5-Bromo-N-[(tert-butoxy)carbonyl]-L-norvaline tert-butyl ester

90194-99-3

91229-86-6

The general procedure for the synthesis of tert-butyl (S)-5-bromo-2-((tert-butoxycarbonyl)amino)-5-hydroxypentanoate from (S)-2-((tert-butoxycarbonyl)amino)-5-hydroxypentanoic acid is as follows: 1. tert-Butyl (S)-2-((tert-butoxycarbonyl)amino)-5-hydroxypentanoate (210.2 mg) was dissolved in dichloromethane (7.3 mL) and cooled to 0°C. 2. Carbon tetrabromide (1.5 eq.) and triphenylphosphine (2.0 eq.) were added sequentially and the reaction mixture was stirred at 0 °C for 20 min. 3. Upon completion of the reaction, the reaction was terminated with hexane/ethyl acetate (2:1, v/v). 4. The reaction mixture was purified by silica gel column chromatography (eluent: hexane/ethyl acetate, 2:1, v/v) to afford 254.6 mg (S)-tert-butyl 5-bromo-2-((tert-butoxycarbonyl)amino)pentanoate in 100% yield as a colorless oil.