(Bis(2-methoxyethyl)amino)sulfur trifluoride → (S)-3-azido-4-fluoro-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

37.1 To stirred, cooled (−78° C.) solution of 695 mg (3S,4S)-3-azido-4-hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester (example 22.2) in 5 ml CH2Cl2 under an argon atmosphere were added 2.69 g bis(2-methoxyethyl)aminosulphur trifluoride (50% solution in THF). The dry ice bath was removed and the mixture was allowed to warm to r.t. and stirring was continued for 22 h. The mixture was poured into 10% aq. Na2CO3. The organic phase was washed with brine, dried (MgSO4), filtered and concentrated. The crude product was purified by chromatography (silica gel; gradient: cyclohexane->cyclohexane/EtOAc 3:2) to give 424 mg (S)-3-azido-4-fluoro-pyrrolidine-1-carboxylic acid tert-butyl ester as light yellow oil. MS 409.0 ([M+H]+)

Provenance & Evidence