(2R,3R,4S,5R,6S)-2-(hydroxymethyl)-6-phenylsulfanyloxane-3,4,5-triol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of phenyl 1-thio-β-D-galactopyranoside (2.1) (3.00 g, 11.0 mmol) and dibutyltin oxide (3.00 g, 12.1 mmol) in dry methanol (80 ml) was refluxed for 2 hours to produce a clear mixture. The solvent was then evaporated under reduced pressure. The resultant residue was dissolved in dry benzene (80 mL) followed by the addition of Bu4NBr (3.90 g, 12.11 mmol) and BnBr (1.3 ml, 12.1 mmol). The mixture was refluxed overnight. After cooling to room temperature, the mixture was concentrated and the residue was purified by silica gel chromatography (50% EtOAc/petroleum ether) to afford the title compound (2.71 g, 7.48 mmol, 67%). 1H NMR (400 MHz, CDCl3): δ 7.60-7.20 (m, 10H, PhH), 4.77, 4.68 (ABq, J=11.7 Hz, 1H each, OCH2Ph), 4.59 (d, J=9.5 Hz, 1H, H-1), 4.08 (d, J=2.6 Hz, 1H, H-4), 3.76 (dd, J=9.5, 9.5 Hz, 1H, H-2), 3.75 (dd, J=11.4, 5.8 Hz, 1H, H-6), 3.70 (dd, J=11.4, 5.8 Hz, 1H, H-6), 3.50 (dd, J=5.8, 5.8 Hz, 1H, H-5), 3.41 (dd, J=9.5, 2.6 Hz, 1H, H-3); 13C NMR (100 MHz, CDCl3): δ 131.0, 128.6, 128.1, 127.8, 127.4, 126.8, 89.1, 82.5, 79.2, 71.5, 69.0, 66.2, 61.4; HRMS calcd for C19H26O5SN [M+NH4]+: 380.1532. found 380.1527. to produce a clear mixture The solvent was then evaporated under reduced pressure The resultant residue was dissolved in dry benzene (80 mL) The mixture was refluxed overnight the mixture was concentrated the residue was purified by silica gel chromatography (50% EtOAc/petroleum ether)

Conditions: temp:95.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1-deoxy-1-(phenylthio)-β-D-galactopyranose (0.38 g, 1.4 mmol) in 25 mL of pyridine, pivaloyl chloride (1.75 mL, 14.0 mmol) and DMAP (0.200 g, 1.40 mmol) are added. The reaction mixture is stirred at 90-100° C. for 8 h. Pyridine is removed under reduced pressure, and the residue is dissolved in 100 mL of CH2Cl2 and washed with dilute HCl (100 mL), H2O (100 mL), dried over Na2SO4, filtered, concentrated and purified by flash chromatography (10% EtOAc/hexane) to give 0.65 g (76%) of 1-deoxy-1-(phenylthio)-2,3,4,6-tetra-O-pivaloyl-β-D-galactopyranose 40: Rf 0.59 (15% EtOAc/hexane); 1H NMR (CDCl3, 270 MHz) δ 7.97 (d, J=8.9 Hz, 2 H, ArH), 7.70 (t, J=7.3 Hz, 1 H, ArH), 7.60 (t, J=7.3 Hz, 2 H, ArH), 5.39 (t, J=9.9 Hz, 1 H, H-2), 5.30 (d, J=3.0 Hz, 1 H, H-4), 5.10 (dd, J=9.9, 3.0 Hz, 1 H, H-3), 4.57 (d, J=9.9 Hz, 1 H, H-1), 4.05-4.20 (m, 2 H, H-6), 3.79 (dd, J=10.6, 5.9 Hz, 1 H, H-5), 1.25-(s, 9 H), 1.18 (s, 9 H), 1.08 (s, 9H), 0.92 (s, 9 H). 13C NMR (CDCl3, 270 MHz) δ 177.7, 177.0, 176.7, 176.3, 134.4, 134.2, 131.0, 128.7, 89.4, 74.9, 71.7, 65.9, 63.9, 60.5, 38.4, 38.7, 38.6, 27.1. Pyridine is removed under reduced pressure the residue is dissolved in 100 mL of CH2Cl2 washed with dilute HCl (100 mL), H2O (100 mL) dried over Na2SO4 filtered concentrated purified by flash chromatography (10% EtOAc/hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of thioglycoside 39 (1.10 g, 2.5 mmol) in 50 mL of MeOH is added K2CO3 in small portions, until the reaction mixture tested basic to pH paper (pH 11). The reaction mixture is stirred at room temperature for 15 min and then neutralized with Amberlite resin (acid form). The resin is removed by filtration and washed with MeOH (2×50 mL). The filtrates are concentrated and azeotroped from toluene to remove the residue MeOH to afford 1-deoxy-1-(phenylthio)-β-D-galactopyranose which is taken on to the next step without further purification. The resin is removed by filtration washed with MeOH (2×50 mL) The filtrates are concentrated azeotroped from toluene to remove the residue MeOH

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To the crude 9 (72.1 mmol, 1 eq) dissolved in dry DMF (1500 mL) under argon at 0° C. was added sodium hydride (10.7 g, 446.8 mmol, 6.2 eq). After 15 min, were added dropwise benzyl bromide (54 mL, 454 mmol, 6.3 eq) and a catalytic amount of potassium iodide. The mixture was stirred at room temperature for 3 h, diluted with water (500 mL) and Et2O (600 mL). The aqueous phase was extracted with Et2O (3×300 mL). The organic extracts were combined, dried over MgSO4 and concentrated. Purification by flash chromatography on silica gel (petroleum ether/EtOAc 90:10) afforded 10 as viscous syrup (27.5 g, 60% over 2 steps). The aqueous phase was extracted with Et2O (3×300 mL) dried over MgSO4 concentrated Purification by flash chromatography on silica gel (petroleum ether/EtOAc 90:10)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 8 (31.7 g, 72.07 mmol, 1 eq) dissolved in dry MeOH (800 mL) under argon was added sodium methanolate (17.3 g, 302.7 mmol, 4.2 eq). After being stirred for 1 h, Amberlite IR 120 (300 g) was added and the mixture was stirred for 15 min up to pH=7. The solution was filtered through alumina. The cake was washed with MeOH (150 mL) and the organic layer was concentrated. The crude was engaged in the next step. the mixture was stirred for 15 min up to pH=7 The solution was filtered through alumina The cake was washed with MeOH (150 mL) the organic layer was concentrated