反应详情

500 mg (R)-5-Biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methylenepentanoic acid methyl ester (2-a, R1=Boc, R2=H, R3=CO2Me) is added to ethanol (5 ml) at ambient temperature. Triethylamine (176 μl) is then added to the mixture. 50 mg Palladium on carbon (10%, 50% water-wet, Degussa E101 NE/W) is then added. Hydrogen gas at ambient pressure is applied to the mixture. The mixture is then stirred overnight at ambient temperature and pressure. The mixture is then filtered and concentrated under reduced pressure to afford 2R,4S)-5-Biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methylpentanoic acid methyl ester (1-a, R1=Boc, R2=H, R3=CO2Me) and (2S,4S)-5-biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methylpentanoic acid methyl ester (1-b, R1=Boc, R2=H, R3=CO2Me). Spectroscopic data as in Example 60. Ratio of diastereomers 66:34 (1-a, R1=Boc, R2=H, R3=CO2Me: 1-b, R1=Boc, R2=H, R3=CO2Me) by integration of signals at 1.76-1.85 (1-b, R1=Boc, R2=H, R3=CO2Me) and 1.92-1.99 (1-a, R1=Boc, R2=H, R3=CO2Me).

1. filtrationThe mixture is then filtered
2. concentrationconcentrated under reduced pressure