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

Beteiligte Stoffe

Reaktionsschritte

To a mixture of (2S,4R)-tert-butyl 2-((1R,2S)-1-(ethoxycarbonyl)-2-vinylcyclopropylcarbamoyl)-4-hydroxypyrrolidine-1-carboxylate (90.0 g), 4-dimethylaminopyridine (1.5 g), diisopropylethylamine (39.5 g) and EtOAc (180 mL), at 5° C., was added p-nitrobenzoyl chloride (49.9 g) as a solution in EtOAc (310 mL). After 1 h at 5° C., the reaction was warmed to rt. After 15 h, the reaction was cooled to rt and additional p-nitrobenzoyl chloride (8.6 g), diisopropylethylamine (11.0 g), and EtOAc (70 mL) were added to the reaction solution. After 4.5 h at 5° C., the reaction was quenched by the addition of water (90 mL). The resulting layers were separated and the organic layer was washed with a 1.0 N aqueous solution of HCl (180 mL), 10% aqueous solution of KHCO3 (2×135 g), water (150 mL), and a 10% aqueous solution of NaCl. The product-containing organic layer was concentrated to an oil (99% yield).

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