tert-butyl N-[2-[(2S)-2-cyano-4,4-difluoropyrrolidin-1-yl]-2-oxoethyl]carbamate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a cooled (0° C.) solution of (S)-tert-butyl 2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethylcarbamate (7.3 g, 25.2 mmol), obtained from step 7, in 150 mL of ACN was added trifluoroacetic acid (38.9 mL, 0.505 mol) dropwise. The mixture was stirred overnight and the volatiles were evaporated. The residue was washed with ether. the volatiles were evaporated The residue was washed with ether

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a cooled (0° C.) solution of (S)-tert-butyl 2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethylcarbamate (7.3 g, 25.2 mmol), obtained from step 7, in 150 mL of ACN was added trifluoroacetic acid (38.9 mL, 0.505 mol) dropwise. The mixture was stirred overnight and the volatiles were evaporated. The residue was washed with ether. the volatiles were evaporated The residue was washed with ether

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In a 50 mL round-bottomed flask (S)-tert-butyl 2-(2-carbamoyl-4,4-difluoropyrrolidin-1-yl)-2-oxoethylcarbamate (41) (0.720 g, 2.343 mmol) was dissolved in dry THF at −15° C. Then pyridine was added, followed by the dropwise addition of the solution of 2,2,2-trifluoroacetic anhydride (0.094 ml, 0.664 mmol) in 5 mL of DCM after the complete addition, the mixture was allowed to reach RT. The reaction mixture was stirred for 90 minutes. The reaction mixture was washed with 1M solution of aqueous solution of hydrochloric acid. Then the organic layer was washed three times with saturated sodium bicarbonate, brine, dried over sodium sulfate and evaporated. The crude mixture was purified using column chromatography (hexane-ethyl acetate 2-3) yielding a yellowish oil Yield: 0.678 g, 70% after the complete addition to reach RT The reaction mixture was washed with 1M solution of aqueous solution of hydrochloric acid Then the organic layer was washed three times with saturated sodium bicarbonate, brine dried over sodium sulfate evaporated The crude mixture was purified

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a cooled (0° C.) solution of (S)-tert-butyl 2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethylcarbamate (7.3 g, 25.2 mmol), obtained from step 7, in 150 mL of ACN was added trifluoroacetic acid (38.9 mL, 0.505 mol) dropwise. The mixture was stirred overnight and the volatiles were evaporated. The residue was washed with ether. the volatiles were evaporated The residue was washed with ether

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In a 50 mL round-bottomed flask (S)-tert-butyl 2-(2-carbamoyl-4,4-difluoropyrrolidin-1-yl)-2-oxoethylcarbamate (41) (0.720 g, 2.343 mmol) was dissolved in dry THF at −15° C. Then pyridine was added, followed by the dropwise addition of the solution of 2,2,2-trifluoroacetic anhydride (0.094 ml, 0.664 mmol) in 5 mL of DCM after the complete addition, the mixture was allowed to reach RT. The reaction mixture was stirred for 90 minutes. The reaction mixture was washed with 1M solution of aqueous solution of hydrochloric acid. Then the organic layer was washed three times with saturated sodium bicarbonate, brine, dried over sodium sulfate and evaporated. The crude mixture was purified using column chromatography (hexane-ethyl acetate 2-3) yielding a yellowish oil Yield: 0.678 g, 70% after the complete addition to reach RT The reaction mixture was washed with 1M solution of aqueous solution of hydrochloric acid Then the organic layer was washed three times with saturated sodium bicarbonate, brine dried over sodium sulfate evaporated The crude mixture was purified