Versatile use of bis-cyclic thionocarbonates of polyols as bis-electrophilic intermediates. Synthesis of polyhydroxylated thioanhydropentitols with D,L-arabino, L-ribo and L-xylo, and thioanhydroaldoses with D-lyxo, L-ribo, D-xylo, D-allo, D-gulo and D-al

Article abstract of DOI:10.1016/j.tetlet.2004.03.197

1-O-Benzylpentitols (with D-arabino, D-lyxo, D,L-xylo and D,L-ribo configurations) and aldose dibenzyldithioacetals (with L-arabino, D-lyxo, D-xylo, D-ribo, D-galacto, D-gluco and D-manno configurations) were directly and efficiently transformed into thei

Full text of DOI:10.1016/j.tetlet.2004.03.197

Tetrahedron
Letters
Tetrahedron Letters 45 (2004) 4365–4369
Versatile use of bis-cyclic thionocarbonates of polyols as
bis-electrophilic intermediates. Synthesis of polyhydroxylated
thioanhydropentitols with
D
,
L
-arabino,
-lyxo, -ribo,
-altro configurations
L
-ribo and
L
-xylo, and
-gulo and
thioanhydroaldoses with
D
D
L
D
-xylo, -allo,
D
D
Alain Danquigny, Mohammed Benazza,* Sylvain Protois and Gilles Demailly
Laboratoire des Glucides, FRE 2779, Universitꢀe de Picardie Jules Verne, 10 rue Baudelocque, F-80039 Amiens, France
Received 20 October 2003; revised 25 March 2004; accepted 31 March 2004
Abstract—1-O-Benzylpentitols (with
D
-arabino,
D
D
-lyxo,
D
D
,
-gluco and D
L
-xylo and
D,L-ribo configurations) and aldose dibenzyldithioacetals
-manno configurations) were directly and efficiently transformed
(with -arabino, -lyxo, -xylo, -ribo,
L
D
D
D
-galacto,
into their cyclic bis-thionocarbonate derivatives (61–73%) by reaction with diimidazolyl thione (Im2CS) in 1,4-dioxane. These bis-
electrophilic adducts react regioselectively with Na2SÆ9H2O to lead to 1,4-, 2,5- or 3,6-thioanhydroalditol derivatives in good yields
(47–65%). Thioanhydro configurations
-altro from aldoses were obtained.
Ó 2004 Elsevier Ltd. All rights reserved.
D
,L
-arabino,
L
-ribo and
L
-xylo from pentitols, and
D
-lyxo,
L
-ribo,
D
-xylo,
D
-allo,
D
-gulo and
D
In our ongoing program we were interested in the
polyhydroxylated tetrahydrothiophenes, as possible
bioisosteric analogues of some pyrrolidine competitive
glycosidase inhibitors.1 These five-membered ring ana-
logues of anhydro sugars, where the oxygen atom has
been replaced by a sulfur atom, are important building
blocks of a large number of very interesting biological
compounds. For instance, they can be incorporated into
nucleoside analogues,2 and constitute the backbone of
compounds where the sulfur atom in the ring is in a
trivalent state including zwitterionic systems such as the
sulfimides,3 salacinol (A) and kotalanol (B), which are
potent a-glycosidase inhibitors used in the treatment of
Type II noninsulin-dependent diabetes.4
OH
OH
OH
OH
OH
HO
HO
-
-
+
+
S
OSO3
OSO3
OH
S
OH
OH
OH
OH
OH
A
B
HO
HO
OH
S
S
OH
OH
OH
OH
C
D (D,L)
One of the most important routes to polyhydroxylated
thiaheterocycles is the S-heterocyclisation of bis-elec-
trophilic alditols such as bis-epoxides,5 bis-halogenated
derivatives,6 bis-sulfonates,7 bis-cyclic sulfates8 and
more recently bis-cyclic thionocarbonates9 in the pres-
ence of sodium sulfide nonahydrate. Some six- and
seven-membered rings obtained following this approach
could subsequently be converted to tetrahydrothioph-
enes by transannular processes by reaction with tri-
methylsilyl halides,10 with PPh3/CBr4 and when
undergoing the Mitsunobu reaction11 or by intramo-
lecular SN2 substitution with appropriately mesylated
thiepane.12
Keywords: Alditols; Aldoses dithioacetals; Pentoses; Hexoses;
Thioanhydro; Bis-thionocarbonates; Thiaheterocyclisation.
* Corresponding author. Tel.: +33-3-22827527; fax: +33-3-22827560;
e-mail: mohammed.benazza@u-picardie.fr
0040-4039/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2004.03.197

4366
A. Danquigny et al. / Tetrahedron Letters 45 (2004) 4365–4369
We recently reported a short synthesis of
D,L
D (a racemic mixture of the thioanhydroarabinitol
subunit of salacinol) for the first time by the use of S-
heterocyclisation of the bis-cyclic sulfate derivatives of
D-talo-tetra-
hydroxythiolane C and -arabinotrihydroxythiolane
OH
HO
OH
n
OH OH
Ref. 9
1,2-O-isopropylidene-D-mannitol and 1-O-benzyl-D,L-
OH
OH
OH
xylitol, respectively.8 The use of this kind of intermedi-
ate obtained by oxidation of the corresponding cyclic
sulfite with substrates like pentose dithioacetals met a
serious limitation because of the oxidation induced a,b-
unsaturated monosulfoxide formation (Scheme 1).13
Owing to this undesirable dithioacetal oxidation, the use
of cyclic-thionocarbonates as electrophilic intermediates
appears to be an alternative because of their easy for-
mation from diols and polyols. For instance, the 1,2:4,5-
and 1,2:5,6-bis-thionocarbonates were formed from
pentitol and hexitol stannyleneacetal complexes,
respectively, and phenyloxychlorothionoformate (PhO-
CSCl) under mild conditions (Scheme 2). We carried
out, on this bis-electrophilic system, for the first time,
HO
n'
Endo-tet
S=
n''
Exo-tet
O
S
O
S
n
O
S=
O
S
S
Scheme 2. n ¼ 0(tetritols) or 1 (pentitols); n0 ¼ 2, 3 or 4; n00 ¼ 2 or 3.
The heterocyclisation involving primary–secondary
electrophilic sites in an exo-tet process is of interest and
could be exploited in the synthesis of a wide range of
thiolane rings. Herein, we describe a short and versatile
synthesis of precursors of trihydroxythiolane derivatives
from monobenzylpentitols with
xylo and
-ribo configurations,14 and from the
dibenzyldithioacetal of aldoses with -arabino, -lyxo,
-xylo, -ribo, -galacto, -gluco and -manno config-
D-arabino, D-lyxo, D,L-
¼
D,L
thiaheterocyclisation using a S bi-anion as a soft
L
D
binucleophilic reagent. Unfortunately this original het-
erocyclisation often led to inseparable mixtures of endo-
tet and exo-tet thiaheterocycles.9
D
D
D
D
D
urations. Both pentitols and aldose dibenzyldithioacetal
substrates react smoothly with diimidazolyl thione
(Im2CS, 2.2 equiv) in dry 1,4-dioxane (0.5 g/mL) at room
temperature overnight to give the corresponding bis-
thionocarbonates in good yields (Table 1).
O
.
.
O
The first synthesis of the bis-thionocarbonate derivatives
O
BnS
+ BnS
O
OH
OH
O
BnS
S
BnS
BnS
was carried out with a mixture of 1-O-benzyl-
binitol (1) and 1-O-benzyl- -lyxitol (4) (entry 1)
obtained regioselectively from the -arabinitol
D-ara-
RuCl3/NaIO4
O
BnS
O
CH3CN
CH2Cl2
H2O
D
O
S
S
O
O
O
S
O
O
O
D
O
O
stannylether complex and BnBr in a 52% overall yield
(in a 1:1 ratio).14 This inseparable mixture was trans-
Scheme 1.
Table 1. Isolated yields of bis-thionocarbonates and thiaheterocyclesꢀ obtained from monobenzyl pentitols14 and aldose dithioacetal derivativesꢀꢀ as
substrates
Entry
Substrate
Bis-thionocarbonate
Yield (%)
32a
Isolated
Yield (%)
47
BnO
OH
OH
S
AcO OAc
S
O
C
1
BnO
O
BnO
OHOH
O
O
C
3 (2,5-Thioanhydro-D-ribo or 1,4-L-ribo)
S
1 (1-O-Bn-
D
-arabino)
-arabino
3
OAc
S
OH
OBn
S
OH
C
O
40a
65
BnO
AcO
O
OBn
OBn
OBn
OHOH
O
C
O
6 (1,4-Thioanhydro-
xylo)
L-xylo or 2,5-D-
4 (5-O-Bn-
D
S
or 1-O-Bn-D-lyxo)
5
OH
OBn
S
BnO
OAc
S
OH
C
O
2
3
61
72
55
45
O
OHOH
OAc
O
O
C
S
7 (D
,
L
-xylo)
9 (1,4-Thioanhydro-D,L-arabino)
8
S
OHOH
AcO
OAc
OBn
BnO
C
O
S
O
OHOH
O
O
C
12 (2,5-Thioanhydro-D,L-arabino)
S
10 (D,L-xylo)
11

A. Danquigny et al. / Tetrahedron Letters 45 (2004) 4365–4369
4367
Table 1 (continued)
Entry
Substrate
Bis-thionocarbonate
Yield (%)
73
Isolated
Yield (%)
60
S
OAc
OH
OH
S
C
O
R
4
O
OBn
R
OHOH
AcO
O
O
C
S
S
13 (
D
-xylo)
15 (2,5-Thioanhydro-D-lyxose)
14
OHOH
S
C
O
R
R
5
76
0
R
O
OHOH
AcO OAc
O
O
C
S
16 (D
-ribo)
17a (2,5-D-arabino)
17
OH
OH
S
AcO OAc
S
O
C
R
R
6
7
68
73
50
60
O
R
OHOH
C
O
O
20 (2,5-Thioanhydro-L-ribose)
S
18 (L-arabino)
19
R
S
OH
S
OH
C
O
R
AcO
R
O
OHOH
AcO
O
O
C
S
21 (D-lyxo)
23 (2,5-Thioanhydro-
D
-xylose)
22
OH OH OH
S
R
OH O
O
C
R
OAc
S
R
8
9
65
60
60
51
O
AcO
OH OH
O
C
OAc
S
24 (D
-galacto)
26 (3,6-Thioanhydro-
D
-gulose)
-allose)
25
S
R
OH OH OH
OH O
C
OAc
S
R
O
R
OH OH
O
O
C
OAc
AcO
27 (D
-gluco)
S
29 (3,6-Thioanhydro-
D
28
S
R
OH OH OH
C
O
OR'
AcO
S
10
R0 ¼ H
23
36b
16c
R
O
R
OH OH
R0 ¼ CSIm 34
O
C
O
AcO OAc
S
30 (D-manno)
33 (3,6-Thioanhydro-
D
-altrose)
31 R ¼ H
32 R0 ¼ CSIm
a From starting mixture of 2 and 5.
b From isolated 31.
c From isolated 32 R ¼ CH(SBn)2.
* 1.5 equiv of Na2SÆ9H2O, 80 °C, 2 h, DMSO.
** HCl (12 N), BnSH (2.2 equiv).
formed to the corresponding bis-cyclic thionocarbonate
derivatives 2 ( -arabino) and 5 ( -lyxo) separated by
chromatography on silica gel in 32% and 40% yields,
respectively (yields evaluated from the starting mixture
of 1 and 4). The identification of these two regioisomers
was achieved by NMR spectroscopy of their anhydro
tion of 2 and 5 with a catalytic amount of MeONa in
MeOH. Compounds 2c (or 2f) and 5c (or 5f) were
characterised by J3;4 coupling constants equal to 5.01 Hz
for the syn-methine configuration of H-3,4 and ꢁ0Hz
for the trans-methine configuration of H-3,4, respec-
tively. Consequently, by TLC performed on silica gel,
the most polar is the bis-thionocarbonate derivative of
D
D
derivatives
Scheme 3a) or
and -lyxo 5c (from 2,3-deprotection, path 1, Scheme
3b) or -xylo 5f (from 4,5-deprotection, path 2)
obtained in 31% and 47% yields, respectively, by reac-
D
-arabino 2c (from 2,3-deprotection, path 1,
L
-ribo 2f (from 4,5-deprotection, path 2)
D
-lyxose 5 (Rf ¼ 0:08, 7/3 hexane–EtOAc) and the less
D
polar is the
possible deprotection of cyclic thionocarbonates in
D
-arabino derivative 2 (Rf ¼ 0:17). The
L
compounds 2 and 5 had not been elucidated until now.

4368
A. Danquigny et al. / Tetrahedron Letters 45 (2004) 4365–4369
a.
S
BnO
OH
BnO
S
O
BnO
O
i
i
O
O
2,3-deprotection
Path 1
4,5-deprotection
Path2
OH
OH
O
O
O
OH
O
2d
S
S
2a
2
(
D
-arabino)
OAc
OAc
OH
OH
BnO
AcO OAc
O
BnO
HO OH
O
O
O
ii
ii
BnO
BnO
2c (2,5-anhydro-
D-arabino)
2f (2,5-anhydro-L-ribo)
2b
2e
b.
S
O
OBn
OBn
OBn
OH
O
i
i
O
S
HO
O
S
4,5-deprotection
2,3-deprotection
OH
O
5d
O
OH
5a
O
O
-lyxo)
Path 2
Path 1
S
5 (
D
BnO
OAc
BnO
O
OAc
O
OH
O
OH
O
ii
ii
BnO
BnO
AcO
AcO
HO
5b
HO
5f (1,4-anhydro-
or 2,5-anhydro-
L
-xylo
5c (2,5-anhydro-
D-lyxo
5e
D-xylo)
or 1,4-anhydro- -arabino)
D
Scheme 3. Reagents and conditions: (i) MeONa in MeOH, rt, 16 h; (ii) Ac2O, pyridine.
With the rest of the pentitol derivatives and pentoses the
vicinal bis-cyclic thionocarbonates were formed simi-
by the cis-configuration of the 3-OH/4-OH group in the
transition state, which limits the thiaheterocyclisation of
2. Steric hindrance could also be invoked in the cases of
12 (entry 3, 45%) and in a large part with 17a (entry 5)
for which the formation was excluded due to the inter-
action between 3-OH, 4-OH and the bulky di-
benzyldithioacetal group in the syn-position.
larly in good isolated yields (from pentitols: 8 (
(61%), 11 -ribo) (72%) (entries and 3));
from pentoses: 14 ( -xylo) (73%), 17 ( -ribo) (76%),
19 ( -arabino) (68%) and 22 ( -lyxo) (73%) (entries 4–7).
D,L-xylo)
(
D
,L
2
D
D
L
D
With hexoses bearing five free hydroxyl groups, the
configurations of the hexose studied appeared to control
the regioselectivity of the bis-cyclic thionocarbonate
A very interesting result was obtained with hexose di-
thioacetals where the 1,4-thiolane rings were formed
regioselectively from both 2,3:5,6- and 3,4:5,6-bis-cyclic
thionocarbonate derivatives. Thus the 2,4,5-tri-O-acetyl-
formation. Thus the
D-galacto and the D-gluco isomers
24 and 27 showed 2,3:5,6-bis-cyclic thionocarbonate
formation with the hydroxyl in the 4-position left free
(entries 8 and 9). In contrast, the manno configuration
30 led to the bis-cyclic thionocarbonate derivatives 31
with the free 2-OH in 23% yield and 32 with the imid-
azolyl thionocarbonate group in the 2-position in 34%
yield.
3,6-thioanhydro-
-altrose (33) (entries 8–10) were obtained in 60%, 51%
and 36% yields, respectively. With the -manno config-
D
-glucose (26),
D-allose (29) and
D
D
uration, the 2-imidazolylthionocarbonate 32 was also
submitted to the thiaheterocyclisation reaction. Only a
16% yield was extracted from a complex mixture.
The 2,3:5,6-positions in 25 (galacto) and 28 (gluco) and
3,4:5,6-position of the cyclic thionocarbonate groups in
31 (manno) were easily confirmed by 13C NMR spec-
troscopy.15 In fact, while 25 and 28 showed 2-C and 4-C
chemical shifts at approximately 84.8 and 69.6 ppm,
respectively, the manno compound 31 showed 2-C at
72.5 and 4-C at 82.6 ppm. The 2-C signals in 25 and 28
and 4-C signal in 31 were shifted upfield due to the cyclic
thionocarbonate group. The unexpected formation of
the trans-2,3:5,6-bis-thionocarbonate 28 is probably due
to the bent conformation involved by the stereoelec-
tronic 1,3-parallel interaction between 2-OH and 4-OH
in zigzag form of the gluco configuration.
The 3,6-thiaheterocyclisation leading to 26, 29 and 33 is
justified by 13C NMR spectroscopy, which shows 3-C
signals at 50.6, 49.2 and 49.6 ppm, and 6-C signals at
16
36.1, 31.0and 31.1 ppm, respectively.
In conclusion, we report a general and versatile use of
bis-cyclic thionocarbonates as intermediates for a wide
range of polyhydroxylated 1,4-, 2,5- and 3,6-thiolanes
from both pentitols and linear aldose substrates. It is of
interest to point out that the eight thiaheterosugar
analogues described herein are enantiopure.
The first thiaheterocyclisation attempted with 2 by
reaction with Na2SÆ9H2O in DMSO at room tempera-
ture led to a complex mixture with no formation of the
expected thioanhydro derivative. When the temperature
was increased to 80 °C for 1 h, 3,4-di-O-acetyl-2,5-thio-
Acknowledgements
ꢀ
The authors thank the Conseil regional de Picardie & le
fonds social Europeen for their financial support.
ꢀ
anhydro-
47% yield (entry 1). The same conditions when applied
to 5 with the -lyxo configuration, led to the -xylo
L-ribitol (3) was isolated after acetylation in
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16. 13C NMR in CDCl3 for 26: d 53.6 (C-1), 72.2 (C-2), 50.6
(C-3), 76.3 (C-4), 78.0(C-5), 36.1 (C-6), 36, 36.8 (Ph CH2–),
127.6–130.5 (Ph–), 137.5, 137.8 (C-ipso), 21.1, 21.4, 21.5
(CH3), 170.0, 170.1, 170.2 (CO); for 29: d 52.8 (C-1), 75.9,
76.0(C-2,4), 49.2 (C-3), 74.0(C-5), 31.0(C-6), 35.5, 36.2
(PhCH2–), 127.5–129.7 (Ph–), 138.1, 138.2 (C-ipso), 20.3
(CH3), 169.5, 169.8, 170.0 (CO); for 33: d 54.0(C-1), 71.9,
73.5, 75.5 (C-2,4,5), 49.6 (C-3), 31.1 (C-6), 35.4, 35.7
(PhCH2–), 127.6–129.7 (Ph–), 137.6 (C-ipso), 21.2, 21.3
(CH3), 170.5 (CO).
6. (a) Halila, S.; Benazza, M.; Demailly, G. Tetrahedron Lett.
2001, 42, 3307–3310; (b) Kim, B. M.; Bae, S. J.; Seomoon,
G. Tetrahedron Lett. 1998, 39, 6921–6922; (c) Lundt, I.;
Madsen, R. Synthesis 1993, 7, 714–720; (d) Minakawa, N.;