(Diethylamino)sulfur trifluoride → tert-Butyl 3-fluoropyrrolidine-1-carboxylate

Participants

Reaction Steps

A −70° C. solution of (R)-(−)-3-Hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester (5 g, 26.7 mmol) in anhydrous EtOAc (250 mL) was treated dropwise with DAST (4.6 mL, 1.3 equiv.) and stirred for 1.5 h. The reaction was allowed to warm to room temperature over a period of 3 h. The reaction mixture was poured into ice cold saturated aqueous sodium bicarbonate solution (300 mL). The EtOAc layer was separated and washed with additional saturated aqueous sodium bicarbonate solution (2×300 mL) and then with brine (300 mL). The organics were dried over anhydrous Na2SO4, filtered and evaporated in vacuo. The crude residue was purified by silica gel chromatography (Hexanes to 1:9 EtOAc:Hexanes, gradient eluant) to yield 3-Fluoro-pyrrolidine-1-carboxylic acid tert-butyl ester as an oil (1.7 g).

Provenance & Evidence