1.1: sodium dihydrogenphosphate; sodium chlorite; 2-methyl-but-2-ene / tetrahydrofuran; water / 2 h 1.2: pH 2 2.1: BOP-Cl; triethylamine / acetonitrile / Inert atmosphere 3.1: lithium hydroxide hydrate / tetrahydrofuran; water / 2 h / 20 °C 3.2: pH 3 4.1: dichloromethane / 2 h / 20 °C 5.1: diphenyl phosphoryl azide / N,N-dimethyl-formamide / 2 h / 20 °C View Scheme