[CH3:1][C:2]([O:5][C:6]([N:8]1[C@@H:12]2[CH2:13][C:14]([CH2:16][C@H:9]1[CH2:10][CH2:11]2)=[O:15])=[O:7])([CH3:4])[CH3:3].[Li+].[CH3:18]C([N-]C(C)C)C.C([C:27]([O-:29])=[O:28])#N>C1COCC1>[O:15]=[C:14]1[CH2:13][C@@H:12]2[N:8]([C:6]([O:5][C:2]([CH3:1])([CH3:3])[CH3:4])=[O:7])[C@@H:9]([CH2:10][CH2:11]2)[CH:16]1[C:27]([O:29][CH3:18])=[O:28]N-Boc-nortropinone (10 g, 44.4 mmol) was dissolved in THF (55 mL) and cooled to −78° C., LDA (2M in THF, 24.4 mL, 48.8 mmol) was added dropwise. After 1 h at −78° C., cyanoformate (4.22 mL, 53.2 mmol) was added, and the reaction mixture was warmed up to room temperature and stirred for 5 hours. After quench with saturated NH4Cl, the reaction mixture was extracted with EtOAc. The combined EtOAc layer was washed with water and brine. Dried and concentrated. The crude product was column purified with mixture of Hexane and EtOAc to give 10 g of (1S,5R)-8-tert-butyl 2-methyl 3-oxo-8-azabicyclo[3.2.1]octane-2,8-dicarboxylate.
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