofuranose analogue described above, [1-3H]-R-fructo-
furanose-1-phosphate and [1-3H]-R-fructofuranose-1,6-
diphosphate analogues. Similar manipulation of aldehyde
3b will yield [6-3H]-â-fructofuranose-6-phosphate, [1-3H]-
â-fructofuranose-1-phosphate and [1,6-3H]-â-fructofura-
nose-1,6-diphosphate analogues.
An a logu e Rin g System fr om P r otected Glu cosea
Key: (a) Ph3P+CH3Br-, BuLi, (CH3OCH2)2; (b) Tf2O, py; (c)
(i) OsO4, NMO, (ii) NaIO4, THF-H2O; (d) Et3N, DMF.
a
cyclic alcohol 4b key intermediate (Scheme 3). This
intermediate, or rather its precursor 3b, could also be
prepared from the corresponding glucose derivative 1c
in a similar manner, following a Mitsunobu epimerization
at C5 (1d ), ring closure (2d ), and unmasking of the
aldehyde functionality (3d ) and its epimerization under
basic conditions.
The relative stereochemistry of the various cyclic
olefins 2 and aldehydes 3 was supported by NOESY
experiments. Since the C3 and C4 positions do not
undergo any changes throughout the synthesis and their
protons do not become labile, their absolute configuration
in the intermediates 2 and 3 (as well as in all other
intermediates and products) is defined. Therefore, this
set of measurements confirmed the absolute stereochem-
istry of these compounds (Scheme 4).
P h osp h or yla tion . Selective mono- and diphosphoryl-
ation were achieved by a similar set of reactions, carried
out in a different order.
D-F r u ctofu r a n ose-6-p h osp h a te An a logu es. Phos-
phorylation of the only free alcohol of 4a and 4b by
diphenyl chlorophosphate afforded the fully protected
derivatives 6a and 6b, respectively. A two-step depro-
tection, first removal of the benzyl protecting groups from
the hydroxyls by catalytic hydrogenation over Pd/C and
then removal of the phenyl protecting groups of the
phosphate by catalytic hydrogenation over PtO2, afforded
the R and the â anomers of the fructofuranose-6-
phosphate analogues 8a and 8b, respectively (Scheme 5).
The â-D-fructofuranose-6-phosphate analogue 8b is also
a â-D-fructofuranose-1-phosphate analogue (by “180°
rotation”). Therefore, it could be used in the study of both
enzymes utilizing fructose-6-phosphate and enzymes
utilizing fructose-1-phosphate as substrates.
2H-La belin g a t C5. Selective incorporation of 2H
labeling into the C5 position was achieved by proton
exchange with 2H2O during the epimerization step of
aldehyde 3c to aldehyde 3a . To mimic conditions of 3H2O
handling for radioactive labeling, the reaction was based
2
on exchange with only 2 molar equiv of H2O, to avoid
large excess of “radioactive” manipulations. This reaction
was explored in order to maximize label incorporation
and equilibrium isomeric ratio of 3a /3c. Various solvents
(25) Phosphorylation was carried out according to ref 13a, with slight
modifications.
(26) Koerner, T. A. W., J r.; Voll, R. J .; Cary, L. W.; Younathan, E.
S. Biochemistry 1980, 19, 2795-2801.
D-Fr u ctofu r an ose an d D-Fr u ctofu r an ose-1,6-diph os-
p h a te An a logu es. The three benzyl protecting groups

D-Fructose Analogues Locked in the Cyclic Furanose Form
J . Org. Chem., Vol. 65, No. 18, 2000 5635
Sch em e 3. Con str u ction of th e â-F u r a n ose An a logu e Rin g System fr om P r otected Ma n n osea
a
Key: (a) Ph3P, DEAD, O2NC6H4CO2H, Et3N, PhCH3; (b) Tf2O, py, CH2Cl2; (c) (i) OsO4, NMO, (ii) NaIO4, THF-H2O; (d) NaBH4,
EtOH.
Sch em e 4. Con fir m a tion of Su bstitu tion P a tter n
of th e Rin g System s 2 a n d 3 by NOESY
Sch em e 5. F in a l Sta ges of th e Syn th esis of
2,5-An h yd r oglu citol (r-F r u ctofu r a n ose An a logu e)
a n d its 6-P a n d 1,6-P 2 Der iva tivesa
a
Key: (a) (PhO)2POCl, DMAP, Py; (b) H2, Pd/C, MeOH; (c) H2,
and bases were tested. The equilibrium 3a /3c ratio and
PtO2, MeOH.
2
the extent of 2H incorporation from H2O are summarized
Ta ble 1. Ep im er iza tion of Ald eh yd e 3c. Isom er ic Ra tio
a n d Exten t of 2H In cor p or a tion
in Table 1.
It shows little dependence of the equilibrium isomeric
ratio on the solvent. The extent of the label incorporation,
on the other hand, is highly dependent. While very little
2H incorporation from two molar equivalents of 2H2O
present in the reaction solution was observed when
carried out in CH2Cl2, very efficient incorporation was
observed when the reaction was carried out in DMF. This
may be the result of solvent polarity, leading to the
formation of a tight ion pair of the triethylammonium -
solvent
base
3a :3c ratio
2H incorporation (%)
CH3CN
CH2Cl2
THF
Na2CO3
Et3N
Et3N
a
2
3
4
20
40
83
DMF
Et3N
a
An unidentified mixture of condensation and other products
was obtained.
access to [5-3H]-â-fructofuranose-6-phosphate, [2-3H]-â-
fructofuranose-1-phosphate and [2,5-3H]-â-fructofuranose-
1,6-diphosphate analogues.
3
- in the nonpolar CH2Cl2, and much better solvation of
the “naked” charges in the polar DMF. The tight ion pair
exchanges its labile proton with the small amount of
water present very slowly. Therefore, the original proton
is returned from the base to the aldehyde 3 (both 3a and
3c) and no labeling is observed. When dissolved well (in
DMF), efficient exchange of the C2 proton with the water
takes place, leading to 2H incorporation into C2. The
extent of labeling in DMF as a solvent reaches the
expected value.
Con clu sion s
The present study describes the synthesis of 2,5-
anhydroglucitol and 2,5-anhydromannitol, cyclic ana-
logues of fructose, and their phosphorylated derivatives,
6-phosphate and 1,6-diphosphate. These analogues are
“locked” in a cyclic configuration, either in the R- or in
the â- furanose form. The focus of the synthetic method
is the efficient selective incorporation of radioactive (3H)
labeling into various positions of the different sugar
This method will yield [5-3H]-R-fructofuranose-6-
phosphate and [5-3H]-R-fructofuranose-1,6-diphosphate
analogues from aldehyde 3a . Aldehyde 3b can provide

5636 J . Org. Chem., Vol. 65, No. 18, 2000
Persky and Albeck
Hz, 1H, Bn), 4.69 (d, J ) 11.3 Hz, 1H, Bn), 4.76 (d, J ) 11.3
Hz, 1H, Bn), 5.31 (ddd, J ) 10.6, 1.6, 1.0 Hz, 1H, C1H2), 5.31
(ddd, J ) 17.0, 1.6, 1.0 Hz, 1H, C1H2), 5.94 (ddd, J ) 17.0,
10.6, 7.4 Hz, 1H, C2H), 7.20-7.40 (m, 20H, Ph); 13C NMR δ
69.63 (C6), 70.53 (Bn), 71.27 (C7), 73.21, 74.82, 74.97 (Bn),
78.76 (C5), 79.82 (C3), 82.11 (C4), 118.86 (C1), 127.60-128.34
(Ph), 135.30 (C2), 138.09, 138.25, 138.32, 138.48 (Ph); HRMS
calcd for C35H39O5 (MH+) 539.2798, found 539.2760; MS m/z
539 (MH+, 4.4), 393 (8), 91 (100).
analogues for further biochemical studies. These com-
pounds will be used as conformational and mechanistic
probes for enzymatic catalytic reactions.
Exp er im en ta l Section
Gen er a l Meth od s. 1H, 13C, and 31P NMR spectra were
recorded at 600, 150, and 81 MHz, respectively, in CDCl3 (TMS
as an internal standard) or, when specified, in D2O (MeOH as
an internal standard). Multiplicity “d” refers to a doublet-like
Cycliza tion : Cyclic olefins 2a -d were prepared from the
opened olefins 1a -d , respectively, as previously described17,30
and purified by chromatography with ether/hexane 1:5.
2a : 47% yield; 1H NMR δ 3.75 (dd, J ) 10.0, 6.2 Hz, 1H,
C7H2), 3.80 (dd, J ) 10.0, 5.5 Hz, 1H, C7H2), 3.84 (dd, J )
3.8, 1.6 Hz, 1H, C4H), 4.00 (dd, J ) 4.2, 1.6 Hz, 1H, C5H),
4.26 (ddd, J ) 6.2, 5.5, 4.2 Hz, 1H, C6H), 4.31 (ddt, J ) 7.4,
3.8, 1 Hz, 1H, C3H), 4.43 (d, J ) 12.0 Hz, 1H, Bn), 4.47 (d, J
) 12.0 Hz, 1H, Bn), 4.49 (d, J ) 12.0 Hz, 1H, Bn), 4.50 (d, J
) 12.0 Hz, 1H, Bn), 4.53 (d, J ) 12.0 Hz, 1H, Bn), 4.59 (d, J
) 12.0 Hz, 1H, Bn), 5.13 (ddd, J ) 10.3, 1.6, 1.0 Hz, 1H, C1H2),
5.32 (ddd, J ) 17.2, 1.6, 1.0 Hz, 1H, C1H2), 5.95 (ddd, J )
17.2, 10.3, 7.4 Hz, 1H, C2H), 7.26-7.33 (m, 15H, Ph); 13C NMR
δ 68.30 (C7), 71.52, 71.62, 73.34 (Bn), 79.92 (C6), 82.83 (C5),
85.00 (C3), 87.18 (C4), 116.87 (C1), 127.44-128.35 (Ph), 136.98
(C2), 137.57, 137.82, 138.11 (Ph); HRMS calcd for C28H31O4
1
second-order peak. H NMR assignments were supported by
COSY experiments, while 13C NMR assignments were sup-
ported by hetero COSY (HMQC and HMBC) experiments.
Mass spectra were recorded in DCI mode with methane or
ammonia as the reagent gas. TLC was performed on E. Merck
0.2 mm precoated silica gel F-254 plates and viewed by UV,
vanillin,27 or malachite green.28 Chromatography refers to flash
column chromatography,29 carried out on silica gel 60 (230-
400 mesh ASTM, E. Merck). Anhydrous solvents were dried
and freshly distilled (THF and toluene from sodium/benzophen-
one, pyridine and triethylamine from CaH2, CH2Cl2 from CaCl2
and DMF from 4 Å molecular sieves).
Manno open olefin 1a and gluco open olefin 1c were
prepared from the corresponding 2,3,4,6-tetra-O-benzyl al-
dohexose as previously described.17 They were purified by
chromatography (ether/hexane 1:3).
(MH+) 431.2222, found 431.2243, calcd for C21H23O4 (MH+
-
CH3Ph) 339.1596, found 339.1565; MS m/z 431 (MH+,7), 339
Mitsu n obu Ep im er iza tion . The open olefin (2.69 g, 5
mmol), triphenyl phosphine (2.62 g, 10 mmol), p-nitrobenzoic
acid (1.67 g, 10 mmol), and triethylamine (3.5 mL, 25 mmol)
were dissolved in 100 mL of dry toluene at 0 °C. DEAD (1.6
mL, 10 mmol) was added dropwise. After 10 min, the solution
was allowed to warm to room temperature. After the solution
was stirred for 5-15 h, the solvent was evaporated, CH2Cl2
(100 mL) was added, and the organic phase was extracted
consecutively with 100 mL of 1 M HCl, saturated NaHCO3,
and water, dried over MgSO4, filtered, and evaporated to
dryness. (The p-nitrobenzoyl ester could be chromatographed
with ether/hexane 1:5. Spectroscopic analysis at this stage is
(10), 91 (100).
1
2b: 75% yield; H NMR δ 3.58 (dd, J ) 10.1, 5.5 Hz, 1H,
C7H2), 3.60 (dd, J ) 10.1, 5.5 Hz, 1H, C7H2), 3.95 (dd, J )
5.1, 3.6 Hz, 1H, C4H), 4.09 (dd, J ) 4.6, 3.6 Hz, 1H, C5H),
4.22 (td, J ) 5.5, 4.6 Hz, 1H, C6H), 4.45 (ddt, J ) 7.0, 5.1, 1.1
Hz, 1H, C3H), 4.51 (d, J ) 11.8 Hz, 1H, Bn), 4.52 (d, J ) 12.2
Hz, 1H, Bn), 4.55 (d, J ) 12.2 Hz, 1H, Bn), 4.57 (s, 2H, Bn),
4.57 (d, J ) 11.8 Hz, 1H, Bn), 5.20 (ddd, J ) 10.4, 1.4,1.3 Hz,
1H, C1H2), 5.35 (dt, J ) 17.2, 1.4 Hz, 1H, C1H2), 5.95 (ddd, J
) 17.2, 10.4, 7.0 Hz, 1H, C2H), 7.25-7.34 (m, 15H, Ph); 13C
NMR δ 70.28 (C7), 71.92, 72.02, 73.37 (Bn), 81.36 (C6), 83.51
(C3), 84.90 (C5), 88.11 (C4), 117.17 (C1), 127.59-128.40 (Ph),
136.65 (C2), 137.89-139.25 (Ph); HRMS calcd for C28H31O4
(MH+) 431.2222, found 431.2198; MS m/z 448 (MNH4+,100),
431 (MH+, 47), 339 (43).
much more informative than after the methanolysis step.24
)
The p-nitrobenzoate was dissolved in methanol (150 mL) and
10 molar equiv of NaOH were added. After 1 h, the methanol
was partially evaporated, CH2Cl2 added and the organic phase
was extracted twice with water, dried over MgSO4, filtered,
and evaporated to dryness. Chromatography (EtOAc/hexane
1:4) afforded the clean product.
2c: 56% yield; 1H NMR δ 3.69 (dd, J ) 9.7, 6.2 Hz, 1H,
C7H2), 3.74 (dd, J ) 9.7, 6.3 Hz, 1H, C7H2), 3.92 (d, J ) 4.0
Hz, 1H, C4H), 4.05 (d, J ) 4.1 Hz, 1H, C5H), 4.42 (td, J ) 6.3,
4.1 Hz, 1H, C6H), 4.46 (d, J ) 12.3 Hz, 2H, Bn), 4.49 (d, J )
12.3 Hz, 1H, Bn), 4.51 (d, J ) 12.0 Hz, 1H, Bn), 4.52 (d, J )
12.3 Hz, 1H, Bn), 4.56 (dd, J ) 7.5, 4.0 Hz, 1H, C3H), 4.60 (d,
J ) 12.0 Hz, 1H, Bn), 5.24 (dd, J ) 10.3, 0.9 Hz, 1H, C1H2),
5.34 (dd, J ) 17.3, 0.9 Hz, 1H, C1H2), 6.02 (ddd, J ) 17.3,
10.3, 7.5 Hz, 1H, C2H), 7.23-7.33 (m, 15H, Ph); 13C NMR δ
68.39 (C7), 72.02, 72.25, 73.36 (Bn), 78.83 (C6), 81.65 (C3),
81.85 (C5), 83.15 (C4), 118.03 (C1), 127.4-129.7 (Ph), 134.08
(C2), 137.8-138.2 (Ph); HRMS calcd for C28H31O4 (MH+)
431.2222, found 431.2230; MS m/z 431 (MH+, 8), 339 (10), 233
(5), 215 (8), 107 (17), 91 (100).
1
Op en olefin 1b: 79% yield; H NMR δ 3.39 (dd, J ) 9.6,
6.0 Hz, 1H, C7H2), 3.43 (dd, J ) 9.6, 6.2 Hz, 1H, C7H2), 3.72
(dd, J ) 6.1, 3.0 Hz, 1H, C5H), 3.83 (dd, J ) 6.1, 5.1 Hz, 1H,
C4H), 3.92 (ddd, J ) 6.2, 6.0, 3.0 Hz, 1H, C6H), 4.04 (bdd, J
) 7.9, 5.1 Hz, 1H, C3H), 4.31 (d, J ) 11.8 Hz, 1H, Bn), 4.38
(d, J ) 11.9 Hz, 1H, Bn), 4.42 (d, J ) 11.9 Hz, 1H, Bn), 4.45
(d, J ) 11.1 Hz, 1H, Bn), 4.58 (d, J ) 11.1 Hz, 1H, Bn), 4.60
(d, J ) 11.8 Hz, 1H, Bn), 4.68 (d, J ) 11.1 Hz, 1H, Bn), 4.73
(d, J ) 11.1 Hz, 1H, Bn), 5.33 (ddd, J ) 17.5, 1.7, 0.8 Hz, 1H,
C1H2), 5.35 (ddd, J ) 10.4, 1.7, 0.8 Hz, 1H, C1H2), 5.96 (ddd,
J ) 17.5, 10.4, 7.9 Hz, 1H, C2H), 7.22-7.28 (m, 20H, Ph); 13
C
1
2d ; 77% yield; H NMR δ 3.54 (dd, J ) 10.0, 6.5 Hz, 1H,
NMR δ 70.14 (C6/Bn), 70.17 (C6/Bn), 71.21 (C7), 73.19, 74.32,
74.87 (Bn), 78.64 (C5), 81.12 (C3), 81.75 (C4), 119.61 (C1),
127.48-129.56 (Ph), 135.53 (C2), 138.05-138.45 (Ph); HRMS
calcd for C35H39O5 (MH+) 539.2798, found 539.2841; MS m/z
539 (MH+, 8), 431 (22), 323 (19), 91 (84).
C7H2), 3.63 (dd, J ) 10.0, 5.8 Hz, 1H, C7H2), 3.88 (dd, J )
4.0, 1.5 Hz, 1H, C4H), 3.94 (dd, J ) 3.4, 1.5 Hz, 1H, C5H),
4.07 (ddd, J ) 6.5, 5.8, 3.4 Hz, 1H, C6H), 4.41 (d, J ) 12.1 Hz,
1H, Bn), 4.43 (ddt, J ) 7.4, 4.0, 1 Hz, 1H, C3H), 4.44 (d, J )
12.1 Hz, 1H, Bn), 4.46 (d, J ) 12.0 Hz, 1H, Bn), 4.49 (d, J )
12.0 Hz, 1H, Bn), 4.50 (d, J ) 12.1 Hz, 1H, Bn), 4.56 (d, J )
12.1 Hz, 1H, Bn), 5.25 (ddd, J ) 10.3, 1.8, 0.8 Hz, 1H, C1H2),
5.36 (ddd, J ) 17.3, 1.8, 1.0 Hz, 1H, C1H2), 6.02 (ddd, J )
17.3, 10.3, 7.4 Hz, 1H, C2H), 7.22-7.30 (m, 15H, Ph); 13C NMR
δ 70.51 (C7), 71.53, 71.64, 73.31 (Bn), 82.31 (C6), 82.63 (C3),
84.27 (C5), 84.31 (C4), 118.74 (C1), 127.54-128.42 (Ph), 133.57
(C2), 137.79,137.88,138.23 (Ph); HRMS calcd for C28H31O4
(MH+) 431.2222, found 431.2230; MS m/z 431 (MH+, 20), 339
(47), 91 (100).
Op en olefin 1d : 72% yield; 1H NMR δ 2.60 (d, J ) 6.5 Hz,
1H, OH), 3.39 (dd, J ) 9.4, 5.9 Hz, 1H, C7H2), 3.46 (dd, J )
9.4, 6.3 Hz, 1H, C7H2), 3.77 (dd, J ) 7.1, 3.9 Hz, 1H, C4H),
3.85 (m, 1H, C6H), 3.86 (m, 1H, C5H), 4.05 (bdd, J ) 7.4, 3.9
Hz, 1H, C3H), 4.34 (d, J ) 11.9 Hz, 1H, Bn), 4.42 (d, J ) 12.0
Hz, 1H, Bn), 4.46 (d, J ) 12.0 Hz, 1H, Bn), 4.55 (d, J ) 11.3
Hz, 1H, Bn), 4.63 (d, J ) 11.9 Hz, 1H, Bn), 4.66 (d, J ) 11.3
(27) Stahl E. Thin-Layer Chromatography, 2nd ed., Springer-
Verlag: Berlin, 1969; p 217-218.
(28) Stahl E. Thin-Layer Chromatography, 2nd ed.; Springer-
Verlag: Berlin, 1969; p 618.
Oxid a tion (Osm ila tion -P er iod in a tion ): Cyclic Ald e-
h yd es 3a -d . To a solution of the cyclic olefin (2a -d , respec-
(29) Still, W. C.; Kahn, M.; Mitra, A. J . Org. Chem. 1978, 43, 2923-
2925.
(30) 13C NMR spectra can be compared with those at ref 17.

D-Fructose Analogues Locked in the Cyclic Furanose Form
J . Org. Chem., Vol. 65, No. 18, 2000 5637
tively) (4.3 g, 10 mmol) in 50 mL of 1:1 THF/H2O was added
4-methylmorpholine N-oxide (234 mg, 10 mmol), followed by
OsO4 (0.04 mmol). After the solution was stirred at room
temperature for 2-15 h, NaIO4 (642 mg, 30 mmol) in MeOH
(50 mL) was added and stirring was continued for additional
2 h. The solution was then partially evaporated (to remove
MeOH and THF) and the remaining aqueous phase was
extracted three times with CH2Cl2. The organic phase was
dried over MgSO4, filtered, and evaporated to dryness. Chro-
matography with CH2Cl2 afforded the clean aldehyde.
3a : 48% yield; 1H NMR δ 3.77 (dd, J ) 10, 5.5 Hz, 1H, C6H2),
3.79 (dd, J ) 10, 6.5 Hz, 1H, C6H2), 3.97 (dd, J ) 3.4, 1.3 Hz,
1H, C4H), 4.19 (dd, J ) 1.3, 1.0 Hz, 1H, C3H), 4.30 (d, J )
11.8 Hz, 1H, Bn), 4.37 (t, J ) 1.0 Hz, 1H, C2H), 4.44 (d, J )
11.8 Hz, 1H, Bn), 4.50 (ddd, J ) 6.5, 5.5, 3.4 Hz, 1H, C5H),
4.51 (d, J ) 12.0 Hz, 1H, Bn), 4.53 (d, J ) 12.0 Hz, 1H, Bn),
4.61 (d, J ) 12.0 Hz, 1H, Bn), 4.62 (d, J ) 12.0 Hz, 1H, Bn),
7.25-7.35 (m, 15H, Ph), 9.59 (d, J ) 1.0 Hz, 1H, C1HO); 13C
NMR δ 68.19 (C6), 71.57, 71.65, 73.40 (Bn), 80.11 (C4), 81.01
(C5), 84.76 (C3), 87.07 (C2), 127.62-128.49, 136.98, 137.04,
137.93 (Ph), 203.17 (C1). HRMS calcd for C27H29O5 (MH+)
433.2015, found 433.1978; MS m/z 433 (MH+, 2), 341 (51), 313
(54), 163 (80).
3b; 76% yield; 1H NMR δ 3.59 (dd, J ) 9.9, 6.4 Hz, 1H,
C6H2), 3.65 (dd, J ) 9.9, 6.4 Hz, 1H, C6H2), 4.02 (dd, J ) 2.4,
1.8 Hz, 1H, C4H), 4.20 (t, J ) 1.8 Hz, 1H, C3H), 4.40 (td, J )
6.4, 2.4 Hz, 1H, C5H), 4.42 (d, J ) 11.8 Hz, 1H, Bn), 4.45 (d,
J ) 11.8 Hz, 1H, Bn), 4.46 (dd, J ) 1.8, 1.0 Hz, 1H, C2H),
4.47 (d, J ) 11.8 Hz, 1H, Bn), 4.52 (d, J ) 12.1 Hz, 1H, Bn),
4.57 (d, J ) 11.8 Hz, 1H, Bn), 4.59 (d, J ) 12.1 Hz, 1H, Bn),
7.25-7.94 (m, 15H, Ph), 9.68 (d, J ) 1.0 Hz, 1H, C1HO); 13C
NMR δ 69.87 (C6), 71.45, 71.90, 73.36 (Bn), 82.61 (C4), 83.90
(C5), 84.75 (C3), 87.57 (C2), 127.70-128.52, 136, 137.11,
137.97 (Ph), 202.60 (C1); HRMS calcd for C27H29O5 (MH+)
433.2015, found 433.2028; MS m/z 433 (MH+, 0.4), 91 (100).
3c: 44% yield; 1H NMR δ 3.74 (dd, J ) 10.8, 6.1 Hz, 1H,
C6H2), 3.77 (dd, J ) 10.8, 6.1 Hz, 1H, C6H2), 4.02 (dd, J )
3.6, 1.3 Hz, 1H, C4H), 4.31 (dd, J ) 4.8, 1.3 Hz, 1H, C3H),
4.37 (d, J ) 12.0 Hz, 1H, Bn), 4.42 (d, J ) 12.1 Hz, 1H, Bn),
4.43 (d, J ) 12.0 Hz, 1H, Bn), 4.48 (d, J ) 12.1 Hz, 1H, Bn),
4.49 (dd, J ) 4.8, 2.0 Hz, 1H, C2H), 4.53 (d, J ) 12.0 Hz, 1H,
Bn), 4.58 (td, J ) 6.1, 3.6 Hz, 1H, C5H), 4.63 (d, J ) 12.0 Hz,
1H, Bn), 7.2-7.4 (m, 15H, Ph), 9.67 (d, J ) 2.0 Hz, 1H, C1HO);
13C NMR δ 67.97 (C6), 72.35, 72.41, 73.53 (Bn), 80.89 (C4),
81.06 (C5), 83.71 (C3), 84.72 (C2), 127.54-128.49, 136.87,
137.35, 137.97 (Ph), 201.88 (C1); HRMS calcd for C27H29O5
(MH+) 433.2015, found 433.2000; MS m/z 433 (MH+, 1), 341
(13), 107 (50), 91 (100).
evaporated to dryness. Chromatography with ether/hexane 1:2
afforded the corresponding clean alcohol (4a or 4b).
4a : 92% yield; 1H NMR δ 2.38 (dd, J ) 7.4, 4.4 Hz, 1H, OH),
3.64 (ddd, J ) 11.8, 7.4, 3.9 Hz, 1H, C6H2), 3.72 (dd, J ) 10.1,
6.2 Hz, 1H, C1H2), 3.75 (dd, J ) 10.1, 5.2 Hz, 1H, C1H2), 3.80
(ddd, J ) 11.8, 4.5, 2.0 Hz, 1H, C6H2), 3.99 (d, J ) 3.8 Hz,
1H, C3H), 4.05 (bs, 2H, C4H, C5H), 4.25 (ddd, J ) 6.2, 5.2,
3.9 Hz, 1H, C2H), 4.42 (d, J ) 11.8 Hz, 1H, Bn), 4.49 (d, J )
11.8 Hz, 1H, Bn), 4.52 (d, J ) 12.0 Hz, 1H, Bn), 4.53 (d, J )
11.8 Hz, 1H, Bn), 4.57 (d, J ) 11.8 Hz, 1H, Bn), 4.61 (d, J )
12.0 Hz, 1H, Bn), 7.23-7.34 (m, 15H, Ph); 13C NMR δ 62.95
(C6), 68.16 (C1), 71.65, 71.87, 73.46 (Bn), 79.96 (C2), 82.33
(C3), 82.80 (C4), 84.48 (C5), 126.91-128.49, 137.43, 137.58,
137.97 (Ph); HRMS calcd for C27H31O5 (MH+) 435.2171, found
435.2140; MS m/z 435 (MH+, 26), 343 (15), 107 (29), 91 (94).
1
4b: 80% yield; H NMR δ 3.51 (dd, J ) 10.0, 6.0 Hz, 1H,
C6H2), 3.56 (dd, J ) 10.0, 6.0 Hz, 1H, C6H2), 3.63 (dd, J )
11.8, 5.3 Hz, 1H, C1H2), 3.70 (dd, J ) 11.8, 3.6 Hz, 1H, C1H2),
4.05 (dd, J ) 4.6, 2.6 Hz, 1H, C3H), 4.06 (t, J ) 3 Hz, 1H,
C4H), 4.12 (td, J ) 5, 3.7 Hz, 1H, C2H), 4.25 (td, J ) 6.0, 3.5
Hz, 1H, C5H), 4.51 (d, J ) 12.0 Hz, 1H, Bn), 4.53 (s, 2H, Bn),
4.54 (d, J ) 12.1 Hz, 2H, Bn), 4.57 (d, J ) 12.1 Hz, 1H, Bn),
7.22-7.30 (m, 15H, Ph); 13C NMR δ 62.80 (C6), 70.10 (C1),
71.67, 72.13, 73.44 (Bn), 81.98 (C3), 83.24 (C4), 84.18 (C2/C5),
84.68 (C2/C5), 127.72-128.47, 137-138 (Ph); HRMS calcd for
C
27H31O5 (MH+) 435.2171, found 435.2172; MS m/z 452
(MNH4+, 100), 435 (MH+, 41), 343 (30).
Ca ta lytic Hyd r ogen a tion of Ben zyl Eth er s. Pd/C (10%,
100 mg) was added to a solution of the protected alcohol (4a
or 4b) (1 g, 2.3 mmol) in MeOH (10 mL), and the reaction
mixture was stirred at room temperature under atmospheric
pressure of H2 for 18 h. Filtration and evaporation to dryness
afforded the free alcohol (2,5-anhydroglucitol 5a or 2,5-
anhydromannitol 5b, respectively).31
1
5a : 61% yield; H NMR (D2O) δ 3.70 (dd, J ) 12.1, 6.0 Hz,
1H, C1H2), 3.74 (dd, J ) 11.9, 7.0 Hz, 1H, C6H2), 3.77 (dd, J
) 12.1, 3.8 Hz, 1H, C1H2), 3.83 (dd, J ) 11.9, 4.3 Hz, 1H,
C6H2), 3.84 (ddd, J ) 6.0, 4.3, 3.8 Hz, 1H, C2H), 4.02 (dd, J )
4.3, 2.5 Hz, 1H, C3H), 4.12 (dt, J ) 7.0, 4.4 Hz, 1H, C5H),
4.18 (dd, J ) 4.4, 2.5 Hz, 1H, C4H); 13C NMR (D2O) δ 60.72
(C1/C6), 62.31 (C1/C6), 77.51, 78.60, 81.55, 85.2 (C2, C3, C4,
C5); HRMS calcd for C6H13O5 (MH+) 165.0723, found 165.0771;
MS m/z 165 (MH+, 100), 147 (16), 129 (32), 111 (20).
5b: 100% yield; 1H NMR (D2O) δ 3.70 (dd, J ) 12.4, 5.6 Hz,
2H, C1H2/C6H2), 3.78 (dd, J ) 12.4, 3.1 Hz, 2H, C1H2/C6H2),
3.90 (m, 2H, C2H/C5H), 4.06 (m, 2H, C3H/C4H); 13C NMR
(D2O) δ 61.80 (C1,C6), 77.06 (C3,C4), 82.96 (C2,C5); HRMS
calcd for C6H13O5 (MH+) 165.0723, found 165.0780; MS m/z
182 (MNH4+, 100), 165 (MH+, 26).
P h osp h or yla tion . The alcohol (either mono-, 4a or 4b, or
tetraol 5a ) (1.5 mmol) was dissolved in dry pyridine (7 mL)
under argon atmosphere. DMAP (10 mg) was added, and the
solution was cooled to 0 °C. Diphenyl chlorophosphate (1.3 g,
5 mmol) was added, and the solution was allowed to warm to
room temperature. After 18 h, EtOAc (for the diphosphates)
or CH2Cl2 (for the monophosphates) was added and extracted
consecutively twice with 1 M HCl, saturated NaHCO3, and
water. The solution was dried over MgSO4, filtered, and
evaporated to dryness. Chromatography with EtOAc/hexane
(1:1 for the monophosphates and 2:1 for the diphosphate)
afforded the clean products.
3d : 50% yield; 1H NMR δ 3.61 (dd, J ) 9.9, 6.8 Hz, 1H,
C6H2), 3.72 (dd, J ) 9.9, 6.0 Hz, 1H, C6H2), 4.02 (dd, J ) 2.7,
1.4 Hz, 1H, C4H), 4.29 (ddd, J ) 6.8, 6.0, 2.7 Hz, 1H, C5H),
4.31 (dd, J ) 4.7, 1.4 Hz, 1H, C3H), 4.35 (d, J ) 11.9 Hz, 1H,
Bn), 4.40 (d, J ) 11.9 Hz, 1H, Bn), 4.43 (dd, J ) 4.7, 1.9 Hz,
1H, C2H), 4.47 (d, J ) 12.0 Hz, 1H, Bn), 4.50 (d, J ) 12.0 Hz,
1H, Bn), 4.53 (d, J ) 12.1 Hz, 1H, Bn), 4.61 (d, J ) 12.1 Hz,
1H, Bn), 7.25-7.34 (m, 15H, Ph), 9.68 (d, J ) 1.9 Hz, 1H,
C1HO); 13C NMR δ 70.03 (C6), 71.64, 72.00, 73.41 (Bn), 82.89
(C4), 83.93 (C5), 84.68 (C3), 85.36 (C2), 127.74-128.52, 137.0-
138.0 (Ph), 200.94 (C1); HRMS calcd for C27H29O5 (MH+)
433.2015, found 433.2015; MS m/z 433 (MH+, 20), 341 (46),
91 (100).
Ep im er iza tion . To a solution of the aldehyde (3c or 3d )
(430 mg, 1 mmol) in 20 mL of dry DMF were added Et3N (0.14
mL, 1 mmol) and 36 µL (2 mmol) water. After the solution
was stirred at room temperature for 18 h, CH2Cl2 was added
and extracted with 1 M HCl. The organic phase was dried over
MgSO4, filtered, and evaporated to dryness, affording a
mixture of two epimers.
Protected monophosphate 6a was obtained from 4a in 55%
yield: 1H NMR δ 3.68 (dd, J ) 10.0, 6.4 Hz, 1H, C1H2), 3.73
(dd, J ) 10.0, 5.5 Hz, 1H, C1H2), 3.97 (dd, J ) 3.9, 1.2 Hz,
1H, C3H), 4.00 (dd, J ) 2.3, 1.2 Hz, 1H, C4H), 4.19 (ddd, J )
7.2, 5.7, 2.3 Hz, 1H, C5H), 4.27 (ddd, J ) 10.2, 6.8, 7.2 Hz,
1H, C6H2), 4.30 (ddd, J ) 6.4, 5.5, 3.9 Hz, 1H, C2H), 4.35 (ddd,
J ) 10.2, 6.8, 5.7 Hz, 1H, C6H2), 4.37 (d, J ) 11.9 Hz, 1H,
Bn), 4.40 (d, J ) 11.8 Hz, 1H, Bn), 4.43 (d, J ) 11.8 Hz, 1H,
Bn), 4.49 (d, J ) 12.0 Hz, 1H, Bn), 4.50 (d, J ) 11.9 Hz, 1H,
Bn), 4.59 (d, J ) 12.0 Hz, 1H, Bn), 7.19-7.32 (m, 25H, Ph);
13C NMR δ 68.10 (d, J ) 5.8 Hz, C6), 68.20 (C1), 71.57, 71.79,
3a and 3c (4:1) were obtained from 3c in 40% yield.
3b and 3d (1:1) were obtained from 3d in 68% yield.
Red u ction . Aldehyde (3a or 3b) (2.16 g, 5 mmol) in EtOH
(10 mL) was treated with NaBH4 (285 mg, 7.5 mmol). Water
was added after 2 h, and the solution was extracted with CH2-
Cl2. The organic phase was dried over MgSO4, filtered, and
(31) Spectra can be compared with refs 9-12 and 26.

5638 J . Org. Chem., Vol. 65, No. 18, 2000
Persky and Albeck
73.44 (Bn), 80.45 (C2), 81.70 (d, J ) 8.4 Hz, C5), 82.05 (C3),
82.87 (C4), 120.11 (d, J ) 4.9, 120.55 (d, J ) 4.7 Hz), 123.58-
129.84, 137.40, 137.53, 138.01, 150.44 (d, J ) 7.4 Hz), 152.12
(d, J ) 5 Hz) (Ph); 31P NMR δ -11.58 (t, J ) 6.8 Hz); HRMS
calcd for C39H40O8P (MH+) 667.2461, found 667.243; MS m/z
667 (MH+, 4), 107 (100), 91 (41).
raphy on DEAE-cellulose (2.5 × 22 cm column), eluted by a
step gradient of 100 mL of H2O, followed by 100 mL of 1 M
- 32
NH4+HCO2
.
The protected monophosphate (6a or 6b) was first hydro-
genated with Pd/C as described above and then with PtO2,
affording the monophosphate (8a or 8b, respectively).32
1
Protected monophosphate 6b was obtained from 4b in 51%
yield: 1H NMR δ 3.53 (dd, J ) 10.1, 5.8 Hz, 1H, C1H2), 3.56
(dd, J ) 10.1, 5.8 Hz, 1H, C1H2), 4.06 (dd, J ) 3.5, 2.6 Hz,
1H, C4H), 4.07 (dd, J ) 3.6, 2.6 Hz, 1H, C3H), 4.21 (td, J )
5.8, 3.6 Hz, 1H, C2H), 4.28 (td, J ) 6.8, 3.5 Hz, 1H, C5H),
4.33 (t, J ) 6.8 Hz, 2H, C6H2), 4.42 (d, J ) 11.8 Hz, 1H, Bn),
4.45 (d, J ) 11.8 Hz, 1H, Bn), 4.47 (d, J ) 11.8 Hz, 1H, Bn),
4.49 (d, J ) 11.8 Hz, 1H, Bn), 4.52 (d, J ) 12.0 Hz, 1H, Bn),
4.55 (d, J ) 12.0 Hz, 1H, Bn), 7.16-7.32 (m, 25H, Ph); 13C
NMR δ 67.90 (d, J ) 7.1 Hz, C6), 70.03 (C1), 71.84, 71.94,
73.35 (Bn), 81.07 (d, J ) 8.1 Hz, C5), 82.30 (C2), 84.08 (C4),
84.36 (C3), 120.07 (d, J ) 4.5 Hz), 125.35, 127.68-128.44,
129.76, 137.45, 137.59, 138.10, 150.50 (d, J ) 2.3 Hz) (Ph);
31P NMR (CD3OD) δ -11.61 (t, J ) 6.8 Hz); HRMS calcd for
Monophosphate 8a : 74% yield; H NMR (D2O) δ 3.59 (m,
1H, C1H2), 3.61 (m, 1H, C6H2), 3.82 (m, 1H, C2H), 3.89 (m,
1H, C6H2), 3.95 (m, 1H, C1H2), 3.95 (m, 1H, C3H), 3.99 (m,
1H, C5H), 4.05 (dd, 1H, C4H).
Monophosphate 8b; 61% yield; 1H NMR (D2O) δ 3.61 (dd, J
) 11.8, 5.3 Hz, 1H, C1H2), 3.70 (dd, J ) 11.8, 3.4 Hz, 1H,
C1H2), 3.82 (ddd, J ) 6.1, 5.3, 3.4 Hz, 1H, C2H), 3.97 (dt, J )
5.6, 3.4 Hz, 1H, C5H), 3.99 (t, J ) 5.9 Hz, 1H, C3H), 4.02 (dd,
J ) 5.9, 3.4 Hz, 1H, C4H), 4.16 (ddd, J ) 10.8, 6.7, 5.6 Hz,
1H, C6H2), 4.24 (ddd, J ) 10.8, 6.1, 3.4 Hz, 1H, C6H2); 13C
NMR (D2O) δ 63.96 (C1), 69.28 (d, J ) 5.7 Hz, C6), 79.20 (C3/
C4), 79.27 (C3/C4), 83.95 (C5), 86.01 (C2); 31P NMR (CD3OD)
δ 0.65 (t, J ) 6 Hz); MS FAB- m/z 243 (M - H+, 19), 183 (23).
Diphosphate 9a : 1H NMR (D2O) δ 3.99 (dt, J ) 6.0, 4.4 Hz,
1H, C5H), 4.07 (ddd, J ) 10.8, 7.4, 6.4 Hz, 2H, C1H2, C6H2),
4.11 (dd, J ) 4.4, 3.2 Hz, 1H, C4H), 4.14 (ddd, J ) 10.8, 6.1,
4.4 Hz, 1H, C6H2), 4.19 (ddd, J ) 10.8, 6.5, 3.8 Hz, 1H, C1H2),
4.28 (dd, J ) 4.8, 3.2 Hz, 1H, C3H), 4.31 (ddd, J ) 6.9, 4.8,
3.8 Hz, 1H, C2H); 13C NMR (D2O) δ 64.19 (d, J ) 7.4 Hz, C1/
C6), 65.64 (d, J ) 8.1 Hz, C1/C6), 77.38 (C3/C4), 78.33 (C3/
C4), 80.60 (d, J ) 12.4 Hz, C2/C5), 84.05 (d, J ) 12.4 Hz, C2/
C5); 31P NMR (D2O) δ 1.37 (t, J ) 6.5 Hz), 1.65 (t, J ) 7 Hz);
MS FAB- m/z 323 (M - H+, 12).
C
39H40O8P (MH+) 667.2461, found 667.246; MS m/z 667 (MH+,
39), 577 (13), 107 (29), 91 (100).
Protected diphosphate 7a was obtained from 5a in 45%
yield: 1H NMR δ 3.98 (td, J ) 5.6, 2.7 Hz, 1H, C2H), 4.00 (dd,
J ) 3.7, 1.8 Hz, 1H, C4H), 4.08 (dd, J ) 2.7, 1.8 Hz, 1H, C3H),
4.23 (ddd, J ) 6.4, 5.7, 3.7 Hz, 1H, C5H), 4.28 (td, J ) 10.8,
5.7 Hz, 1H, C6H2), 4.30 (ddd, J ) 10.8, 8.9, 5.6 Hz, 1H, C1H2),
4.35 (ddd, J ) 10.8, 8.0, 5.6 Hz, 1H, C1H2), 4.47 (ddd, J )
10.8, 8.4, 6.5 Hz, 1H, C6H2); 13C NMR δ 67.15 (d, J ) 5.9 Hz,
C1/C6), 68.92 (d, J ) 6.3 Hz, C1/C6), 76.96 (C3/C4), 78.35 (C3/
C4), 79.56 (d, J ) 6.9 Hz, C2/C5), 83.43 (d, J ) 7.0 Hz, C2/
C5), 120.1 (d, J ) 4 Hz), 125.6, 129.9, 150.3 (d, J ) 9.0 Hz)
(Ph); 31P NMR δ -11.47 (t, J ) 8.4 Hz), -10.80 (dd, J ) 10.8,
8.4 Hz); HRMS calcd for C30H31O11P2 (MH+) 629.1342, found
629.1345; MS m/z 629 (MH+, 39), 535 (9), 379 (9), 95 (100).
Ca ta lytic Hyd r ogen a tion of P h en yl P h osp h a te Ester s.
The protected diphosphate 7a (1 mmol) was dissolved in MeOH
(7 mL). PtO2 (10 mg) was added and the mixture was stirred
under atmospheric pressure of H2 for 18 h. Filtration and
evaporation afforded the clean diphosphate 9a in quantitative
yield. It could be further purified by ion exchange chromatog-
Ack n ow led gm en t. This work was supported in part
by the “Marcus Center for Pharmaceutical and Medici-
nal Chemistry” at Bar Ilan University.
Su p p or tin g In for m a tion Ava ila ble: Figures showing 1H
and 13C NMR spectra. This material is available free of charge
via the Internet at http://pubs.acs.org.
J O0003908
(32) 13C NMR spectra can be compared with those at ref 26.