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J. Org. Chem. 1991,56, 6606-6611
atmosphere of H2 (65 psi) in a Parr hydrogenator apparatus for 48 h. The catalyst was removed by suction filtration and the filtrate concentrated under reduced pressure. The residue was purified by flash chromatography (1:3 hexaneslEt0Ac) to provide 0.091 g (99%) of 23 as a clear colorless oil: [a]%D = 25.5' (c = 1.0, CHCl,); 'H NMR (300 MHz) 6 5.05 (ddd, J = 8.5,3.9,3.3 Hz, 1 H), 4.86 (dd, J = 8.5, 1.7 Hz, 1 H), 4.29 (ddd, J = 8.1,6.3,4.8 Hz, 1 H), 4.16 (dd, J = 8.6, 6.3 Hz, 1 H), 3.90 (dd, J = 8.6, 4.8 Hz, 1 H), 3.79 (d, J = 11.8 Hz, 1 H), 3.73 (J = 8.1,1.7 Hz, 1 H), 3.52 (d, J = 11.8 Hz,1H), 3.29 (a, 3 H), 2.62 (dd, J = 16.0, 3.9 Hz, 1 H), 1.80 (br s, 1 H), 1.78 (dd, J = 16.0,3.3 Hz, 1 H), 1.42 (8, 3 H), 1.36 (8, 3 H); 13C NMR (75 MHz) 6 154.0, 109.7, 99.1, 73.3, 72.9, 72.3, 68.7, 67.5, 48.5, 30.4, 26.7, 25.0; IR v 1805 cm-'; mass spectrum m/z 304.1165 (C13HmO8 requires 304.1158),289, 273, 257, 153, 11, 101, 95, 43. Methyl 3-Deoxy-7,8-0 -( l-methylet hy1idene)-a-D-mannooctos-2-ulo-2,6-pyranoside, Cyclic Carbonate (25). To a solution of DMSO (0,086g, 1.1mmol) in CHzClz(4 mL) at -78 "C was added oxalyl chloride (0.070 g, 0.55 "01). The solution was stirred for 15 min, and alcohol 23 (0.0834 g, 0.274 mmol) dissolved in CH2Clz(5 mL) was added dropwise. After 15 min at -78 "C, triethylamine (0.17 g, 2.2 mmol) was added, and the solution was stirred for 0.5 h while warming to rt. The reaction mixture was poured into saturated NaHCO3 (5 mL), and the mixture was extracted with ether (3 x 10 mL). The combined organic extracts were washed with saturated NaHC03 (5mL), dried (MgS0,) and concentrated under reduced pressure. The residue was purified by flash chromatography (3:2 hexanes EtOAc) to furnish 0.067 +40.3' (c = 1.0, CHClJ; g (80%)of 25 as a clear colorless oil; lH NMR (300 MHz) 6 9.48 (s, 1 H), 5.04 (ddd, J = 8.5, 3.6, 2.9 Hz, 1 H), 4.91 (dd, J = 8.5, 1.7 Hz, 1 H), 4.41 (ddd, J = 8.1, 6.2, 4.6 Hz, 1 H), 4.23 (dd, J = 8.6, 6.2 Hz, 1 H), 3.98 (dd, J = 8.6, 4.6 Hz, 1 H), 3.82 (dd, J = 8.1, 1.7 Hz, 1 H), 3.32 (s, 3 H), 2.60 (dd, J = 16.2,3.6 Hz, 1 H), 1.95 (dd, J = 16.2, 2.9 Hz, 1 H), 1.45 ( 8 , 3 H), 1.39 ( 8 , 3 H); 13C NMR (75 MHz) 6 197.4, 153.3, 109.9, 98.6, 72.8, 72.5, 71.2, 70.5, 67.0, 51.1, 30.9, 26.8, 24.9; IR Y 1805 cm-'; mass spectrum m/z287.0759 [C12HlS08(M+- CHS) requires 287.07671, 273, 111, 101, 95, 43. Methyl 3-Deoxy-7,8-0 -(l-methy1ethylidene)-a-Pmannooctos-2-ulo-2,6-pyranosonic Acid (26). A mixture of 25 (0.014 in 2 N NaOH (0.11 g, 0.045 mmol) and Ag20(0.011g, 0.045 "01) mL) and 50% aqueous EtOH (0.4 mL) was stirred for 24 h at rt with the exclusion of light. The solids were removed by filtration through a pad of Celite, and the filtrate was concentrated under reduced pressure. The residue was purified by flash chromatography on purified cellulose (1:l CHCl,/MeOH) to deliver 0.13 g (96%) of 26 as a white solid: [(YImD= +43.4' (c = 0.3, H20); lH NMR (300 MHz, DzO) 6 4.41 (m, 1 H), 4.24 (dd, J = 9.0,6.1 Hz, 1H), 4.08 (dd, J = 9.0, 4.6 Hz, 1 H), 4.02 (m, 1 H), 3.91 (d, J = 2.2 Hz, 1H), 3.56 (d, J = 8.2 Hz, 1 H), 3.15 (s,3 H), 2.00 (dd, J = 13.4, 5.1 Hz,1 H), 1.76 (dd, J = 13.4, 12.8 Hz, 1 H), 1.44 (8, 3 H), 1.39 ( ~ , H); 3 '3C NMR (75 MHz, D20) 6 175.3, 109.6, 100.7,
73.4, 72.7,67.4,66.5,65.4,50.5,34.8,25.7,24.2;IR (film) v 1690 cm-l; mass spectrum 277.0929 [CllH170s (M+ - CH3) requires 277.09231, 262, 201, 44. 3-Deoxy-o-~-manno-2-octulopyranosonic Acid, Ammonium Salt [(+)-KDO] (1). The pH of a solution of 26 (0.139 g, 0.52 mmol) in water (2 mL) was adjusted to
