Potassium Carbonate → Tert-butyl (3R,4R)-3-azido-4-hydroxypyrrolidine-1-carboxylate

Participants

Reaction Steps

A 500 mL round-bottomed flask was charged with tert-butyl 6-oxa-3-azabicyclo[3.1.0]hexane-3-carboxylate (15.42 g, 83.25 mmol), (1S,2S)-(−)-[1,2-cyclohexanediamino-N,N′-bis(3,5-di-t-butylsalicylidene)]chromium (III) chloride (1.18 g, 1.67 mmol) and azidotrimethylsilane (12.8 mL, 91.58 mmol) and the resulting mixture was stirred at ambient temperature under a nitrogen atmosphere for 48 hours. The dark red-brown mixture was diluted with chloroform (250 mL) and washed sequentially with water and brine, dried (MgSO4), filtered and concentrated under reduced pressure. The residue was dissolved in methanol (830 mL) and treated with potassium carbonate (11.51 g, 83.25 mmol) and the mixture was stirred at ambient temperature for 5 hours. The methanolic solution was filtered through a pad of Celite washed with methanol and concentrated under reduced pressure. The residue was partitioned between water and ethyl acetate. The layers were separated and the aqueous back extracted with EtOAc. The combined organic extracts were washed with saturated sodium bicarbonate solution, water and brine, dried (MgSO4), filtered and concentrated. The residue was purified by column chromatography (Biotage 40M; 20% ethyl acetate/hexanes) to give (3R,4R)-tert-butyl 3-azido-4-hydroxypyrrolidine-1-carboxylate (18 g, 95%). Enantiomeric excess was determined by Chiral HPLC (AD-H, Chiralcel, 10% EtOH: 90% hexanes at 0.80 mL/min, 94.5% e.e.

Provenance & Evidence