4-Nitrobenzoyl chloride → (2S,4R)-tert-butyl 2-((1R,2S)-1-(ethoxycarbonyl)-2-vinylcyclopropylcarbamoyl)-4-(4-nitrobenzoyloxy)pyrrolidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirring slurry of (2S,4R)-tert-butyl 2-((1R,2S)-1-(ethoxycarbonyl)-2-vinylcyclopropylcarbamoyl)-4-hydroxypyrrolidine-1-carboxylate (1.69 kg), 4-dimethylaminopyridine (28.0 g), diisopropylethylamine (946 g) and EtOAc (4.82 kg), at 10° C., was added p-nitrobenzoyl chloride (1.06 kg) as a solution in EtOAc (3.48 kg). After 2.5 h at 10° C., the reaction was cooled to 5° C. and quench by the addition of water (1.85 kg). The resulting layers were separated and the organic layer was washed with a 1.0 N aqueous solution of HCl (3.75 kg), 10% aqueous solution of KHCO3 (2×2.8 kg), water (3.1 kg), and a 10% aqueous solution of NaCl (3.1 kg). The organic layer was washed again with a 1.0 N aqueous solution of HCl (1.88 kg), 10% aqueous solution of KHCO3 (4.2 kg), H2O (1.5 kg), and a 10% aqueous solution of NaCl (2×755 g). The organic layer was concentrated under reduced pressure, diluted with EtOAc (5.6 kg), and then concentrated again. The resulting oil was diluted with EtOAc (10.0 kg), filtered, and then concentrated. EtOAc (10.0 kg) was added and then the resulting solution was concentrated to a mass of 7.9 kg. The assay yield was determined on the product-containing solution to be 98%.

Provenance & Evidence