反应详情

500 mg (R)-5-Biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methylenepentanoic acid ethyl ester (2-a, R1=Boc, R2=H, R3=CO2Et) is added to ethanol (5 ml) at ambient temperature. Triethylamine (170 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 ethyl ester (1-a, R1=Boc, R2=H, R3=CO2Et) and (2S,4S)-5-biphenyl-4-yl-4-tert-butoxycarbonylamino-2-methylpentanoic acid ethyl ester (1-b, R1=Boc, R2=H, R3=CO2Et). Spectroscopic data as in Example 63. Ratio of diastereomers 70:30 (1-a, R1=Boc, R2=H, R3=CO2Et: 1-b, R1=Boc, R2=H, R3=CO2Et) as determined by hplc (hplc method as in Example 65)

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