Benzyl chloroformate → N-(carbobenzyloxy)-4-[3-[(tert-butyldimethylsilyl)oxy]-1-azetidinyl]-3-fluoroaniline

Participants

Reaction Steps

4-[3-[(tert-Butyldimethylsilyl)oxy]-1-azetidinyl]-3-fluoronitrobenzene (1.00 g, 3.07 mmol) was combined with 10% palladium on carbon (0.100 g) in 3:1 tetrahydrofuran/water (25 mL) under a nitrogen atmosphere. The atmosphere was replaced with hydrogen (balloon) by repeated evacuation and filling. After 2 h the initial yellow color of the reaction solution disappeared and TLC analysis (15% ethyl acetate/hexane) revealed the reduction to be complete. The reaction mixture was filtered through Celite® and the filtrate immediately placed under a nitrogen atmosphere and treated with sodium bicarbonate (1.41 g, 16.8 mmol) and benzyl chloroformate (0.528 mL, 3.69 mmol). After 30 min at ambient temperature, TLC analysis (15% ethyl acetate/hexane) indicated the reaction was complete. The reaction mixture was concentrated under reduced pressure to an off-white solid. Cromatography over silica gel (125 g), eluting with a gradient of 5-30% ethyl acetate/hexane, afforded, after concentration of appropriate fractions, 0.565 g (43%) of the title compound as a white solid with mp 91°-93° C. and MS(EI) 430 (M+).

Provenance & Evidence