1.1: sodium tetrahydroborate / ethanol / 0 - 20 °C 2.1: potassium hydroxide / ethanol; water / 14 h / 80 °C 3.1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 1 h / 20 °C 3.2: 80 °C 4.1: hydrogenchloride / diethyl ether; water; ethyl acetate / 20 °C View Scheme

1: sodium tetrahydroborate / ethanol / 0 - 20 °C 2: CHIRALCEL OD / Resolution of racemate 3: potassium hydroxide / ethanol; water / 12 h / 90 °C 4: thionyl chloride; N,N-dimethyl-formamide / toluene / 1 h / 20 °C 5: triethylamine / toluene / 3 h / 70 °C View Scheme

1: sodium tetrahydroborate / ethanol / 0 - 20 °C 2: CHIRALCEL OD / Resolution of racemate 3: potassium hydroxide / ethanol; water / 12 h / 90 °C 4: thionyl chloride; N,N-dimethyl-formamide / toluene / 1 h / 20 °C 5: triethylamine / toluene / 3 h / 70 °C View Scheme