Large scale synthesis of the acetonides of l-glucuronolactone and of l-glucose: easy access to l-sugar chirons

Article abstract of DOI:10.1016/j.tetlet.2009.08.124

1,2-O-Isopropylidene-α-l-glucurono-3,6-lactone may be synthesized on a 100-200 g scale from cheaply available d-glucoheptonolactone in an overall yield of 94% in four steps via l-glucuronolactone. Subsequent elaboration to l-glucose, diacetone-l-glucose (1,2:5,6-di-O-isopropylidene-α-l-glucofuranose), and monoacetone-l-glucose (1,2-O-isopropylidene-α-l-glucofuranose) allows easy access to a range of l-sugar chirons.

Full text of DOI:10.1016/j.tetlet.2009.08.124

Tetrahedron Letters 50 (2009) 6307–6310
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Large scale synthesis of the acetonides of L-glucuronolactone
and of L-glucose: easy access to L-sugar chirons
a
a
b
c
Alexander C. Weymouth-Wilson a, , Robert A. Clarkson , Nigel A. Jones , Daniel Best , Francis X. Wilson ,
*
Maria-Soledad Pino-González d, George W. J. Fleet b,
*
a Dextra Laboratories Ltd, The Science and Technology Centre, Whiteknights Road, Reading RG6 6BZ, UK
b Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
c Summit PLC, 91, Milton Park, Abingdon, Oxon OX14 4RY, UK
d Departamento de Bioquímica, Biología Molecular y Química Orgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain
a r t i c l e i n f o
a b s t r a c t
Article history:
1,2-O-Isopropylidene-
a
-
L
-glucurono-3,6-lactone may be synthesized on a 100–200 g scale from cheaply
-glucuronolactone. Subse-
-glucose (1,2:5,6-di-O-isopropylidene- -glucofuranose),
Received 21 July 2009
Revised 18 August 2009
Accepted 28 August 2009
Available online 2 September 2009
available
quent elaboration to
and monoacetone- -glucose (1,2-O-isopropylidene-
-sugar chirons.
D-glucoheptonolactone in an overall yield of 94% in four steps via
L
L
-glucose, diacetone-
L
a-L
L
a
-
L-glucofuranose) allows easy access to a range of
L
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
of natural products have significant and different biological
activity.15
Diacetone glucose 1D (with the C3–OH group free) and mono-
acetone glucose 2D have long been used as the most common
This Letter describes the conversion of
9D on a 100–200 g scale into the acetonide of
12L in an overall yield of 94% in four steps without chromatogra-
D
-glucoheptonolactone
L-glucuronolactone
chirons derived from carbohydrates.1 The acetonide 3D from
D
-glu-
curonolactone (with only the C5–OH group unprotected) has also
been widely used as a chiron for the synthesis of iduronic acid,2
inositols,3 vitamin C,4 sugar amino acids5, fluoro-,6 amino-,7 and
higher8 monosaccharides, oxetanes,9 imino sugars,10 gonofurone
and related compounds,11 and many other homochiral targets.12
phy; subsequent reduction by sodium borohydride affords
monoacetone-
tone- -glucose 1L or
theses of -glucose, such as chemical syntheses from diacetone
glucose 1D or
L
-glucose 2L and then conversion into either diace-
L
L
-glucose 4L. There are many published syn-
L
L
-arabinose,16 -gulonolactone,17 ab initio asymmet-
D
The use of these acetonides depends on the low prices of
4D (the cheapest monosaccharide) and of -glucuronolactone 12D.
However, the cost of -glucose 4L makes the use of the enantiomers
1L and 2L prohibitive as starting materials for homochiral synthe-
sis; -glucuronolactone 12L is simply not commercially available.
Accessibility to the
-enantiomers of such building blocks13 would
D
-glucose
ric syntheses18 and enzymatic19 or biotechnological20 procedures;
D
however, none of these approaches provide substantial amounts of
L
L
-sugars cheaply.
potential as a food substitute and for other uses.21
Two strategies for the isomerization of -glucose 4D to L-glucose
L-Glucose tastes as sweet as D-glucose and has
L
D
L
4L are shown in Scheme 1. Lundt reported a procedure by which
allow access to a range of targets not approachable at present from
the chiral pool. Additionally, this would allow the preparation of
enantiomers of biologically active compounds;14 the enantiomers
inversion of configuration at all four chiral carbon atoms in the lac-
tone from
D-gluconic acid 7D [obtained by oxidation of glucose]
formed
L-gluconic acid 8L. The conversion involves reaction with
O
O
O
O
O
O
OH
O
HO
O
OH
HO
O
O
O
O
O
O
O
O
O
O
CH2OH HOH2C
O
O
O
O
O
O
O
O
OH HO
OH
HO
D-sugars in green
L-sugars in red
1L
1D
2L
2D
3L
3D
* Corresponding authors.
E-mail address: george.fleet@chem.ox.ac.uk (G.W.J. Fleet).
0040-4039/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2009.08.124

6308
A. C. Weymouth-Wilson et al. / Tetrahedron Letters 50 (2009) 6307–6310
5
OH OH OH
OH OH
1
OH OH
1
CH2OH
5
NaBH4
NaIO4
6
OHC
OHC
5
HOH2C
COOH
COOH
1
NaCN
OH OH
5D D-glucoheptonic acid
OH OH
6L L-glucuronic acid
OH OH
OH OH
5
1
6
4L L-glucose
CHO
D-sugars in green
L-sugars in red
HOH2C
OH OH
oxidation
1
OH OH
OH OH
OH OH
1
1
HBr, AcOH;
NaBH4
6
6
6
COOH
COOH
CHO
HOH2C
HOH2C
HOH2C
4D D-glucose
then K2CO3; then KOH
OH OH
7D D-gluconic acid
-glucose 4D into -glucose 4L (numbering applies to carbons in D
OH OH
8L L-gluconic acid
-glucose; aldonic acids are usually handled as their lactones).
OH OH
Scheme 1. Strategies for the conversion of
D
L
hydrogen bromide in acetic acid followed by a series of base-in-
duced epimerisations and Payne rearrangements in which no pro-
tecting groups are used. Subsequent borohydride reduction of the
In summary, this Letter reports an efficient large scale prepara-
tion of the acetonide of -glucuronolactone 3L from glucoheptonic
acid and further elaboration to the mono-2L and di-1L acetonides
of -glucose. These procedures provide a family of readily available
-sugar chirons which may be of value for the synthesis of complex
L
lactone of 8L yields
L
-glucose 4L. This work has only appeared in
L
a preliminary form with no indication of yield.22 A second approach
L
depends on the highly Felkin-Ahn diastereoselective Kiliani cyanide
targets from the chiral pool. Full experimental details are given.
reaction of D-glucose 4D to give D-glucoheptononic acid 5D (both
salts of 5D and the corresponding lactone, glucoheptonolactone
9D are cheaply available). Suitable protection allows selective
oxidative cleavage of the original C5–C6 bond of glucose to afford
2. Experimental
2.1. 3,5-O-Benzylidene-
D-glucoheptono-1,4-lactone 10D
L-glucuronic acid 6L; subsequent reduction of a protected deriva-
tive of 3L by borohydride gives L-glucose 4L. This strategy was dem-
D
-Glucoheptonolactone 9D (200 g, 0.962 mol) was added to a
onstrated long ago by Sowa23 but not developed into a scalable
procedure.
mixture of benzaldehyde (600 mL) and concentrated aqueous
hydrochloric acid (32%, 60 mL) in a 4-L-jacketed glass reactor fitted
with a mechanical overhead stirrer. The reaction mixture was stir-
red at room temperature for 2 h, after which the reaction was
judged complete by TLC analysis (EtOAc:EtOH:H2O, 45:5:1), with
the formation of a major product (Rf 0.44) observed. Petroleum-
ether (40–60; 1600 mL) was added to the mixture and the result-
ing crystalline mass was stirred for 30 min and collected by filtra-
tion. The filter cake was washed with ether (500 mL) and then
dried under vacuum to give the benzylidene acetal 9D (273 g,
Reaction of glucoheptonolactone 9D with benzaldehyde and
concentrated aqueous hydrochloric acid gave the highly crystalline
benzylidene derivative 10D in 96% yield (Scheme 2). Periodate
cleavage of the diol 10D afforded the protected
11L which, without purification, was treated with aqueous trifluo-
roacetic acid to give -glucuronolactone 12L in 99% yield. Reaction
L-glucuronic acid
L
of 12L with acetone in the presence of concentrated sulfuric acid
formed the crystalline acetonide 3L in 99% yield. The overall yield
96%), [mp 202–206 °C; ½a D25
ꢀ
ꢁ57.0 (c, 1.01 in MeOH), lit.24 mp
of
be performed on a 100–200 g scale. Reduction of the protected lac-
tone 3L by sodium borohydride in water gave -glucose monoace-
L-glucuronolactone acetonide 3L from 9D is 94% and may readily
188–191 °C; ½a 2D0
ꢀ
ꢁ56.1 (c, 1.0 in MeOH)], which was used in the
L
next step without further purification.
tonide 2L in 60% yield. Treatment of the crude product 2L from the
borohydride reduction of 3L with acetone in the presence of sulfu-
2.2. L-Glucurono-3,6-lactone 12L
ric acid afforded diacetone
alternatively, hydrolysis of crude 2L gave
over the two steps. The 13C and 1H NMR spectra of all the
L
-glucose 1L [39% yield over two steps];
-glucose 4L in 41% yield
-sugars
L
A suspension of the benzylidene lactone 10D (100 g, 0.338 mol)
in THF:water (10:1, 770 mL) was warmed to 40 °C to give a clear
solution. Sodium periodate (75 g, 0.35 mol) was added portion-
wise to the stirred reaction mixture over 35 min in order to control
L
1L, 2L, 3L, 4L, and 12L were identical with those of authentic sam-
ples of their enantiomers.
HOH2C
HO
OH
HOH2C
OH
O
HO
HO
O
(ii)
(iv)
(v)
(i)
(iii)
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
HO
Ph
O
Ph
O
OH
OH
10D
OH
OH
12L
OH
9D
11L
3L
OH
O
O
O
OH
CH2OH
OH
O
HO
HO
OH
CH2OH
(vi)
(vii)
O
O
O
O
O
OH
4L
2L
1L
Scheme 2. Reagents: (i) PhCHO, HCl, 96%; (ii) NaIO4, THF/H2O; (iii) CF3COOH/H2O, 99% over two steps; (iv) Me2CO, H2SO4, 99%; (v) NaBH4, H2O, 60%; (vi) Me2CO, H2SO4, 39%
from 3L; (vii) H+, H2O, 41% from 3L.

A. C. Weymouth-Wilson et al. / Tetrahedron Letters 50 (2009) 6307–6310
6309
the exotherm and maintain the reaction temperature below 45 °C.
TLC analysis (EtOAc:EtOH:H2O, 45:5:1) after a further 30 min
showed complete consumption of starting material (Rf 0.44) and
clean conversion into aldehyde 11L (Rf 0.67). The thick precipitate
was removed by filtration and the filter cake washed with
THF:water (10:1, 250 mL). The combined filtrates were concen-
trated in vacuo to give the aldehyde 11L as a residue which was
used for the following step without further purification. A suspen-
sion of the crude aldehyde 11L in trifluoroacetic acid:water (9:1,
200 mL) was stirred at room temperature for 30 min; the reaction
mixture was then warmed to 45 °C for 30 min by which time a
clear solution formed. TLC analysis (EtOAc:EtOH:H2O, 45:5:1)
showed clean conversion into the deprotected lactone 12L (Rf
0.51). Trifluoroacetic acid was evaporated under reduced pressure
following co-evaporation with toluene (2 ꢂ 100 mL). Water
(250 mL) and ethyl acetate (100 mL) were added to the oily resi-
due; the aqueous layer was collected and the organic phase ex-
tracted with water (50 mL). The combined aqueous layers were
then washed with ethyl acetate (50 mL) and concentrated to give
cessively with aqueous hydrochloric acid (1 N, 100 mL), water
(100 mL), saturated aqueous sodium bicarbonate (200 mL) and
water (100 mL). The organic layer was then dried (magnesium sul-
fate) and concentrated under reduced pressure. Crystallization of
the residue from hot cyclohexane (60 mL) gave the pure diaceto-
nide 1L (22 g, 39% over two steps) [mp 108–110 °C; ½a D25
ꢀ
+17.0
(c, 1.03 in H2O). For the enantiomer 1D lit.27 mp 110–111 °C;
½
a 1D5
ꢀ
ꢁ18.4 (c, 1.2 in H2O)].
2.6.
L-Glucose 4L
Trifluoroacetic acid (25 mL) was added to a solution of the crude
monoacetonide 2L (64.8 g, assumed 0.215 mol) in water (400 mL)
and the reaction mixture stirred at 40 °C. TLC analysis (BuOH:E-
tOH:H2O, 5:3:2) after 1 h showed the formation of a major product
(Rf 0.51). The reaction mixture was concentrated to 75 mL and
loaded onto an IR120 column (H+ form, 500 g), eluting with water.
The fractions containing L-glucose were combined and concen-
trated to 75 mL before being loaded onto a Dowex 1 ꢂ 4 column
a viscous oil, which crystallized on standing to afford
L
-glucurono-
(HOꢁ form, 500 g), eluting with water, and the product fractions
lactone 12L (59 g, 99% over two steps), mp 164–168 °C; ½a D25
ꢀ
initial:
concentrated to yield L-glucose 1L (15.9 g, 41% over two steps)
ꢁ17.8; equilibrium: ꢁ21.5 (c, 1.05 in H2O) [lit.22 mp 165–167 °C;
[mp 138–146 °C; ½a D25
initial: ꢁ107.4; equilibrium: ꢁ53.0 (c, 1.05
ꢀ
½
a 2D2
ꢀ
ꢁ18 (c, 2.0 in H2O); for enantiomer 12D lit.25 mp 168–
in H2O), lit.28 mp 128–142 °C; ½a 2D3
ꢁ52 (c, 0.8 in H2O)].
ꢀ
170 °C; ½a 2D5
ꢀ
+18.7 (c, 1.0 in H2O)].
References and notes
2.3. 1,2-O-Isopropylidene-a-L-glucurono-3,6-lactone 3L
1. Hanessian, S. Total Synthesis of Natural Products: Chiron Approach; Elsevier,
1983, ISBN: 0080307159.
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27, 3205–3208.
A solution of concentrated sulfuric acid (50 mL, 0.96 mol) in
acetone (1.5 L) was added to -glucuronolactone 12L (169 g,
L
0.960 mol) in a 3-L round-bottomed flask and the mixture stirred
at 20 °C for 3 h. TLC analysis (petroleum-ether 40–60:acetone,
7:3) revealed the formation of a major product (Rf 0.28) and the
reaction mixture was quenched by the addition of solid sodium
bicarbonate (ꢃ900 g). The resulting precipitate was removed by fil-
tration and the filter cake washed with acetone (500 mL). The com-
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(206 g, 99%), [mp 118–120 °C; ½a D25
ꢀ
ꢁ56.9 (c, 1.09 in CHCl3); lit.22
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Tetrahedron 1997, 53, 15147–15156; (b) Blériot, Y.; Masaguer, C. F.; Charlwood,
J.; Winchester, B. G.; Lane, A. L.; Crook, S.; Watkin, D. J.; Fleet, G. W. J.
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mp 122–123 °C; ½a D20
ꢁ68 (c, 1.2 in H2O); for the enantiomer 3D
ꢀ
lit.5a mp 120.5–121.5 °C; ½a 2D0
ꢀ
+52.5 (c, 1.95 in CHCl3)].
2.4. 1,2-O-Isopropylidene-a-L-glucose 2L
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A solution of sodium borohydride (13.2 g, 0.349 mol) in water
(230 mL) was added over 5 min to a chilled (10 °C) solution of
the lactone 3L (116 g, 0.537 mol) in water (700 mL). The reaction
mixture was stirred for 90 min at 10 °C and then quenched by
the addition of acetic acid (20 mL, 0.348 mol). The reaction mixture
was concentrated under reduced pressure and the water co-evap-
orated with methanol (3 ꢂ 500 mL) at 40 °C to give the crude
monoacetonide 2L (162 g) [Rf 0.49 (EtOAc:EtOH:H2O, 45:5:1)] con-
taining salts which was used for subsequent reactions without fur-
ther purification. An aliquot of the crude product 2L (32.4 g,
assumed 0.107 mol) was purified by column chromatography [0–
2% water in acetone] to afford the pure monoacetonide 2L
(14.2 g, 60%), [mp 156–158 °C; ½a D25
ꢀ
+11.4 (c, 1.07 in H2O), lit.26
mp 160–161 °C; ½a D19
ꢀ
+11.4 (c, 1 in H2O)].
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