4-Nitrobenzenesulfonyl chloride → trans-Tert-butyl 4-fluoro-5-(4-nitrophenylsulfonyloxy)azepane-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

trans-tert-butyl 4-fluoro-5-hydroxyazepane-1-carboxylate (12.36 g, 52.98 mmol) was dissolved in CH2Cl2 (110 mL). The solution was cooled to 0° C., 4-nitrobenzene-1-sulfonyl chloride (14.09 g, 63.58 mmol) was added and the mixture was stirred for 10 minutes. NEt3 (11.08 mL, 79.48 mmol) was added and the mixture was slowly warmed to ambient temperature over 1 hour and stirred for an additional 2 hours. The mixture was diluted with CH2Cl2 and washed with water followed by 1N KHSO4 (2×50 mL), then with saturated aqueous NaHCO3 (50 mL) and brine, and the combined organic layers were dried over Na2SO4, filtered and concentrated. The crude product was purified via column chromatography (10 to 70% MTBE/hexanes) to provide 18.4 g of the product (84%) as a single isomer and as a faint orange powder.

Provenance & Evidence