General procedure for the synthesis of exo-8-benzyl-8-azabicyclo[3.2.1]octan-3-one oxime from 8-benzyl-8-azabicyclo[3.2.1]octan-3-amine:[105] 8-benzyl-8-azabicyclo[3.2.1]octan-3-one oxime (7.65 g, 33 mmol) was dissolved in 1-pentanol (130 mL) at 120 °C. Sodium metal (7.6 g, 0.33 mol, 10.0 eq.) was added in batches over 2 hours. The mixture was stirred and heated under reflux conditions for 5 hours, then cooled to 5°C. The reaction mixture was slowly acidified with 6 M HCl until the pH reached acidic, and then the aqueous phase was further extracted with 6 M HCl (3 x 100 mL). The aqueous layer was gradually alkalized to pH 10 by addition of 5 M NaOH. the resulting aqueous solution was extracted with EtOAc (3 × 100 mL). The organic extracts were combined, dried with MgSO4, filtered and concentrated in vacuum. The crude product was purified by column chromatography (5-10% MeOH/CH2Cl2) to afford pure exo-8-benzyl-8-azabicyclo[3.2.1]octan-3-amine as a solid (2.60 g, 36%).
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