Cool a solution of (3-bromo-4-fluoro-phenoxy)-tert-butyl-dimethyl-silane (472 mg, 1.547 mmol) in THF (40 mL) to −78° C. under N2. Then add dropwise a solution of n-BuLi (0.63 mL, 1.547 mmol) in hexane via syringe to the reaction solution. After being stirred at −78° C. for 2 hour, add dropwise a solution of 5-Dimethylaminomethyl-spiro[2.5]octan-6-one (70 mg, 0.387 mmol) in THF (1 mL) to the reaction mixture and stir the mixture at −78° C. for additional 2 hours. Quench the reaction with 20 mL of diluted HCl (2N), and stir at ambient temperature for 2 hours. Basify the resultant mixture with K2CO3 to pH=9, and extract with EtOAc (30 mL×2). The combined organic layers are washed with brine, dried over Na2SO4, filtered, and concentrated under vacuum. Purify the residue by silica gel chromatography (CH2Cl2 to CH2Cl2:MeOH=10:1) to afford 5-dimethylaminomethyl-6-(2-fluoro-5-hydroxy-phenyl)-spiro[2.5]octan-6-ol as white solid (41 mg, yield: 36.3%). MS (m/z): 294 (M+1).
