(Diethylamino)sulfur trifluoride → (2R,4R)-1-tert-butyl 2-methyl 4-fluoropyrrolidine-1,2-dicarboxylate

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Reaction Steps

Add (diethylamino)sulfur trifluoride (10.5 mL, 80 mmol) to a −78° C. cooled solution of 4-(S)-hydroxypyrrolidine-N1,2-(R)-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (9.83 g, 40 mmol) in dichloromethane (60 mL). Stir 2 h, then remove cooling bath and stir 18 h at room temperature. Heat to reflux for 30 min, then cool in ice bath and add saturated aqueous sodium bicarbonate solution. Warm to room temperature, dry (magnesium sulfate), concentrate (350 mbar, 25° C.) and purify (silica gel chromatography, eluting with diethyl ether and dichloromethane) and then concentrate at 120 mbar at 25° C. to give the title compound as an oil (9.09 g, 92%).

Provenance & Evidence