1,1'-Carbonyldiimidazole → tert-butyl (1R,2S)-1-(1-(fluoromethyl)cyclopropylsulfonylcarbamoyl)-2-vinylcyclopropylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of (1R,2S)-1-(tert-butoxycarbonylamino)-2-vinylcyclopropanecarboxylic acid (7.5 g, 33 mmol) in DMF (50 mL) was added 1,1′-carbonyldiimidazole (“CDI”, 10.7 g, 66.0 mmol) and the reaction mass was heated at 55° C. for 4 h. To this reaction mass was added 1-fluoromethylcyclopropane-1-sulfonamide (6.5 g, 42.9 mmol) followed by 1,8-diazabicyclo[5.4.0]undec-7-ene (“DBU”, 6.0 mL, 43 mmol). The reaction mixture was stirred at 55° C. for 18 h. The solvent was evaporated under reduced pressure and the residue was diluted with water and acidified to pH˜2 by using aq. 1.5 N HCl solution. The precipitated solid was isolated via filtration and washed with water to afford tert-butyl(1R,2S)-1-(1-(fluoromethyl)cyclopropylsulfonylcarbamoyl)-2-vinylcyclopropylcarbamate as off-white solid (11.5 g, 96%). MS: MS m/z 361.4 (M+−1).

Provenance & Evidence