At room temperature, a solution of 1.00 g (3.81 mmol) of tert-butyl 3-(4-formylphenyl)-2,2-dimethylpropionate (Example I-3) and 0.37 g (3.81 mmol) of furfurylamine in 10 ml of dichloroethane is stirred for 30 min, 1.21 g (5.72 mmol) of sodium triacetoxyborohydride are added and the mixture is then stirred at room temperature for 22 h. 6 ml of sat. NaHCO3 solution and 10 ml of ethyl acetate are then added, the phases are separated, the aqueous phase is extracted 2× with ethyl acetate and the combined organic phases are dried over sodium sulphate. The solvent is removed under reduced pressure, and chromatographic purification on silica gel (cyclohexane→cyclohexane/ethyl acetate 10:1→2:1) then gives 720 mg (55%) of tert-butyl 3-(4-{[(2-furylmethyl)amino]methyl}phenyl)-2,2-dimethylpropionate.
