3-Flυoroaniline (376 g, 3.38 mol) was added drop-wise to a solution of ketone compound (418 g, 1.69 mol) in acetic acid (3 L) at room temperature. Zinc cyanide (430 g, 3.68 mol) was then added in portions. The reaction mixture was stirred at room temperature for 18 hours, at which point thin layer chromatography (petroleum ether/ethyl acetate = 4:1) showed the reaction was complete. The mixture was cooled to O°C, and aqueous ammonium hydroxide solution (2 L) was added drop-wtse until pH = 7- 8. The resulting mixture was extracted with ethyl acetate (3 x 2 L). The combined organic iayers were washed with saturated aqueous sodium chloride solution (1 L), dried oher sodium sulfate and concentrated in vacuo to give crude (530 g), which was purified by column chromatography on silica gel (Gradient: 1:20 to 1 :2 ethyl acetate/petroleum ether) to give as a brown oil comprised of a mixture of diastereomers. Yieid: 846 g, 2 batches, 2.30 mol, 68%.
Patent reference: WO201005833 (Pfizer)