Benzyl chloroformate → 1-Benzyloxycarbonyl-3-(S)-tert-butyldimethylsilyloxy-4-(R)-(1-ethoxycarbonylcyclopropyl)pyrrolidine
Reaction equation
[Si:1]([O:8][C@H:9]1[C@H:13]([C:14]2([C:17]([O:19][CH2:20][CH3:21])=[O:18])[CH2:16][CH2:15]2)[CH2:12][N:11]([C@H](C2C=CC=CC=2)C)[CH2:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].Cl[C:31]([O:33][CH2:34][C:35]1[CH:40]=[CH:39][CH:38]=[CH:37][CH:36]=1)=[O:32]>>[CH2:34]([O:33][C:31]([N:11]1[CH2:12][C@@H:13]([C:14]2([C:17]([O:19][CH2:20][CH3:21])=[O:18])[CH2:16][CH2:15]2)[C@H:9]([O:8][Si:1]([C:4]([CH3:5])([CH3:7])[CH3:6])([CH3:3])[CH3:2])[CH2:10]1)=[O:32])[C:35]1[CH:40]=[CH:39][CH:38]=[CH:37][CH:36]=1Participants
3
Procedure
3-(S)-Tert-butyldimethylsilyloxy-4-(R)-(1-ethoxycarbonylcyclopropyl)-1-[1-(S)-phenylethyl]pyrrolidine (5.48 g, 13.15 mnmol) was dissolved in dry dichloroinethane (120 ml), and benzyl chloroformate (3.76 ml, 26.3 mmol) was added dropwise to the thus prepared solution which was cooled in an ice bath. After heating the reaction solution under reflux for 2 hours, dichloroinethane was evaporated under reduced pressure. Thereafter, the resulting residue was subjected to flash silica gel chromatography and eluted with an eluant of n-hexane:ethyl acetate=5:1, to thereby obtain 4.52 g (77%) of the title coinpound as a colorless oil.