Helvetica Chimica Acta ± Vol. 83 (2000)
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(0.4, M ), 287 (8), 285 (100), 211 (6), 73 (25), 59 (3), 45 (20), 43 (9), 41 (3). HR-MS: 445.2296 (C21H37O8Si ,
[M À Me] ; calc. 445.2258).
Ethyl 2,6-Anhydro-3-deoxy-8,9-O-isopropylidene-7-O-(methoxymethyl)-d-glycero-d-talo-non-4-ulosonate
(20). To a soln. of 18a (1.10 g, 2.39 mmol) in acetone/H2O 4:1 (25 ml) stirred at r.t., K 2[OsO2(OH)4] (18 mg,
2 mol-%) and NMO (810 mg, 6 mmol) were added. Stirring was continued overnight. When TLC showed full
consumption of the starting material, NaHSO3 (500 mg) was added, and the mixture was stirred for another
hour before the solids were filtered off. The filtrate was evaporated to give a colorless syrup (623 mg, 74%)
consisting of 20 and an isomer (presumably a 5-epimer) in a ratio of ca. 4:1. In prep. runs, this mixture was used
directly in the subsequent reduction with NaBH4. For characterization, a small anal. sample of 20 was obtained
by FC (AcOEt/petroleum ether 1:2): [a]2D0 42.0 (c 0.91, CHCl3). IR (film): 3450m, 2950m, 1750s, 1725s,
1
1370m, 1208s, 1160s. H-NMR: 5.03 (s, OH); 4.90 (d, J 6.6, 1 H); 4.76 (d, J 6.6, 1 H); 4.47 (q, J 6.7, 2 H);
4.42 (br. d, J 11.3, 1 H); 4.25 (q, J 7.1, 2 H); 4.22 (dd, J 15, 3.3, 1 H); 4.15 (dd, J 6.3, 8.5, 1 H); 4.09
(br. d, J 7.4, 1 H); 4.03 (dd, J 6.0, 8.8, 1 H); 3.73 (dd, J 10.2, 0.9, 1 H); 3.42 (s, 3 H); 2.88 (dd, J 14,
3.4, 1 H); 2.81 (br. dd, J 14, 15, 1 H); 1.43 (s, 3 H); 1.36 (s, 3 H); 1.31 (t, J 7.1, 3 H). EI-MS: 362 (0.6, M ),
347 (2, [M À Me] ), 331 (15), 273 (49), 101 (98), 73 (23), 45 (100), 43 (48), 41 (11). HR-MS: 347.1318
(C15H23O9 , [M À Me] ; calc. 347.1342).
Ethyl 2,6-Anhydro-3-deoxy-8,9-O-isopropylidene-7-O-(methoxymethyl)-d-erythro-l-gluco-nononate (21).
To an ice-cooled soln. of 20 (290 mg, 0.80 mmol) in EtOH (20 ml), NaBH4 (32 mg, 1.05 equiv.) was added.
After stirring for 1 h, the basic mixture was neutralized with 5% HCl soln. and then evaporated. FC (petroleum
ether/AcOEt 1:2) afforded 21 (274mg, 94%). Colorless syrup. [ a]2D0 21.0 (c 1.09, CHCl3). IR (film): 3500s,
1
2950s, 1750s, 1380m, 920w. H-NMR: 4.80 (s, MeOCH2); 4.42 (m, HÀC(8)); 4.20 (q, J 7.1, MeCH2O); 4.15 ±
4.07 (m, HÀC(7), HÀC(9)); 4.06 ± 3.97 (m, HÀC(2), HÀC(9)); 3.72 (ddd, J 12.9, 8.3, 4.9, HÀC(4)); 3.48
(t, J 9.0, HÀC(5)); 3.42 (s, MeOCH2); 3.40 ± 3.36 (m, HÀC(6)); 3.14(v. br. s, 2 OH); 2.30 (ddd, J 12, 4.7, 1.9,
HaÀC(3)); 1.65 (q, J 12, HbÀC(3)); 1.42 (s, 3 H, Me2C); 1.36 (s, 3 H, Me2C); 1.28 (t, J 7.1, MeCH2O). EI-
MS: 364(0.2, M ), 349 (10, [M À Me] ), 275 (14), 101 (76), 73 (27), 59 (10), 45 (100), 43 (52), 41 (13). HR-MS:
349.1521 (C15H25O9 , [M À Me] ; calc. 349.1499).
Ethyl 4,5-O-Diacetyl-2,6-anhydro-3-deoxy-8,9-O-isopropylidene-7-O-(methoxymethyl)-d-erythro-l-gluco-
nononate (22). A soln. of 21 (560 mg, 1.54mmol) and DMAP (50 mg) in pyridine (5 ml) and Ac 2O (3 ml) was
stirred at r.t. for 24h before being partitioned between H 2O and AcOEt. The crude product obtained from the
org. phase was purified by FC (petroleum ether/AcOEt 4:1): 22 (650 mg, 94%). Colorless syrup. [a]2D7 21.1
(c 1.01, CHCl3). IR (film): 2960s, 1755s, 1440m, 1365s, 1230s, 1150s. 1H-NMR: 5.10 ± 4.94 (m, 2 H); 4.76 (d, J
6.6, 1 H); 4.73 (d, J 6.6, 1 H); 4.26 ± 4.01 (m, 5 H); 3.96 (dd, J 7.1, 8.5, 1 H); 3.88 ± 3.83 (m, 1 H); 3.76 ± 3.71
(m, 1 H); 3.37 (s, 3 H); 2.41 (ddd, J 2.2, 4.7, 11.3, 1 H); 2.05 (s, 3 H); 2.01 (s, 3 H); 1.75 (dd, J 3.4, 11.3, 1 H);
1.38 (s, 3 H); 1.34( s, 3 H); 1.27 (t, J 7.1, 3 H). EI-MS: 433 (7, [M À Me] ), 183 (18), 171 (11), 101 (88), 73 (18),
72 (9.7), 45 (94), 43 (100). HR-MS: 433.1734 (C19H29O11, [M À Me] ; calc. 433.1710).
Ethyl 4,5,7,8,9-Penta-O-acetyl-2,6-anhydro-3-deoxy-d-erythro-l-gluco-nononate (23). A soln. of 22 (70 mg,
0.16 mmol), propane-1,3-dithiol (40 ml, 0.40 mmol), and a cat. amount of BF3 ´ Et2O in dry CH2Cl2 (2 ml) was
stirred at r.t. overnight. After evaporation, the residue was dissolved in pyridine (2 ml) and treated with Ac2O
(1 ml) in the presence of a cat. amount of DMAP. After stirring for 24h, the mixture was poured into cold H 2O
and extracted with AcOEt. The crude residue recovered from the org. phase was submitted to FC (petroleum
ether/AcOEt 2 :1): 23 (70 mg, 91%). Colorless syrup. [a]2D7 19.1 (c 1.50, MeOH). IR (film): 2950m, 1745s,
1430m, 1360s, 1200s, 1030s, 94 w0. 1H-NMR: 5.34± 5.26 ( m, HÀC(7), HÀC(8)); 5.10 ± 4.92 (m, HÀC(4),
HÀC(5)); 4.53 (dd, J 2.5, 13.7, HÀC(9)); 4.25 ± 4.14 (m, HÀC(9), MeCH2O); 4.04 (dd, J 2.2, 12.1,
HÀC(2)); 3.63 (dd, J 1.5, 9.8, HÀC(6)); 2.41 (ddd, J 2.2, 5.0, 12.9, HeqÀC(3)); 2.07, 2.06, 2.05, 2.01, 2.00
(5s, each 3 H); 1.76 (br. q, J 12.6, HaxÀC(3)); 1.25 (t, J 7.1, MeCH2O). EI-MS: 491 (0.3, [M 1] ), 432 (8),
431 (35), 417 (8), 268 (10), 213 (11), 195 (8), 43 (100). HR-MS: 472.1537 (C21H28O12, [M À H2O] ; calc.
472.1581).
5,7,8,9-Tetra-O-acetyl-2,6-anhydro-deoxy-d-erythro-l-gluco-nonono-1,4-lactone (24).
A mixture of 21
(91 mg, 0.25 mmol), MeOH (10 ml), conc. HCl soln. (10 drops), and H2O (2 ml) was heated under reflux for
12 h. After neutralization with dil. NaOH soln., the mixture was evaporated and the residue treated with Ac2O/
py in the presence of DMAP to give, after chromatographic purification, 24 (ca. 80 mg). Colorless syrup. [a]D20
62.6 (c 0.99, CHCl3). IR (film): 2900m, 1745s, 1730s, 1660m, 1360m, 1210s, 1020s, 800m. 1H-NMR: 5.24
(ddd, J 2.4, 4.9, 7.3, 1 H); 5.02 (br. d, J 2.4, 1 H); 4.71 (br. s, 1 H); 4 .64 d(d, J 2.4, 12.2, 1 H); 4.59 (d, J 7.9,
1 H); 4.44 (br. d, J 4.3, 1 H); 4.21 (dd, J 4.9, 12.2, 1 H); 4.05 (br. s, 1 H); 2.14( s, 3 H); 2.10 (s, 3 H); 2.07
(s, 3 H); 2.04( s, 3 H). EI-MS: 403 (2, [M 1] ), 167 (8), 166 (12), 109 (17), 85 (8), 81 (8), 67 (34), 43 (100).
HR-MS: 402.1417 (C17H22O11 ; calc. 402.1462).