A solution of (R)-tert-butyl 3-((R)-(3-chloro-5-fluorophenyl)(cyanomethoxy)methyl)piperidine-1-carboxylate (90 g) in anhydrous THF (1.3 L), under protection of N2, was heated to reflux followed by the dropwise addition of 10 M H3B.SMe2 in THF (70 mL, 0.7 mol). The mixture was stirred at reflux overnight. The reaction was quenched with MeOH (500 mL) and the solvent removed in vacuo, the residue was purified by column chromatography to give (R)-tert-butyl 3-((R)-(2-aminoethoxy)(3-chloro-5-fluorophenyl)methyl)piperidine-1-carboxylate (24 g, 0.062 mol).
