(Diethylamino)sulfur trifluoride → tert-Butyl(4S,5R)-4-(fluoromethyl)-2,2-dimethyl-5-[4-(fluoromethylthio)phenyl]-1,3-oxazolidine-3-carboxylate

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Reaction Steps

A solution of diethylamino sulfurtrifluoride (DAST), (9.34 g, 1.75 eq) in 10 ml of dichloromethane was added drop wise to the solution of 14 (12.3 g) and antimony (III) chloride (0.23 g, 0.03 eq) in 150 ml of dichloromethane (anhydrous) at −5° C., and the reaction mixture was warmed up to room temperature overnight. A cold saturated solution of sodium bicarbonate (80 ml) was added and stirred for 30 min and extracted with dichloromethane (100 ml×2). The organic layer was washed with a 10% solution of sodium bicarbonate and with brine (50 ml) and dried over sodium sulfate. After purification, via a column, 10.7 g of the desired product (as a heavy oil) was obtained.

Provenance & Evidence