(Diethylamino)sulfur trifluoride → Tert-butyl (2-fluoro-2-methylpropyl)carbamate

Participants

Reaction Steps

A solution of tert-butyl 2-hydroxy-2-methylpropylcarbamate (19.2 g, 101 mmol) in dichloromethane (500 mL) was stirred at −78° C. under a nitrogen atmosphere, and (diethylamino)sulfur trifluoride (DAST) (18.0 g, 112 mmol) was added dropwise. The solution was allowed to warm to room temperature and stirred overnight. Saturated aqueous sodium bicarbonate (150 mL) was added. The organic layer was then separated and washed sequentially with saturated aqueous sodium bicarbonate (150 mL), water (150 mL), and brine (150 mL); dried over magnesium sulfate; filtered; and concentrated under reduced pressure. The resulting oil was purified by automated flash chromatography (FLASH 65I cartridge, eluting with 10% ethyl acetate in hexane) to provide 13.7 g of tert-butyl 2-fluoro-2-methylpropylcarbamate as a light yellow oil that crystallized overnight.

Provenance & Evidence