To a solution of (S)-1-amino-2-(5-bromo-2-fluoro-phenyl)-propan-2-ol (34.7 g, 140 mmol) in THF (400 ml) was added 2-nitro-benzenesulfonyl chloride (34.9 g, 154 mmol) at 0-5° C. and afterwards 1N aqueous NaOH over a period of 0.5 h. The reaction mixture was stirred for 2 h at 20° C. The reaction mixture was diluted with TBME and washed with water and NaH2PO4 solution and brine, dried over MgSO4, filtered and concentrated to provide the title compound after crystallization from TBME-hexane as beige crystals: TLC (toluene-EtOAc 3:1): Rf=0.51; UPLC RtH5=1.118 min; ESIMS: 450, 452 [(M+NHa)+]; 1H NMR (360 MHz, CDCl3): δ 7.98 (m, 1H), 7.81 (m, 1H), 7.65 (m, 2H), 7.59 (dd, 1H), 7.24 (m, 1H), 6.79 (dd, 1H), 5.60 (t, 1H), 4.16 (br s, 1H), 3.55 (dd, 1H), 3.44 (dd, 1H), 2.51 (s, 1H), 1.51 (s, 3H).
