Hydrogen Peroxide → (4S)-4-Benzyl-3-[(2S,3R)-3-(3-benzyloxyphenyl)-3-hydroxy-2-isopropoxypropionyl]-1,3-oxazolidin-2-one

Participants

Reaction Conditions

Reaction Steps

A toluene (2.4 L) solution of 150 g of (4S)-4-benzyl-3-(2-isopropoxyacetyl)oxazolidin-2-one and 90 mL of triethylamine was cooled to −70° C., to which 550 mL of dibutylboron triflate (1M dichloromethane solution) was added dropwise at an internal temperature of −70° C. or less. After the dropwise addition, the internal temperature was increased to 0° C. and the reaction mixture was stirred at 0° C. for 30 minutes, followed by again cooling to −70° C. A dichloromethane (300 mL) solution of 121 g of 3-benzyloxybenzaldehyde was added to the reaction mixture using a cannula, followed by increasing the internal temperature to 0° C. over a period of 40 minutes. The reaction mixture was stirred at 0° C. for 1.5 hours, to which 1 L of methanol, 1.5 L of pH 7 buffer (sodium dihydrogenphosphate-citric acid) and 250 mL of hydrogen peroxide (30% aqueous solution) were then added, followed by stirring the solution at room temperature for 30 minutes. Subsequently, the reaction mixture was extracted with ethyl acetate (3 L). The organic layer was washed with a saturated sodium chloride solution (1.5 L), and then dried with anhydrous magnesium sulfate, followed by distilling off the solvent under a reduced pressure. The residue was purified using silica gel column chromatography to obtain 274.3 g of the title compound in the form of colorless oily matter from a hexane-ethyl acetate (2:1→3:2)-eluted fraction.

Provenance & Evidence