(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