Triethylamine → 4-Fluoro-L-proline

Participants

Reaction Steps

13.0 mL of acetonitrile, 3.50 g (34.59 mmol, 3.46 eq) of triethylamine, and 1.60 g (9.92 mmol, 0.99 eq) of triethylamine tris(hydrogen fluoride) complex, followed by lowering the inside temperature to −40° C. and then bubbling 2.00 g (19.60 mmol, 1.96 eq) of sulfuryl fluoride from a cylinder. The inside temperature was returned to room temperature, and stirring was conducted for 20 hours. Conversion of the reaction was found by gas chromatography measurement to be 100%. The reaction-terminated liquid was poured into a potassium carbonate aqueous solution [prepared from 6.30 g (45.58 mmol, 4.56 eq) of potassium carbonate and 100.0 mL of water], followed by extraction two times with 100.0 mL of ethyl acetate. The recovered organic layer was concentrated under reduced pressure, followed by vacuum drying, thereby obtaining a crude product of 4-fluoroproline derivative represented by the following formula,

Provenance & Evidence