Multi-step reaction with 3 steps 1.1: isopropylmagnesium chloride / tetrahydrofuran / 20 °C1.2: 3.75 h / -25 - 0 °C1.3: 0 °C / pH 72.1: [Ru2(p-PriC6H4Me)2(μ-Cl)Cl]2; formic acid; triethylamine; N,N-dimethyl-formamide; N-[(1S,2S)-2-amino-1,2-diphenylethyl]-p-tolylsulphonamide / tert-butyl methyl ether / 12 h / 20 °C2.2: 0.83 h3.1: sodium hydroxide / 2-methyl tetrahydrofuran / 0.67 h / 20 °C