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H.Streicher et al./ Tetrahedron 57 '2001) 8851±8859
20
1
d7.35±7.25 <m, 5H, C6H5), 5.89 <d, 1H, H-1,
J1±23.9 Hz), 4.68, 4.49 <2d, 2H, CH2Ph, J11.8 Hz),
4.61 <d, 1H, H-2), 4.57 <m, 1H, H-4), 4.20±4.13<m, 8H,
4CH2CH3), 3.85 <d, 1H, H-3, J3±43.3 Hz), 2.57 <m, 1H,
C<CH3)2), 1.36±1.29 <m, 15H, C<CH3)2, 4CH2CH3). 13C
NMR <150.9 MHz, CDCl3): d104.5 <C-1), 82.5 <C-2),
81.9 <C-3), 77.9 <C-4), 71.7 <CH2Ph), 62.8±62.3<4
CH2CH3), 33.3 <C-6), 26.5 <C-5), 16.3 <CH2CH3). 31P
NMR <242.9 MHz, CDCl3): d24.5, 24.4 <2s, 2P,
2P<O)<OEt)2). C24H40P2O10 <M 550.52). MALDI-MS <pos.
mode, DHB): 588.6 <M1K1), 572.7 <M1Na1).
1:1); [a]D 211.4 <c1, MeOH); H NMR <600 MHz,
DMSO-d6): d6.24 <bd, 1H, H-2, JP-221 Hz), 4.10±3.90
<m, 6H, H-3, H-5, 2CH2CH3), 3.71 <m, 2H, CH2CH3), 3.31
<m, 1H, H-4), 2.38, 2.04 <2m, 2H, H-6, H-60), 1.22, 1.09
<2m, 9H, 3CH2CH3). 13C NMR <150.9 MHz, DMSO-d6):
d144.0 <C-2), 124.0 <C-1), 75.7 <C-4), 72.5 <C-3), 71.2
<C-5), 31.7 <C-6). 31P NMR <242.9 MHz, DMSO-d6):
d19.23<1s, 1P, P<O)<OEt)2), 2.21 <bs, 1P, OP<OH)<OEt).
C12H24P2O9 <M 374.089). MALDI-MS <pos. mode, DHB):
396.9 <M1Na)1, 418.9 <M2H12Na)1. FAB-MS <pos.
mode, NBA): 397 <M1Na)1, 419 <M2H12Na)1.
0
H-6), 2.43<m, 1H, H-5), 2.16 <m, 1H, H-5 ), 1.48 <s, 3H,
4.1.9. Ammonium [,3R,4R,5S)-3,4,5-trihydroxy-1-cyclo-
hexenephosphonate-5-yl]phosphate ,12). Compound 11
<50 mg, 0.19 mmol) is dissolved in CHCl3 <5 ml) and a
solution of TMSBr in CHCl3 <10%, v/v, 0.5 ml) is added.
The mixture is stirred for 24 h, water <2 ml) is added and the
mixture is concentrated in vacuo and the crude product is
puri®ed by gel ®ltration <Biogel P2, 0.1 M NH4HCO3) to
give 12. [a]D 22 <c0.5, H2O/MeOH 1:1). H NMR
<600 MHz, D2O): d5.98 <ddd, 1H, H-2, JP-219.4 Hz,
J2±32.5 Hz, J2±62.5 Hz), 4.14 <m, 1H, H-3), 4.07 <m,
1H, H-5), 3.49 <dd, 1H, H-4, J4±38.2 Hz, J4±59.7 Hz),
2.68 <m, 1H, H-6), 2.20 <m, 1H, H-60). 13C NMR
<150.9 MHz, D2O): d134.4 <C-2), 76.4 <C-4), 73.2
<C-5), 73.0 <C-3), 32.7 <C-6). 31P NMR <242.9 MHz,
D2O): d12.6 <1s, 1P, PO32-), 3.6 <bs, OPO32-).
4.1.6. Tetraethyl [3-O-benzyl-5,6-dideoxy-a,b-l-xylofur-
anose-6,60-diyl]bisphosphonate ,9). Diphosphonate
8
<500 mg, 0.91 mmol) is dissolved in dioxane/water <1:1,
20 ml), toluenesulfonic acid monohydrate <170 mg) is
added and the mixture is stirred at 808C until TLC indicates
absence of starting material <, 20 h). Following neutraliza-
tion with saturated NH4HCO3 solution the mixture is
concentrated to approximately half its volume and extracted
with CHCl3. The organic layer is dried <MgSO4), evaporated
and the residue is chromatographed to give 9 <a,b-mixture,
413mg, 89%) as a colourless oil. Rf0.18 <Tol/EE 10:1);
1H NMR <600 MHz, DMSO-d6): d7.37±7.27 <m, 10H,
C6H5a,b), 6.22, 6.13, 5.39, 5.05 <4d, 4H, 2OHa, 2OHb),
4.66, 4.62, 4.47, 4.44 <4d, 4H, 4CH2Ph, J12 Hz), 4.40,
4.32 <2m, 2H, H-4a, H-4b), 4.03±3.95 <m, 16H,
4CH2CH3a,b), 3.97, 3.91 <2m, 2H, H-2a, H-2b), 3.85, 3.73
<2m, 2H, H-3a, H-3b), 2.45 <m, 2H, H-6a, H-6b), 2.03<m,
20
1
4.1.10. Ammonium ,3R,4R,5S)-3,4,5-trihydroxy-1-cyclo-
hexenephosphonate ,1). The ammonium salt of phosphate
monoester 12 <30 mg, , 0.1 mmol) is dissolved in buffer
<1 ml, Tris HCl, 0.1 M, pH 8.6, 0.25 M MgCl2), and alkaline
phosphatase from calf intestine <50 U) is added. The
mixture is incubated for 4 h at 378C, the precipitate formed
is ®ltered off through a 0.45 mm ®lter and the product
puri®ed by gel ®ltration <Biogel P2, 0.1 M NH4HCO3)
a
b
4H, H-5a, H-50 , H-5b, H-50 ), 1.23±1.17 <m, 24H,
4CH2CH3a,b). 13C NMR <150.9 MHz, CDCl3): d102.3,
95.1 <C-1a, C-1b), 83.3, 82.7 <C-3a, C-3b), 79.4, 74.8
<C-2a, C-2b), 73.9, 73.8 <C-4a, C-4b). 31P NMR
<242.9 MHz, CDCl3): d25.34, 25.31 <2s, 2P,
2P<O)<OEt)2a,b), 25.21 <2P, 2P<O)<OEt)2a,b). C21H36P2O10
<M 510.52). MALDI-MS <pos. mode, DHB): 549.0
<M1K1), 533.2 <M1Na1).
1
to give 1. H NMR <600 MHz, D2O): d5.88 <dd, 1H,
H-2, JP-218.4 Hz), 4.06 <ddd, 1H, H-3, J3±48 Hz), 3.62
<m, 1H, H-5, J5±410.2 Hz), 3.35 <dd, 1H, H-4), 2.56 <m,
1H, H-6), 2.07 <m, 1H, H-60). 13C NMR <150.9 MHz, D2O):
d132.3 <C-2), 77.4 <C-4), 73.2 <C-3), 69.9 <C-5), 33.8
<C-6). 31P NMR <242.9 MHz, D2O): d11.9 <1s, 1P,
PO322). C6H11PO6 <free acid) <M 210.03). FAB-MS <pos.
Mode, glycerol): 421 <2M1H)1, 233 <M1Na)1, 228
<M1NH4)1, 211 <M1H)1, 193<M 2H2O1H)1.
4.1.7. Tetraethyl [5,6-dideoxy-a,b-l-xylofuranose-6,60-
diyl]bisphosphonate ,10). The mixture of anomeric di-
phosphonates 9 <100 mg, 0.2 mmol) in dioxane/water <1.1,
8 ml) is hydrogenated overnight over palladium±charcoal
<10%, 10 mg) at room temperature. The mixture is ®ltered
through Celite and evaporated to give 10 <a,b-mixture,
82 mg, qu) as a colourless oil of excellent purity. Rf0.5
<EE/MeOH/H2O 70:30:3); 1H NMR <250 MHz, MeOH-d4):
d5.32, 5.03 <1d, 1bs, 2H, H-1a, H-1b), 4.18, 4.06, 3.94
<3m, 22H, H-2a, H-2b, H-3a, H-3b, H-4a, H-4b,
4.1.11. 1,2-O-Isopropylidene-5-O-triisopropylsilyl-a-l-
erythro-pentos-3-ulose ,13). Alcohol
4
<12.06 g,
34.8 mmol) is oxidized as described in the literature for
the comparable TBDMS-protected compound.11 Flash chro-
matography of the crude product gave carbonyl compound
4CH2CH3 4CH2CH3 ), 2.76 <m, 2H, H-6a, H-6b), 2.32±
a
b
,
2.04 <m, 4H, H-5a, H-50 , H-5b, H-50 ), 1.38±1.32 <m, 24H,
4CH2CH3a,b). C14H30P2O10 <M 420.39). MALDI-MS <pos.
mode, DHB): 443.3 <M1Na)1.
a
b
20
13 <11.4 g, 95%). Rf0.5±0.7 <Tol/EE 9:1); [a]D 298.8
<c1, CHCl3); 1H NMR <250 MHz, CDCl3): d6.14 <d, 1H,
H-1, J1±24.5 Hz), 4.34 <m, 1H, H-4), 4.28 <dd, 1H, H-2,
J2±41 Hz), 3.97 <dd, 1H, J5±510.6 Hz, J5±41.8 Hz), 3.93
<dd, 1H, H-50, J5±42.1 Hz), 1.44, 1.43<2s, 6H, C<C H3)2),
1.33±0.96 <m, 21H, 3CH<CH3)2). Anal. Calcd for
C17H32O5Si <M 344.56): C, 59.26; H, 9.37. Found: C,
59.36; H, 9.51.
4.1.8. Ethyl [diethyl ,3R,4R,5S)-3,4,5-trihydroxy-1-
cyclohexenephosphonate-5-yl]phosphoric acid ,11). The
anomeric mixture of compound 10 <800 mg, 1.90 mmol) is
stirred in a solution of NaOEt in EtOH <0.1 M) until TLC
indicates the absence of starting material <,1 h). The solu-
tion is neutralized with Amberlite IR-120 <H1-form),
®ltered and evaporated. The residue is chromatographed
<EE/MeOH 1:1) to give cyclohexenephosphonate 11
<260 mg, 52%) as a colourless foam. Rf0.37 <EE/MeOH
4.1.12. 1,2-O-Isopropylidene-5-O-triisopropylsilyl-a-l-
ribofuranose ,14). Carbonyl compound 13 <8.7 g,
25.25 mmol) is reduced with NaBH4 as described11,19 for