1,2-Dichloroethane → (2R,3S,4R,5R,6R)-2-(Acetoxymethyl)-6-(benzyloxy)-5-(1,3-dioxoisoindolin-2-yl)tetrahydro-2H-pyran-3,4-diyl diacetate

Participants

Reaction Steps

Under anhydrous conditions, 1,3,4,6-tetra-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranose (5) (47.7 g, 100 mM), molecular sieves (4 Å) powder (20 g) and 250 ml of 1,2-dichloroethane and benzyl alcohol (12.5 ml, 120 mM) were placed in a dry 1 liter round bottom flask equipped with magnetic stirring bar, septum inlet and bent tube adapter. During a 5 minute period, trimethylsilyl trifluoromethane sulfonate (19.3 ml, 100 mM) was then added to the stirred mixture. The contents were stirred at room temperature for 16 hours. The reaction was found to be complete as evidenced by the products present on thin layer chromtography (TLC, 2:3 ethyl acetate:hexane). The reaction mixture was cooled in an ice-bath, quenched with saturated sodium bicarbonate and extracted with dichloromethane in the manner well known to those skilled in the art. The combined extract was washed with water, brine and dried over anhydrous magnesium sulfate. The residue after removal of solvent was purified by "flash chromatography" (silica gel, 500 g, solvent 1:3 ethyl acetate:hexane) to provide 40.6 g (85% yield) of benzyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucopyranoside (6).

Provenance & Evidence