[CH3:1][O:2][C:3]([C:5]1([CH2:10][NH2:11])[CH2:9][CH2:8][CH2:7][CH2:6]1)=[O:4].[C:12]1(=O)[CH2:16][CH2:15][CH2:14][CH2:13]1.C([O-])(=O)C.[Na+].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>C(Cl)Cl>[CH3:1][O:2][C:3]([C:5]1([CH2:10][NH:11][CH:12]2[CH2:16][CH2:15][CH2:14][CH2:13]2)[CH2:6][CH2:7][CH2:8][CH2:9]1)=[O:4]
Methyl1-(aminomethyl)cyclopentane-1-carboxylate (Intermediate 259; 1.5 g, 9.54 mmol) and cyclopentanone (1.0 mL, 11.45 mmol) were stirred in DCM (40 mL). Sodium acetate (940 mg, 11.45 mmol) and sodium triacetoxyborohydride (3.04 g, 14.31 mmol) were added. The mixture was stirred at room temperature for 48 hours. The reaction mixture was filtered and the filtrate concentrated. The residue was dissolved in methanol and absorbed on to an SCX column, which was then washed with methanol and eluted with ammonia in methanol. Product containing fractions were combined and evaporated to yield the title compound as a colourless oil (1.64 g, 81%).
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