Diazabicyclo(2.2.2)octane → 2,4,6-tri-O-benzyl-3-O-methyl-D-glucopyranose

Beteiligte Stoffe

Reaktionsschritte

Allyl-3-O-methyl-2,4,6-tri-O-benzyl-glucopyranose (7.4 g) was refluxed for 5 hours in a mixture of ethanol/benzene/water (7:3:1) (500 mL) containing tris triphenylphosphine rhodium (I) chloride (1.05 g) and diazabicyclo[2.2.2]octane (445 mg). The isomerized product was hydrolyzed in acetone-water (9:1) (140 mL) using mercuric chloride (18.6 g) and mercuric oxide (383 mg) by stirring the reaction mixture at room temperature for 1 hour. The resulting solution was evaporated to dryness, diluted with methylene chloride (500 mL), filtered and washed with 30% KBr (3×500 mL) and water (3×500 mL), dried over Na2SO4, concentrated and purified by chromatography on silica gel using hexane-ethyl acetate (4:1) and (3:1) as eluents to provide 2,4,6-tri-O-benzyl-3-O-methyl-D-glucopyranose (5.0 g).

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