Multi-step reaction with 5 steps 1.1: hydrazine hydrate / ethanol; tetrahydrofuran / 22 h / 20 - 55 °C2.1: sodium hydrogencarbonate / water; tetrahydrofuran / 1 h / 20 °C3.1: Chiralcel OJ / methanol / Resolution of racemate4.1: zinc; zinc diacetate / (1,1'-bis(diphenylphosphino)ferrocene)palladium(II) dichloride / N,N-dimethyl-formamide / 18 h / 100 °C5.1: hydrogenchloride / 1,4-dioxane / 18 h / 20 °C5.2: 4 h / 20 °C