[O:1]=[C:2]1[CH2:5][CH:4]([NH:6][C:7](=[O:13])[O:8][C:9]([CH3:12])([CH3:11])[CH3:10])[CH2:3]1.[Li].CCOC(C)=O>C1COCC1>[C:9]([O:8][C:7](=[O:13])[NH:6][C@H:4]1[CH2:5][C@@H:2]([OH:1])[CH2:3]1)([CH3:12])([CH3:10])[CH3:11]To a solution of tert-butyl (3-oxocyclobutyl)carbamate (100 g, 54 mmol) in THF (2000 mL) at −72° C. was added dropwise a solution of lithium trisec-butylhidridoborate (648 mL, 1 M) in THF over 1.5 hrs. The resulting solution was allowed to warm up to rt and stirred for another 1 hr. TLC (petroleum ether: EtOAc=2:1) showed that the starting material was consumed completely. The reaction was quenched with NH4Cl aqueous. Water (1000 mL) and EtOAc (2000 mL) were added to the mixture. The organic layer was separated, dried over MgSO4 and concentrated to give crude material, which was purified by column chromatography with petroleum ether: EtOAc from 10:1 to 1:2 to afford the title compound (62 g, 61% yield) as a white solid.
Wird geladen…
